Engine Control System - Tests W/codes - DTC p0352-p0452

MODEL IDENTIFICATION

Vehicle model is identified by fourth character (cars), or fifth character (trucks) of Vehicle Identification Number (VIN). VIN is stamped on metal pad on top of left end of instrument panel, near windshield. See MODEL IDENTIFICATION (CARS) table, or MODEL IDENTIFICATION (TRUCKS) table under MODEL IDENTIFICATION in INTRODUCTION article.

DTC P0352 &/OR P1352: IC CIRCUITS NO. 2 & 3 MALFUNCTION OR SHORTED (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Circuit Description

PCM control dwell and spark timing during all engine running conditions. The Electronic Ignition (EI) module charges the coil pack when the PCM supplies 5 volts to the 2/3 coil. The coil will then discharge or fire through its secondary coil towers whenever the voltage has been turned off by the PCM.

During long cranking, PCM pulses the Ignition Control (IC) circuit high and low. The PCM monitors the diagnostic feedback circuit to diagnose circuit faults. DTC P0352 will set if there is an open, short to voltage or short to ground in IC 2 and 3 circuits or DTC P0352 or P1352 will set if there is a short to voltage in IC 2 and 3 circuits when engine is in cranking mode. IC circuits No. 2 and No. 3 are checked continuously whenever crankshaft position sensor pulses are received by the PCM during cranking mode only.

Diagnostic Procedures

Connect scan tool. Start engine and check if DTC P0352 or P1352 is set. If DTCs are present, go to next step. If DTCs are not present, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452__diagnostic-aids) .
If only DTC P0352 is present, go to next step. If both DTC P0352 and P1352 are present, turn ignition off. Disconnect EI module harness connector. Attempt to start engine. If DTC P0352 resets, replace EI module. If both DTC P0352 and P1352 resets, check for short to voltage in IC 2/3 diagnostic feedback circuit or for faulty PCM.
Turn ignition off. Disconnect EI module harness connector. Using DVOM connected to ground, probe IC 2/3 diagnostic feedback circuit while cranking engine. If voltage is varying between 0-5 volts, check terminal tightness to EI module or for faulty EI module. If voltage is not varying, go to next step.
Check IC 2/3 circuit for open or short to ground. Repair as necessary. If circuit is okay, check for tightness at EI module harness connector.

Diagnostic Aids

When attempting to diagnose an intermittent problem, use scan tool to review malfunction history information. This data can be used to duplicate a problem.

A malfunctioning 2/3 coil, 2/3 ignition wire or 2/3 spark plug will not cause DTC P0352 and/or P1352 to set. A blown EIS fuse will cause a no-start condition but an IC 2/3 DTC may not set. An IC 2/3 circuit fault may set a cam missing DTC P0340. If engine starts with a fault on the IC circuit, a misfire DTC P0300 may also be set. If there is an open in the IC 1/4 circuit a misfire on those cylinders will occur.

DTC P0352: IGNITION COIL NO. 2 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

This engine uses an individual ignition coil/module and circuit for each cylinder. Sequencing and timing are controlled by PCM. DTC will set if PCM detects ignition control circuit is grounded, open or shorted to voltage within one second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC NO. 1 status. If scan tool displays this DTC, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter this DTC. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 2 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 1 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 2 signal circuit. If voltage reading is greater than 1.0 volt, go to step 9 . If voltage reading is not greater than 1.0 volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 2 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 2 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at ignition coil and PCM. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

Using FREEZE FRAME and/or FAILURE RECORDS data mode may aid in locating an intermittent condition. If DTC cannot be duplicated, information included in FREEZE FRAME and/or FAILURE RECORDS data can be useful in determining how many miles since DTC set. FAIL COUNTER and PASS COUNTER can also be used to determine how many ignition cycles diagnostic reported a pass or a fail condition. To isolate when DTC failed, operate vehicle within same freeze frame conditions (RPM, load, vehicle speed, temperature, etc.).

DTC P0352: IGNITION COIL NO. 2 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

This engine uses an individual ignition coil/module and circuit for each cylinder. Sequencing and timing are controlled by PCM. DTC will set if IC circuit is out of range. DTC will set when the following conditions are present

System voltage is 9-17 volts.
PCM detects IC circuit is open or shorted to ground or voltage.
Conditions met for less than one second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 2 status. If scan tool displays DTC P0352, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter DTC P0352. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 2 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 2 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 2 signal circuit. If voltage reading is greater than one volt, go to step 9 . If voltage reading is not greater than one volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 2 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 2 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0352. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at CMP sensor. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0353: IGNITION COIL NO. 3 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 3 status. If scan tool displays this DTC, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter this DTC. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 3 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 3 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 3 signal circuit. If voltage reading is greater than 1.0 volt, go to step 9 . If voltage reading is not greater than 1.0 volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 3 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 3 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at ignition coil and PCM. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0353: IGNITION COIL NO. 3 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

System voltage is 9-17 volts.
PCM detects IC circuit is open or shorted to ground or voltage.
Conditions met for less than one second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 3 status. If scan tool displays DTC P0353, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter DTC P0353. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 3 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 3 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not 3-20 Hz, go to next step.
Using DVOM, check voltage on IC No. 3 signal circuit. If voltage reading is greater than one volt, go to step 9 . If voltage reading is not greater than one volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 3 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 3 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0353. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at CMP sensor. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0354: IGNITION COIL NO. 4 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 4 status. If scan tool displays this DTC, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter this DTC. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 4 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 4 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 4 signal circuit. If voltage reading is greater than 1.0 volt, go to step 9 . If voltage reading is not greater than 1.0 volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 4 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 4 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at ignition coil and PCM. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0354: IGNITION COIL NO. 4 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

System voltage is 9-17 volts.
PCM detects IC circuit is open or shorted to ground or voltage.
Conditions met for less than one second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 4 status. If scan tool displays DTC P0354, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter DTC P0354. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 4 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 4 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 4 signal circuit. If voltage reading is greater than one volt, go to step 9 . If voltage reading is not greater than one volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 4 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 4 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0354. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at CMP sensor. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0355: IGNITION COIL NO. 4 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 5 status. If scan tool displays this DTC, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter this DTC. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 5 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 5 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 5 signal circuit. If voltage reading is greater than 1.0 volt, go to step 9 . If voltage reading is not greater than 1.0 volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 5 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 5 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at ignition coil and PCM. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0355: IGNITION COIL NO. 5 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

System voltage is 9-17 volts.
PCM detects IC circuit is open or shorted to ground or voltage.
Conditions met for less than one second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 5 status. If scan tool displays DTC P0355, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter DTC P0355. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 5 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 5 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 5 signal circuit. If voltage reading is greater than one volt, go to step 9 . If voltage reading is not greater than one volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 5 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 5 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0355. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at CMP sensor. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0356: IGNITION COIL NO. 6 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC NO. 1 status. If scan tool displays this DTC, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter this DTC. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 1 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 1 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 1 signal circuit. If voltage reading is greater than 1.0 volt, go to step 9 . If voltage reading is not greater than 1.0 volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 1 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 1 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at ignition coil and PCM. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0356: IGNITION COIL NO. 6 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

System voltage is 9-17 volts.
PCM detects IC circuit is open or shorted to ground or voltage.
Conditions met for less than one second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 6 status. If scan tool displays DTC P0356, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter DTC P0356. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 6 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 6 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 6 signal circuit. If voltage reading is greater than one volt, go to step 9 . If voltage reading is not greater than one volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 6 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 6 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0356. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at CMP sensor. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0357: IGNITION COIL NO. 7 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 7 status. If scan tool displays this DTC, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter this DTC. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 7 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 7 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 7 signal circuit. If voltage reading is greater than 1.0 volt, go to step 9 . If voltage reading is not greater than 1.0 volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 7 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 7 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at ignition coil and PCM. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0357: IGNITION COIL NO. 7 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

System voltage is 9-17 volts.
PCM detects IC circuit is open or shorted to ground or voltage.
Conditions met for less than one second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 7 status. If scan tool displays DTC P0357, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter DTC P0357. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 7 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 7 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 7 signal circuit. If voltage reading is greater than one volt, go to step 9 . If voltage reading is not greater than one volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 7 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 7 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0357. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at CMP sensor. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0358: IGNITION COIL NO. 8 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 8 status. If scan tool displays this DTC, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter this DTC. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 8 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 8 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 8 signal circuit. If voltage reading is greater than 1.0 volt, go to step 9 . If voltage reading is not greater than 1.0 volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 8 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 8 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at ignition coil and PCM. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0358: IGNITION COIL NO. 8 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

System voltage is 9-17 volts.
PCM detects IC circuit is open or shorted to ground or voltage.
Conditions met for less than one second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST and monitor IC No. 8 status. If scan tool displays DTC P0358, go to step 4 . If scan tool does not display this DTC, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter DTC P0358. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect ignition coil No. 8 connector. Using a DVOM in AC Hertz (Hz) scale, check frequency of IC No. 8 signal circuit. Start and operate engine at idle. If frequency is 3-20 Hz, go to step 8 . If frequency is not as specified, go to next step.
Using DVOM, check voltage on IC No. 8 signal circuit. If voltage reading is greater than 1.0 one volt, go to step 9 . If voltage reading is not greater then 1.0 volt, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using DVOM, check continuity of IC signal circuit from ignition coil No. 8 connector to PCM connector. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Using DVOM, check resistance of IC signal between ground and ignition coil No. 8 connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 10 .
Replace ignition coil. After replacing ignition coil, go to step 13 .
Repair IC signal circuit for short to voltage. After repairs, go to step 13 .
Repair IC signal circuit for open or short to ground. After repairs, go to step 13 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection or terminal tension is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0358. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connections/terminal tension at CMP sensor. Check for rubbed-through wire insulation, broken wire inside insulation or misrouted harness.

DTC P0371: IGNITION CONTROL (IC) MODULE 24X REFERENCE CIRCUIT-TOO MANY PULSES (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

This test checks for 49 or greater 24X reference pulses between CAM pulses. If pulses vary between too few or too many of the allowed range between CAM events, DTC will set. Conditions for setting DTC

DTC P1376 not set.
At least one CAM pulse received in the last 0.25 second.
Engine speed 496-3500 RPM.
Number of CAM edges since key on is 7 or greater.
Eight 24X pulses seen between cam pulses.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check for possible cause of Electromagnetic Interference (EMI), such as spark plug wires routed too close to IC module, high power transmitters operating within vicinity or the use of a battery charger. If possible source of EMI is found, remove source. If EMI interference is not noticed, go to next step.
Clear DTCs and retest. If DTC P0371 resets, go to next step. If DTC P0371 does not reset, fault is not present.
Check terminal contact of 24X spark reference circuit at IC module and PCM harness connector. Repair as necessary. If terminal contact is okay, go to next step.
Replace IC module.

DTC P0372: IGNITION CONTROL (IC) MODULE 24X REFERENCE CIRCUIT-MISSING PULSES (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

This test checks for less than 48 pulses between CAM pulses. If pulses vary between too few or too many of the allowed range between CAM events, DTC will set. Conditions for setting DTC

DTC P1376 not set.
At least one CAM pulse received in the last 0.25 second.
Engine speed 496-3500 RPM.
Number of CAM edges since key on is 7 or greater.
Eight 24X pulses seen between cam pulses.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Using scan tool, verify if DTC P1323 is also present. If DTC P1323 is present, diagnose this DTC first. If DTC P1323 is not present, go to next step.
Turn ignition off. Disconnect IC module harness connector C4. Using 6-Pin IC Module Diagnostic Jumpers, jumper the following IC module connector C4 terminals to the following module terminals: C4 Terminal "A" To Module Pin "A" C4 Terminal "B" To Module Pin "B" C4 Terminal "C" To Module Pin "C" C4 Terminal "D" To Module Pin "D" C4 Terminal "E" To Module Pin "E" C4 Terminal "F" To Module Pin "F" Set DVOM to 400 mV AC scale and push Hz button. Connect DVOM between terminal "A" jumper and ground. Start engine and check frequency. If frequency is 200 Hz or greater, go to next step. If frequency is not 200 Hz or greater, go to step 5 .
Check terminal contact for 24X spark reference circuit at PCM connector C2. Check 24X reference circuit between PCM and IC module harness connectors. Repair as necessary. If terminal contact and circuit are okay, go to step 10 .
Turn ignition on. Disconnect all jumpers. Turn ignition on. Using DVOM, check voltage between ground and cam low circuit terminal at IC module connector C4. If voltage reading is greater than 4.2 volts, go to next step. If voltage reading is not greater than 4.2 volts, go to step 8 .
Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector C2. Reconnect IC module harness connector C4. Turn ignition on. Using DVOM, check voltage between ground and 24X spark reference circuit at PCM harness connector C2. Voltage reading should be 4.2 volts. If voltage reading is greater than 4.2 volts, go to step 4 . If voltage reading is not greater than 4.2 volts, go to next step.
Repair short to ground in 24X spark reference circuit.
Check terminal contact of cam signal circuit at IC module harness connector C4. Repair as necessary. If circuit is okay, go to next step.
Replace IC module.
Replace PCM. Program replacement PCM using required equipment.

DTC P0385: CRANKSHAFT POSITION (CKP) SENSOR "B" CIRCUIT (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Crankshaft Position (CKP) sensor in this engine are actually 2 sensors within a single housing. Each sensor has a separate power, ground (reference low) and a signal circuit. PCM supplies battery voltage, ground (return circuit) to both sensors. The power and reference low circuits are also connected to the Camshaft Position (CMP) sensor. Two separate signal circuits connect the CKP sensor to the PCM.

The PCM uses 3 different modes of decoding crankshaft position. During normal operation, PCM performs an angle based calculation using both signals to determine crankshaft position. The dual sensor allows engine to run even if one signal is lost. If either signal is lost, PCM switches to a time based method of calculating crankshaft position. In Time "A" mode, PCM is using only the signal from sensor "A". In Time "B" mode, PCM is using only the signal from sensor "B". If the lost signal is restored, PCM will continue to operate in Time "A" or "B" mode for the remainder of the current ignition cycle.

PCM will automatically revert back to angle mode on the next start-up if fault is not present. scan tool can display the crank position sensing decode mode. DTC will set when PCM detects a problem with CKP sensor "A" signal.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Using scan tool, check if DTC P0340 is also set. If DTC P0340 is set, diagnose DTC P0340. If DTC P0340 is not set, go to next step.
Start and operate engine. If engine starts, go to next step. If engine does not start or starts and stalls/dies, go to step 6 .
Using scan tool, select CKP SENSOR STATUS. Start engine. If scan tool indicates CKP sensor status angle, go to next step. If scan tool does not indicate CKP sensor status angle, go to step 6 .
Wiggle related harnesses and connectors while monitoring scan tool display. If scan tool indicates that CKP sensor status changes from Time "A" or Time "B", or engine stalls, go to step 13 . If scan tool does not indicate that CKP sensor status changed or engine did not stall, problem is intermittent.
This step applies to the sensor and related circuit that is malfunctioning. For example, if scan tool indicates Time "A", the system is using the signal from CKP sensor "A". Diagnose CKP sensor "B" and related circuits. To diagnose, turn ignition off. Disconnect affected CKP sensor harness connector. Using DVOM, check voltage on power circuit at CKP sensor harness connector. If battery voltage is present, go to next step. If battery voltage is not present, go to step 14 .
Check voltage between power circuit and ignition circuit at CKP sensor harness connector. If battery voltage is present, go to next step. If battery voltage is not present, go to step 15 .
Turn ignition off and wait 15 seconds. Turn ignition on. Using scan tool, clear DTCs. Using scan tool, command system to operate in appropriate Time mode for sensor being tested. Monitor 24X crank sensor data. Using a test light connected to battery voltage, momentarily touch signal circuit several times. If RPM is indicated on scan tool, go to step 20 . If RPM is not indicated, go to next step.
Turn ignition off. Disconnect PCM harness connector C1. Turn ignition on. Check voltage on CKP sensor signal circuit on PCM harness connector. If voltage is indicated, go to step 18 . If voltage is not indicated, go to next step.
Using DVOM, check signal circuit resistance between CKP harness connector and PCM harness connector. If resistance is 5 ohms or less, go to next step. If resistance is not 5 ohms or less, go to step 16 .
Check resistance between ground and signal circuit. If resistance is infinite, go to next step. If resistance is not infinite, go to step 17 .
Check resistance between CKP sensor "A" and "B" signal circuits. If resistance is infinite, go to step 22 . If resistance is not infinite, go to step 19 .
Repair harness or connections as necessary. After repairs, go to step 24 .
Repair open/high resistance power circuit between sensor and splice. After repairs, go to step 24 .
Repair open/high resistance ground circuit between sensor and splice. After repairs, go to step 24 .
Repair open/high resistance in sensor signal circuit. After repairs, go to step 24 .
Repair sensor signal circuit shorted to ground. After repairs, go to step 24 .
Repair sensor signal circuit shorted to power. After repairs, go to step 24 .
Repair signal circuits shorted together. After repairs, go to step 24 .
Check for poor connections/terminal tension at CKP sensor. Repair as necessary. After repairs, go to step 24 . If connections are okay, go to next step.
Replace CKP sensor. After replacing sensor, go to step 24 .
Check for poor connections/terminal tension at PCM harness connector. Repair as necessary. After repairs, go to step 24 . If connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, clear DTCs. Turn ignition off. Wait 15 seconds, then operate vehicle within conditions required to set this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

For any test that requires probing PCM or component harness connectors, use Connector Test Adapter Kit (J-35616-A). This will prevent damage to harness connector terminals. Check for poor connections at PCM or at component. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connection.

Check for misrouted wiring harness. Inspect harness to ensure that it is not routed too close to high voltage wires (spark plug wires) or too close to high current devices (alternator, motors, solenoids).

Check for damaged wiring harness. If harness appears to be okay, observe scan tool while moving related connectors and wiring harnesses. A change in scan tool display may help to locate fault. If sensor signal is only affected when harness is moved at component, and there is no problem with harness or connections, component may be faulty.

Check CKP sensor for proper installation. A sensor that is loose or not fully seated, causing an excessive air gap between sensor and reluctor wheel, may cause this DTC to set.

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM directly controls the ground for the linear EGR valve when certain conditions have been met. Voltage is supplied by the underhood fuse/relay block to the EGR valve when ignition is turned on. When PCM grounds the valve, a diagnostic feedback signal can determine if valve had actually moved.

EGR flow restrictions are diagnosed during a deceleration. EGR valve is commanded closed during normal deceleration and a change in MAP is expected. If the change in MAP is less than a threshold, a restricted flow is indicated.

DTC will set if calculated value compared to an engine speed barometric pressure determines that there is restriction in EGR flow when engine speed is 1350-2000 RPM, VSS is greater than 30 MPH, throttle is closed, coolant temperature is greater than 150°F (70°C), vehicle in top gear and no EGR, TP sensor, MAP, VSS, IAT, ECT or IAC DTCs have been set. EGR flow insufficient test is checked once per ignition cycle during deceleration.

Note. If DTC P0404, P0405 or P1404 is present, diagnose affected DTC first.

Install scan tool. Start engine. Using scan tool, command EGR valve to full open. If engine begins to run rough when EGR is opened, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If engine does not run rough when EGR is opened, go to next step.
If EGR pintle position increases when valve is opened, clean or replace EGR valve. If EGR pintle position does not increase when valve is opened, refer to DTC P0404 test for diagnosis.

When attempting to diagnose an intermittent problem, use scan tool to review malfunction history information. This data can be used to duplicate a problem.

Scan tool can read the number of deceleration tests that have been performed since the DTCs were cleared. If can also display the EGR decel average value as well as the fail threshold when DTC was set. The average must be greater than the threshold to set DTC.

Battery voltage is supplied to EGR valve terminal "E" with ignition on. Carbon build-up around pintle valve may restrict exhaust gas flow. Diagnose other DTCs first, especially MAP DTC, before diagnosing DTC P0401.

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (2.4L "N" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

A linear Exhaust Gas Recirculation (EGR) valve is used on this system. Powertrain Control Module (PCM) commands EGR valve to operate when necessary by controlling a ground signal through PCM. This can be monitored on a scan tool by selecting DESIRED EGR POSITION function. Ignition voltage is supplied to EGR valve thorough a fuse. PCM monitors results of its command through a feedback signal. Feedback signal is the actual position of the EGR pintle. This feedback signal can also be monitored on a scan tool by selecting ACTUAL EGR POSITION function. The ACTUAL EGR POSITION should always be near the commanded or DESIRED EGR POSITION. Conditions for setting this DTC are as follows

DTCs P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300-P0304, P0335, P0502, P0506, P0507 and P1441 not set.
Engine speed is 900-1700 RPM (A/T).
Engine speed is 1000-2200 RPM (M/T).
ECT greater than 167°F (75°C).
BARO greater than 72 kPa.
MAP is 12-32 kPa.
TP angle less than one percent.
Vehicle speed is greater than 20 MPH.
EGR flow restricted.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine and allow it to idle. Using scan tool, command EGR valve to 50 percent. If engine stalls or runs rough, go to step 5 . If engine does not stall or run rough, go to next step.
Turn ignition off. Remove EGR valve. Inspect EGR valve, passages and pipe for restriction or damage. Repair as necessary. After repairs, go to step 5 . If no problems are found, go to next step.
Replace EGR valve. After replacing EGR valve, go to next step.
Disconnect negative battery cable for 10 seconds, then reconnect battery cable. Road test vehicle. Increase vehicle speed to 60 MPH, then release accelerator and allow vehicle to decelerate to 20 MPH. If Decel Exponentially Weighted Moving Average (EWMA) value is not greater than zero, return to step 3 . If EWMA is greater than zero, go to next step.
Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0401. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

Decel Exponentially Weighted Moving Average (EWMA) value is an average of the difference in expected MAP change and actual MAP change caused by opening EGR valve during deceleration. By driving vehicle to 60 MPH and decelerating to 20 MPH, it can be determined if EGR system is okay, partially restricted or fully restricted.

A negative number, less than -3 indicates system is functioning properly. A positive number indicates system is fully restricted and the expected amount of EGR flow is incorrect. A number that falls between -3 and +2 indicates system is partially restricted. The Decel EWMA value should always be -3 or less. If value becomes more positive, check for damaged EGR pipe, restricted EGR passage or defective EGR valve.

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM tests Exhaust Gas Recirculation (EGR) valve during deceleration by momentarily commanding EGR valve on while monitoring engine MAP. PCM will illuminate MIL and store DTC P0401 if expected increase in MAP is not seen under certain conditions during deceleration. Conditions required to set DTC are

No CKP, ECT, EGR pintle position, IAT, MAP, or TP sensor DTCs set.
No misfire or VSS DTCs set.
BARO is greater than 65 kPa (70 kPa on 3.4L).
On 3.1L, ECT greater than 180°F (80°C).
On 3.4L, ECT greater than 167°F (75°C).
Engine speed is 800-1500 RPM (800-1200 RPM on 3.4L).
IAC position steady.
Vehicle speed greater than 25 MPH.
TP angle less than one percent.
Commanded state of A/C relay is steady.
MAP changes monitored during EGR flow test indicate insufficient EGR flow.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Inspect exhaust system for modifications or leaks. If a problem is found, repair as necessary and go to step 5 . If no problem is found, go to next step.
Remove EGR valve and check pintle, valve and passages and adapter for excessive deposits or restriction. Check EGR valve gasket and pipes for leaks. If a problem is found, repair as necessary. After repairs, go to step 5 . If no problem is found, go to next step.
Remove EGR inlet and outlet pipes from exhaust and intake manifolds. Inspect manifold EGR ports and pipes for blockage or damage. Repair as necessary. After repairs, go to next step. If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Read and record FAILURE RECORDS data for DTC P0401. Clear DTCs and monitor EGR TEST COUNT while operating vehicle within conditions noted in DIAGNOSTIC AIDS until 9-12 test samples have been taken. Read SPECIFIC DTC. If scan tool displays DTC P0401 TEST RAN AND PASSED, repair is complete. If scan tool does not display DTC P0401 TEST RAN AND PASSED, return to step 2 .

PCM will only run EGR flow test during gradual deceleration, a closed throttle condition and with vehicle speed greater than 20 MPH. Accelerate vehicle to greater than 20 MPH, and gradually decelerate 9-13 times.

Check for faulty connections or damaged harness. Inspect PCM harness connector EGR control circuit for backed-out terminal. Observe ACTUAL EGR POSITION display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

If EGR valve shows signs of excessive heat, check exhaust system for blockage or plugged catalytic converter.

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM tests Exhaust Gas Recirculation (EGR) valve during acceleration by momentarily commanding valve on/open while monitoring engine MAP sensor signal. PCM will illuminate MIL and store DTC P0401 if expected increase is not seen under certain conditions during deceleration.

Conditions required to set DTC are: no fuel injector faults, misfire, idle speed, EGR pintle position, VSS, TP, IAT, MAP, ECT, CKP or MAF sensor related DTCs are set. DTC will also set when BARO is greater than 77 kPa, coolant temperature is greater than 176°F (80°C), engine speed at 900-1300 RPM, vehicle speed greater than 22.5 MPH, throttle is closed, EGR pintle position at less than one percent (valve closed), IAC position, MAP, engine RPM and vehicle speed steady or A/C clutch state and transmission state is unchanged. DTC will also set when MAP changes monitored during EGR flow test indicate insufficient EGR flow.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Inspect exhaust system for modifications or leaks. Repair as necessary. After repairs, go to step 5 . If no problem is found, go to next step.
Remove EGR valve and check pintle, valve and passages and adapter for excessive deposits or restriction. Check EGR valve gasket and pipes for leaks. Repair as necessary. After repairs, go to step 5 . If no problem is found, go to next step.
Remove EGR inlet and outlet pipes from exhaust and intake manifolds. Inspect manifold EGR ports and pipes for blockage or damage. Repair as necessary. After repairs, go to next step. If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Read and record FAILURE RECORDS data for DTC P0401. Clear DTCs and monitor EGR TEST COUNT while operating vehicle within conditions noted in DIAGNOSTIC AIDS until 9-12 test counts/samples have been taken. Read SPECIFIC DTC. If scan tool displays DTC P0401 TEST RAN AND PASSED, go to next step. If scan tool does not display DTC P0401 TEST RAN AND PASSED, repeat step 2 .
Using scan tool, review CAPTURED INFO data. If any undiagnosed DTCs are displayed, go to applicable DTC test.

PCM will only run EGR flow test during gradual deceleration, a closed throttle condition and with vehicle speed greater than 25 MPH. Accelerate vehicle to greater than 23 MPH, and gradually decelerate 6-9 times.

Check for faulty connections or damaged harness. Inspect PCM harness connector EGR control circuit for backed-out terminal. Observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

If EGR valve shows signs of excessive heat, check exhaust system for blockage or plugged catalytic converter.

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (3.8L "C", "F", "G", "H" & "W" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM tests Exhaust Gas Recirculation (EGR) valve by momentarily commanding valve on while monitoring engine MAP. PCM will illuminate MIL and store DTC P0401 if expected increase is not seen under certain conditions during deceleration. Conditions required to set DTC are

No ECT, IAT, MAP, or TP sensor DTCs set.
No misfire, linear EGR (pintle position) or vehicle speed sensor DTCs set.
BARO is greater than 10 psi (0.7 kg/cm 2 ).
ECT greater than 180°F (80°C).
Vehicle speed greater than 25 MPH.
Engine speed is 800-1400 RPM.
IAC position steady.
TP angle less than one percent.
Commanded state of A/C relay is steady.
MAP changes monitored during EGR flow test indicate insufficient EGR flow.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Inspect exhaust system for modifications or leaks. Repair as necessary. After repairs, go to step 5 . If no problem is found, go to next step.
Remove EGR valve and check pintle, valve and passages and adapter for excessive deposits or restriction. Check EGR valve gasket and pipes for leaks. Repair as necessary. After repairs, go to step 5 . If no problem is found, go to next step.
Remove EGR inlet and outlet pipes from exhaust and intake manifolds. Inspect manifold EGR ports and pipes for blockage or damage. Repair as necessary. After repairs, go to next step. If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Read and record FAILURE RECORDS data for DTC P0401. Clear DTCs and monitor EGR TEST COUNT while operating vehicle within conditions noted in DIAGNOSTIC AIDS until 9-12 test counts have been taken. Read SPECIFIC DTC. If scan tool displays DTC P0401 TEST RAN AND PASSED, repair is complete. If scan tool does not display DTC P0401 TEST RAN AND PASSED, return to step 2 .

PCM will only run EGR flow test during gradual deceleration, a closed throttle condition and with vehicle speed greater than 25 MPH. Accelerate vehicle to greater than 25 MPH, and gradually decelerate 9-12 times.

If EGR valve shows signs of excessive heat, check exhaust system for blockage or plugged catalytic converter.

DTC P0401: EGR SYSTEM MALFUNCTION (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EGR operation will cause variations in MAP sensor because when EGR valve opens, exhaust gas is drawn through it with intake manifold vacuum. When all test enable conditions are met, the test begins with PCM cycling the EGR from off to on and on to off, and recording the change in MAP. The PCM then converts MAP change to percentage and calculates the MAP error, or the difference between the actual percentage MAP change and the percentage MAP change that the PCM expected to see. The PCM performs this test several times to gain an average. If at least 8 tests have occurred, PCM compares its current average MAP error to the failure limit.

For EGR "off" test, if the current average MAP error is 6 kPa or greater, DTC is set. If error is less than the limit, EGR operation is returned to normal software control.

For the EGR "on" test, if at least 8 tests have occurred, the PCM compares its current average MAP error to the failure limit. If current average MAP error is 7 kPa or greater, DTC is set. If error is less than the limit, EGR operation is returned to normal software control.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If fuel trim DTCs P0170, P0171, P0172, P0173, P0174 or P0175 are present, diagnose affected DTCs first. If these DTCs are not present, go to next step.
Ignition on, with engine off. Check MAP sensor parameter on scan tool. If value is greater than 75 kPa (95 kPa at sea level), go to next step. If value is not greater than 75 kPa (95 kPa at sea level), go to step 9 .
Unplug MAP sensor vacuum hose. Connect a hand-held vacuum pump to MAP sensor. Apply 20 in. Hg to sensor. Each one in. of vacuum should result in a 3-4 kPa drop in MAP sensor reading. Change should be smooth. If a skip or jump occurs during application of vacuum, go to step 9 . If change in reading is smooth, go to next step.
With 20 in. Hg applied to sensor, if MAP reading is 34 kPa or less, go to next step. If MAP reading is not 34 kPa or less, go to step 9 .
Remove vacuum source from MAP sensor. If MAP sensor parameter returns to original reading, go to next step. If MAP parameter does not return to original reading, go to step 9 .
Reconnect MAP sensor vacuum hose. Start and idle engine. While monitoring MAP sensor value, command EGR from 0-70 percent in 10 percent increments. MAP sensor value should increase by about 4 kPa for each 10 percent increment. If MAP value does not increase accordingly and engine does not stall, go to next step. If MAP value increases accordingly or engine stalls, check EGR system for intermittent restrictions, blockages and/or leaks. If no fault is found, problem is intermittent.
Check EGR valve and all engine passages for restrictions and/or blockages. Repair as necessary. If no repairs are required, go to step 10 .
Replace MAP sensor.
Replace EGR valve and verify if problem is no longer present.

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

VCM tests exhaust gas recirculation valve by momentarily commanding valve on while monitoring manifold absolute pressure. If expected manifold absolute pressure increase is not seen under certain operating conditions (decel) for a calibrated number of tests, VCM will turn on Malfunction Indicator Light (MIL) and store DTC P0401.

Conditions for setting DTC

No ECT, IAC, IAT, MAP, TP, VSS sensor DTCs are set.
No linear EGR pintle position DTCs are set.
No transmission DTCs set.
ECT is greater than 154°F (70°C).
BARO is greater than 70 kPa (less than 10,3000 ft.).
Vehicle speed is greater than 25 MPH.
A/C clutch status is unchanged.
Transmission status is unchanged.
No misfire DTCs are set.
Engine speed is 1000-1600 RPM.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Install scan tool. Start engine. Using scan tool, select MISCELLANEOUS TESTS, EGR CONTROL and cycle EGR valve through 25, 50, 75 and 100 percent positions. Increase engine speed to greater than 1500 RPM. RPM should drop and engine should run rough as EGR valve is cycled. If engine runs rough as EGR valve is cycled, go to step 5 . If engine does not run rough as EGR valve is cycled, go to next step.
Turn ignition off. Disconnect EGR valve connector. Turn ignition on, with engine off. Connect test light between EGR control circuit and ignition feed circuit of EGR valve connector (engine harness side). If test light illuminates, go to next step. If test light does not illuminate, go to step 7 .
Start engine. Using scan tool, select MISCELLANEOUS TESTS, EGR CONTROL and cycle EGR valve. With test light still connected, observe test light as EGR valve is cycled through 100 percent. If test light illuminates, go to step 8 . If test light does not illuminate, go to step 11 .
Remove EGR valve and inspect for restrictions. Inspect if valve pintle is sticking partially open. If a problem is found, go to step 10 . If no problem is found, go to next step.
DTC is intermittent. Check if additional DTCs are set. If additional DTCs are set, diagnose affected DTCs. If not additional DTCs are set, see «DIAGNOSTICS AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Check for short to ground in EGR control circuit. If circuit is shorted, go to step 14 . If circuit is okay, go to step 15 .
Check for a restriction in EGR tube or passage. If a problem is found, go to step 10 . If no problem is found, go to next step.
Check for poor connection at EGR valve. If connection is faulty, go to step 14 . If connection is okay, go to next step.
Replace EGR valve. After replacing EGR valve, go to step 16 .
Check for open in EGR control circuit. If circuit is open, go to step 14 . If circuit is okay, go to next step.
Check for open in ignition feed circuit. If circuit is open, go to step 14 . If circuit is okay, go to next step.
Check for poor connection at VCM. If a problem is found, go to next step. If no problem is found, go to step 15 .
Repair circuit as necessary. After repairs, go to step 16 .
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Inspect VCM connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal to wire connection. Inspect wiring harness for damage. If connections and harness are okay, observe scan tool while wiggling related connectors and wiring harness. A change in display will indicate location of fault.

If EGR valve indicates signs of excessive heat, check exhaust system for blockage (i.e., plugged converter). If exhaust system is restricted, check for possible open injector cause by grounded driver circuit, injector stuck open or faulty VCM. If problem is not found, check oil for possible fuel contamination.

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (4.3L "L", "M", "S" & "T" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

VCM test Exhaust Gas Recirculation (EGR) valve by momentarily commanding valve on while monitoring engine MAP. VCM will illuminate MIL and store DTC P0401 if expected increase is not seen under certain conditions during deceleration.

Conditions for setting DTC

No ECT, EGR, EVAP, IAC, IAT, MAP, TP or VSS sensor DTCs set.
No transmission DTCs set.
Change in IAC less than 8 counts.
ECT greater than 172°F (78°C).
Vehicle speed greater than 27 MPH.
BARO greater than 70 kPa.
A/C clutch status unchanged.
Transmission locked/unlocked status unchanged.
No misfire DTC set.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and warm engine to normal operating temperature. Operate engine at greater than 1500 RPM. Using scan tool, command EGR duty cycle through 25, 50, 75 and 100 percent positions. If engine runs rough as EGR is cycled, go to step 5 . If engine does not run rough, go to next step.
Turn engine off. Turn ignition on, engine off. Disconnect EGR valve harness connector. Connect a test light between EGR valve harness connector ignition feed and control circuits. If test light does not illuminate, go to next step. If test light illuminates, go to step 7 .
Start engine. Using scan tool, select MISCELLANEOUS TESTS, EGR CONTROL. With test light still connected, command EGR duty cycle increase to 100 percent. If test light illuminates as EGR is cycled, go to step 8 . If test light does not illuminate, go to step 11 .
Remove EGR valve and inspect valve and passages for damage. Inspect valve pintle to ensure it is not sticking partially open. If a problem is found, go to step 10 . If no problem is found, go to next step.
DTC is intermittent. Check if additional DTCs are present. Diagnose affected DTCs. If no additional DTCs are present, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Check for short to ground in EGR valve control circuit. If circuit is shorted, go to step 14 . If circuit is okay, go to step 15 .
Check for restriction in EGR tube or passage. If restriction is found, go to step 10 . If no restriction is found, go to next step.
Check for faulty electrical connection at EGR valve. If faulty connection is found, go to step 14 . If connection is okay, go to next step.
Replace faulty EGR valve. After replacing EGR valve, go to step 16 .
Check for an open in EGR control circuit. If circuit is open, go to step 14 . If circuit is okay, go to next step.
Check for an open in EGR ignition feed circuit. If circuit is open, go to step 14 . If circuit is okay, go to next step.
Check for faulty connection at VCM. If connection is faulty, go to next step. If connection is okay, go to step 15 .
Repair circuit as necessary. After repairs, go to step 16 .
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter this DTC. Operate vehicle within conditions required to set DTC. If scan tool indicates that this DTC RAN AND PASSED, go to next step. If scan tool does not display that this DTC RAN AND PASSED, repeat step 2 .
Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Inspect VCM harness connector EGR control circuit for backed-out terminal. Observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

If EGR valve shows signs of excessive heat, check exhaust system for blockage or plugged catalytic converter. Ensure fuel injectors are functioning properly and check engine oil for fuel contamination.

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM will test EGR system during deceleration by momentarily commanding EGR valve to open. The pressure in intake manifold increases when EGR valve is open. PCM monitors MAP sensor signal during EGR system diagnostic in order to determine amount of EGR flow. PCM calculates an error based on the difference between actual MAP increase and a predetermined value, and records the error and adjusts an internal fail counter towards the fail threshold if error is too great.

PCM sets DTC when the fail counter exceeds the fail threshold. The number of test samples required to exceed the fail threshold varies according to magnitude of detected flow errors.

PCM allows only one EGR flow test sample to be taken during an ignition cycle. PCM will allow 12 test samples during the first ignition cycle in order to aid in verifying a repair after battery is disconnected or after performing CLEAR INFO on scan tool.

DTC will set when change in MAP is less than a predetermined value during EGR flow test.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If a MAP related DTC is present, diagnose DTC first. If no other DTCs are present, go to next step.
Inspect exhaust system for modifications from original parts or leaks. Repair as necessary. After repairs, go to step 7 . If exhaust system is okay, go to next step.
Check EGR valve gasket and pipe for leaks. Repair or clean EGR components as necessary. After repairs, go to step 7 . If EGR components are okay, go to next step.
Remove EGR valve. Check EGR pintle and passages for leak or restriction. Repair or replace as necessary. After repairs, go to step 7 . If EGR valve is okay, go to next step.
Remove EGR inlet and outlet pipes from exhaust and intake manifolds. Check for leaks or restrictions. Repair as necessary. After repairs, go to next step. If repairs were not required, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Use scan tool to clear DTC. Run EGR flow test to verify repairs. Check for vacuum restriction to MAP sensor, causing EGR flow test to fail due to insufficient MAP changes being monitored during test. Ensure engine is not running poorly. Check harness connectors and circuits for damage.

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (5.7L "F" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM sets DTC when the fail counter exceeds the fail threshold. The number of test samples required to exceed the fail threshold varies according to magnitude of detected flow errors.

Conditions required to set DTC are

DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0404, P0500, P0502, P0503, P0560, P0562 or P0563 are not set.
Ignition voltage is 11.7-16.0 volts.
BARO greater than 70 kPa.
ECT is 140-243°F (60-117°C).
IAT less than 140°F (65°C).
Engine speed at 800-2000 RPM.
Engine vacuum (BARO minus MAP) 9-12 psi (60-83 kPa).
IAC position steady.
Vehicle speed at 27-70 MPH.
Change in VSS is less than 4 MPH.
Change in MAP is less than 0.5 kPa.
A/C clutch status is steady.
Change in MAP is less than a predetermined value the EGR flow test.
Conditions present for 2 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If a MAP or MAF DTC is present, diagnose affected DTCs first. If no other DTCs are present, go to next step.
Inspect exhaust system for modifications from original parts or leaks. Repair as necessary. After repairs, go to step 7 . If exhaust system is okay, go to next step.
Check EGR valve gasket and pipe for leaks. Repair or clean EGR components as necessary. After repairs, go to step 7 . If EGR components are okay, go to next step.
Remove EGR valve. Check EGR pintle and passages for leak or restriction. Repair or replace as necessary. After repairs, go to step 7 . If EGR valve is okay, go to next step.
Remove EGR inlet and outlet pipes from exhaust and intake manifolds. Check for leaks or restrictions. Repair as necessary. After repairs, go to next step. If repairs were not required, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0401. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0403: EGR SOLENOID CONTROL CIRCUIT (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM monitors EGR valve pintle position input to ensure that valve responds properly to commands from PCM. The EGR (linear) valve is controlled by using an ignition positive driver and ground circuit within the PCM. The driver has the ability to detect an electrical malfunction in the ignition voltage or ground circuit, then signal the PCM to set the DTC.

Conditions for setting this DTC

Ignition switch in CRANK or RUN positions.
No CKP, ECT, IAT, MAF, MAP, TP, VSS sensors, misfire, idle speed or fuel injector related DTCs set.
System voltage at 10-16 volts.
EGR feedback is 0.4 volt greater than EGR closed valve pintle position when EGR is commanded to zero percent.
Conditions present for longer than 20 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, observe actual EGR position. If actual EGR position is zero percent, go to next step. If actual EGR position is not zero percent, go to step 9 .
Turn ignition on, engine off. Using scan tool select EGR VALVE OUTPUT CONTROL function. Increment EGR valve through all positions while comparing DESIRED EGR POSITION to ACTUAL EGR POSITION. If desired EGR position remains close to actual EGR position at all commanded positions, go to next step. If EGR position is not as specified, go to step 5 .
Using scan tool, review FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions and monitor SPECIFIC DTC info. If scan tool indicates that DTC P0403 failed this ignition cycle, go to next step. If scan tool does not indicate that DTC P0403 failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect EGR valve harness connector. Using a test light, connect test light between EGR ground and control circuit at EGR harness connector. Using scan tool, command EGR valve to 100 percent. If test light illuminates, go to step 10 . If test light does not illuminate, go to next step.
Using test light connected to battery voltage, probe EGR ground circuit at EGR harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 14 .
Probe EGR control circuit at EGR harness connector. If test light illuminates, go to step 13 . If test light does not illuminate, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check for open in EGR control circuit at PCM connector. Repair as necessary. After repairs, go to step 21 . If circuit is okay, go to step 19 .
Turn ignition off. Disconnect PCM harness connector. Turn ignition on, engine off. Using test light connected to ground, probe EGR control circuit at PCM connector. If test light illuminates, go to step 12 . If test light does not illuminate, go to step 20 .
Check for poor terminal contact at EGR valve. Repair as necessary. After repairs, go to step 21 . If terminals are okay, go to next step.
Replace EGR valve. After replacing EGR valve, go to step 21 .
Locate and repair short to voltage in EGR valve control circuit. After repairs, go to step 21 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR control circuit at EGR harness connector. If test light illuminates, go to step 18 . If test light does not illuminate, go to step 17 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to ground, probe EGR ground circuit at EGR harness connector. If test light illuminates, go to step 16 . If test light does not illuminate, go to next step.
Check for open in EGR valve ground circuit. Repair as necessary. After repairs, go to step 21 . If circuit is okay, go to step 20 .
Locate and repair short to voltage in EGR valve ground circuit. After repairs, go to step 21 .
Check EGR valve control circuit for short to EGR ground circuit. Check for short between EGR valve control circuit and EGR pintle position sensor. Repair as necessary. After repairs, go to step 21 . If circuits are okay, go to step 20 .
Locate and repair short to ground in EGR valve control circuit. After repairs, go to step 21 .
Check circuits related to EGR valve for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 21 . If terminal connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURED INFO data. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connection at PCM or EGR valve harness connectors.

DTC P0403: EGR SOLENOID CONTROL CIRCUIT (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions for setting this DTC are: system voltage at 9-18 volts, engine speed greater than 80 RPM, PCM driver transitions from on to off or from off to on, there is a short to ground, open in circuit or short to battery voltage detected on control circuit and conditions are present for at least 30 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, observe actual EGR position. If actual EGR position is zero percent, go to next step. If actual EGR position is not zero percent, go to step 9 .
Turn ignition on, engine off. Using scan tool select EGR VALVE OUTPUT CONTROL function. Increment EGR valve through all positions while comparing DESIRED EGR POSITION to ACTUAL EGR POSITION. If desired EGR position remains close to actual EGR position at all commanded positions, go to next step. If EGR position is not as specified, go to step 5 .
Using scan tool, review FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions and monitor SPECIFIC DTC info. If scan tool indicates that DTC P0403 failed this ignition cycle, go to next step. If scan tool does not indicate that DTC P0403 failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect EGR valve harness connector. Using a test light, connect test light between EGR ground and control circuit at EGR harness connector. Using scan tool, command EGR valve to 100 percent. If test light illuminates, go to step 10 . If test light does not illuminate, go to next step.
Using test light connected to battery voltage, probe EGR ground circuit at EGR harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 14 .
Probe EGR control circuit at EGR harness connector. If test light illuminates, go to step 13 . If test light does not illuminate, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check for open in EGR control circuit at PCM connector. Repair as necessary. After repairs, go to step 21 . If circuit is okay, go to step 19 .
Turn ignition off. Disconnect PCM harness connector. Turn ignition on, engine off. Using test light connected to ground, probe EGR control circuit at PCM connector. If test light illuminates, go to step 12 . If test light does not illuminate, go to step 20 .
Check for poor terminal contact at EGR valve. Repair as necessary. After repairs, go to step 21 . If terminals are okay, go to next step.
Replace EGR valve. After replacing EGR valve, go to step 21 .
Locate and repair short to voltage in EGR valve control circuit. After repairs, go to step 21 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR control circuit at EGR harness connector. If test light illuminates, go to step 18 . If test light does not illuminate, go to step 17 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to ground, probe EGR ground circuit at EGR harness connector. If test light illuminates, go to step 16 . If test light does not illuminate, go to next step.
Check for open in EGR valve ground circuit. Repair as necessary. After repairs, go to step 21 . If circuit is okay, go to step 20 .
Locate and repair short to voltage in EGR valve ground circuit. After repairs, go to step 21 .
Check EGR valve control circuit for short to EGR ground circuit. Check for short between EGR valve control circuit and EGR pintle position sensor. Repair as necessary. After repairs, go to step 21 . If circuits are okay, go to step 20 .
Locate and repair short to ground in EGR valve control circuit. After repairs, go to step 21 .
Check circuits related to EGR valve for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 21 . If terminal connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURED INFO data. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for poor connection at PCM or EGR valve harness connectors.

DTC P0403: EGR SOLENOID CONTROL CIRCUIT (3.8L "C", "F", "G", "H" & "W" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM monitors EGR valve pintle position input to ensure that valve responds properly to commands from PCM. The EGR (linear) valve is controlled by using an ignition positive driver and ground circuit within the PCM. The driver has the ability to detect an electrical malfunction in the ignition positive or ground circuit, then signal the PCM to set the DTC.

Conditions for setting this DTC

No CKP, ECT, IAT, MAF, MAP, TP, VSS sensors, misfire, idle speed or fuel injector related DTCs set.
System voltage at 10-16 volts.
EGR feedback is 0.4 volt greater than EGR closed valve pintle position when EGR is commanded to zero percent.
Conditions present for longer than 20 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command EGR from zero percent to 10 percent. If solenoid turns on and off with each command, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If solenoid does not turn on and off with each command, go to next step.
Turn ignition off. Disconnect EGR. Turn ignition on, with engine off. Using a test light connected to ground, probe solenoid control circuit. Using scan tool, command EGR from zero percent to 10 percent. If test light turns on and off with each command, go to next step. If test light does not turn on and off with each command, go to step 5 .
Connect test light between solenoid control and ground circuits. Using scan tool, command EGR from zero percent to 10 percent. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to step 10 .
If test light remains illuminated with each command, go to step 7 . If test light does not remain illuminated with each command, go to next step.
Check solenoid control circuit for an open or short to ground. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
Check solenoid control circuit for a short to voltage. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
Check for faulty connections at EGR. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
Check PCM for poor connections. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
Repair solenoid ground circuit. After repairs, go to step 13 .
Replace EGR. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0403. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, system is okay. If scan tool did not indicate that this test ran and passed, go to step 2 .

Check for poor connection at PCM or EGR valve harness connectors.

DTC P0404: EGR PINTLE POSITION ERROR (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM directly controls the ground for the linear EGR valve when certain conditions have been met. PCM contains a diode feedback circuit which dissipates energy when valve is cycled off. When PCM grounds the valve, a diagnostic feedback signal can determine is valve had actually moved. This DTC has been defined to monitor feedback signal. This diagnostic will determine if the position feedback signal properly falls within the correct range under different valve operating conditions.

If commanded EGR position is greater than 80 percent, actual position must be within 26 counts (10 percent or 0.5 volt) of commanded position. If commanded position is less than 80 percent, actual position must be within 60 counts (24 percent or 1.1 volts) of commanded position. DTC will set if either condition exists for greater than 10 seconds. When either one of these tests have failed, a DTC will set and EGR will be disabled for this ignition cycle. The malfunction history record will indicate which one of these tests has failed to aid in diagnosis. EGR position error is continuously checked when the EGR is commanded on. The EGR valve may operate at any engine coolant temperature regardless of loop mode.

Note. If DTC P1635 is also set, diagnose P1635 first.

Turn ignition on, engine off. Using scan tool, command EGR valve open at different increments. Verify actual EGR position follows desired position percentage as valve opens. If desired percentage is accomplished, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If desired percentage is not accomplished, go to next step.
Using scan tool, monitor EGR pintle position voltage. If voltage reading is greater than 1.5 volts, go to next step. If voltage reading is not greater than 1.5 volts, go to step 5 .
Start engine. If engine idles and runs okay, disconnect EGR harness connector. After performing OBD system check, go to next step. If engine runs rough or stalls, disconnect EGR harness connector. If engine does not smooth out, go to next step. If engine smooths out, check for short to ground in circuit between EGR harness connector terminal "A" (Light Blue wire) to PCM. Repair as necessary. If circuit is okay, replace PCM.
Connect a test light between battery voltage and EGR harness connector terminal "B" (Black wire). If test light illuminates, go to step 8 . If test light does not illuminate, check for open in Black wire between EGR and PCM or for terminal tightness. Repair as necessary. If circuit and terminals are okay, replace PCM.
Disconnect EGR harness connector. Turn ignition on, engine off. Using a test light, backprobe between PCM harness connector terminals No. J3C16 (Black wire) and No. J2B11 (Pink wire). If test light illuminates, go to step 7 . If test light does not illuminate, go to next step.
Check voltage between Pink wire and ground. If voltage reading is greater than 11 volts, go to step 4 . If voltage reading is not greater than 11 volts, check if DTC P0443 is also present. If P0443 is present, check EGR fuse. If only DTC P0404 is present, repair open in Pink wire between EVAP purge solenoid and PCM.
Using a test light, backprobe between PCM harness connector terminals No. J2B10 (Light Blue wire) and No. J2B11 (Pink wire). Using scan tool, command EGR valve full open (100 percent). If test light illuminates, go to next step. If test light does not illuminate, check for terminal tightness or open/short in circuit. Repair as necessary. If circuit and terminals are okay, replace faulty PCM.
Using scan tool, again command EGR valve to full open (100 percent) then back to closed position. Repeat for 3 times. Drive vehicle to obtain a PASS or FAIL diagnostic. Ensure vehicle is driven for a sufficient time and distance to obtain at least 4 EGR valve openings. If a diagnostic PASS is obtained, go to next step. If a diagnostic FAIL is obtained, go to step 10 .
Problem was most likely caused by debris in EGR pintle. Clean EGR valve. Clear DTCs and test drive vehicle again.
Replace EGR valve. Check and clean carbon deposit or debris in EGR supply port. Road test vehicle and verify diagnostic PASS result.

When attempting to diagnose an intermittent problem, use scan tool to review malfunction history information. This data can be used to duplicate a problem.

Battery voltage is supplied to EGR valve terminal "E" when ignition is on. Check EGR fuse in underhood fuse/relay block before diagnosing this DTC. Carbon build-up around EGR pintle may restrict pintle movement. An open in PCM diode feedback circuit will result in unstable valve operation resulting in engine surge. Moisture associated with exhaust system may also cause EGR valve to freeze and stick in extreme cold weather conditions.

DTC P0404: EGR VALVE PINTLE POSITION OPEN (2.4L "N" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

A linear EGR is used to accurately supply exhaust gasses to engine without the use of intake manifold vacuum. EGR is controlled by the PCM using inputs from TP and MAP sensors. PCM monitors the results of its command through a feedback signal. By sending a 5-volt reference and ground to EGR, a voltage signal representing the EGR valve pintle position is sent to PCM. This feedback signal can also be monitored on scan tool and is the actual position of EGR pintle. The actual EGR position should always be near the commanded or desired EGR position.

Conditions for setting DTC

DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300-P0304, P0335, P0502, P0506, P0507 and P1441 not set.
Ignition voltage greater than 11.7 volts.
EGR commanded on (desired EGR position greater than zero percent).
Actual EGR position differs from desired EGR position by greater than 9 percent for 18 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command EGR valve to 25, 50, 75, 100 percent. If actual EGR position follow the desired EGR position, go to step 19 . If actual EGR position does not follow the desired EGR position, go to next step.
Disconnect EGR harness connector. Using a test light connected to battery voltage, probe EGR valve harness connector ground circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 5 .
Connect test light to ground. Probe EGR harness connector control circuit. Using scan tool, command EGR to 25, 50, 75, 100 percent. If test light flash, maintain a steady glow or illuminates and gets brighter as command is raised, go to step 6 . If test light does not flash or maintain a steady glow, or does not illuminate, go to step 7 .
Repair open or poor connection in EGR ground circuit. After repairs, go to step 19 .
With test light still connected to ground, probe EGR signal circuit. If test light illuminates, go to step 8 . If test light does not illuminate, go to step 9 .
With test light still connected to ground, probe EGR control circuit without commanding EGR with scan tool. If test light illuminates, go to step 10 . If test light does not illuminate, go to step 11 .
Check signal circuit for short to voltage. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 12 .
Using a DVOM connected to ground, probe 5-volt reference circuit. If voltage reading is about 5 volts, go to step 13 . If voltage reading is not about 5 volts, go to step 14 .
Check control circuit for short to voltage. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 12 .
Connect test light to battery voltage and probe EGR control circuit. If test light illuminates, go to step 15 . If test light does not illuminate, go to step 16 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 19 .
Check EGR ground circuit for poor connection or proper terminal tension at PCM and repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 17 .
Check 5-volt reference circuit for short to voltage and repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 12 .
Check control circuit for short to ground. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 12 .
Check control circuit for an open or poor connection at EGR harness connector. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 18 .
Replace EGR valve. After replacing EGR valve, go to step 19 .
Check for poor connection at PCM harness connector. Repair as necessary. After repairs, go to next step. If connection is okay, go to step 12 .
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Due to moisture in exhaust system, EGR valve may sometimes freeze and stick in colder weather. Problem may disappear after vehicle is brought into a warm shop for repairs. By using scan tool and watching actual EGR and desired EGR positions on a cold engine, fault can be easily verified. Check FREEZE FRAME data to determine if DTC was set when engine was cold by viewing ECT.

DTC P0404: EGR SYSTEM PERFORMANCE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM monitors EGR valve pintle position input to ensure that valve responds properly to commands from PCM. PCM compares actual EGR position with desired EGR position when valve is commanded open. If actual EGR position is 15 percent less than desired EGR position when PCM is commanding EGR valve opened, DTC will set.

Conditions for setting DTC

No CKP, ECT, IAT, MAF, MAP, TP, VSS sensor, idle speed, fuel injector, misfire DTCs set.
System voltage is 10-16 volts.
Actual EGR position is 15 percent less than desired EGR position.
Conditions present for longer than 20 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, check if DTC P0403 or P0405 is present. If any of this DTC is present, diagnose affected DTC first. If DTC P0403 or P0405 is not present, select EGR OUTPUT CONTROL function. Increment EGR valve through all positions while comparing desired to actual EGR position. If desired and actual EGR position remains close to each other at all commanded positions, go to next step. If desired and actual EGR position is not within range, go to step 4 .
Using scan tool, review FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions and monitor SPECIFIC DTC info. If scan tool indicates that this DTC failed this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect EGR valve harness connector. Check voltage between EGR pintle position sensor ground circuit and 5-volt reference circuit at EGR harness connector. If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 10 .
Using test light connected to battery voltage, probe EGR pintle position signal circuit at EGR harness connector. If test light illuminates, go to step 8 . If test light does not illuminate, go to next step.
Using a fused jumper wire, jumper EGR 5-volt reference circuit and EGR pintle position signal circuit at EGR harness connector. Using scan tool, observe actual EGR position. If actual EGR position is 100 percent, go to step 9 . If actual EGR position is not 100 percent, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check for open in EGR pintle position signal circuit. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 15 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR pintle position signal circuit. If test light illuminates, go to step 13 . If test light does not illuminate, go to step 14 .
Check for poor terminal connections at EGR valve. Repair as necessary. After repairs, go to step 17 . If terminal connections are okay, go to step 12 .
Check 5-volt reference circuit for open between EGR and PCM. Check 5-volt reference circuit for short to ground. Repair as necessary. After repairs, go to step 17 . If circuits are okay, go to next step.
Check EGR pintle position ground sensor circuit for open or short to voltage. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 15 .
Replace EGR valve. After replacing EGR valve, go to step 17 .
Locate and repair short to ground in EGR pintle position signal circuit. After repairs, go to step 17 .
Check for short in EGR pintle position signal circuit to sensor ground. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 16 .
Check circuits related to EGR valve for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 17 . If circuits are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .

Check for excessive deposits on EGR valve pintle or seat. Check for poor connection at PCM or EGR valve harness connectors.

DTC P0404: EGR SYSTEM PERFORMANCE (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

DTC P0404 will set when no ECT, HO2S, IAT, MAF or TP sensor DTCs are set, TP sensor angle is greater than 2 percent, DTC P040 diagnostic not running, or system voltage is greater than 10 volts.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, check if DTC P0403 or P0405 is present. If any of this DTC is present, diagnose affected DTC first. If DTC P0403 or P0405 is not present, select EGR OUTPUT CONTROL function. Increment EGR valve through all positions (0-100 percent) while comparing desired to actual EGR position value. If desired and actual EGR position remains close to each other at all commanded positions, go to next step. If desired and actual EGR position is not within range, go to step 4 .
Using scan tool, review FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions and monitor SPECIFIC DTC info. If scan tool indicates that this DTC failed this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect EGR valve harness connector. Check voltage between EGR pintle position sensor ground circuit and 5-volt reference circuit at EGR harness connector. If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 10 .
Using test light connected to battery voltage, probe EGR pintle position signal circuit at EGR harness connector. If test light illuminates, go to step 8 . If test light does not illuminate, go to next step.
Using a fused jumper wire, jumper EGR 5-volt reference circuit and EGR pintle position signal circuit at EGR harness connector. Using scan tool, observe actual EGR position. If actual EGR position is 100 percent, go to step 9 . If actual EGR position is not 100 percent, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check for open in EGR pintle position signal circuit. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 15 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR pintle position signal circuit. If test light illuminates, go to step 13 . If test light does not illuminate, go to step 14 .
Check for poor terminal connections at EGR valve. Repair as necessary. After repairs, go to step 17 . If terminal connections are okay, go to step 12 .
Check 5-volt reference circuit for open between EGR and PCM. Check 5-volt reference circuit for short to ground. Repair as necessary. After repairs, go to step 17 . If circuits are okay, go to next step.
Check EGR pintle position ground sensor circuit for open or short to voltage. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 15 .
Replace EGR valve. After replacing EGR valve, go to step 17 .
Locate and repair short to ground in EGR pintle position signal circuit. After repairs, go to step 17 .
Check for short in EGR pintle position signal circuit to sensor ground. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 16 .
Check circuits related to EGR valve for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 17 . If circuits are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .
Using scan tool, review CAPTURED INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for excessive deposits on EGR valve pintle or seat. Check for poor connection at PCM or EGR valve harness connectors.

DTC P0404: EGR VALVE PINTLE STUCK CLOSED (3.8L "C", "F", "G", "H" & "W" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions for setting DTC

No CKP, ECT, IAT, MAF, MAP, TP, VSS sensor, idle speed, fuel injector, misfire DTCs set.
System voltage is 10-16 volts.
Actual EGR position is 15 percent less than desired EGR position.
Conditions present for longer than 20 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, check if DTC P0403 or P0405 is present. If any of this DTC is present, diagnose affected DTC first. If DTC P0403 or P0405 is not present, select EGR OUTPUT CONTROL function. Increment EGR valve through all positions while comparing desired to actual EGR position. If desired and actual EGR position remains close to each other at all commanded positions, go to next step. If desired and actual EGR position is not within range, go to step 4 .
Using scan tool, review FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions and monitor SPECIFIC DTC info. If scan tool indicates that this DTC failed this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect EGR valve harness connector. Check voltage between EGR pintle position sensor ground circuit and 5-volt reference circuit at EGR harness connector. If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 10 .
Using test light connected to battery voltage, probe EGR pintle position signal circuit at EGR harness connector. If test light illuminates, go to step 8 . If test light does not illuminate, go to next step.
Using a fused jumper wire, jumper EGR 5-volt reference circuit and EGR pintle position signal circuit at EGR harness connector. Using scan tool, observe actual EGR position. If actual EGR position is 100 percent, go to step 9 . If actual EGR position is not 100 percent, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check for open in EGR pintle position signal circuit. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 15 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR pintle position signal circuit. If test light illuminates, go to step 13 . If test light does not illuminate, go to step 14 .
Check for poor terminal connections at EGR valve. Repair as necessary. After repairs, go to step 17 . If terminal connections are okay, go to step 12 .
Check 5-volt reference circuit for open between EGR and PCM. Check 5-volt reference circuit for short to ground. Repair as necessary. After repairs, go to step 17 . If circuits are okay, go to next step.
Check EGR pintle position ground sensor circuit for open or short to voltage. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 15 .
Replace EGR valve. After replacing EGR valve, go to step 17 .
Locate and repair short to ground in EGR pintle position signal circuit. After repairs, go to step 17 .
Check for short in EGR pintle position signal circuit to sensor ground. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 16 .
Check circuits related to EGR valve for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 17 . If circuits are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .
Using scan tool, review CAPTURED INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check for excessive deposits on EGR valve pintle or seat. Check for poor connection at PCM or EGR valve harness connectors.

DTC P0404: EGR SYSTEM PERFORMANCE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

This test checks for malfunction in the circuitry and hardware of the linear EGR valve. The ability of the PCM to control the EGR valve is checked with this test. When PCM commands the EGR valve to desired position and changes that position less than a calibrated amount, this test then checks the EGR pintle position error (difference between desired and actual pintle position). If pintle position error is too great, this DTC will set.

Conditions for setting DTC

Ignition voltage 12 volts or less.
EGR pintle position error is greater than 75 counts.
Ignition voltage greater than 12 volts.
EGR pintle position error is greater than 25 counts.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, check EGR pintle position. If scan tool displays 0.18-2.06 volts, go to next step. If scan tool does not display 0.18-2.06 volts, go to step 8 .
Using scan tool, select OUTPUT TESTS for EGR. Command EGR to zero percent. Check EGR pintle position display. If scan tool displays one volt or less, go to next step. If scan tool does not display one volt or less, go to step 20 .
Command EGR to 50 percent. Check EGR pintle position display. If scan tool displays 2-3 volts, go to next step. If scan tool does not display 2-3 volts, go to step 25 .
Command EGR to 100 percent. Check EGR pintle position display. If scan tool displays 4 volts, go to next step. If scan tool does not display 4 volts, go to step 22 .
Select FREEZE FRAME or FAILURE REC. Check EGR pintle position when DTC was set. If voltage reading is 0.18 volt or greater, go to next step. If voltage reading is not 0.18 volt or greater, go to step 21 .
If voltage reading is 5 volts or greater, go to step 24 . If voltage reading is not 5 volts or greater, go to step 21 .
If voltage reading is 0.18 volts or less, go to next step. If voltage reading is not 0.18 volts or less, go to step 16 .
Exit OUTPUT TESTS. Using scan tool, check EGR pintle position. Disconnect EGR valve harness connector. Jumper EGR harness connector terminals "C" and "D". If voltage reading is 0.18 volts or less, go to next step. If voltage reading is not 0.18 volts or less, go to step 15 .
Using DVOM, check voltage between ground and jumper wire. If voltage reading is less than 4.5 volts, go to next step. If voltage reading is not less than 4.5 volts, go to step 26 .
Remove jumper wire. Check voltage between ground and EGR harness connector terminal "D". If voltage reading less than 4.5 volts, go to next step. If voltage reading is not less than 4.5 volts, go to step 27 .
Using scan tool, store fluid life data. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector. Disconnect TP sensor harness connector. Check resistance between ground and EGR harness connector terminal "D". If resistance is greater than 10,000 ohms, go to next step. If resistance is not greater than 10,000 ohms, go to step 28 .
Check resistance between PCM harness connector terminal No. 62 and EGR valve harness connector terminal "D". If resistance is less than 5 ohms, go to next step. If measured resistance is not less than 5 ohms, go to step 29 .
Check terminal contact at PCM harness connector C1 terminal No. 62. Repair as necessary. If terminal contact is okay, go to step 35 .
Check terminal contact at EGR harness connector. Repair as necessary. If terminal contact is okay, go to step 34 .
Exit OUTPUT TESTS. Using scan tool, check EGR pintle position. Disconnect EGR harness connector. If voltage reading is less than 2.06 volts, go to next step. If voltage reading is not less than 2.06 volts, go to step 30 .
Disconnect TP sensor and ECT sensor harness connectors. Using DVOM, check voltage between ground and EGR harness connector terminal "B". If voltage reading is 0.1 volt or less, go to next step. If voltage reading is not 0.1 volt or less, go to step 31 .
Check voltage between ground and EGR harness connector terminal "D". If voltage reading is 5.5 volts or less, go to next step. If voltage reading is not 5.5 volts or less, go to step 32 .
Store fluid life data. Turn ignition off. Wait 30 seconds, then disconnect PCM harness connector C1. Check resistance between PCM harness connector terminal No. 7 and EGR harness connector terminal "B". If resistance is less than 5 ohms, go to step 15 . If resistance is not less than 5 ohms, go to step 33 .
Check for poor terminal contact at EGR harness connector and PCM harness connector C1. Check for high resistance in EGR pintle position ground, and sticky EGR valve. Check for intermittent short to ground in EGR position feedback circuit, 5-volt reference circuit and EGR pintle position ground circuit. Repair as necessary. If circuits are okay, fault is not present.
Check terminal contact at PCM and EGR harness connectors. Check for sticky EGR valve or debris in EGR system, causing EGR valve to stick. Repair as necessary. If repairs were not required, fault is not present.
Check for terminal contact at PCM and EGR harness connectors. Check for high resistance in EGR position feedback circuit 5-volt reference circuit. Check for a sticky EGR valve. Repair as necessary. If repairs were not required, fault is not present.
Check for intermittent opens or shorts to ground in 5-volt reference circuit and EGR position feedback circuit. Repair as necessary. If repairs were not required, fault is not present.
Check for intermittent open in EGR pintle position ground circuit. Check for intermittent short to voltage in EGR position feedback circuit, EGR pintle position ground circuit or the 5-volt reference circuit. The reference circuit short may be located on any of the PCM 5-volt reference circuit (i.e. TP sensor 5-volt reference). Repair as necessary. If repairs were not required, fault is not present.
Check for intermittent open or short in the ignition feed circuit and EGR valve control circuit. Check for a sticky EGR valve. Repair as necessary. If repairs were not required, fault is not present.
Repair open in EGR position feedback circuit.
Repair short to ground in EGR position feedback circuit.
Repair short to ground in 5-volt reference circuit. Short may be located on any of the PCM 5-volt reference circuits (i.e. TP sensor 5-volt reference).
Repair open in 5-volt reference circuit.
Repair short to voltage in EGR position feedback circuit.
Repair short to voltage in EGR pintle position ground circuit.
Repair short to voltage in 5-volt reference circuit.
Repair open in EGR pintle position ground circuit.
Replace EGR valve.
Replace PCM. Program replacement PCM using required equipment.

DTC P0404: EGR VALVE OPEN PINTLE POSITION (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EGR is used to lower Oxides of Nitrogen (NOx) emission levels. VCM controls EGR pintle position using inputs from TP and MAP sensors. Scan tool can be used to monitor desired EGR position.

VCM supplies 5-volt reference and ground signal to EGR valve. Feedback signal is the actual position of the EGR pintle. Actual EGR position should always be close to commanded desired EGR position.

Conditions for setting DTC

No ECT, EVAP, IAC, IAT, MAP or TP sensor DTCs set.
DTC P0300, P1336 or P1404 not set.
Ignition voltage greater than 11.7 volts.
EGR commanded on (desired EGR position greater than zero percent).
Actual EGR position differs from desired EGR position by greater than 9 percent for 18 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command EGR valve to 20, 50, 70, 100 percent. If actual EGR position follow the desired/commanded EGR position, go to step 5 . If actual EGR position does not follow the desired/commanded EGR position, go to next step.
Turn ignition off. Disconnect EGR harness connector. Turn ignition on, engine off. Using test light connected to battery voltage, probe EGR valve sensor ground circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 7 .
Connect test light to ground. Using test light, probe EGR feed control circuit at EGR harness connector. Using scan tool, command EGR valve to 20, 50, 70, 100 percent. If test light glows brighter, flash or maintain a steady dim glow as EGR is commanded, go to step 6 . If test light does not glow or flash, go to step 10 .
DTC is intermittent. Check for additional DTCs set. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition on. Connect test light between battery voltage and EGR valve ground circuit. If test light illuminates, go to step 9 . If test light does not illuminate, go to step 8 .
Check for open or poor connection in EGR valve feed control circuit. Repair as necessary. After repairs, go to step 22 . If circuit or connection is okay, go to step 20 .
Check for open or poor connection in EGR valve feed control circuit. Repair as necessary. After repairs, go to step 22 . If circuit or connection is okay, go to step 20 .
Connect test light between ground and EGR pintle position signal circuit. If test light illuminates, go to step 11 . If test light does not illuminate, go to step 12 .
Using test light connected to ground, probe EGR valve feed control circuit without commanding EGR valve with scan tool. If test light illuminates, go to step 13 . If test light does not illuminate, go to step 14 .
Check signal circuit for short to voltage. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 20 .
Using DVOM, check voltage in 5-volt reference circuit. If voltage reading is about 5 volts, go to step 15 . If voltage reading is not about 5 volts, go to step 16 .
Check EGR valve feed control circuit for short to voltage. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 20 .
Connect test light between battery voltage and EGR valve feed control circuit. If test light illuminates, go to step 17 . If test light does not illuminate, go to step 18 .
Check EGR sensor ground circuit for poor connection at EGR valve. Repair as necessary. After repairs, go to step 22 . If connection is okay, go to step 19 .
Check 5-volt reference circuit for short to voltage. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 20 .
Check EGR valve feed control circuit for short to ground. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 20 .
Check EGR valve feed control circuit for open or poor connection at EGR valve harness connector. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 20 .
Replace EGR valve. After replacing EGR valve, go to step 22 .
Check VCM harness connector for poor connection. Repair as necessary. After repairs, go to step 22 . If connection is okay, go to next step.
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no additional DTCs are set, system is okay.

DTC P0404: EGR VALVE OPEN PINTLE POSITION (4.3L "L", "M", "S" & "T" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EGR is used to lower oxides of nitrogen (NOx) emission levels. VCM controls EGR pintle position using inputs from TP and MAP sensors. Scan tool can be used to monitor desired EGR position.

VCM supplies 5-volt reference and ground signal to EGR valve. Feedback signal is the actual position of the EGR pintle. Actual EGR position should always be close to commanded desired EGR position.

Conditions for setting DTC

No ECT, EVAP, IAC, IAT, MAP or TP sensor DTCs set.
DTC P0300, P1336 or P1404 not set.
Ignition voltage greater than 11.7 volts.
EGR commanded on (desired EGR position greater than zero percent).
Actual EGR position differs from desired EGR position by greater than 9 percent for 18 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command EGR valve to 20, 50, 70, 100 percent. If actual EGR position follow the desired/commanded EGR position, go to step 5 . If actual EGR position does not follow the desired/commanded EGR position, go to next step.
Turn ignition off. Disconnect EGR harness connector. Turn ignition on, engine off. Using a test light connected to battery voltage, probe EGR valve sensor ground circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 7 .
Connect test light to ground. Probe EGR feed control circuit at EGR harness connector. Using scan tool, command EGR valve to 20, 50, 70, 100 percent. If test light glows brighter, flash or maintain a steady dim glow as EGR is commanded, go to step 6 . If test light does not glow as EGR is commanded, go to step 10 .
DTC is intermittent. Check for additional DTCs set. If DTCs are set, diagnose affected DTCs. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition on. Connect test light between battery voltage and EGR valve ground circuit. If test light illuminates, go to step 9 . If test light does not illuminate, go to step 8 .
Check for open or poor connection in EGR valve feed control circuit. Repair as necessary. After repairs, go to step 22 . If circuit or connection is okay, go to step 20 .
Check for open or poor connection in EGR valve feed control circuit. Repair as necessary. After repairs, go to step 22 . If circuit or connection is okay, go to step 20 .
Connect test light between ground and EGR pintle position signal circuit. If test light illuminates, go to step 11 . If test light does not illuminate, go to step 12 .
Using test light connected to ground, probe EGR valve feed control circuit without commanding EGR valve with scan tool. If test light illuminates, go to step 13 . If test light does not illuminate, go to step 14 .
Check signal circuit for short to voltage. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 20 .
Using DVOM, check voltage in 5-volt reference circuit. If voltage reading is about 5 volts, go to step 15 . If voltage reading is not about 5 volts, go to step 16 .
Check EGR valve feed control circuit for short to voltage. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 20 .
Connect test light between battery voltage and EGR valve feed control circuit. If test light illuminates, go to step 17 . If test light does not illuminate, go to step 18 .
Check EGR sensor ground circuit for poor connection at EGR valve. Repair as necessary. After repairs, go to step 22 . If connection is okay, go to step 19 .
Check 5-volt reference circuit for short to voltage. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 20 .
Check EGR valve feed control circuit for short to ground. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 20 .
Check EGR valve feed control circuit for open or poor connection at EGR valve harness connector. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 20 .
Replace EGR valve. After replacing EGR valve, go to step 22 .
Check VCM harness connector for poor connection. Repair as necessary. After repairs, go to step 22 . If connection is okay, go to next step.
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no additional DTCs are set, system is okay.

DTC P0404: EGR VALVE OPEN PINTLE POSITION (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EGR is used to lower Oxides of Nitrogen (NOx) emission levels. PCM controls EGR pintle position using inputs from TP and MAP sensors. Scan tool can be used to monitor desired EGR position.

PCM supplies 5-volt reference and ground signal to EGR valve. Feedback signal is the actual position of the EGR pintle. Actual EGR position should always be close to commanded desired EGR position.

DTC will set when the difference between the commanded EGR position and actual EGR position is greater than 10 percent for greater than predetermined value.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command EGR valve to 50 percent. If engine runs rough or stall, go to next step. If engine does not run rough or stall, go to step 6 .
Operate engine at idle. Command EGR valve to 50 percent. Monitor actual EGR position on scan tool. If actual EGR position is 48-52 percent, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If actual EGR position is not 48-52 percent, go to next step.
Turn ignition off. Disconnect PCM harness connector C2. Disconnect EGR harness connector. Using DVOM, check resistance of EGR valve control circuit. If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 14 .
Check resistance of EGR valve ground circuit. If resistance is 0-2 ohms, go to step 16 . If resistance is not 0-2 ohms, go to step 15 .
Turn ignition off. Disconnect EGR valve harness connector. Turn ignition on. Connect a test light between ground and EGR control circuit. Using scan tool, command EGR valve to 100 percent. If test light illuminates, go to next step. If test light does not illuminate, go to step 8 .
Connect test light between battery voltage and EGR ground circuit. If test light illuminates, go to step 16 . If test light does not illuminate, go to step 11 .
Turn ignition off. Disconnect PCM harness connector C2. Disconnect EGR harness connector. Using DVOM, check continuity of EGR valve control circuit. If continuity exists, go to next step. If continuity does not exist, go to step 12 .
Check continuity between ground and EGR valve control circuit. If continuity exists, go to step 12 . If continuity does not exist, go to next step.
Check continuity from EGR control circuit to all other circuits in the PCM harness connector. If continuity exists, go to step 12 . If continuity does not exist, go to step 18 .
Turn ignition off. Disconnect PCM harness connector C2. Disconnect EGR harness connector. Using DVOM, check continuity of EGR valve ground circuit. If continuity exists, go to step 18 . If continuity does not exist, go to step 13 .
Repair open or short to ground in EGR valve control circuit. After repairs, go to step 20 .
Repair open in EGR valve ground circuit. After repairs, go to step 20 .
Repair high resistance in EGR valve control circuit. After repairs, go to step 20 .
Repair high resistance in EGR valve ground circuit. After repairs, go to step 20 .
Check for poor connections at EGR valve harness connector. Repair as necessary. After repairs, go to step 20 . If connections are okay, go to next step.
Replace EGR valve. After replacing EGR valve, go to step 20 .
Check for poor connection at PCM connector. Repair as necessary. After repairs, go to step 20 . If connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no additional DTCs are set, system is okay.

DTC P0404: EGR SYSTEM PERFORMANCE (5.7L "F" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

The PCM's ability to control the EGR is checked in this test. PCM calculates an error based on the difference between actual EGR position and desired EGR position. PCM sets this DTC if error is too great.

Conditions required to set DTC are

Ignition voltage is greater than 11.7 volts.
Desired EGR position is greater than zero percent.
Difference between desired EGR position and actual EGR position is greater than 20 percent.
Failure counter is greater than predetermined value.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, command EGR valve to 50 percent. If engine runs rough or stalls, go to next step. If engine does not run rough or stall, go to step 4 .
Using scan tool, command EGR valve to 50 percent. Check if actual EGR position is within specified range. If EGR position is 48-52 percent, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If actual EGR position is not within 48-52 percent, go to step 11 .
Turn ignition off. Disconnect EGR valve harness connector. Start and operate engine at idle. Using scan tool, command EGR to 100 percent. Using a test light connected to ground, probe EGR control circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 6 .
Using a test light connected to battery voltage, probe EGR valve ground circuit. If test light illuminates, go to step 8 . If test light does not illuminate, go to step 7 .
Check for open or short to ground in EGR control circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 10 .
Check for open in EGR ground. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 10 .
Check terminal contact at EGR valve harness connector. Repair as necessary. After repairs, go to step 12 . If contacts are okay, go to next step.
Replace EGR valve. After replacing EGR valve, go to step 12 .
Check for poor connection or proper terminal contact at PCM. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0405: EGR FEEDBACK VOLTAGE OUT OF RANGE-OPEN/SHORTED (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM directly controls the ground for the linear EGR valve when certain conditions have been met. PCM contains a diode feedback circuit which dissipates energy when the valve is cycled off. When PCM grounds the valve, a diagnostic feedback signal can determine is valve had actually moved. This DTC has been defined to monitor the feedback signal. This diagnostic will determine if the position feedback signal properly falls within the correct range under different valve operating conditions.

If this DTC is present, EGR will be disabled for the entire ignition cycle. The malfunction history record will aid in diagnosis. The EGR valve may operate at any engine coolant temperature regardless of loop mode.

Note. If DTC P1635 is present, diagnose DTC P1635 first.

Install scan tool. Turn ignition on. Using scan tool, monitor EGR pintle voltage. If voltage reading is less than 0.2 volt, problem is intermittent, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If voltage reading is greater than 0.2 volt, go to next step.
Turn ignition off. Disconnect EGR valve harness connector. Using a jumper wire, jumper EGR harness connector terminals "C" and "D". Turn ignition on, engine off. If EGR pintle voltage is now greater than 4 volts, check terminal tightness to EGR. Repair as necessary. If terminal is okay, replace EGR valve. If EGR pintle voltage is not greater than 4 volts, go to next step.
Check voltage between EGR harness connector terminal "D" and ground. If voltage reading is not 4-6 volts, go to next step. If voltage reading is 4-6 volts, check for open or short to ground in EGR harness connector terminal "C". If circuit is okay, check for terminal tightness or faulty PCM.
Check for open between EGR valve harness connector terminal "D" and underhood fuse block. Repair as necessary. If circuit is okay, check for proper terminal connections at PCM. Repair as necessary. If terminals are okay, replace PCM.

When attempting to diagnose an intermittent problem, use scan tool to review malfunction history information. This data can be used to duplicate a problem.

Check for faulty terminal connections. A short to ground in the 5-volt reference circuit will set both DTC P0405 and P1635. If both DTCs are present, diagnose DTC P1635 first. An open in the 5-volt reference circuit will only set DTC P0405. An open in the PCM diode feedback circuit will result in unstable valve operation resulting in engine surge.

DTC P0405: EGR VALVE SENSOR SIGNAL CIRCUIT-LOW VOLTAGE (2.4L "N" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions for setting DTC

DTCs P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300-P0304, P0335, P0502, P0506, P0507 and P1441 not set.
Ignition voltage greater than 11.7 volts.
EGR commanded ON (desired EGR position greater than zero percent).
Actual EGR position differs from desired EGR position by greater than 9 percent for 11 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command EGR valve to 25, 50, 75, 100 percent. If actual EGR position follow the desired EGR position, go to step 15 . If actual EGR position does not follow the desired EGR position, go to next step.
Disconnect EGR harness connector. Using DVOM connected to ground, probe EGR valve harness connector 5-volt reference circuit. If DVOM reads about 5 volts, go to next step. If DVOM does not read about 5 volts, go to step 5 .
Using a jumper wire, jumper EGR 5-volt reference circuit to signal circuit. If actual EGR position display is 100 percent, go to step 6 . If display is not 100 percent, go to step 7 .
Using a test light connected to battery voltage, probe test light to EGR 5-volt reference circuit. If test light illuminates, go to step 8 . If test light does not illuminate, go to step 9 .
Check 5-volt reference and signal circuits for poor connection or proper terminal tension. Repair as necessary. After repairs, go to step 15 . If circuits are okay, go to step 10 .
Using test light connected to battery voltage, probe EGR signal circuit. If test light illuminates, go to step 11 . If test light does not illuminate, go to step 12 .
Check for short to ground in EGR 5-volt reference circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to step 13 .
Check for open in EGR 5-volt reference circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to step 14 .
Replace EGR valve. After replacing EGR valve, go to step 15 .
Check for short to ground in EGR signal circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to step 13 .
Check for open in EGR signal circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 15 .
Check affected circuit for poor connection or proper terminal tension at PCM. Repair as necessary. After repairs, go to next step. If circuit is okay, go to step 13 .
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0405: EGR SENSOR CIRCUIT-LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions for setting DTC

No ECT, HO2S, IAT, MAF or TP sensor DTCs set.
Engine run time met. Time ranges from 45 seconds to 8.5 minutes depending upon ECT at start-up.
TP angle greater than 2 percent.
System voltage greater than 10 volts.
EGR feedback is less than 0.14 volt at anytime.
Conditions present for longer than 20 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, select EGR OUTPUT CONTROL function. Increment EGR valve through all positions while comparing desired to actual EGR position. If desired and actual EGR position remains close to each other at all commanded positions, go to next step. If desired and actual EGR position is not within range, go to step 4 .
Using scan tool, review FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions and monitor SPECIFIC DTC info. If scan tool indicates that this DTC failed this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect EGR valve harness connector. Check voltage between EGR pintle position sensor ground circuit and 5-volt reference circuit at EGR harness connector. If voltage reads 5 volts, go to next step. If voltage does not read 5 volts, go to step 9 .
Using test light connected to battery voltage, probe EGR pintle position signal circuit at EGR harness connector. If test light illuminates, go to step 8 . If test light does not illuminate, go to next step.
Using a fused jumper wire, jumper EGR 5-volt reference circuit and EGR pintle position signal circuit at EGR harness connector. Using scan tool, observe actual EGR position. If actual EGR position is 100 percent, go to step 13 . If actual EGR position is not 100 percent, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check for open in EGR pintle position signal circuit. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 17 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR pintle position signal circuit. If test light illuminates, go to step 12 . If test light does not illuminate, go to step 15 .
Using test light connected to battery voltage, probe EGR 5-volt reference circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Turn ignition off. Disconnect PCM harness connector. Using test light connected to battery voltage, probe EGR 5-volt reference circuit. If test light illuminates, go to step 16 . If test light does not illuminate, go to step 18 .
Check for open in 5-volt reference circuit between EGR and PCM. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to step 17 .
Locate and repair short to ground in EGR valve pintle position circuit. After repairs, go to step 19 .
Check for poor terminal connections at EGR valve. Check for short in EGR pintle position signal circuit to control circuit. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to next step.
Replace EGR valve. After replacing EGR valve, go to step 19 .
Check for short in EGR pintle position signal circuit to sensor ground. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 18 .
Locate and repair short to ground in 5-volt reference circuit. After repairs, go to step 19 .
Check circuits related to EGR valve for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, system is okay. If scan tool does not indicate that this test ran and passed, repeat step 2 .

Check for excessive deposits on EGR valve pintle or seat. Check for poor connection at PCM or EGR valve harness connectors.

DTC P0405: EGR SENSOR CIRCUIT-VOLTAGE OUT OF RANGE (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM monitors EGR valve pintle position input to ensure that valve responds properly to commands from PCM and to detect a fault if pintle position sensor circuit is open or shorted. If PCM detects an excessively low EGR feedback signal voltage, DTC will set.

DTC will also set when EGR feedback is less than 0.14 volt at any time and condition is present for greater than 20 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, select EGR OUTPUT CONTROL function. Increment EGR valve through all positions (0-100 percent) while comparing desired to actual EGR position value. If desired and actual EGR position remains close to each other at all commanded positions, go to next step. If desired and actual EGR position is not within range, go to step 4 .
Using scan tool, review FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions and monitor SPECIFIC DTC info. If scan tool indicates that this DTC failed this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect EGR valve harness connector. Check voltage between EGR pintle position sensor ground circuit and 5-volt reference circuit at EGR harness connector. If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 9 .
Using test light connected to battery voltage, probe EGR pintle position signal circuit at EGR harness connector. If test light illuminates, go to step 8 . If test light does not illuminate, go to next step.
Using a fused jumper wire, jumper EGR 5-volt reference circuit and EGR pintle position signal circuit at EGR harness connector. Using scan tool, observe actual EGR position. If actual EGR position is 100 percent, go to step 13 . If actual EGR position is not 100 percent, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check for open in EGR pintle position signal circuit. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 17 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR pintle position signal circuit. If test light illuminates, go to step 12 . If test light does not illuminate, go to step 15 .
Using a test light connected to battery voltage, probe EGR 5-volt reference circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR 5-volt reference circuit. If test light illuminates, go to step 16 . If test light does not illuminate, go to step 18 .
Check 5-volt reference circuit for open between EGR and PCM. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to step 17 .
Locate and repair short to ground in EGR valve pintle position circuit. After repairs, go to step 19 .
Check for poor terminal connections at EGR valve. Check for short in EGR pintle position signal circuit to control circuit. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to next step.
Replace EGR valve. After replacing EGR valve, go to step 19 .
Check for short in EGR pintle position signal circuit to sensor ground. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 18 .
Locate and repair short to ground in 5-volt reference circuit. After repairs, go to step 19 .
Check circuits related to EGR valve for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are set, go to applicable DTC test.

Check for excessive deposits on EGR valve pintle or seat. Check for poor connection at PCM or EGR valve harness connectors.

DTC P0405: EGR PINTLE POSITION SENSOR CIRCUIT-LOW VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions for setting DTC

No ECT, HO2S, IAT, MAF or TP sensor DTCs set.
Engine run time met. Time ranges from 45 seconds to 8.5 minutes depending upon ECT at start-up.
TP angle greater than 2 percent.
System voltage greater than 10 volts.
EGR feedback is less than 0.14 volt at anytime.
Conditions present for longer than 20 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, select EGR OUTPUT CONTROL function. Increment EGR valve through all positions while comparing desired to actual EGR position. If desired and actual EGR position remains close to each other at all commanded positions, go to next step. If desired and actual EGR position is not within range, go to step 4 .
Using scan tool, review FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions and monitor SPECIFIC DTC info. If scan tool indicates that this DTC failed this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect EGR valve harness connector. Check voltage between EGR pintle position sensor ground circuit and 5-volt reference circuit at EGR harness connector. If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 9 .
Using test light connected to battery voltage, probe EGR pintle position signal circuit at EGR harness connector. If test light illuminates, go to step 8 . If test light does not illuminate, go to next step.
Using a fused jumper wire, jumper EGR 5-volt reference circuit and EGR pintle position signal circuit at EGR harness connector. Using scan tool, observe actual EGR position. If actual EGR position is 100 percent, go to step 13 . If actual EGR position is not 100 percent, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check for open in EGR pintle position signal circuit. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 17 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR pintle position signal circuit. If test light illuminates, go to step 12 . If test light does not illuminate, go to step 15 .
Using a test light connected to battery voltage, probe EGR 5-volt reference circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR 5-volt reference circuit. If test light illuminates, go to step 16 . If test light does not illuminate, go to step 18 .
Check 5-volt reference circuit for open between EGR and PCM. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to step 17 .
Locate and repair short to ground in EGR valve pintle position circuit. After repairs, go to step 19 .
Check for poor terminal connections at EGR valve. Check for short in EGR pintle position signal circuit to control circuit. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to next step.
Replace EGR valve. After replacing EGR valve, go to step 19 .
Check for short in EGR pintle position signal circuit to sensor ground. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 18 .
Locate and repair short to ground in 5-volt reference circuit. After repairs, go to step 19 .
Check circuits related to EGR valve for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0405. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are set, go to applicable DTC test.

Check for excessive deposits on EGR valve pintle or seat. Check for poor connection at PCM or EGR valve harness connectors.

DTC P0405: EGR VALVE SENSOR CIRCUIT-VOLTAGE OUT OF RANGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

This test checks for a malfunction in circuitry and hardware of linear EGR valve. The pintle position sensor voltage is monitored for an out of range condition when EGR valve is closed.

Conditions of setting DTC

Ignition voltage is greater than 11 volts.
Closed EGR valve pintle position sensor voltage is 0.32 volt or less, or 3.69 volts or greater.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Check EGR PINTLE POS on scan tool. If scan tool reads 0.18-2.06 volts, go to next step. If scan tool does not read 0.18-2.06 volts, go to step 8 .
Select OUTPUT TESTS on scan tool. Command EGR to zero percent. Check EGR pintle position display. If scan tool reading is one volt or less, go to next step. If scan tool reading is not one volt or less, go to step 20 .
Command EGR to 50 percent. Check EGR pintle position display. If scan tool reading is 2-3 volts, go to next step. If scan tool reading is not 2-3 volts, go to step 25 .
Command EGR to 100 percent. Check EGR pintle position display. If scan tool reading is 4 volts or greater, go to next step. If scan tool reading is not 4 volts or greater, go to step 22 .
Using scan tool, select FREEZE FRAME or FAILURE REC. Check EGR pintle position when DTC was set. If scan tool reading is 0.18 volt or greater, go to next step. If scan tool reading is not 0.18 volt or greater, go to step 23 .
If scan tool reading is 5 volts or greater, go to step 24 . If scan tool reading is not 5 volts or greater, go to step 21 .
If scan tool reading is 0.18 volt or less, go to next step. If scan tool reading is not 0.18 volt or less, go to step 16 .
Exit OUTPUT TESTS. Using scan tool, check EGR pintle position. Disconnect EGR valve harness connector. Jumper EGR harness connector terminals "C" and "D". If scan tool reading is 0.18 volt or less, go to next step. If scan tool reading is not 0.18 volt or less, go to step 15 .
Using DVOM, check voltage between ground and jumper wire. If voltage reading is 4.5 volts or less, go to next step. If voltage reading is not 4.5 volts or less, go to step 26 .
Remove jumper wire. Check voltage between ground and EGR harness connector terminal "D". If voltage reading is less than 4.5 volts, go to next step. If voltage reading is not less than 4.5 volts, go to step 27 .
Using scan tool, store fluid life data. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector. Disconnect TP sensor harness connector. Check resistance between ground and EGR harness connector terminal "D". If resistance is greater than 10,000 ohms, go to next step. If resistance is not greater than 10,000 ohms, go to step 28 .
Check resistance between PCM harness connector terminal No. 62 and EGR harness connector terminal "D". If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, go to step 29 .
Check terminal contact at PCM harness connector C1 terminal No. 62. Repair as necessary. If terminal contact is okay, go to step 35 .
Check terminal contact at EGR harness connector. Repair as necessary. If terminal contact is okay, go to step 34 .
Exit OUTPUT TESTS. Using scan tool, check EGR pintle position. Disconnect EGR harness connector. If voltage reading is less than 2.06 volts, go to next step. If voltage reading is not less than 2.06 volts, go to step 30 .
Disconnect TP sensor and ECT sensor harness connectors. Using DVOM, check voltage between ground and EGR harness connector terminal "B". If voltage reading is 0.1 volt or less, go to next step. If voltage reading is not 0.1 volt or less, go to step 31 .
Check voltage between ground and EGR harness connector terminal "D". If voltage reading is 5.5 volts or less, go to next step. If voltage reading is not 5.5 volts or less, go to step 32 .
Store fluid life data. Turn ignition off. Wait 30 seconds, then disconnect PCM harness connector C1. Check resistance between PCM harness connector terminal No. 7 and EGR harness connector terminal "B". If resistance is less than 5 ohms, go to step 15 . If resistance is not less than 5 ohms, go to step 33 .
Check for poor terminal contact at EGR harness connector and PCM harness connector C1. Check for high resistance in EGR pintle position ground, and sticky EGR valve. Check for intermittent short to ground in EGR position feedback circuit, 5-volt reference circuit and EGR pintle position ground circuit. Repair as necessary. If circuits are okay, fault is not present.
Check terminal contact at PCM and EGR harness connectors. Check for sticky EGR valve or debris in EGR system, causing EGR valve to stick. Repair as necessary. If repairs were not required, fault is not present.
Check for terminal contact at PCM and EGR harness connectors. Check for high resistance in EGR position feedback circuit 5-volt reference circuit. Check for a sticky EGR valve. Repair as necessary. If repairs were not required, fault is not present.
Check for intermittent opens or shorts to ground in 5-volt reference circuit and EGR position feedback circuit. Repair as necessary. If repairs were not required, fault is not present.
Check for intermittent open in EGR pintle position ground circuit. Check for intermittent short to voltage in EGR position feedback circuit, EGR pintle position ground circuit or the 5-volt reference circuit. The reference circuit short may be located on any of the PCM 5-volt reference circuit (i.e. TP sensor 5-volt reference). Repair as necessary. If repairs were not required, fault is not present.
Check for intermittent open or short in the ignition feed circuit and EGR valve control circuit. Check for a sticky EGR valve. Repair as necessary. If repairs were not required, fault is not present.
Repair open in EGR position feedback circuit.
Repair short to ground in EGR position feedback circuit.
Repair short to ground in 5-volt reference circuit. Short may be located on any of the PCM 5-volt reference circuits (i.e. TP sensor 5-volt reference).
Repair open in 5-volt reference circuit.
Repair short to voltage in EGR position feedback circuit.
Repair short to voltage in EGR pintle position ground circuit.
Repair short to voltage in 5-volt reference circuit.
Repair open in EGR pintle position ground circuit.
Replace EGR valve.
Replace PCM. Program replacement PCM using required equipment.

DTC P0405: EGR PINTLE POSITION CIRCUIT-LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EGR is used to lower Oxides of Nitrogen (NOx) emission levels. VCM controls EGR pintle position using inputs from TP and MAP sensors. Scan tool can be used to monitor desired EGR position.

VCM supplies 5-volt reference and ground signal to EGR valve. Feedback signal is the actual position of the EGR pintle. Actual EGR position should always be close to commanded desired EGR position.

Conditions for setting DTC

DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0300, P0440, P0442, P0446, P0502, P0506, P0507, P1336, P1404 or P1441 not set.
Ignition voltage greater than 9 volts.
VCM sees less than 0.12 volt from EGR valve sensor.
Malfunction present for 10 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command EGR valve to 20, 50, 70, 100 percent. If actual EGR position follow the desired/commanded EGR position, go to step 5 . If actual EGR position does not follow the desired/commanded EGR position, go to next step.
Turn ignition off. Disconnect EGR valve harness connector. Turn ignition on, engine off. Using DVOM, check voltage between ground and EGR 5-volt reference circuit at EGR valve. If voltage reading is less than 5 volts, go to step 8 . If voltage reading is not less than 5 volts, go to next step.
Using jumper wire, jumper EGR valve 5-volt reference circuit to signal circuit. If actual EGR position displayed is 100 percent, go to step 6 . If actual EGR position displayed is not 100 percent, go to step 7 .
DTC is intermittent. Check if additional DTCs are set. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Check EGR valve 5-volt reference and signal circuits for poor connection or proper terminal connection. Repair as necessary. After repairs, go to step 15 . If circuits or connections are okay, go to step 10 .
Connect test light between battery voltage and EGR valve signal circuit. If test light illuminates, go to step 11 . If test light does not illuminate, go to step 12 .
Check for short to ground in EGR valve 5-volt reference circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
Check for open in EGR valve 5-volt reference circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to step 13 .
Replace EGR valve. After replacing EGR valve, go to step 15 .
Check for short to ground in EGR valve signal circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to step 13 .
Check for open in EGR valve signal circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
Check affected circuit for poor connection at VCM. Repair as necessary. After repairs, go to step 15 . If connection is okay, go to next step.
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Due to moisture associated with exhaust systems, the EGR valve may freeze and stick in colder weather conditions at times. Using scan tool, watch actual EGR and desired EGR positions on a cold engine to verify fault. Check freeze frame data to determine if DTC was set when vehicle was cold by viewing ECT.

DTC P0405: EGR PINTLE POSITION CIRCUIT-LOW VOLTAGE (4.3L "L", "M", "S" & "T" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EGR is used to lower Oxides of Nitrogen (NOx) emission levels. VCM controls EGR pintle position using inputs from TP and MAP sensors. Scan tool can be used to monitor desired EGR position.

VCM supplies 5-volt reference and ground signal to EGR valve. Feedback signal is the actual position of the EGR pintle. Actual EGR position should always be close to commanded desired EGR position.

Conditions for setting DTC

DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0300, P0440, P0442, P0446, P0502, P0506, P0507, P1336, P1404 or P1441 not set.
Ignition voltage greater than 9 volts.
VCM sees less than 0.12 volt from EGR valve sensor.
Malfunction present for 10 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command EGR valve to 20, 50, 70, 100 percent. If actual EGR position follow the desired/commanded EGR position, go to step 5 . If actual EGR position does not follow the desired/commanded EGR position, go to next step.
Turn ignition off. Disconnect EGR valve harness connector. Turn ignition on, engine off. Using DVOM, check voltage between ground and EGR 5-volt reference circuit at EGR valve. If voltage reading is less than 5 volts, go to step 8 . If voltage reading is not less than 5 volts, go to next step.
Using a jumper wire, jumper EGR valve 5-volt reference circuit to signal circuit. If actual EGR position displayed is 100 percent, go to step 6 . If actual EGR position displayed is not 100 percent, go to step 7 .
DTC is intermittent. Check if additional DTCs are set. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Check EGR valve 5-volt reference and signal circuits for poor connection or proper terminal connection. Repair as necessary. After repairs, go to step 15 . If circuits or connections are okay, go to step 10 .
Connect test light between battery voltage and EGR valve signal circuit. If test light illuminates, go to step 11 . If test light does not illuminate, go to step 12 .
Check for short to ground in EGR valve 5-volt reference circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
Check for open in EGR valve 5-volt reference circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to step 13 .
Replace EGR valve. After replacing EGR valve, go to step 15 .
Check for short to ground in EGR valve signal circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to step 13 .
Check for open in EGR valve signal circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
Check affected circuit for poor connection at VCM. Repair as necessary. After repairs, go to step 15 . If connection is okay, go to next step.
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0405: EGR PINTLE POSITION CIRCUIT-LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EGR system is used in order to lower NOx emission levels, by feeding small amounts of exhaust gas back into the combustion chamber. High combustion temperatures cause NOx and combustion temperatures are reduced when air/fuel mixture is diluted with exhaust gasses.

PCM controls the EGR pintle position using inputs from TP sensor, MAP sensor and ECT sensor. PCM commands the EGR valve in order to supply correct amount of exhaust gas recirculation for the current engine operating conditions. Actual EGR position should always be near the commanded or desired EGR position.

DTC will set when EGR feedback signal voltage is less than 0.14 volts for 0.1 second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, monitor FAILED THIS IGNITION under DTC INFORMATION option. If scan tool indicates that DTC P1635 failed this ignition cycle, diagnose DTC P1635 first. If scan tool does not indicates that DTC P1635 failed this ignition cycle, go to next step.
Using scan tool, select ENGINE 1 DATA LIST and monitor EGR pintle position value. If EGR pintle position value is less than 0.14 volt, go to step 5 . If EGR pintle position value is not less than 0.14 volt, go to next step.
Turn ignition on, engine off. Using scan tool review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start engine. Operate vehicle within conditions required to set this DTC and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC option, then SPECIFIC DTC option. Enter this DTC. If scan tool indicates that this DTC failed in this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect EGR valve harness connector. Jumper EGR 5-volt reference circuit and EGR pintle circuit at EGR valve harness connector. Observe EGR pintle position voltage display on scan tool. If EGR pintle voltage is about 5 volts, go to step 11 . If EGR pintle voltage is not about 5 volts, go to next step.
Connect a test light between battery voltage and EGR pintle position signal circuit at EGR harness connector. Observe EGR pintle position voltage display on scan tool. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 8 .
Turn ignition off. Disconnect PCM harness connector. Check 5-volt reference circuit for an open, short to ground or short to voltage. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor connection at PCM connector. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 13 .
Turn ignition off. Disconnect PCM harness connector. Check EGR pintle position signal circuit for open, short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Check EGR pintle position signal circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 13 .
Check connections at EGR valve. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to next step.
Replace EGR valve. After replacing EGR valve, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0405: EGR PINTLE POSITION CIRCUIT-LOW VOLTAGE (5.7L "F" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions for setting this DTC are

Ignition voltage greater than 11.7 volts.
EGR feedback signal voltage less than 0.14 volt.
Conditions present for 10 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, monitor FAILED THIS IGNITION under DTC INFORMATION option. If scan tool indicates that DTC P1635 failed this ignition cycle, diagnose DTC P1635 first. If scan tool does not indicates that DTC P1635 failed this ignition cycle, go to next step.
Select ENGINE 1 DATA LIST on scan tool and monitor EGR pintle position value. If EGR pintle position value is less than 0.14 volt, go to step 5 . If EGR pintle position value is not less than 0.14 volt, go to next step.
Turn ignition on, engine off. Using scan tool review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start engine. Operate vehicle within conditions required to set this DTC and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC option, then SPECIFIC DTC option. Enter DTC P0405. If scan tool indicates that this DTC failed in this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect EGR valve harness connector. Jumper EGR 5-volt reference circuit and EGR pintle circuit at EGR valve harness connector. Observe EGR pintle position voltage display on scan tool. If EGR pintle voltage is about 5 volts, go to step 11 . If EGR pintle voltage is not about 5 volts, go to next step.
Connect a test light between battery voltage and EGR pintle position signal circuit at EGR harness connector. Observe EGR pintle position voltage display on scan tool. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 8 .
Turn ignition off. Disconnect PCM harness connector. Check 5-volt reference circuit for an open, short to ground or short to voltage. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor connection at PCM connector. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 13 .
Turn ignition off. Disconnect PCM harness connector. Check EGR pintle position signal circuit for open, short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Check EGR pintle position signal circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 13 .
Check connections at EGR valve. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to next step.
Replace EGR valve. After replacing EGR valve, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0410. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0410: AIR SYSTEM (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

During air pump operation, PCM monitors oxygen sensor output. The additional air pumped into the exhaust manifold causes oxygen sensor to indicate a lean condition in a properly operating system. If oxygen sensor does not indicate a lean condition for a fixed amount of time, DTC P0410 will set.

Note. If DTCs P1670 or P1671 are also set, diagnose these DTCs first.

Turn ignition on, with engine off. Using scan tool, perform AIR PUMP SPECIAL TEST. If test passes, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If test does not pass, go to next step.
If air pump turned on during test, go to next step. If air pump did not turn on during test, check AIR PUMP fuse (30-amp) located in underhood junction block. If fuse is okay, go to step 4 . If fuse is open, check air pump battery feed circuit for short to ground. Repair as necessary and replace fuse.
Check vacuum lines, air hose, in-line check valve and air pipe for leaks or restrictions. Repair as necessary. If no problems are found, go to step 5 .
Check for an open in air pump battery feed or ground circuits. Repair as necessary. If circuits are okay, replace air pump.
Disconnect vacuum line to combination valve. Using a hand held vacuum pump, apply 15 in. Hg vacuum to combination valve. If vacuum holds, go to next step. If vacuum does not hold, replace combination valve.
Disconnect air hose at combination valve. Turn ignition on, with engine off. Using scan tool, command air pump on. If air is felt at hose, replace air pump solenoid. If no air is felt at hose, replace air pump.

Use scan tool to perform AIR PUMP SPECIAL TEST to verify if a problem exists. This test will turn on air pump for 30 seconds and forces DTC P0410 diagnostic test to run.

DTC P0410: AIR SYSTEM (3.1L "N" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

An AIR pump is used on this vehicle to lower tail pipe emissions on start-up. The PCM grounds the AIR pump relay control circuit, which energizes the AIR pump. The PCM also grounds the AIR solenoid valve control circuit, which energizes the AIR solenoid valve. The PCM enables both circuits simultaneously when AIR system operation is desired. When the AIR system is active, the AIR pump forces fresh air into the exhaust stream in order to accelerate catalyst operation. The AIR solenoid valve replaces the conventional check valve. When the AIR system is inactive the AIR solenoid valve prevents air flow in either direction. DTC P0412 applies to the AIR solenoid control circuit. DTC P0418 applies to the AIR pump relay control circuit. DTC P0410 sets if an air flow problem is detected.

The PCM will run up to 3 diagnostic tests using the HO2S1 voltage to diagnose the AIR system. The first test is a passive test, it has 2 parts. The 2 parts are named AIR Passive Test 1, and AIR Passive Test 2 on the scan tool. The second test is an active test, it has 1 part. This test is named AIR Active Test on the scan tool. Tests consist of

AIR Passive Test I AIR Passive Test 1 is performed during regular AIR pump operation. The AIR Passive Test 1 consists of the following: When the AIR system is enabled, the PCM monitors the HO2S1 voltage for a specific amount of time calculated by the coolant temperature at start-up. The HO2S1 is monitored for 10 seconds if the coolant temperature is more than 194°F (90°C), or 70 seconds if the coolant temperature is less than 194°F (90°C). If the HO2S1 voltage goes below a calibrated threshold, the PCM interprets this as an indication the AIR system is operational and it is considered a test passed. If the HO2S1 voltage does NOT go below a calibrated threshold, the PCM cannot determine if the AIR system is operational and will proceed with the AIR Passive Test 2. When AIR Passive Test 1 completes, the PCM then runs the AIR Passive Test 2.
AIR Passive Test 2 AIR Passive Test 2 is performed during regular AIR pump operation. The AIR Passive Test 2 consists of the following: When the AIR system is disabled, the PCM monitors the HO2S1 voltage. The HO2S1 voltage should increase above a threshold and switch normally. When the AIR Passive Test 2 is complete and both AIR Passive tests indicate a pass, no further action is taken. If either one of the above tests have failed or is inconclusive, the diagnostic will proceed to the AIR Active Test.
AIR Active Test The AIR Active Test has the PCM turn on the AIR pump specifically for diagnostic purposes. The AIR Active Test consists of the following: During this test the PCM turns the AIR system on during closed loop operation. When the AIR system is activated, the PCM monitors the HO2S voltage. If the AIR system is operating properly, the HO2S1 voltage should go below a predetermined threshold. The PCM will repeat this test up to 6 consecutive times with a short delay between each command. If PCM determines that the HO2S1 voltage did not respond as expected during the tests, DTC P0410 will set.

Conditions For Running DTC

DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0172, P0300, P0412, P0418, P0442, P0443, P1441 and HO2S DTCs not set.
The engine operates for greater than 2 seconds.

AIR Passive Test 1 and AIR Passive Test 2

Engine Speed is greater than 600 RPM.
Engine load is less than 80 percent.
Engine air flow is less than 35 g/s.
Ignition voltage is greater than 11.0 volts.
Air fuel ratio is greater than 11.5:1.
ECT is 40-239°F (4-115°C).
IAT is 40-158°F (4-70°C).
Power Enrichment, Deceleration Fuel Cut Off, or Catalyst Over Temperature not active.
The AIR system is enabled for up to 70 seconds or until system goes into closed loop (on a hot start the AIR system operation will be delayed for 60 seconds after start-up).

Condition For Not Passing AIR Passive Test 1

The HO2S1 voltage goes more than 600 mV for a calibrated amount of time during AIR pump operation.

Condition For Not Passing AIR Passive Test 2

The HO2S1 voltage does NOT go more than 600 mV after the AIR pump is turned OFF.

AIR Active Test

The AIR Passive Test not passed.
The engine must operate in fuel trim cell 0 (Idle, Purge ON) for up to 130 seconds.
EVAP Purge Active in Cell 0 (Idle, Purge ON).
Maximum air flow is 35 g/s.
ECT is greater than 167°F (75°C).
Ignition voltage is greater than 11.0 volts.
Engine load is less than 42 percent.
Fuel system operating in Closed Loop.

Condition For Not Passing AIR Active Test

The HO2S1 voltage is more than 225 mV for 1.5 seconds during 2.5 seconds of AIR pump operation.

Condition For Setting DTC

If the HO2S1 voltage does not behave as expected, a fail is reported.

Action Taken When DTC Sets

PCM will illuminate the Malfunction Indicator Light (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

Conditions For Clearing MIL/DTC

PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has run and passed.
The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using a scan tool.

Test Description

The numbers below refer to the step numbers on the diagnostic procedures.

2 DTC P0412 AIR Solenoid Valve Control Circuit and P0418 AIR Pump Relay Control Circuit should be diagnosed first if either are set.
3 Begins testing for a short to ground in the AIR pump feed circuit.
4 Listen for a running motor. Command both the ON and OFF states. Repeat the commands as necessary.
5 Begins testing for a short to voltage in the pump feed circuit.
6 Tests for voltage at the AIR pump relay switch feed circuit.
7 Bypasses the relay.
8 Tests for voltage on the AIR pump feed circuit.
9 Tests for an open on the pump ground circuit.
28 The AIR Pump is not designed to run continuously. If the pump needs to be replaced, check for conditions that may cause continuous pump operation.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Are DTCs P0412 or P0418 set? If yes, diagnose affected DTC(s). If no, go to next step.
Is the AIR pump relay switch feed fuse okay? If yes, go to next step. If no, go to step 13 .
With a scan tool, command the AIR pump ON and OFF. Does the AIR pump turn ON and OFF with each command? If yes, go to step 10 . If no, go to next step.
Does the AIR pump run continuously? If yes, go to step 16 . If no, go to next step.
Disconnect the AIR pump relay. Probe the relay switch feed circuit using a Test Light (J 34142-B). Does the test light illuminate? If yes, go to next step. If no, go to step 17 .
With a fused jumper wire, jumper the relay switch feed circuit to the AIR pump feed circuit. Does the AIR pump operate? If yes, go to step 25 . If no, go to next step.
Leave the fused jumper in place. Disconnect the AIR pump. Probe the feed circuit of the pump with a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 18 .
Connect test light between the feed circuit of the pump and ground circuit of the pump. Does the test light illuminate? If yes, go to step 27 . If no, go to step 19 .
Disconnect the AIR hose/pipe from the AIR Pump. With scan tool, command the AIR pump ON. Is air flow present at the AIR pump outlet? If yes, go to next step. If no, go to step 28 .
Reconnect the AIR hose/pipe to the AIR pump. Disconnect the AIR hose/pipe from the AIR combination valve. With scan tool, command the AIR pump ON. Is air flow present at the AIR hose/pipe outlet? If yes, go to next step. If no, go to step 22 .
Start engine. Visually inspect for engine vacuum at the AIR combination valve. If vacuum is not present, inspect for a damaged, pinched or disconnected vacuum line, a blocked/restricted vacuum port or a faulty vacuum control solenoid valve. Inspect for a damaged, pinched or disconnected vacuum line between the vacuum control solenoid and actuator diaphragm. Was a problem found? If yes, go to step 23 . If no, go to step 26 .
Disconnect AIR pump relay. Test feed circuit of the relay switch for a short to ground. Was a problem found? If yes, go to step 20 . If no, go to next step.
Disconnect AIR pump. Test the feed circuit of the pump for a short to ground. Was a problem found? If yes, go to step 21 . If no, go to next step.
Reconnect relay. Reconnect AIR pump. Install a new fuse. With scan tool, command the AIR pump ON. Does the fuse open? If yes, go to step 28 . If no, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect AIR pump relay. Is pump still running? If yes, go to step 24 . If no, go to step 25 .
Repair open relay switch feed circuit. After repairs, go to step 29 .
Test for an open in the AIR pump feed circuit. Repair circuit as necessary. Did you find and correct the condition? If yes, go to step 29 . If no, go to step 25 .
Repair open/high resistance in the AIR pump ground circuit. After repairs, go to step 29 .
Repair short to ground in the relay switch feed circuit. After repairs, go to 29 .
Repair short to ground in the AIR pump feed circuit. After repairs, go to step 29 .
Visually inspect and repair as necessary for a blocked or damaged combination valve, a restriction, blockage, disconnect or other damage to the AIR hoses/pipes from the combination valve to the exhaust system. After repairs, go to step 29 .
Repair vacuum system as necessary. After repairs, go to step 29 .
Repair short to voltage in the AIR pump feed circuit. After repairs, go to step 29 .
Replace AIR pump relay. After replacing relay, go to step 29 .
Replace AIR combination valve. After replacing valve, go to step 29 .
Check for poor connections at the AIR pump. Repair as necessary. Did you find and correct the condition? If yes, go to step 29 . If no, go to next step.
Replace AIR pump. After replacing AIR pump, go to next step.
Using scan tool, clear the DTCs. Turn OFF the ignition and wait 15 seconds. Operate vehicle within the conditions that are required for this diagnostic to run. Refer to «CONDITIONS FOR RUNNING DTC»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452__conditions-for-running-dtc) . Does scan tool indicate that this test ran and passed? If yes, go to next step. If no, go to step 2 .
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no DTCs are displayed, system is okay.

Use the connector Test Adapter Kit (J 35616-A) for any test that requires probing the PCM harness connectors, electrical center fuse/relay cavities, component terminals, and component harness connector. Using this kit will prevent damage caused by the improper probing of connector terminals.

DTC P0410: AIR SYSTEM (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Secondary Air Injection (AIR) system is used to lower tailpipe emissions during start up. PCM supplies ground to AIR pump relay, energizing pump. PCM enables both circuits simultaneously when AIR system operation is desired. When AIR system is active, AIR pump forces fresh air into the exhaust stream to accelerate catalyst operation.

PCM runs 2 tests using HO2S voltages to diagnose AIR system. Tests consist of

Test I PCM monitors HO2S voltages when AIR pump is enabled. If HO2S voltage drops to a predetermined range, PCM assumes that AIR pump is operational. If HO2S voltage increases to a predetermined range, PCM assumes that AIR pump is disabled. If HO2S voltages are out of range or inconclusive, diagnostic will proceed to next test.
Test II During this test, PCM will activate AIR pump during "closed loop" operation. When AIR is activated, PCM will monitor HO2S voltages and short term trim values for both banks of engine. If PCM determines that HO2S voltages for both banks does not respond as expected during tests, DTC P0410 will set. If only one sensor responded, PCM will set either a DTC P1415 or P1416 to indicate which bank AIR system is inoperative.

DTC will set when the following conditions are present

TEST I

DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0172, P0300, P0412, P0418, P0442, P0443, P1441 or any HO2S DTCs not set.
Engine operating for more than 3 seconds.
Engine load less than 80 percent.
Engine airflow less than 35 gm/s.
Ignition voltage greater than 11.5 volts.
Air fuel ratio greater than 13:1.
ECT less than 104°F (40°C).
IAT greater than 50°F (10°C).
HO2S voltage does not drop to less than 300 mV for 25 seconds during pump operation.
HO2S voltage does not got greater than 600 mV for 15 seconds after pump operation is turned off.
Power enrichment, deceleration fuel cut-off, or catalyst over-temperature not active.
AIR system is enabled for 50 seconds (60 seconds on hot starts).

TEST II

DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0172, P0300, P0412, P0418, P0442, P0443, P1441 or any HO2S DTCs not set.
Engine operating greater than 5 minutes.
Engine speed greater than 400 RPM.
EVAP purge active.
Maximum airflow is 35 gallons per second.
Ignition voltage greater than 11.5 volts.
Engine load less than 80 percent.
Fuel system operating in closed-loop.
This test will fail if HO2S voltage is greater than 300 mV for 4 seconds during pump operation.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P0412 or P0418 is also present, diagnose DTC. If DTCs are not present, go to next step.
Check AIR pump fuse. If fuse is okay, go to next step. If fuse is open, go to step 13 .
Turn ignition on, with engine off. Using scan tool, enable AIR pump. If pump turns on and off, go to step 10 . If AIR pump does not turn on and off, go to next step.
Check if air pump is running continuously. If air pump is running continuously, go to step 16 . If air pump is not running continuously, go to next step.
Turn ignition off. Disconnect AIR pump relay. Turn ignition on, engine off. Using a test light connected to ground, probe power supply circuit to relay. If test light illuminates, go to next step. If test light does not illuminate, go to step 17 .
Using a fused jumper wire, connect jumper between battery voltage supply to the AIR pump feed circuit. If AIR pump operates, go to step 25 . If AIR pump does not operate, go to next step.
Leave jumper wire in place. Disconnect AIR pump harness connector. Using a test light connected to ground, connect test light to AIR pump harness connector terminal "A". If test light illuminates, go to next step. If test light does not illuminate, go to step 18 .
Using test light, connect test light between AIR pump harness connector terminals. If test light illuminates, go to step 27 . If test light does not illuminate, go to step 19 .
Disconnect AIR hose/pipe from AIR pump. Using scan tool, activate AIR pump. If air flow is present at pump outlet, go to next step. If air flow is not present, go to step 28 .
Reconnect AIR pump. Disconnect AIR pump hose/pipe from AIR solenoid valve. Using scan tool, activate AIR pump. If air flow is present at outlet, go to next step. If air flow is not present at outlet, go to step 22 .
Start engine. Check for engine vacuum at AIR solenoid valve. If vacuum is present, go to step 26 . If vacuum is not present, check for damaged, pinched, blocked or disconnected vacuum hose or for faulty vacuum check valve. Repair as necessary. After repairs, go to step 23 .
Disconnect AIR pump relay and AIR pump harness connector. Install new fuse. If fuse blows, go to step 20 . If fuse does not blow, go to next step.
Install AIR pump relay. Using scan tool, enable AIR pump. Recheck fuse. If fuse blows, go to step 28 . If fuse does not blow, go to next step.
Install AIR pump harness connector. Using scan tool, enable AIR pump. Recheck fuse. If fuse blows, go to step 28 . If fuse does not blow, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect AIR pump relay. If pump is still running, go to step 24 . If pump stops running, go to step 25 .
Repair open in power circuit. After repairs, go to step 29 .
Repair open in feed circuit to AIR pump. After repairs, go to step 29 .
Repair open/high resistance in AIR pump ground circuit. After repairs, go to step 29 .
Repair short to ground in ignition feed circuit to relay. Repair as necessary. After repairs, go to step 29 .
Repair short to ground in ignition feed circuit to relay. After repairs, go to step 29 .
Check for restriction, blockage or other damage to AIR hoses/pipes between AIR pump and solenoid valve. After repairs, go to step 29 .
Repair vacuum systems. After repairs, go to step 29 .
Replace AIR bleed valve solenoid. After replacing solenoid, go to step 29 .
Replace AIR pump solenoid. After replacing solenoid, go to step 29 .
Replace AIR solenoid valve. After replacing solenoid valve, go to step 29 .
Check AIR pump electrical connections. Repairs as necessary. After repairs, go to step 29 . If connections are okay, go to next step.
Replace AIR pump. After replacing pump, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0410. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0410: AIR INJECTION SYSTEM (4.3L "C", "K", "S" & "T" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

The VCM supplies ground to AIR pump relay which energizes AIR pump and AIR solenoid. The VCM will run a test using HO2S voltages to diagnose AIR system. During this test, the VCM will activate AIR pump during closed loop operation. When AIR system is activated, VCM will monitor HO2S voltages and short term fuel trim values for both engine banks. If AIR system is operating properly, HO2S voltages should go low and short term fuel trim should go high. The VCM checks if HO2S voltages return to greater than the rich threshold when AIR pump is disabled.

DTC P0410 will set when VCM determines HO2S voltages for both engine banks did not respond as expected during the tests. If only one sensor responded, VCM will set either a DTC P1415 or P1416 to indicate which engine bank of AIR system is inoperative.

For duplication of DTC, ensure

No active HO2S, misfire, fuel trim, EVAP system, ECT, IAC, MAP, TP, IAT, or MAF sensor DTCs are set.
MAF is less than 25 gm/s.
Commanded air/fuel ratio is 14.7:1.
Engine load is less than 34 percent.
Power enrichment mode is not active.
Decel Fuel Cut-Off (DFCO) mode is not active.
Catalyst over-temperature protection is not active.
System has been in closed loop mode for more than 20 second.
Short term fuel trim is 124-132 counts.
Engine speed is greater than 550 RPM.
ECT is 176-230°F (80-110°C).
System voltage is 11.7 volts or greater.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine and allow it to reach normal operating temperature. Ensure system is in closed loop. Using scan tool, command AIR pump on and monitor short term fuel trim. If short term fuel trim changes more than 16 percent within 30 seconds, go to next step. If short term fuel trim does not change more than 16 percent within 30 seconds, go to step 4 .
DTC is intermittent. If any additional DTCs are present, go to applicable DTC. If no additional DTCs are present, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition on, with engine off. Using scan tool, command AIR pump on. If AIR pump runs, go to step 16 . If AIR pump does not run, go to next step.
Turn ignition off. Disconnect AIR pump harness connector. Check for poor connection. If a problem is found, go to step 27 . If connection is okay, go to next step.
Turn ignition on, with engine off. Using test light connected to ground, probe battery feed circuit at AIR pump harness connector. Using scan tool, command AIR pump on. If test light illuminates, go to next step. If test light does not illuminate, go to step 8 .
Using test light connected to battery positive, probe ground circuit at AIR pump harness connector. If test light illuminates, go to step 38 . If test light does not illuminate, go to step 28 .
Turn ignition off. Disconnect AIR pump relay. Check for poor connections. If a problem is found, go to step 27 . If connections are okay, go to next step.
Check for open in AIR pump battery feed circuit between AIR pump and AIR pump relay. If a problem is found, go to step 27 . If circuit is okay, go to next step.
Using test light connected to ground, probe battery feed circuit at AIR pump relay connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 29 .
Turn ignition on, with engine off. Using test light connected to ground, probe ignition feed circuit at AIR pump relay connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 30 .
Using test light connected to battery positive, probe control circuit at AIR pump relay connector. Using scan tool, command AIR pump on. If test light illuminates, go to step 35 . If test light does not illuminate, go to next step.
Turn ignition off. Disconnect VCM harness connector C1. Check for poor connections. If a problem is found, go to step 27 . If connections are okay, go to next step.
Check for open in control circuit between AIR pump relay and VCM. If a problem is found, go to step 27 . If circuit is okay, go to next step.
Turn ignition on, with engine off. Using test light connected to ground, probe control circuit at AIR pump relay connector. If test light illuminates, go to step 31 . If test light does not illuminate, go to step 39 .
Disconnect AIR shutoff valve output hose from AIR shutoff valve. Start engine. Using scan tool, command AIR pump on. If air flows from AIR shutoff valve, go to step 24 . If air does not flow from AIR shutoff valve, go to next step.
Turn ignition off. Disconnect AIR pump output hose from AIR shutoff valve. Turn ignition on, with engine off. Using scan tool, command AIR pump on. If air flows from hose, go to next step. If air does not flow from hose, go to step 25 .
Start engine. Disconnect vacuum hose from AIR shutoff valve. Connect vacuum gauge to AIR shutoff valve vacuum hose. Using scan tool, command AIR pump on. If vacuum is greater than 10 in. Hg with AIR pump running, go to step 36 . If vacuum is not greater than 10 in. Hg with AIR pump running, go to next step.
Check for leak or restriction in vacuum hose between AIR solenoid and AIR shutoff valve. If a problem is found, go to step 34 . If vacuum hose is okay, go to next step.
Remove vacuum connector from AIR solenoid. Connect vacuum gauge to vacuum source hose from engine. Start engine. If vacuum is greater than 10 in. Hg, go to next step. If vacuum is not greater than 10 in. Hg, go to step 26 .
Turn ignition off. Disconnect AIR solenoid harness connector. Check for poor connection. If a problem is found, go to step 27 . If connection is okay, go to next step.
Turn ignition on, with engine off. Using test light connected to ground, probe battery feed circuit at AIR solenoid harness connector. Using scan tool, command AIR pump on. If test light illuminates, go to next step. If test light does not illuminate, go to step 33 .
Turn ignition off. Using test light connected to battery positive, probe ground circuit at AIR solenoid harness connector. If test light illuminates, go to step 37 . If test light does not illuminate, go to step 32 .
Check for leaks or restrictions at AIR shutoff valve, hoses, check valves, fittings, AIR pipes and exhaust manifolds. If a problem is found, go to step 34 . If components are okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Check for restrictions in AIR pump inlet hose. If a problem is found, go to step 34 . If hose is okay, go to step 38 .
Repair leak or restriction in vacuum source hose to AIR solenoid. After repairs, go to step 40 .
Repair circuit as necessary. After repairs, go to step 40 .
Repair open in AIR pump ground circuit. After repairs, go to step 40 .
Repair open or short to ground in AIR pump relay battery feed circuit. After repairs, go to step 40 .
Repair open or short to ground in AIR pump relay ignition feed circuit. After repairs, go to step 40 .
Repair short to voltage in AIR pump relay control circuit. After repairs, go to step 40 .
Repair open in AIR solenoid ground circuit. After repairs, go to step 40 .
Repair open in AIR solenoid battery feed circuit. After repairs, go to step 40 .
Repair as necessary. After repairs, go to step 40 .
Replace AIR pump relay. After repairs, go to step 40 .
Replace AIR shutoff valve. After repairs, go to step 40 .
Replace AIR solenoid. After repairs, go to step 40 .
Replace AIR pump. After repairs, go to step 40 .
Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP system variation learn procedures. After repairs, go to step 40 .
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Low AIR system volume may set DTC P1415 or P1416, or cause an intermittent complaint. Check for the following conditions

Pinched, kinked or restricted AIR pipes, hoses or fittings.
Leaks, holes, loose fittings or hoses.
Obstruction in AIR pump inlet.
Leaks or restrictions in vacuum hoses for AIR shutoff valve.
Melted AIR supply hose, indicating exhaust back-flow past check valve.

An intermittent may be caused by a poor connection, rubbed-through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness.

DTC P0410: AIR INJECTION SYSTEM (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

A fused ignition voltage is supplied to AIR relay. PCM controls AIR pump by grounding AIR relay control circuit which energizes relay and supplies voltage to AIR pump clutch. When fuel system goes to closed loop, PCM opens ground to AIR control circuit.

PCM monitors HO2S voltages to diagnose the AIR system. During the AIR test, PCM activates the AIR pump during closed-loop operation. If PCM determines that HO2S voltages for both banks did not respond as expected during this tests, DTC will set. If only one sensor responded, PCM will either set DTC P1415 or P1416 to indicate which bank the AIR system is inoperative.

DTC will set when HO2S voltage does not go less than 222 mV within 1.2 seconds when AIR pump turns on during closed-loop operation and when short term fuel trim does not go greater than the predetermined amount when AIR pump turns on during closed-loop operation.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Ensure vacuum source is on proper side of AIR solenoid before proceeding with test. Using scan tool, check if DTC P0418 is also set. If DTC P0418 is set, go to DTC P0418 test. If DTC P0418 is not set, go to next step.
Check AIR Maxifuse®. If fuse is okay, go to next step. If fuse is blown, go to step 12 .
Turn ignition on, engine off. Using scan tool, command AIR pump on. If AIR pump turns on, go to step 9 . If AIR pump does not turn on, go to next step.
Turn ignition off. Remove AIR pump relay. Connect test light between ground and ignition feed circuit of AIR relay harness connector. Turn ignition on. If test light illuminates, go to next step. If test light does not illuminate, go to step 18 .
Using a fused jumper wire, connect jumper between battery voltage and AIR pump feed circuit at relay harness connector. If AIR pump turns on, go to step 24 . If AIR pump does not turn on, go to next step.
Leave jumper wire connected. Disconnect AIR pump harness connector. Using a test light connected to ground, probe AIR pump harness connector terminal "A". If test light illuminates, go to next step. If test light does not illuminate, go to step 19 .
Leave jumper wire connected. Connect test light between AIR pump harness connector terminals "A" and "B". If test light illuminates, go to step 27 . If test light does not illuminate, go to step 20 .
If AIR solenoid valve turned on when AIR system was enabled, go to step 15 . If AIR solenoid did not turn on when AIR system was enabled, go to next step.
Disconnect AIR solenoid harness connector. Using a test light connected to ground, probe solenoid harness connector terminal "A". Using scan tool, enable AIR pump. If test light illuminates, go to next step. If test light does not illuminate, go to step 22 .
Connect test light between solenoid harness connector terminals "A" and "B". Using scan tool, enable AIR pump. If test light illuminates, go to step 25 . If test light does not illuminate, go to step 20 .
Turn ignition off. Disconnect harness connectors from AIR pump, AIR pump relay, AIR solenoid valve. Remove AIR Maxifuse® from underhood fuse/relay block. Using a test light connected to battery voltage, probe battery feed terminal for AIR pump relay at harness connector. If test light illuminates, go to step 21 . If test light does not illuminate, go to next step.
Using test light connected to battery voltage, probe AIR pump solenoid feed circuit at relay harness connector. If test light illuminates, go to step 23 . If test light does not illuminate, go to next step.
Turn ignition off. Reinstall AIR fuse, relay and solenoid connector. Turn ignition on, with engine off. Using scan tool, turn on AIR pump. Check AIR fuse. If fuse blows, go to step 26 . If fuse does not blow, go to step 28 .
Start engine. Disconnect vacuum harness for AIR solenoid valve. Connect vacuum gauge to vacuum source. If engine vacuum is present, go to next step. If engine vacuum is not present, go to step 29 .
Reconnect vacuum source to AIR solenoid valve. Connect vacuum gauge to other port of AIR solenoid valve. Using scan tool, enable AIR pump. If engine vacuum is indicated on vacuum gauge when AIR pump is enabled, go to next step. If engine vacuum is not indicated on vacuum gauge when AIR pump is enabled, go to step 26 .
Reconnect vacuum harness to AIR solenoid valve. Disconnect air outlet hose from AIR shutoff valve. Using scan tool, enable AIR pump. If air is present at shutoff valve outlet, go to step 30 . If air is not present at shutoff valve outlet, go to step 31 .
Repair open in circuit between fuse and relay. After repairs, go to step 33 .
Repair open in circuit between AIR pump and relay. After repairs, go to step 33 .
Repair faulty ground connection or open ground circuit. After repairs, go to step 33 .
Repair short to ground in ignition feed circuit between fuse and relay. After repairs, go to step 33 .
Repair open in circuit between AIR solenoid and pump relay. After repairs, go to step 33 .
Repair short to ground in circuit between AIR pump relay and pump solenoid. After repairs, go to step 33 .
Replace AIR pump relay. After replacing relay, go to step 33 .
Check for poor connections at AIR solenoid valve harness connector. Repair as necessary. After repairs, go to step 33 . If connections are okay, go to next step.
Replace AIR solenoid valve. After replacing solenoid, go to step 33 .
Check for poor connections at AIR pump harness connector. Replace AIR relay. Repair as necessary. After repairs, go to step 33 . If connections are okay, go to next step.
Connect AIR pump harness connector. Using scan tool, turn on AIR pump. Check AIR pump Maxifuse®. If fuse blows, go to step 32 . If fuse does not blow, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Repair vacuum source. After repairs, go to step 33 .
Repair restriction or disconnected hose at point where AIR system branches to both sides. After repairs, go to step 33 .
Replace AIR shutoff valve. After replacing solenoid, go to step 33 .
Replace AIR pump. After replacing pump, go to next step.
Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0410: AIR INJECTION SYSTEM (5.0L, 5.7L & 7.4L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

A fused ignition voltage is supplied to AIR relay. VCM controls AIR pump by grounding AIR relay control circuit which energizes relay and supplies voltage to AIR pump clutch. When fuel system goes to closed loop, VCM opens ground to AIR control circuit.

DTC will set when the following conditions are present

AIR Passive Test Enable

No ECT, EVAP, HO2S, IAC, IAT, MAF, MAP and TP sensor DTCs are set.
No misfire DTCs are set.
No fuel trim DTCs are set.
MAF less than 25 gm/s.
Air/fuel ratio greater than 13.1:1.
Engine load less than 40 percent.
Power enrichment mode not active.
Decel Fuel cut-off mode not active.
Engine run time greater than 2 seconds.
HO2S voltage greater than 0.35 volt during open-loop.

AIR Active Test Enable

AIR passive test failed
No ECT, EVAP, HO2S, IAT, MAF, MAP or TP sensor DTCs.
No misfire DTCs are set.
No fuel trim DTCs are set.
No TP sensor DTCs are set.
Power enrichment not active.
Decel fuel cut-off not active.
Air/fuel ratio is 14.7:1.
Engine speed is greater than 550 RPM.
Closed-loop for greater than 15 seconds.
Engine load is less than 50 percent.
MAF sensor is less than 100 gm/s.
ECT between 131-221°F (55-105°C).
IAT greater than 32°F (0°C).
HO2S voltage greater than 0.2 volt for greater than 1.5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Install scan tool. Start and operate engine for greater than 2 minutes. Ensure engine is operating at normal operating temperature. Using scan tool, command AIR pump on. If short term fuel trim indicates a change of greater than 6 percent within 30 seconds, go to next step. If short term fuel trim does not indicate a change of greater than 6 percent within 30 seconds, go to step 4 .
DTC is intermittent. Check for additional DTCs set. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If any additional DTCs are set, diagnose affected DTC test.
Turn ignition on, engine off. Using scan tool, command AIR pump on. Observe AIR pump clutch. If AIR pump clutch is engaged, go to next step. If AIR pump clutch is not engaged, go to step 6 .
Command AIR pump off. Observe AIR pump clutch. If AIR pump clutch is engaged, go to step 7 . If AIR pump clutch is not engaged, go to step 21 .
Turn ignition off. Remove AIR relay. Connect test light between ground and ignition feed circuit of AIR relay connector (engine harness side). If test light illuminates, go to next step. If test light does not illuminate, go to step 13 .
Remove AIR relay. Connect test light between battery voltage and AIR relay control circuit at relay harness connector. If test light illuminates, go to step 16 . If test light does not illuminate, go to next step.
Connect test light between battery voltage and AIR relay control circuit of AIR relay connector (engine harness side). If test light illuminates, go to step 14 . If test light does not illuminate, go to next step.
Connect test light between ground and AIR pump control circuit. If test light illuminates, go to step 20 . If test light does not illuminate, go to next step.
Connect fused jumper wire between battery voltage and AIR pump clutch control circuit of AIR relay connector (engine harness side). If AIR pump clutch is engaged, go to step 27 . If AIR pump clutch is not engaged, go to next step.
Check for open in AIR pump clutch control circuit. If a problem is found, go to step 26 . If circuit is okay, go to next step.
Check for open in AIR pump ground circuit. If a problem is found, go to step 26 . If circuit is okay, go to next step.
Check for open fuse in AIR ignition feed circuit. If fuse is open, go to step 17 . If fuse is okay, go to step 18 .
Check for open in AIR relay control circuit. If circuit is open, go to step 26 . If circuit is okay, go to next step.
Check for poor terminal contact at VCM AIR relay control circuit terminal. If a problem is found, go to step 26 . If terminal contact is okay, go to step 30 .
Turn ignition off. Disconnect Blue VCM connector. Connect test light between battery voltage and AIR relay control circuit of AIR relay connector (engine harness side). If test light illuminates, go to step 19 . If test light does not illuminate, go to step 30 .
Repair short to ground in AIR relay ignition feed circuit. After repairs, go to step 31 .
Repair open in AIR relay battery/ignition feed circuit. After repairs, go to step 31 .
Repair short to ground in AIR relay control circuit. After repairs, go to step 31 .
Repair short to voltage in AIR pump clutch control circuit. After repairs, go to step 31 .
Disconnect AIR pump output hose at AIR valve. Using scan tool, command AIR pump on. Accelerate engine and observe airflow coming from hose. If airflow increases as engine is accelerated, go to step 23 . If airflow is not present or does not increase as engine is accelerated, go to next step.
Check for leaks or restrictions in AIR pipes, hoses and fitting between AIR pump and AIR valve. If a problem is found, go to step 26 . If no problem is found, go to step 29 .
Turn ignition off. Disconnect AIR valve harness connector. Turn ignition on, engine off. Connect test light between ground and AIR valve feed circuit. Using scan tool, command AIR pump on. If test light illuminates, go to next step. If test light does not illuminate, go to step 25 .
Check for open in AIR valve ground circuit. Repair as necessary. After repairs, go to step 31 . If circuit is okay, go to step 28 .
Repair open in AIR valve feed circuit. After repairs, go to step 31 .
Repair as necessary. After repairs, go to step 31 .
Replace AIR relay. After replacing relay, go to step 31 .
Replace AIR valve. After replacing valve, go to step 31 .
Replace AIR pump. After replacing pump, go to step 31 .
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0410: AIR SYSTEM (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Secondary Air Injection (AIR) system is used to lower tailpipe emissions during start up. PCM supplies ground to AIR pump relay, energizing pump.

PCM runs 2 tests using HO2S voltages to diagnose AIR system. Tests consist of

Test I PCM monitors HO2S voltages when AIR pump is enabled. If HO2S voltage drops to a predetermined range, PCM assumes that AIR pump is operational. If HO2S voltage increases to a predetermined range, PCM assumes that AIR pump is disabled. If HO2S voltages are out of range or inconclusive, diagnostic will proceed to next test.
Test II During this test, PCM will activate AIR pump during "closed loop" operation. When AIR is activated, PCM will monitor HO2S voltages and short term trim values for both banks of engine. If PCM determines that HO2S voltages for both banks does not respond as expected during tests, DTC P0410 will set. If only one sensor responded, PCM will set either a DTC P1415 or P1416 to indicate which bank AIR system is inoperative.

DTC will set when the following conditions are present

TEST I

DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0172, P0174, P0175, P0300, P0401, P0404, P0405, P0412, P0418, P0441, P0443, P0506, P0507, P1120, P1220, P1221, P1404, P1441 or any HO2S DTCs not set.
Engine operating greater than 2 seconds.
TP sensor angle not moving greater than one percent.
Engine load less than 25 percent.
Engine airflow less than 30 gm/s.
Ignition voltage greater than 11.7 volts.
Air fuel ratio greater than 13:1.
ECT less than 228°F (109°C).
HO2S voltage drops to less than 400 mV.

TEST II

DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0172, P0174, P0175, P0300, P0401, P0404, P0405, P0412, P0418, P0441, P0443, P0506, P0507, P1120, P1220, P1221, P1404, P1441 or any HO2S DTCs not set.
Engine operating greater than 200 seconds.
Engine speed greater than 600 RPM.
Engine airflow less than 22 gm/s.
Ignition voltage greater than 11.7 volts.
ECT greater than 158°F (70°C).
IAT greater than 50°F (10°C).
Engine load less than 25 percent.
HO2S voltage does not drop to less than 222 mV within 1.5 seconds.
Short term fuel trim does not go above a predetermined amount.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P0412 or P0418 is also present, diagnose DTC. If DTCs are not present, go to next step.
Check AIR pump fuse. If fuse is okay, go to next step. If fuse is open, go to step 11 .
Turn ignition on, with engine off. Using scan tool, enable AIR pump. If pump turns on, go to step 8 . If AIR pump does not turn on, go to next step.
Turn ignition off. Disconnect AIR pump relay. Turn ignition on, engine off. Using test light connected to ground, probe power supply circuit to relay. If test light illuminates, go to next step. If test light does not illuminate, go to step 17 .
Turn ignition off. Reconnect AIR pump relay. Disconnect AIR pump harness connector. Connect test light between battery negative terminal and probe AIR pump harness connector terminal "A". Turn ignition on, engine off. Using scan tool, enable AIR pump. If test light illuminates, go to next step. If test light does not illuminate, go to step 18 .
Connect test light between AIR pump harness connector terminals "A" and "C". Using scan tool, enable AIR pump. If test light illuminates, go to step 27 . If test light does not illuminate, go to step 19 .
Turn ignition off. Disconnect AIR pump harness connector. Using test light connected to negative battery terminal, probe AIR pump harness connector terminal "B". Turn ignition on, with engine off. Using scan tool, enable AIR pump. If test light illuminates, go to next step. If test light does not illuminate, go to step 20 .
Turn ignition off. Reconnect AIR pump harness connector. Disconnect AIR pump outlet hose. Turn ignition on. Using scan tool, enable AIR pump. If air is present at pump outlet, go to next step. If air is not present, go to step 27 .
Check for restriction or blockage in AIR hoses/pipes between AIR pump and to where system branches to both sides of engine. Repair as necessary. After repairs, go to step 29 . If AIR hoses/pipes are not restricted or blocked, go to next step.
Turn ignition off. Remove AIR pump relay, AIR solenoid relay and AIR pump bleed valve solenoid. Install new fuse(s). Turn ignition on, with engine off. Recheck fuse(s). If fuse blows, go to step 21 . If fuse does not blow, go to next step.
Install AIR solenoid relay. Using scan tool, enable AIR pump relay/solenoid relay. Recheck fuse(s). If fuse blows, go to step 22 . If fuse is okay, go to next step.
Install AIR pump harness connector. Using scan tool, enable AIR pump. Recheck fuse(s). If fuse blows, go to step 28 . If fuse is okay, go to next step.
Disconnect AIR pump harness connector. Install AIR pump relay. Using scan tool, enable AIR pump. Recheck fuse(s). If fuse blows, go to step 23 . If fuse is okay, go to next step.
Install AIR pump harness connector. Using scan tool, enable AIR pump. Recheck fuse(s). If fuse blows, go to step 28 . If fuse is okay, go to next step.
Install EVAP canister purge valve pump harness connector. Using scan tool, enable EVAP canister purge valve. Recheck fuse(s). If fuse blows, go to step 24 . If fuse is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Repair open circuit between fuse and relay. After repairs, go to step 29 .
Check for continuity between AIR pump and AIR pump relay. If circuit is open, repair as necessary. After repairs, go to step 29 . If circuit is okay, go to step 25 .
Repair faulty ground connection or open AIR pump ground circuit. After repairs, go to step 29 .
Check for continuity between AIR pump and AIR pump relay. If circuit is open, repair as necessary. After repairs, go to step 29 . If circuit is okay, go to step 26 .
Repair short to ground in ignition feed circuit between fuse and relay. After repairs, go to step 29 .
Repair short to ground between AIR solenoid relay and AIR pump. After repairs, go to step 29 .
Repair short to ground between AIR pump relay and AIR pump. After repairs, go to step 29 .
Replace AIR bleed valve solenoid. After replacing solenoid, go to step 29 .
Replace AIR pump solenoid. After replacing solenoid, go to step 29 .
Repair AIR solenoid relay. After replacing relay, go to step 29 .
Check AIR pump electrical connections. Repairs as necessary. After repairs, go to step 29 . If connections are okay, go to next step.
Replace AIR pump. After replacing pump, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0410. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

If no problem can be found in ignition feed circuit, check IGN 1 mini relay for proper operation. Check both sides or ENG IGN 1 fuse to determine if power is being supplied from IGN 1 mini-relay.

DTC P0410: AIR SYSTEM (7.4L "G" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

The VCM supplies ground to AIR pump relay control circuit. This energizes AIR pump relay and supplies voltage to AIR pump clutch. The VCM uses HO2S voltages and short term fuel trim to diagnose secondary air injection system.

The VCM monitors HO2S voltages and short term fuel trim value when AIR pump is energized. The additional air causes HO2S voltages to shift low, reflecting a leaner mixture. Short term fuel trim should increase to greater than 128, confirming VCM is supplying additional fuel. Low HO2S voltages and higher short term fuel trim value provides confirmation that secondary air injection system in operating properly. When AIR pump is de-energized, HO2S voltages should increase and begin switching normally.

DTC P0410 will set when VCM determines that HO2S voltages for both banks did not respond as expected during this test. If only one HO2S responded as expected, VCM sets either a DTC P1415 or P1416 depending on which engine bank AIR system is inoperative.

For duplication of DTC, ensure

No active AIR, EGR, fuel trim, IAC, HO2S, VSS, transmission, EVAP system, misfire, CMP, ECT, IAT, MAF, MAP, or TP sensor DTCS are set.
Commanded air/fuel ratio is 14.7:1.
System voltage is greater than 10 volts.
Engine speed is greater than 550 RPM.
Engine load is less than 50 percent.
MAF is less than 100 gm/s.
System has been in closed loop operation for more than 15 seconds.
IAT is greater than 32°F (0°C).
ECT is 167-221°F (75-105°C).

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Install scan tool. Start and operate engine for more than 2 minutes. Ensure engine is operating at normal operating temperature. Using scan tool, command AIR pump on. If short term fuel trim indicates a change of more than 16 percent within 30 seconds, go to next step. If short term fuel trim does not indicate a change of more than 16 percent within 30 seconds, go to step 4 .
DTC is intermittent. Check for additional DTCs set. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If any additional DTCs are set, diagnose affected DTC test.
With engine still running, command AIR pump on using scan tool. Observe AIR pump clutch. If AIR pump clutch is engaged, go to step 15 . If AIR pump clutch is not engaged, go to next step.
Turn ignition off. Disconnect AIR pump clutch harness connector. Check for poor connection. If a problem is found, go to step 22 . If connections are okay, go to next step.
Turn ignition on, with engine off. Using test light connected to ground, probe ignition feed circuit at AIR pump clutch harness connector. Using scan tool, command AIR pump on. If test light illuminates, go to next step. If test light does not illuminate, go to step 8 .
Using test light connected to battery positive, probe ground circuit at AIR pump clutch harness connector. If test light illuminates, go to step 29 . If test light does not illuminate, go to step 23 .
Turn ignition off. Disconnect AIR pump relay. Check for poor connection. If a problem is found, go to step 22 . If connections are okay, go to next step.
Check for an open in AIR pump clutch ignition feed circuit between relay and clutch. If a problem is found, go to step 22 . If circuit is okay, go to next step.
Turn ignition on. Using test light connected to ground, probe both ignition feed circuits at AIR pump relay socket. If test light illuminates for both circuits, go to next step. If test light does not illuminate for both circuits, go to step 24 .
Using test light connected to battery positive, probe AIR pump relay control circuit at relay socket. Using scan tool, command AIR pump on. If test light illuminates, go to step 27 . If test light does not illuminate, go to next step.
Turn ignition off. Disconnect VCM harness connector C1. Check for poor connections. If a problem is found, go to step 22 . If connections are okay, go to next step.
Check for an open in AIR pump relay control circuit between relay and VCM. If a problem is found, go to step 22 . If circuit is okay, go to next step.
Turn ignition on, with engine off. Using test light connected to ground, probe AIR pump relay control circuit at VCM harness connector. If test light illuminates, go to step 25 . If test light does not illuminate, go to step 30 .
Turn ignition off. Disconnect AIR output hose at outlet of AIR shutoff valve. Start engine and allow it to idle. Using scan tool, command AIR pump on. If air flows from valve, go to step 20 . If air does not flow from valve, go to next step.
Turn ignition off. Disconnect AIR pump output hose at inlet of AIR shutoff valve. Start engine and allow it to idle. Using scan tool, command AIR pump on. If air flows from hose, go to next step. If air does not flow from hose, go to step 19 .
Using scan tool, command AIR pump on. Increase engine speed to 1500 RPM. If airflow increases, go to next step. If airflow does not increase, go to step 21 .
Check for leaks or loose hose connections at hose between AIR pump and AIR shutoff valve. If a problem is found, go to step 26 . If hose is okay, go to step 28 .
Check for leaks or restrictions in hose between AIR pump and AIR shutoff valve. If a problem is found, go to step 26 . If hose is okay, go to step 21 .
Check for leaks or restrictions in AIR shutoff valve, hoses, check valves, fittings, AIR pipes, and exhaust manifolds. If a problem is found, go to step 26 . If no problems are found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Check for restriction in inlet hose of AIR pump. If a problem is found, go to step 26 . If no problem is found, go to step 29 .
Repair circuit as necessary. After repairs, go to step 31 .
Repair open in AIR pump clutch ground circuit. After repairs, go to step 31 .
Repair open or short to ground in AIR pump relay ignition feed circuits. After repairs, go to step 31 .
Repair short to voltage in AIR pump relay control circuit. After repairs, go to step 31 .
Repair as necessary. After repairs, go to step 31 .
Replace AIR pump relay. After repairs, go to step 31 .
Replace AIR shutoff valve. After repairs, go to step 31 .
Replace AIR pump. After repairs, go to step 31 .
Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP variation learn procedures. After repairs, go to step 31 .
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0410. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Secondary AIR shutoff valve is spring loaded and requires air pressure to open. A leak in hose between AIR pump and AIR shutoff valve could cause a no-flow condition even if AIR pump is flowing air. A weak or worn AIR pump may flow air, but may not be able to overcome spring pressure in AIR shutoff valve.

Low AIR system volume may set DTCs P1415, P1416, or cause an intermittent complaint. Check for the following conditions

Pinched, kinked or restricted AIR pipes, hoses or fittings.
Leaks, holes, loose fittings or hoses.
Restricted or obstructed AIR pump inlet hose.
Worn or loose AIR pump drive belt.

An AIR supply hose that is melted before check valve could indicate an exhaust gas back-flow past check valve. An intermittent may be caused by poor connections, rubbed through wire insulation, or broken wire inside insulation.

DTC P0411: AIR SYSTEM-NO FLOW DETECTED (3.0L "V" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Secondary Air Injection (AIR) system reduces hydrocarbons, carbon monoxide and oxides of nitrogen exhaust emissions. When engine is started, ECM commands AIR pump relay and AIR solenoid valve on, injecting clean air into engine exhaust ports. ECM switches AIR system off when oxygen sensors become active. Airflow is controlled by vacuum operated cutoff valve. Vacuum to valve is controlled by AIR solenoid valve. A check valve close to engine prevents hot exhaust gasses from backing up into AIR system.

ECM uses short term fuel trim to diagnose AIR system. When AIR system is enabled, ECM monitors short term fuel trim. If short term fuel trim goes below a threshold, ECM interprets this as an indication that AIR system is operational. When AIR pump is disabled, short term fuel trim should return to normal.

For duplication of DTC, short term fuel trim must not go above expected value within 6 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command AIR pump relay on and off. If AIR pump turns on and off, go to step 10 . If AIR pump does not turn on and off, go to next step.
Turn ignition off. Disconnect AIR pump relay connector. Turn ignition on, with engine off. Using test light connected to ground, probe relay battery supply circuit. If test light is on, go to next step. If test light is off, go to step 16 .
Using test light connected to ground, probe relay switched battery feed circuit. If test light is on, go to next step. If test light is off, go to step 17 .
Using test light connected to battery voltage, probe relay control circuit. Using scan tool, command AIR pump relay on and off. If test light turns on and off, go to next step. If test light does not turn on and off, go to step 9 .
Using a fused jumper wire, jumper battery feed circuit to AIR pump feed circuit at relay connector. If AIR pump turns on, go to step 25 . If AIR pump does not turn on, go to next step.
Leave fused jumper connected. Disconnect electrical connector from AIR pump. Using test light connected to ground, probe AIR pump harness connector feed circuit. If test light is on, go to next step. If test light is off, go to step 18 .
Using test light connected to battery voltage, probe AIR pump harness connector ground circuit. If test light is on, go to step 27 . If test light is off, go to step 19 .
Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Using DVOM, check harness continuity of control circuit. If continuity exists, go to step 29 . If continuity does not exist, go to step 20 .
Start engine. Disconnect vacuum hose from cutoff valve. Using scan tool, command AIR solenoid valve on. If vacuum is present at cutoff valve, go to step 13 . If vacuum is not present at cutoff valve, go to next step.
Disconnect manifold vacuum supply hose at AIR solenoid valve. If manifold vacuum is present at solenoid valve, go to next step. If manifold vacuum is not present at solenoid valve, go to step 21 .
Reconnect vacuum supply hose, and disconnect hose to cutoff valve at solenoid valve. Connect the 2 hoses together using suitable coupler. If vacuum is present at cutoff valve, go to step 23 . If vacuum is not present at cutoff valve, go to step 22 .
Remove cutoff valve. Using a hand held vacuum pump, apply vacuum to valve and attempt to blow through valve. If valve is open, go to next step. If valve is not open, go to step 24 .
Disconnect AIR pump outlet hose. Using scan tool, command AIR pump relay on and off. If air is present at AIR pump outlet when pump is running, go to next step. If air is not present at AIR pump outlet when pump is running, go to step 28 .
Check for damaged or blocked AIR hoses and pipes between AIR pump and engine. Repair as necessary. After repairs, go to step 31 .
Repair battery supply circuit to relay. After repairs, go to step 31 .
Repair switched battery feed circuit to relay. After repairs, go to step 31 .
Repair AIR pump feed circuit between AIR pump and AIR pump relay. After repairs, go to step 31 .
Repair open or high resistance in AIR pump ground circuit. After repairs, go to step 31 .
Repair open or high resistance in relay control circuit. After repairs, go to step 31 .
Repair vacuum supply hose or plugged vacuum source. After repairs, go to step 31 .
Repair vacuum hose to cutoff valve. After repairs, go to step 31 .
Replace solenoid valve. After replacing valve, go to step 31 .
Replace AIR cutoff valve. After replacing valve, go to step 31 .
Check for poor connections and terminal tension at relay harness connector. Repair as necessary. After repairs, go to step 31 . If connections and terminals are okay, go to next step.
Replace relay. After replacing relay, go to step 31 .
Check for poor connections and terminal tension at AIR pump harness connector. Repair as necessary. After repairs, go to step 31 . If connections and terminals are okay, go to next step.
Replace AIR pump. After replacing AIR pump, go to step 31 .
Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 31 . If connections and terminals are okay, go to next step.
Replace ECM. New ECM must be programmed with theft deterrent module frequency code currently on vehicle. After replacing ECM, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0411 is set, repeat step 2 . If DTC P0411 is not set, go to next step.
If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.

For any test that requires probing ECM or component harness connectors, use Connector Test Adapter Kit (J-35616-A). This will prevent damage to harness connector terminals.

Using FREEZE FRAME data may aid in locating intermittent condition. If DTC cannot be duplicated, review information in FREEZE FRAME. Try to operate vehicle within same FREEZE FRAME conditions (RPM, MAF, vehicle speed and temperature). This may help to recreate malfunction.

DTC P0412: AIR SOLENOID VALVE CONTROL CIRCUIT (3.0L "V" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

AIR solenoid valve is supplied power via the main relay (switched battery feed circuit). ECM controls solenoid by grounding control circuit via an internal driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by ECM. When ECM is commanding a component on, voltage of control circuit should be low (near zero volt). When ECM is commanding control circuit to component off, voltage should be high (near battery voltage). If fault detection circuit senses a voltage other than what is expected, this DTC will set.

For duplication of DTC, a short to ground, open, or short to battery voltage must be detected on control circuit.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command solenoid on and off. If solenoid turns on and off with each command, go to next step. If solenoid does not turn on and off with each command, go to step 5 .
Turn ignition off. Disconnect ECM connector located in engine compartment, in relay center. Jumper main relay control circuit to ground. Using DVOM on 10-amp scale, measure current between ground and solenoid control circuit at ECM harness connector for 2 minutes. If current draw is 0.1-0.75 amp, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not 0.1-0.75 amp, go to next step.
Turn ignition off. Disconnect solenoid connector. Using DVOM, check resistance between ground and solenoid control circuit at ECM harness connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 9 .
Turn ignition off. Disconnect solenoid connector. Connect test light between solenoid coil terminals at solenoid harness connector. Turn ignition on. Using scan tool, command solenoid on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
With test light connected to ground, probe solenoid harness connector switched battery feed circuit. If test light is on, go to next step. If test light is off, go to step 10 .
Turn ignition off. Reconnect solenoid connector. Disconnect ECM connector located in engine compartment, in relay center. Jumper main relay control circuit to ground. Using a fused jumper wire connected to ground, probe solenoid control circuit at ECM harness connector. If solenoid operates, go to step 12 . If solenoid does not operate, go to step 9 .
Check connections at solenoid. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 11 .
Repair solenoid control circuit. After repairs, go to step 14 .
Repair switched battery feed circuit to solenoid. After repairs, go to step 14 .
Replace solenoid. After replacing solenoid, go to step 14 .
Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 14 . If connections and terminals are okay, go to next step.
Replace ECM. New ECM must be programmed with theft deterrent module frequency code currently on vehicle. After replacing ECM, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0412 is set, repeat step 2 . If DTC P0412 is not set, go to next step.
If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.

For any test that requires probing ECM or component harness connectors, use Connector Test Adapter Kit (J-35616-A). This will prevent damage to harness connector terminals. Check for the following conditions

Check for poor connections at ECM or at component. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connection.

Check for damaged wiring harness. If harness appears to be okay, observe scan tool while moving related connectors and wiring harnesses. A change in scan tool display may help to locate fault.

DTC P0412: AIR SOLENOID VALVE CONTROL CIRCUIT (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

AIR solenoid valve is supplied power via the main relay (switched battery feed circuit). PCM controls solenoid by grounding control circuit via an internal driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by PCM. When PCM is commanding a component on, voltage of control circuit should be low (near zero volt). When PCM is commanding control circuit to component off, voltage should be high (near battery voltage). If fault detection circuit senses a voltage other than what is expected, this DTC will set.

DTC will set when there is a short to ground, open, or short to battery voltage detected on control circuit and condition is present for at least 30 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command solenoid on and off. If solenoid turns on and off with each command, go to next step. If solenoid does not turn on and off with each command, go to step 5 .
Turn ignition off. Disconnect PCM harness connector. Using a DVOM on 10-amp scale, measure current between ground and solenoid control circuit at ECM harness connector for 2 minutes. If current draw is 0.1-0.75 amp, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not 0.1-0.75 amp, go to next step.
Turn ignition off. Disconnect solenoid connector. Using DVOM, check resistance between ground and solenoid control circuit at PCM harness connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 9 .
Turn ignition off. Disconnect solenoid connector. Connect test light between solenoid coil terminals at solenoid harness connector. Turn ignition on. Using scan tool, command solenoid on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
With test light connected to ground, probe solenoid harness connector switched battery feed circuit. If test light is on, go to next step. If test light is off, go to step 10 .
Turn ignition off. Reconnect solenoid connector. Disconnect PCM harness connector. Jumper main relay control circuit to ground. Using a fused jumper wire connected to ground, probe solenoid control circuit at PCM harness connector. If solenoid operates, go to step 12 . If solenoid does not operate, go to step 9 .
Check connections at solenoid. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 11 .
Repair solenoid control circuit. After repairs, go to step 14 .
Repair switched battery feed circuit to solenoid. After repairs, go to step 14 .
Replace solenoid. After replacing solenoid, go to step 14 .
Check for poor connections and terminal tension at PCM harness connector. Repair as necessary. After repairs, go to step 14 . If connections and terminals are okay, go to next step.
Replace PCM. New PCM must be programmed with theft deterrent module frequency code currently on vehicle. After replacing PCM, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0412 is set, repeat step 2 . If DTC P0412 is not set, go to next step.
If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.

Check for poor connections at PCM or at component. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connection.

Check for damaged wiring harness. If harness appears to be okay, observe scan tool while moving related connectors and wiring harnesses. A change in scan tool display may help to locate fault.

DTC P0412: AIR SOLENOID RELAY CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Ignition voltage is supplied directly to AIR injection pump relay coil. PCM controls relay by grounding control circuit through an internal switch called a driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by PCM.

When PCM is commanding a component ON, voltage of control circuit should be low (near zero volts). When PCM is commanding control circuit to a component OFF, voltage potential of circuit should be high (near battery voltage). If fault detection circuit senses a voltage other than what is expected, fault line status will change, causing DTC to set.

DTC will set when the following conditions are present

Engine speed greater than 600 RPM.
Ignition voltage 6-16 volts.
PCM detects commanded state of driver and actual state do not match.
Conditions met for 10 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command AIR solenoid relay on and off. If relay turns on and off as commanded, go to next step. If relay does not turn on or off when commanded, go to step 5 .
Turn ignition off. Disconnect PCM harness connector containing relay control circuit. Turn ignition on. Install DVOM. Set DVOM to 10-amp scale. Check current from relay control circuit in PCM harness connector to ground for 2 minutes. If current draw is less than 0.75 amp (but not zero), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not as specified, go to next step.
Turn ignition off. Remove AIR solenoid relay. Check resistance from relay control circuit in PCM harness connector to ground. If resistance is infinite, go to step 12 . If resistance is not infinite, go to step 10 .
Turn ignition off. Remove AIR solenoid relay. Connect test light between relay coil terminals in relay harness connector. Turn ignition on. Using scan tool, command relay on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
Connect test light to ground and probe ignition feed circuit in AIR solenoid relay harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Turn ignition off. Reinstall AIR solenoid relay. Disconnect PCM harness connector containing relay control circuit. Turn ignition on. Connect a fused jumper wire between ground and PCM connector (harness side) relay control circuit. If relay operates, go to step 9 . If relay does not operate, go to step 10 .
Check connections at AIR solenoid relay. Repair as necessary. After repairs, go to step 14 . If relay connection is okay, go to step 12 .
Check connections at PCM. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
Repair faulty AIR solenoid relay control circuit. After repairs, go to step 14 .
Repair faulty AIR solenoid relay ignition feed circuit. After repairs, go to step 14 .
Replace AIR solenoid relay. After replacing relay, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After repair is completed, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0412. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Using FREEZE FRAME and/or FAILURE RECORD data mode may aid in locating an intermittent condition. If DTC cannot be duplicated, information included in FREEZE FRAME and/or FAILURE RECORDS data can be useful in determining how many miles since DTC set. FAIL COUNTER and PASS COUNTER can also be used to determine how many ignition cycles diagnostic reported a pass or a fail condition. To isolate when DTC failed, operate vehicle within same freeze frame conditions (RPM, load, vehicle speed, temperature, etc.).

DTC P0418: AIR PUMP RELAY CONTROL CIRCUIT (3.0L "V" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

When engine is started, ECM commands AIR pump relay and AIR cut-off valve on, allowing ambient air into engine exhaust ports. The ECM switches AIR system off when oxygen sensors become active.

The ECM uses short term fuel trim to diagnose AIR system. When AIR system is enabled, ECM monitors short term fuel trim. If short term fuel trim goes below a predetermined threshold, ECM interprets this as an indication that AIR system is operational. When AIR pump is disabled, short term fuel trim should return to normal.

If ECM detects an open or short to ground in AIR pump relay control circuit, DTC will set. For duplication of DTC, ensure engine is running and battery voltage is 7.5-15 volts.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If multiple DTCs are set, check fuse No. 49 (50-amp) located in ECM housing. If fuse is open, go to step 6 . If fuse is okay, go to next step.
Remove AIR pump relay. Turn ignition on, with engine off. Using a test light connected to ground, probe switched B+ circuit at relay harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 7 .
Using a test connected to battery positive, probe AIR pump relay control circuit at relay harness connector. Using scan tool, command AIR pump on. If test light illuminates, go to next step. If test light does not illuminate, go to step 8 .
Replace AIR pump relay. After repairs, go to step 10 .
Check battery feed circuit for short to ground. Repair as necessary and replace fuse. After repairs, go to step 10 .
Check switched B+ circuit for an open or short to ground. Repair as necessary. After repairs, go to step 10 .
Check AIR pump relay control circuit for an open or short to ground. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Replace ECM. Program replacement ECM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0418. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

DTC P0418: AIR PUMP RELAY CONTROL CIRCUIT (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

DTC will set when the following conditions are present: engine speed greater than 80 RPM, ignition voltage 9-18 volts or when PCM transitions from on to off or off to on. DTC will also set when, a short to ground, an open circuit, or a short to voltage is detected on the control circuit and when these conditions are present for at least 30 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command AIR pump relay on and off. If relay turns on and off as commanded, go to next step. If relay does not turn on or off when commanded, go to step 5 .
Turn ignition off. Disconnect PCM harness connector containing relay control circuit. Turn ignition on. Using a DVOM set to 10-amp scale, check current from relay control circuit in PCM harness connector to ground for 2 minutes. If current draw is 0.10-0.75 amp, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not 0.10-0.75 amp, go to next step.
Turn ignition off. Remove AIR pump relay. Check resistance from relay control circuit in PCM harness connector to ground. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 9 .
Turn ignition off. Remove AIR pump relay. Connect test light between relay coil terminals in relay harness connector. Turn ignition on. Using scan tool, command relay on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
Connect test light to ground and probe ignition feed circuit in AIR pump relay harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Turn ignition off. Reinstall AIR pump relay. Disconnect PCM harness connector. Turn ignition on. Connect a fused jumper wire between ground and PCM harness connector relay control circuit. If relay operates, go to step 12 . If relay does not operate, go to step 9 .
Check connections at AIR pump relay. Repair as necessary. After repairs, go to step 14 . If relay connection is okay, go to step 11 .
Repair relay control circuit. After repairs, go to step 14 .
Repair ignition feed circuit to relay coil. After repairs, go to step 14 .
Replace relay. After replacing relay, go to step 14 .
Check for poor connection at PCM harness connector. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0418. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0418: SECONDARY AIR INJECTION (AIR) PUMP RELAY CONTROL CIRCUIT (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

DTC will set when PCM detects that commanded state of driver and actual state of control circuit do no match and conditions are present for a minimum of 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command AIR pump relay on and off. If relay turns on and off as commanded, go to next step. If relay does not turn on or off when commanded, go to step 5 .
Turn ignition off. Disconnect PCM harness connector. Install a fused jumper to control circuit at PCM harness connector. Turn ignition on, with engine off. Using a DVOM, check current from relay control circuit in PCM harness connector to ground for 2 minutes. If current draw is less than 0.75 amp (but not zero), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not less than 0.75 amp, go to next step.
Turn ignition off. Remove AIR pump relay. Check resistance from relay control circuit in PCM harness connector to ground. If resistance is infinite, go to step 12 . If resistance is not infinite, go to step 10 .
Turn ignition off. Remove AIR pump relay. Connect test light between relay coil terminals in relay harness connector. Turn ignition on. Using scan tool, command relay on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
Connect test light to ground and probe ignition feed circuit in AIR pump relay harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Turn ignition off. Reinstall AIR pump relay. Disconnect PCM harness connector. Turn ignition on. Momentarily connect a fused jumper wire between ground and PCM harness connector relay control circuit. If relay turns on when circuit is grounded and off when circuit is opened, go to step 9 . If relay does not turn on when circuit is grounded and off when circuit is opened, go to step 10 .
Check connections at AIR pump relay. Repair as necessary. After repairs, go to step 14 . If relay connection is okay, go to step 12 .
Check connections at PCM. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
Repair faulty relay control circuit. After repairs, go to step 14 .
Repair faulty ignition feed circuit. After repairs, go to step 14 .
Replace AIR pump relay. After replacing relay, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After repair is completed, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0418: AIR PUMP RELAY CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

DTC will set when the following conditions are present

Engine speed greater than 600 RPM.
Ignition voltage 6-16 volts.
PCM detects commanded state of driver and actual state do not match.
Conditions met for 10 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command AIR pump relay on and off. If relay turns on and off as commanded, go to next step. If relay does not turn on or off when commanded, go to step 5 .
Turn ignition off. Disconnect PCM harness connector containing relay control circuit. Turn ignition on. Using a DVOM set to 10-amp scale, check current from relay control circuit in PCM harness connector to ground for 2 minutes. If current draw is less than 0.75 amp (but not zero), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not as specified, go to next step.
Turn ignition off. Remove AIR pump relay. Check resistance from relay control circuit in PCM harness connector to ground. If resistance is infinite, go to step 12 . If resistance is not infinite, go to step 10 .
Turn ignition off. Remove AIR pump relay. Connect test light between relay coil terminals in relay harness connector. Turn ignition on. Using scan tool, command relay on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
Connect test light to ground and probe ignition feed circuit in AIR pump relay harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Turn ignition off. Reinstall AIR pump relay. Disconnect PCM harness connector containing relay control circuit. Turn ignition on. Connect a fused jumper wire between ground and PCM connector (harness side) relay control circuit. If relay operates, go to step 12 . If relay does not operate, go to step 10 .
Check connections at AIR pump relay. Repair as necessary. After repairs, go to step 14 . If relay connection is okay, go to step 12 .
Check connections at PCM. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
Repair faulty AIR pump relay control circuit. After repairs, go to step 14 .
Repair faulty AIR pump relay ignition feed circuit. After repairs, go to step 14 .
Replace AIR pump relay. After replacing relay, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After repair is completed, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0418. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0420: CATALYST EFFICIENCY LOW (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

The catalyst monitor test is performed once per drive cycle if all test conditions are met. The main enable criteria to enable a catalyst test are, a steady TP sensor reading and calculated temperature of catalytic converter (using ECT, IAT, load and run time) indicating system is fully warmed up. Once the enable criteria are met, 50 samples of the sensor voltage amplitudes are collected. The results of the 50 samples are averages and converted to a millivolt (mV) reading which indicates the efficiency of the converter.

The catalyst monitor test consists of 2 stages. Stage 1 voltage ranges from -555 mV to +550 mV. When this value goes to greater than zero mV indicating that stage 1 has failed, the stage 2 test will start to be used in determining the converter efficiency. When stage 2 reaches the fail threshold, MIL will be illuminated and DTC will set. Scan tool can display the value for stage 1 test and indicate if it passed or failed.

Whenever DTCs are cleared or the battery has been disconnected, the results of stage 1 will be reset to -555 mV. Stage 1 will fail when the catalyst efficiency drops to less than 75 percent efficient. After stage 1 fails, the 50 sample test results are used by stage 2. When the results of stage 2 are greater than the fail threshold (catalyst efficiency less than 70 percent), MIL will be illuminated and DTC will set.

DTC can be set due to exhaust system leaks between the front and rear O2S or just the rear O2S leaking, deteriorated or contaminated catalyst. A catalyst monitor test will not be performed if a fault exists in the rear or front 02S circuits.

Check exhaust system for leaks between the front and rear O2S. Check rear O2S for proper tightness. If sensors are not okay, go to next step. If both sensors are okay, ensure that engine misfire condition does not exist. If misfire is not present, replace converter.
Repair leak(s). Test drive vehicle until test either passes or fails this ignition. If test fails, ensure that engine misfire condition does not exist. If misfire is not present, replace converter.

DTC P0420 once set, should remain active. However, under certain driving conditions, the catalyst monitor test may pass. This condition may occur if vehicle is driven at highway speeds (high airflow). If DTC is set and no exhaust leaks are found, converter should be replaced. If a misfire (P0300) is detected, DTC P0420 test will not run. Repair misfire condition before replacing converter.

DTC P0420: TWC SYSTEM-LOW EFFICIENCY (2.2L "J" BODY & "S" SERIES & 2.4L "J" & "N" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

A three-way catalytic converter is used to maintain low emissions. The PCM monitors exhaust gasses from converter using Heated Oxygen Sensor (HO2S). HO2S is located in exhaust stream past the three-way catalytic converter. HO2S produces an output signal which indicates the oxygen capacity of the catalyst. This determines the catalyst's ability to convert exhaust emissions effectively.

During normal operation, HO2S signal will be less active than that produced by the front Oxygen Sensor (O2S). Powertrain Control Module (PCM) monitors catalyst efficiency in 2 stages. If catalyst efficiency falls to less than 75 percent, PCM will set a stage one fail flag, but will not illuminate Malfunction Indicator Light (MIL). If catalyst efficiency falls to less than 50 percent, PCM will set a stage 2 fail flag and MIL will be illuminated.

Conditions for setting this DTC are

DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300-P0304, P0335, P0502, P0506, P0507 and P1441 not set.
Ignition voltage greater than 11.7 volts.
PCM sees less than 0.11 volt from EGR sensor.
Malfunction present for 25 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
Check for exhaust system leak, especially near HO2S. Ensure HO2S connectors are secured and not touching exhaust. If a problem is found, go to next step. If no problem is found, go to step 5 .
Repair exhaust system as necessary. After repairs, go to step 6 .
Replace catalytic converter. After repairs, go to next step.
Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0420. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation.

Three-Way Catalyst (TWC) system is used to control emission. PCM uses signal from Heated Oxygen Sensors (HO2S) to read efficiency of TWC. PCM will set DTC P0420 if TWC oxygen storage capacity is less than a predetermined threshold.

Conditions required to set DTC are

No CKP, ECT, HO2S, IAT, MAF, MAP, or TP sensor DTCs set.
No EGR pintle position, EVAP purge, fuel trim, injector circuit, misfire or VSS DTCs set.
Converter warm-up test passed.
Engine speed 1000-3000 RPM.
Vehicle speed 30-75 MPH.
PCM determines TWC oxygen storage capacity less than predetermined threshold.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Diagnose any other DTCs before proceeding. If no other DTCs are set, go to next step.
Using scan tool, clear DTCs. Ensure A/C is off. Start and warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. Test may need to be performed up to 6 times in order to pass or fail. If test has been performed or attempted for more than 6 times and DTC has not passed or failed this ignition cycle, test may be aborting. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If scan tool indicates that DTC ran and passed in this ignition cycle, system is okay. If scan tool does not indicate that DTC ran and passed in this ignition cycle, go to next step.
Ensure TWC is an original equipment part. Check TWC for dents or discoloration caused by excessive heat. Ensure no internal damaged catalyst rattle exists. If a problem is found, repair as necessary. After repairs, go to step 9 . If no problem is found, go to next step.
Check exhaust system for leaks, damage, loose or missing hardware. If a problem is found, repair as necessary. After repairs, go to step 7 . If no problems are found, go to next step.
Ensure HO2S 2 is securely installed and that harness is not damaged or contacting exhaust. If a problem is found, repair as necessary. After repairs, go to step 8 . If no problems are found, go to step 9 .
Repair exhaust system. After repairs, go to step 10 .
Repair HO2S sensor circuit. After repairs, go to step 10 .
Replace TWC. Check for possible engine misfire DTC or engine mechanical problem. After repairs, go to next step.
Using scan tool, clear DTCs. Ensure A/C is off. Start and warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. Test may need to be performed up to 6 times in order to pass or fail. If test has been performed or attempted for more than 6 times and DTC has not passed or failed this ignition cycle, test may be aborting. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If scan tool indicates that DTC ran and passed in this ignition cycle, go to next step. If scan tool does not indicate that DTC ran and passed in this ignition cycle, repeat step 2 .
If additional DTCs are present, diagnose affected DTCs. If no additional DTCs are present, system okay.

PCM will not enable the catalyst test if

Engine speed is plus or minus 100 RPM from desired idle speed.
TP is zero percent.
Short term integrator is between -20 percent and +20 percent.

The catalyst test will abort if vehicle falls out of following the conditions

Engine speed is plus or minus 125 RPM from desired idle speed.
TP is zero percent.
Short term integrator is between -20 percent and +20 percent.

The catalyst test may abort due to change in engine load (i.e., A/C, cooling fan on). If this problem occurs, use scan tool to force cooling fans to turn on, then repeat test.

Three-Way Catalyst (TWC) system is used to control emissions. PCM uses signal from Heated Oxygen Sensors (HO2S) to read efficiency of TWC. PCM will set DTC P0420 if TWC oxygen storage capacity is less than a predetermined threshold.

Conditions required to set DTC are: no misfire, fuel trim, injector or ignition control circuit, EVAP, HO2S, VSS IAC, EGR, TP, IAT, MAP, ECT, MAF or CKT DTCs set, engine running longer about 9 minutes, IAT 0-176°F (-18-80°C), ECT at 167-248°F (75-120°C), BARO greater than 75 kPa, and system is in closed-loop.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Diagnose any other DTCs present before proceeding. If no other DTCs are present, go to next step.
Using scan tool, clear DTCs. Ensure A/C is off. Start and warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. Test may need to be performed up to 6 times in order to pass or fail. If test has been performed or attempted for more than 6 times and DTC has not passed or failed this ignition cycle, test may be aborting. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If scan tool indicates that DTC ran and passed in this ignition cycle, system is okay. If scan tool does not indicate that DTC ran and passed in this ignition cycle, go to next step.
Ensure TWC is an original equipment part. Check TWC for dents or discoloration caused by excessive heat. Ensure no internal damaged catalyst rattle exists. If a problem is found, repair as necessary. After repairs, go to step 7 . If no problems are found, go to next step.
Check exhaust system for leaks, damage, loose or missing hardware. Repair as necessary. After repairs, go to step 7 . If no problems are found, go to next step.
Ensure HO2S 2 is securely installed and that harness is not damaged or contacting exhaust. Repair as necessary. After repairs, go to step 8 . If no problems are found, go to step 9 .
Replace TWC converter. After replacing catalytic converter, go to next step.
Using scan tool, clear DTCs. Ensure A/C is off. Start and warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. Test may need to be performed up to 6 times in order to pass or fail. If test has been performed or attempted for more than 6 times and DTC has not passed or failed this ignition cycle, test may be aborting. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If scan tool indicates that DTC ran and passed in this ignition cycle, go to next step. If scan tool does not indicate that DTC ran and passed in this ignition cycle, repeat step 2 .
Using scan tool, review CAPTURED INFO data. If any undiagnosed DTCs are present, diagnose affected DTCs. If no additional DTCs are present, system okay.

PCM will not enable the catalyst test until the following conditions are met: engine speed is plus or minus 100 RPM from desired idle speed, TP is zero percent, short term integrator is between -20 percent and +20 percent. The catalyst test will abort if vehicle falls out of following the conditions. Engine speed is plus or minus 125 RPM from desired idle speed. TP is zero percent. Short term integrator is between -20 percent and +20 percent.

The catalyst test may abort due to change in engine load (i.e., A/C or cooling fan on). If this problem occurs, use scan tool to force cooling fans to turn on, then repeat test.

Conditions required to set DTC are

IAT greater than 32°F (0°C).
ECT greater than 167°F (75°C).
MAF 15-32 gm/s.
Engine load less than 63 percent and steady.
Engine speed less than 4000 RPM.
Conditions present for up to 4 minutes.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Diagnose any other DTCs present before proceeding. If no other DTCs are present, go to next step.
Using scan tool, clear DTCs. Ensure A/C is off. Start and warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. Test may need to be performed up to 6 times in order to pass or fail. If test has been performed or attempted for more than 6 times and DTC has not passed or failed this ignition cycle, test may be aborting. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If scan tool indicates that DTC ran and passed in this ignition cycle, system is okay. If scan tool does not indicate that DTC ran and passed in this ignition cycle, go to next step.
Ensure TWC is an original equipment part. Check TWC for dents or discoloration caused by excessive heat. Ensure no internal damaged catalyst rattle exists. If a problem is found, repair as necessary. After repairs, go to step 9 . If no problems are found, go to next step.
Check exhaust system for leaks, damage, loose or missing hardware. Repair as necessary. After repairs, go to step 7 . If no problems are found, go to next step.
Ensure HO2S 2 is securely installed and that harness is not damaged or contacting exhaust. Repair as necessary. After repairs, go to step 8 . If no problems are found, go to step 9 .
Repair exhaust system. After repairs, go to step 10 .
Repair HO2S sensor circuit. After repairs, go to step 10 .
Replace TWC. Check for possible engine misfire DTC or engine mechanical problem. After repairs, go to next step.
Using scan tool, clear DTCs. Ensure A/C is off. Start and warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. Test may need to be performed up to 6 times in order to pass or fail. If test has been performed or attempted for more than 6 times and DTC has not passed or failed this ignition cycle, test may be aborting. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If scan tool indicates that DTC ran and passed in this ignition cycle, go to next step. If scan tool does not indicate that DTC ran and passed in this ignition cycle, repeat step 2 .
If additional DTCs are present, diagnose affected DTCs. If no additional DTCs are present, system okay.

PCM will not enable the catalyst test if

Engine speed is plus or minus 100 RPM from desired idle speed.
TP is zero percent.
Short term integrator is between -20 percent and +20 percent.

The catalyst test will abort if vehicle falls out of following the conditions

Engine speed is plus or minus 125 RPM from desired idle speed.
TP is zero percent.
Short term integrator is between -20 percent and +20 percent.

The catalyst test may abort due to change in engine load (i.e., A/C or cooling fan on). If this problem occurs, use scan tool to force cooling fans to turn on, then repeat test.

DTC P0420: TWC SYSTEM-LOW EFFICIENCY (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

This test monitors catalytic converter efficiency. This runs only once per ignition cycle and only after the converter has warmed up to operating temperature. Converter efficiency is calculated using data collected from pre- and post-converter oxygen sensors during steady driving conditions. The pre-converter oxygen sensor signal should fluctuate like those of the front and rear oxygen sensor. The post-converter oxygen sensor signal should fluctuate less than the pre-converter oxygen sensor.

The catalytic converter efficiency test is performed in 2 stages. The first stage calculates post-converter oxygen sensor deviations (difference from the average value), compares these deviations to the maximum allowable deviation (based on air flow), and records a failure if those deviations are excessive. The second stage is only run if the first stage fails or DTC P0420 is currently set. The second stage averages the difference between the deviations calculated in the first stage and the maximum allowable deviations. If the second stage average is too high, DTC will set.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, check if other DTCs are present. If other DTCs are present, diagnose affected DTCs first. If other DTCs are not present, go to next step.
Check exhaust system for leaks, damage, loose or missing hardware. Repair as necessary. After repairs, go to step 5 . If exhaust system is okay, go to next step.
Ensure original three-way catalytic converter is installed. Check catalytic converter for damage or tampering. Ensure oxygen sensors are properly installed and wiring and connections are okay. Repair or replace components as necessary. After repairs, go to next step. If components are okay, go to step 6 .
Using scan tool, select DTC INFO then DTC STATUS under DTC mode. Operate vehicle under which DTC was set. Observe scan tool display of DTC STATUS, looking for DTC to run or fail. If this DTC failed, go to next step. If this DTC did not fail, system is okay.
Replace catalytic converter.

Fuel with high sulfur content can cause a marginal converter to look bad. Check fuel quality.

DTC P0420: TWC SYSTEM-LOW EFFICIENCY-BANK 1 (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Three-Way Catalytic Converter (TWC) controls emissions of hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx). Catalyst within converter promotes a chemical reaction which oxidizes HC and CO present in exhaust gas, converting them into water vapor and carbon dioxide. Catalyst reduces NOx, converting it to nitrogen. VCM monitors this process using HO2S located in exhaust stream after catalyst.

HO2S produces a signal indicating oxygen storage capacity of catalyst and indicates catalyst's ability to convert exhaust emissions effectively. If catalyst is properly functioning, HO2S signal will be less active than other HO2S located further upstream from catalyst. DTC P0420 will set is HO2S signal is outside of acceptable range for an extended period of time, indicating three-way catalytic converter oxygen storage capacity is below acceptable threshold.

Conditions for setting DTC

Engine in "closed loop" fuel control.
Commanded air/fuel ratio equals 14.7:1.
Engine run time equals 346 seconds.
IAT 20-167°F (-6.8 to 75°C).
ECT 167-243°F (75-117°C).
BARO equal 73 kPa.
Predicted catalyst temperature is greater than or equal to 809°F (475°C).
TP sensor not greater than 1.7 percent.
Idle at recommended RPM.
VSS not greater than one MPH.
No transmission related DTCs.
No ECT, HO2S, IAT, MAF, MAP, TP, VSS DTCs are set.
Engine run time greater than 6 minutes.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if any MAP sensor, HO2S, misfire, fuel trim, VSS or ECT sensor DTCs are set. If any other DTCs are set, go to applicable DTC test. If no other DTCs are set, go to next step.
Check for the following conditions: Ensure TWC system is original equipment installed by manufacturer. Check TWC system for damage (i.e., dents, severe discoloration caused by excessive temperatures, holes). Ensure internal converter rattle (caused by damaged catalyst) is not present. Check exhaust system between TWC system and rear converter flange for leaks, damage, or loose or missing hardware. Ensure HO2S bank 1 sensor 3 on 4.3L and 5.0L; or HO2S bank 1 sensor 2 on 5.7L and 7.4L is secure, and pigtail and wiring is not damaged or contacting exhaust. On all models, if a problem is found, go to step 9 . If no problem is found, go to next step.
Check all VCM grounds. If a problem is found, go to step 9 . If no problem is found, go to next step.
Check all sensor grounds. If a problem is found, go to step 9 . If no problem is found, go to next step.
Check for intermittent open in catalyst monitored HO2S signal and ground circuits. If a problem is found, go to step 9 . If no problem is found, go to next step.
Check for intermittent short to ground on catalyst monitored HO2S signal and ground circuits. If a problem is found, go to step 9 . If no problem is found, go to next step.
Replace TWC system. Check for possible misfire (DTC P0300) or engine mechanical problem. After repairs, go to step 10 .
Repair problem as necessary. After repairs, go to next step.
Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Difficulty running OBD-II status DTC P0420 test may be encountered in areas where test conditions cannot be easily maintained, especially in urban areas.

DTC P0420: TWC SYSTEM-LOW EFFICIENCY-BANK 1 (4.3L "L" & "M" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Three-Way Catalyst (TWC) system is used to control emission. VCM uses signal from Heated Oxygen Sensor (HO2S) behind TWC read efficiency of TWC. VCM will set DTC P0420 if TWC oxygen storage capacity is less than a predetermined threshold.

Conditions for setting DTC

System in "closed-loop".
Commanded air/fuel ratio is 14.7:1.
Engine run time equals 346 seconds.
IAT 20-167°F (-6.75-75°C).
ECT 167-243°F (75-117°C).
BARO equals 73 kPa.
Converter warm-up test passed.
TP sensor not greater than 1.7 percent.
Engine idle speed near specifications.
VSS not greater than one MPH.
No transmission related DTCs.
No ECT, EGR, EVAP, HO2S, IAC, IC, IAT, MAF, MAP, TP or VSS sensor DTCs set.
No fuel trim or misfire DTCs set.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Diagnose any other DTCs before proceeding. If no other DTCs are set, go to next step.
Check for and repair the following condition(s): Ensure TWC is an O.E. part. TWC for damage. Ensure no internal damaged catalyst rattle exists. Exhaust system for leaks, damage, loose or missing hardware. Ensure HO2S bank 1 sensor 3 is securely installed, and harness and connector are not damaged or contacting exhaust. If problem is found, go to step 9 . If no problem is found, go to next step.
Check all VCM ground circuits. If problem is found, go to step 9 . If no problem is found, go to next step.
Check all sensor ground circuits. If problem is found, to step 9 . If no problem is found, go to next step.
Check HO2S bank 1 sensor 3 signal and ground circuits for intermittent opens. If problem is found, go to step 9 . If no problem is found, go to next step.
Check HO2S bank 1 sensor 3 signal and ground circuits for intermittent short to ground. If problem is found, go to step 9 . If no problem is found, go to next step.
Replace TWC. Check for possible engine misfire DTC or engine mechanical problem. After repairs, go to step 10 .
Repair problem as necessary. After repairs, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter this DTC. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step 2 .
Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

Difficulty may be experienced in simulating conditions to set DTC, especially in urban areas.

DTC P0420: TWC SYSTEM-LOW EFFICIENCY-BANK 1 (4.3L "S" & "T" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions for setting DTC

No CMP, ECT, EGR, EVAP, HO2S, IAT, MAF, MAP, TP or VSS DTCs set.
No fuel trim, misfire or transmission DTCs set.
Engine speed is 900 RPM or more for more than 35 seconds since last idle period.
Engine has been running for at least 346 seconds and the long term fuel trim is stable.
Predicted catalyst temperature is at least 887°F (475°C).
System is in closed loop.
BARO is 73 kPa or more.
IAT is between 20°F-167°F (-7°C-117°C).
ECT is between 167°F- 243°F (75°C-117°C).
Engine has been idling for less than 60 seconds.
Actual engine speed is within 100 RPM of the desired idle speed.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if any other DTCs are present. Diagnose affected DTCs. If no other DTCs are set, go to next step.
Check exhaust system for leaks, loose or missing hardware. Repair as necessary. After repairs, go to step 5 . If no problems were found, go to next step.
Ensure correct OE three-way catalytic converter is installed. Check converter for dents, severe discoloration or holes. Ensure that oxygen sensors are properly installed and that wiring connections are properly retained and not damaged. Repair as necessary. After repairs, go to next step. If no problems were found, go to step 6 .
Using scan tool, clear DTCs. Warm engine to normal operating temperature. Select DTC and SPECIFIC DTC function. Operate vehicle within conditions for setting this DTC and until scan tool indicates that this diagnostic test passed and ran. If scan tool indicates that this diagnostic passed, system is okay. If scan tool does not indicate that this diagnostic passed, go to next step.
Correct engine misfire or mechanical fault before replacing catalytic converter. After replacing converter, retest system operation.

Difficulty may be experienced in simulating conditions to set DTC, especially in urban areas.

DTC P0420: CATALYST SYSTEM-LOW EFFICIENCY-BANK 1 (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

A three-way catalytic converter is used to maintain low emissions. PCM monitors exhaust gasses from converter using Bank 1 HO2S 2. Sensor is located in exhaust stream past three-way catalytic converter. These sensors produce an output signal which indicates oxygen capacity of catalyst. This determines catalyst's ability to convert exhaust emissions effectively.

During normal operation, Bank 1 HO2S 2 signal will be far less active than that produced by Bank 1 HO2S 1. If a problem exists causing PCM to detect excessive Bank 1 HO2S 2 activity outside of an acceptable range for an extended period of time, PCM will set a DTC. This indicates that three-way catalytic converter's oxygen storage capacity is less than acceptable range.

DTC will set when PCM determines the oxygen storage capability of the catalytic converter gas degraded below a calibrated threshold.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other DTCs are present, diagnose affected DTCs first. If no other DTCs are present, go to next step.
Check if three-way catalytic converter is original equipment. Check for damage and rattle inside converter. Inspect for exhaust system leak, especially near HO2S. Ensure HO2S connectors are secured and not touching exhaust. Repair as necessary. After repairs, go to step 5 . If repairs were not necessary, go to next step.
Replace catalytic converter. After replacing converter, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0420: TWC SYSTEM-LOW EFFICIENCY-BANK 1 (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

DTC will set when the following conditions are present

No AIR, CKP, CMP, IAT, IC, MAF, MAP, ECT, TP, EVAP, left bank HO2S, misfire, left bank fuel trim, injector, VSS, engine protection or transmission related DTCs set.
ECT greater than 149°F (65°C).
Vehicle speed between 20-85 MPH.
IAT greater than -22°F (-30°C).
TP sensor angle greater than 2 percent.
Engine speed 800-3000 RPM.
MAP 25-80 kPa.
Engine airflow 14-40 gm/s.
Closed loop fuel control enabled.
PCM determines oxygen storage capability of catalytic converter has degraded to less than a calibrated threshold.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other DTCs are present, diagnose affected DTCs first. If other DTCs are not present, go to next step.
Check that three-way catalytic converter is original equipment. Check for converter damage and rattle inside converter. Inspect for exhaust system leak, especially near HO2S. Ensure HO2S connectors are secured and not touching exhaust. If damage to converter is obvious, go to next step. Repair other exhaust leaks. After repairs, go to step 5 .
Replace catalytic converter. After replacing converter, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0420. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0422/P0432: TWC SYSTEM-LOW EFFICIENCY-BANK 1 & BANK 2 (3.0L "V" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Three-Way Catalytic Converter (TWC) controls emissions of hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx). Catalyst within converter promotes a chemical reaction which oxidizes HC and CO present in exhaust gas, converting them into water vapor and carbon monoxide. Catalyst reduces NOx, converting it to nitrogen. ECM monitors this process using HO2S located in exhaust stream after catalyst.

HO2S produces a signal indicating oxygen storage capacity of catalyst and indicates catalyst's ability to convert exhaust emissions effectively. If catalyst is functioning properly, HO2S signal will be less active then other HO2S located further upstream from catalyst. If ECM detects excessive post catalyst signal activity (outside of acceptable range) for an extended period of time, ECM will set this DTC. This indicates TWC converter's oxygen storage capacity is below a threshold considered acceptable.

For duplication of DTC, amplitude ratio (rear HO2S to front HO2S) must be greater than a predetermined value.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other DTCs are set, go to applicable DTC. If no other DTCs are set, go to next step.
Verify catalytic converter is an original equipment part. Inspect catalytic converter for holes, dents or severe discoloration caused by excessive heat. Ensure internal catalytic converter rattle is not present. Inspect exhaust system for leaks, damage or loose or missing hardware. Ensure HO2S is secure and that pigtail and wiring are not damaged or contacting exhaust. Repair as necessary. After repairs, go to step 5 . If components are okay, go to next step.
Replace catalytic converter. After performing OBD system check, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0422 or DTC P0432 is set, go to step 2 . If DTC P0422 or DTC P0432 is not set, go to next step.
If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.

DTC P0430: CATALYST SYSTEM-LOW EFFICIENCY-BANK 2 (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

DTC will set when PCM determines the oxygen storage capability of the catalytic converter gas degraded below a calibrated threshold.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other DTCs are present, diagnose affected DTCs first. If no other DTCs are present, go to next step.
Check if three-way catalytic converter is original equipment. Check for damage and rattle inside converter. Inspect for exhaust system leak, especially near HO2S. Ensure HO2S connectors are secured and not touching exhaust. Repair as necessary. After repairs, go to step 5 . If repairs were not necessary, go to next step.
Replace catalytic converter. After replacing converter, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0430: TWC SYSTEM-LOW EFFICIENCY-BANK 2 (4.3L , 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Three-Way Catalytic (TWC) converter controls emissions of hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx). Catalyst within converter promotes a chemical reaction which oxidizes HC and CO present in exhaust gas, converting them into water vapor and carbon dioxide. Catalyst reduces NOx, converting it to nitrogen. VCM monitors this process using HO2S located in exhaust stream after catalyst.

HO2S produces a signal indicating oxygen storage capacity of catalyst and indicates catalyst's ability to convert exhaust emissions effectively. If catalyst is properly functioning, HO2S signal will be less active than other HO2S located further upstream from catalyst. DTC P0430 will set is HO2S signal is outside of acceptable range for an extended period of time, indicating three-way catalytic converter oxygen storage capacity is below acceptable threshold.

Conditions for setting DTC

No AIR, ECT, EGR, EVAP, HO2S, IAT, MAF, MAP, TP and VSS DTCs are set.
No misfire DTCs are set.
No fuel trim DTCs are set.
Engine run time greater than 6 minutes.
ECT greater than 169°F (76°C) but less than 244°F (118°C).
Engine in closed-loop operation.
IAT greater than 19°F (-7°C) but less than 167°F (75°C).

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if any MAP sensor, HO2S, misfire, fuel trim, VSS or ECT sensor DTCs are set. If any other DTCs are set, diagnose affected DTCs. If no other DTCs are set, go to next step.
Check for the following conditions: Ensure TWC system is original equipment installed by manufacturer. Check TWC system for damage (i.e., dents, severe discoloration caused by excessive temperatures, holes). Ensure internal converter rattle (caused by damaged catalyst) is not present. Check exhaust system between TWC system and rear converter flange for leaks, damage, or loose or missing hardware. Ensure HO2S bank 2, sensor 2 is secure, and pigtail and wiring is not damaged or contacting exhaust. If a problem is found, go to step 9 . If no problem is found, go to next step.
Check all VCM grounds. If a problem is found, go to step 9 . If no problem is found, go to next step.
Check all sensor grounds. If a problem is found, go to step 9 . If no problem is found, go to next step.
Check for intermittent open in catalyst monitored HO2S signal and ground circuits. If a problem is found, go to step 9 . If no problem is found, go to next step.
Check for intermittent short to ground on catalyst monitored HO2S signal and ground circuits. If a problem is found, go to step 9 . If no problem is found, go to next step.
Replace TWC system. Check for possible misfire (DTC P0300) or engine mechanical problem. After replacing converter, go to step 10 .
Repair problem as necessary. After repairs, go to next step.
Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Difficulty running OBD-II status DTC P0430 test may be encountered in areas where test conditions cannot be easily maintained, especially in urban areas. To minimize driving time required to complete test, catalyst can be warmed up in service bay previous to drive cycle. Engine can also be warmed up in service bay.

Using scan tool, monitor MAP sensor, HO2S bank 2 sensor 1, and HO2S bank 2 sensor 2 displays with gear selector in Park or Neutral with engine above idle. Compare HO2S activity (amplitude and frequency) to each other during a 30 second time period. If HO2S 2 activity is nearly as great as HO2S 1 activity, a problem is present. If less activity is indicated, TWC system is properly functioning.

DTC P0430: TWC SYSTEM-LOW EFFICIENCY-BANK 2 (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

A Three-Way Catalytic (TWC) converter is used to maintain low emissions. PCM monitors exhaust gasses from converter using Bank 2 HO2S 2 located in exhaust stream past TWC converter. These sensors produce an output signal which indicates oxygen capacity of catalyst. This determines catalysts ability to convert exhaust emissions effectively.

During normal operation Bank 2 HO2S 2 signal will be far less active than that produced by Bank 2 HO2S 1. If a problem exists causing PCM to detect excessive Bank 2 HO2S 2 activity outside of an acceptable range for an extended period of time, PCM will set a DTC. This indicates that three-way catalytic converter's oxygen storage capacity is less than acceptable range.

DTC will set when the following conditions are present

No AIR, CKP, CMP, ECT, engine protection, IAT, IC, injector, left bank HO2S, MAF, MAP, misfire, right bank fuel trim or transmission DTCs set.
Engine operating.
ECT greater than 149°F (65°C).
IAT greater than -22°F (-30°C).
TP sensor angle greater than 2 percent.
Engine speed 800-3000 RPM.
MAP 25-80 kPa.
Engine airflow between 14-40 gm/s.
Fuel system in closed loop fuel control.
PCM determines oxygen storage capability of catalytic converter has degraded to less than calibrated threshold.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other DTCs are present, diagnose affected DTCs first. If other DTCs are not present, go to next step.
Check that three-way catalytic converter is original equipment. Check for converter damage and rattle inside converter. Inspect for exhaust system leak, especially near HO2S. Ensure HO2S connectors are secured and not touching exhaust. If damage to converter is obvious, go to next step. Repair other exhaust leaks. After repairs, go to step 5 .
Replace catalytic converter. After replacing catalytic converter, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0430. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0440: EVAP SYSTEM-LARGE LEAK DETECTED (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

The EVAP system is tested with on-board diagnostics by applying pressure (vacuum) to the system and monitoring pressure change. PCM monitors vacuum level at fuel tank vapor pressure sensor. At appropriate time, the EVAP vent solenoid is commanded closed (normally open) and EVAP canister purge valve is commanded to a fixed duty cycle, allowing engine to draw vacuum on the entire evaporative emission system.

After a calibrated vacuum level is achieved, EVAP canister purge valve is turned off, sealing the system. If a sufficient vacuum pressure level cannot be achieved, a large leak fault is detected.

The following are possible conditions that can result in a large leak detection

Missing, loose or faulty fuel cap.
Poor electrical connections or faulty fuel tank pressure sensor.
Disconnected or damaged EVAP vent hose.
Disconnected, damaged, pinched or blocked fuel tank vapor lines.
Poor connections or faulty EVAP canister purge valve or vent solenoid.
Open ignition feed to either vent or purge solenoids.
Damaged or leaking EVAP canister.
Leaking fuel sender assembly or "O" ring, or leaking fuel tank or filler neck

Conditions for setting this DTC

DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0133, P0134 and P1144 are not set.
BARO is greater than 80.8 kPa.
Both ECT and IAT are 14-122°F (-10-50°C) at engine start-up.
ECT and IAT are within 10 degrees of each other at start-up.
Fuel tank level 15-85 percent.
Engine run time is greater than 2 seconds.
Abort time is 600 seconds and 240 seconds to finish once started.
Vacuum threshold of 8 in. H2O not achieved.

Connect scan tool. Turn ignition on, engine off. Using scan tool, view malfunction history. If DTC P0452, P0453 or P0460 is set, diagnose affected DTC. If DTCs are not present, go to next step.
Using scan tool, select SPECIAL TEST function and run SERVICE BAY TEST. If test indicates PASS, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If test does not indicate PASS, go to next step.
Use EVAP pressure/purge diagnostic station and ultrasound leak detector to locate and repair leak. After repairs, run SERVICE BAY TEST to verify repair.

When diagnosing intermittent problem, use scan tool to review malfunction history diagnostic information. Using scan tool, select SPECIAL TEST functions to run a service bay diagnostic test. This verifies large leak is present. If diagnostic passes, it may necessary to review the importance of a tight, secure fuel cap with vehicle owner.

DTC P0440: EVAP SYSTEM (2.2L "J" BODY & "S" SERIES & 2.4L "J" & "N" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Evaporative leak detection strategy is based on applying vacuum to EVAP system and monitoring vacuum decay. Powertrain Control Module (PCM) monitors vacuum level by means of fuel tank vacuum sensor input. At a predetermined time, EVAP purge solenoid and EVAP vent solenoid are turned on. This allows engine vacuum to draw a small vacuum on entire EVAP system. Whenever a sufficient vacuum level cannot be achieved, a large leak or faulty EVAP purge solenoid is indicated.

Conditions for setting this DTC are as follows

BARO greater than 75 kPa.
IAT and ECT are 41-84°F (5-29°C).
IAT is not greater than 2°F (1°C), greater than ECT at start-up.
ECT is not greater than 12°F (7°C), greater than IAT at start-up.
Fuel tank level is 26-74 percent.
EVAP solenoid is enabled.
EVAP system is unable to achieve or maintain vacuum during diagnostic test. Amount of vacuum decay will vary with fuel level.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P0452, P0453 or P0460 is also set, go to that DTC first. If not, go to next step.
Check fuel cap for missing or loose condition. Repair or replace as necessary. After repairs, go to step 19 . If repair is not necessary, go to next step.
Turn ignition on, with engine off. Using scan tool, command EVAP canister purge valve and EVAP vent solenoid on and off. If purge valve and vent solenoid clicks, go to next step. If purge valve and/or vent solenoid does not click, diagnose PCM.
Turn ignition off. Disconnect purge line from fuel tank at EVAP canister. Turn ignition on, engine off. Using scan tool, observe fuel tank pressure sensor value. If scan tool reads zero mm Hg, go to step 7 . If scan tool does not read zero mm Hg, go to next step.
Check if EVAP purge line from fuel tank to EVAP canister is pinched, kinked or plugged. Repair or replace as necessary. After repairs, go to step 20 . If purge line is okay, diagnose system using DTC P0452 or P0453 tests.
Reconnect all EVAP hoses that was disconnected. Using scan tool, command EVAP vent solenoid on (closed). Connect the EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Attempt to pressurize EVAP system to 5 in. H2O while holding EVAP Pressure/Purge Diagnostic Station in HOLD position. If specified pressure is obtained, go to next step. If specified pressure cannot be obtained, go to step 10 .
Maintain EVAP system pressure at 5 in. H2O. Using scan tool, observe FUEL TANK VACUUM PRESSURE. If pressure reading is 3-7 in. H2O, go to step 12 . If pressure reading is not 3-7 in. H2O, go to next step.
Turn ignition off. Install Fuel Tank Cap Adapter (J-41415-40). Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to fuel tank cap adaptor. Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid on. Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 15 in. H2O. Monitor pressure for 2 minutes. If pressure drops to less than 10 in. H2O, go to next step. If pressure does not drop to less than 10 in. H2O, go to step 14 .
Disconnect fuel tank vapor and EVAP purge hoses from EVAP canister. Plug canister fitting for fuel tank vapor hose. Ensure EVAP vent solenoid is still commanded on. Connect a hand-held vacuum pump to EVAP purge hose fitting on EVAP canister and apply 5 in. Hg. If vacuum holds, go to step 15 . If vacuum does not hold, go to step 14 .
Check for restricted fuel tank vapor and EVAP purge hoses. Repair as necessary. After repair is completed, go to step 20 . If hoses are okay, diagnose fuel tank pressure sensor using DTC P0452 or P0453 tests.
Disconnect vacuum hose at EVAP canister purge valve (from throttle body). Connect a hand-held vacuum pump to EVAP canister purge valve vacuum source fitting. Apply 10 in. Hg. Using scan tool, command EVAP canister purge valve on. If vacuum does not hold, go to next step. If vacuum holds, go to step 17 .
Connect a vacuum gauge to EVAP canister purge valve vacuum hose (from throttle body). Start engine. Increase engine speed to 2500 RPM. If vacuum is greater than 10 in. Hg, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vacuum is 15 in. Hg or less, go to step 18 .
Check for disconnected or damaged vent hose. Also, check for damaged EVAP canister. Repair as necessary. After repair is completed, go to step 20 . If no problem is found, go to step 19 .
Check for missing or faulty fuel cap. Check for disconnected or leaking fuel tank vapor hose or disconnected or damaged EVAP purge hose. Repair as necessary. After repairs, go to step 20 . If no problem is found, go to next step.
Using scan tool, command EVAP vent solenoid on. With EVAP pressure/purge diagnostic station connected to EVAP service port, attempt to pressurize EVAP system by leaving control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41416), locate and repair EVAP system leak. It may be necessary to partially lower fuel tank to examine hose connections at top of tank. After repair is completed, go to step 20 .
Replace EVAP canister purge valve. After replacing purge valve, go to step 20 .
Locate and repair cause of low or no vacuum. After repairs, go to step 20 .
Replace EVAP vent solenoid. After replacing solenoid, go to next step.
Turn ignition on, with engine off. Using scan tool, command EVAP vent solenoid on (closed). Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 15 in. H2O. Set rotary switch on diagnostic station to HOLD and observe EVAP pressure gauge. If pressure decreases to less than 10 in. H2O within 2 minutes, repeat step 3 . If pressure does not decrease to less than 10 in. H2O within 2 minutes, go to next step.
Clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that the diagnostic ran and passed, go to next step. If scan tool does not indicate that the diagnostic ran and passed, repeat step 2 .
Using scan tool, check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, system is okay.

Check for the following

Cranked and punctured EVAP canister.
Damaged or disconnected source vacuum line, EVAP purge line, vent hose, for fuel tank vapor line.
Poor connection at PCM.
Inspect harness connectors for backed-out terminals, improper mating, broken lock, damaged terminals, or poor wire connection.
Check for intermittent in circuit.
Check for kinked, pinched or plugged vacuum lines to EVAP purge or fuel tank vapor line. Also check for restrictions.
Faulty or damaged evaporative canister.

DTC P0440: EVAP SYSTEM (3.0L "V" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

During specific operating conditions, ECM performs various tests on Evaporative Emission (EVAP) system. System tests consist of the following series of events.

After ensuring that EVAP purge solenoid valve duty cycle has dropped to zero percent, indicating that valve is closed, ECM commands EVAP canister vent valve closed, sealing system. ECM monitors accumulation of vapor pressure within fuel tank via fuel tank pressure sensor. EVAP test is aborted if vapor pressure is too high. If any vapor pressure is measured, it will be used later to compensate a pressure reading during small leak detection test. If a vacuum is measured which exceeds a calculated limit during vapor accumulation, this DTC will set. EVAP canister purge solenoid valve is then opened. Simultaneously, vent valve is opened.

If vapor pressure does not bleed off or bleeds off too slowly, this DTC is set. Once EVAP purge solenoid valve reaches its desired position for remainder of diagnostic test, vent valve will be closed again. This causes vacuum to be applied to entire EVAP system. ECM monitors vacuum level within system. If desired vacuum level cannot be achieved, or if vacuum level is reached but took too much time, DTC P0455 will set. Once desired vacuum level is reached, purge solenoid is closed, sealing system. ECM continues to monitor fuel tank pressure sensor signal, measuring rate of vacuum decay. If system holds vacuum, vent valve is opened and test is completed. In addition to system tests, ECM monitors circuit integrity of purge solenoid (DTC P0443), vent valve (DTC P0446) and fuel tank pressure sensor (DTC P0450).

Conditions required to set DTC are

Vent valve mechanical failure.
Purge solenoid mechanical failure.
Blocked or restricted lines, hoses or components.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTCs P0443 or P0446 are also set, go to applicable DTC. If DTCs P0443 or P0446 are not set, go to next step.
Inspect EVAP system for disconnected, kinked or deteriorated hoses and lines. Check for loose hose connections or missing or loose fuel cap. Inspect for obvious damage to any system component. Repair components as necessary, then go to step 23 . If components are okay, go to next step.
Disconnect manifold vacuum source hose at purge valve. Connect a vacuum gauge to manifold vacuum source hose. EVAP Pressure/Purge Diagnostic Station (J-41413) can be used for this purpose, if necessary. Start and operate engine to greater than 2000 RPM. Observe source vacuum level. If vacuum gauge indicates 15 in. Hg, go to next step. If vacuum gauge does not indicate 15 in. Hg, go to step 16 .
Turn ignition off. Remove fuel cap. Turn ignition on, with engine off. Using scan tool, observe fuel tank pressure. If fuel tank pressure is minus one to plus one inch H2O, go to next step. If fuel tank pressure is not minus one to plus one inch H2O, go to DTC P0450.
Zero gauges on EVAP Pressure/Purge Diagnostic Station (J-41413) prior to installation. Connect pressure/purge diagnostic station to EVAP service port. Reinstall fuel cap. Plug EVAP vent hose or disconnect vent hose from vent valve and plug hose. Attempt to pressurize EVAP system using pressure/purge diagnostic station. Monitor pressure using gauge on EVAP pressure/purge diagnostic station. If pressure reading is 15 in. H2O, go to next step. If pressure reading is not 15 in. H2O, go to DTC P0455.
Maintain EVAP system pressure at 15 in. H2O. Observe fuel tank pressure on scan tool. If fuel tank pressure is at or greater than 11 in. H2O, go to next step. If fuel tank pressure is not at or greater than 11 in. H2O, go to DTC P0450.
Switch rotary switch on pressure/purge diagnostic station to HOLD and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 10 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to next step.
Unplug EVAP vent hose and/or reconnect vent hose at vent valve. Disconnect ECM connector located in engine compartment, in relay center. Remove main relay. Using fused jumper, connect between battery circuit and switched battery feed circuit at relay harness connector. Using another fused jumper, ground EVAP vent valve control circuit at ECM harness connector. This closes vent valve. Restore system pressure to 15 in. H2O using EVAP pressure/purge diagnostic station. Switch rotary switch to HOLD and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 18 . If pressure does not drop to less than 10 in. H2O within 2 minutes, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank to EVAP canister vapor hose at canister and plug port on canister. Restore system pressure to 15 in. H2O using EVAP pressure/purge diagnostic station. Switch rotary switch to HOLD and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not drop to less than 10 in. H2O within 2 minutes, go to step 14 .
Disconnect purge valve to EVAP canister vapor hose at purge valve and plug hose. Restore system pressure to 15 in. H2O using EVAP pressure/purge diagnostic station. Switch rotary switch to HOLD and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not drop to less than 10 in. H2O within 2 minutes, go to step 17 .
Disconnect vent hose at EVAP canister and plug port on canister. Restore system pressure to 15 in. H2O using EVAP pressure/purge diagnostic station. Switch rotary switch to HOLD and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not drop to less than 10 in. H2O within 2 minutes, go to step 20 .
Disconnect and plug purge hose at EVAP canister. Restore system pressure to 15 in. H2O using EVAP pressure/purge diagnostic station. Switch rotary switch to HOLD position and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 21 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to step 19 .
Reconnect fuel tank vapor hose at EVAP canister. Disconnect fuel tank vapor hose at fuel tank and plug hose. Restore system pressure to 15 in. H2O using EVAP pressure/purge diagnostic station. Switch rotary switch to HOLD and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 22 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to next step.
Reconnect fuel tank vapor hose at fuel tank. With EVAP pressure/purge diagnostic station connected to EVAP service port, continuously attempt to pressurize EVAP system by leaving control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41416), locate fuel tank system leaks. Check fuel tank, tank seams, fuel cap, fill pipe, sending unit, sending unit-to-tank seal, or fuel tank pressure sensor. Repair as necessary. After repairs, go to step 23 .
Check for damaged vacuum source hose, blocked or restricted manifold vacuum port or low engine vacuum. Repair as necessary. After repairs, go to step 23 .
Replace purge valve. After replacing valve, go to step 23 .
Replace vent valve. After replacing valve, go to step 23 .
Replace canister. After replacing canister, go to step 23 .
Replace vent hose. After replacing hose, go to step 23 .
Replace purge hose (valve-to-canister). After replacing hose, go to step 23 .
Replace vapor hose (tank-to-canister). After replacing hose, go to next step.
Ensure that vent valve is on (closed). Pressurize EVAP system to 15 in. H2O using EVAP pressure/purge diagnostic station. Monitor pressure using gauge on EVAP pressure/purge diagnostic station. Switch rotary switch to HOLD and observe pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 6 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0440 is set, go to step 2 . If DTC P0440 is not set, go to next step.
If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.

Check for faulty fuel cap, damaged, pinched or blocked EVAP purge line, damaged EVAP vent hose, or pinched or blocked fuel tank vapor line. Check for EVAP canister purge valve or vent valve malfunction (non-electrical). Check for damaged EVAP canister. Inspect for leaking fuel sender assembly "O" ring, or leaking fuel tank or fuel filler neck.

DTC P0440: EVAP SYSTEM (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions for setting this DTC are as follows

No TP sensor, ODM, IAT sensor, or MAP sensor DTCs present.
Start-up ECT 40-86°F (4-30°C).
Start-up ECT not greater than 14°F (8°C) greater than start-up IAT.
Start-up IAT not greater than 4°F (2°C) of start-up ECT.
Fuel tank level is 15-85 percent.
BARO is greater than 75 kPa.
Vehicle has been driven at least 11 miles.
EVAP system is unable to achieve or maintain vacuum during diagnostic test.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if DTC P1665 or P1676 is also set. If any of DTCs is present, diagnose affected DTCs. If DTCs are not present, go to next step.
Turn ignition off. Remove fuel filler cap. Turn ignition on. Using scan tool, observe fuel tank pressure. If fuel tank pressure is zero in. H2O, go to next step. If fuel tank pressure in not zero in. H2O, diagnose evaporative system.
Replace fuel filler cap. Using scan tool, capture FAILURE RECORD data for DTC P0440 and clear DTC. Command EVAP vent solenoid on. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Pressurize EVAP system using diagnostic station. Monitor pressure on EVAP pressure gauge on diagnostic station. If pressure is 5 in. H2O, go to next step. If pressure is not 5 in. H2O, go to step 6 .
Maintain EVAP pressure at 5 in. H2O. Observe fuel tank pressure on scan tool. If fuel tank pressure reading on scan tool is 5 in. H2O, go to step 8 . If reading is not 5 in. H2O, go to next step.
Disconnect fuel tank vapor line and EVAP purge line from EVAP canister. Block canister fitting for fuel tank pressure line. Connect a hand-held vacuum pump to canister fitting for EVAP purge line. Ensure that EVAP vent solenoid is still commanded on. Apply vacuum to EVAP canister. If vacuum can be maintained at 5 in. Hg, go to step 11 . If vacuum cannot be maintained at 5 in. Hg, go to step 10 .
Check for restriction in fuel tank vapor line or EVAP purge line. Repair as necessary. After repairs, go to step 16 . If restriction is not found, diagnose EVAP system.
Disconnect vacuum source line at EVAP purge solenoid and plug vacuum source fitting on solenoid. Using scan tool's output tests function, select and activate SYSTEM PERF. Pressurize EVAP system to 5 in H2O. Observe EVAP pressure gauge on diagnostic station while removing plug from EVAP purge solenoid vacuum source fitting. If EVAP pressure decreases to zero in. H2O within 15 seconds while system performance is activated, go to next step. If EVAP pressure does not decrease to zero in. H2O within 15 seconds, go to step 13 .
Install vacuum gauge on EVAP diagnostic station to vacuum source line. Start and operate engine to greater than 2000 RPM. Observe source vacuum level. If vacuum level is greater than -15 in. Hg, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vacuum level is not greater than -15 in. Hg, go to step 14 .
Check for disconnected or damaged vent hose. Check for damaged EVAP canister. Repair as necessary. After repairs, go to step 16 . If no problems are found, go to next step.
Check for faulty or missing fuel filler cap. Check for disconnected or leaking fuel tank vapor line. Check for disconnected or damaged EVAP purge line. If problem is found, repair as necessary. After repairs, go to step 16 . If no problems are found, go to next step.
Using scan tool, command EVAP vent solenoid on. Continuously attempt to pressurize the EVAP system by leaving the EVAP diagnostic station control knob in the pressurized position. Using the Ultrasonic Leak Detector (J-41416), locate and repair leak in EVAP system. After repairs, go to step 16 .
Replace EVAP purge solenoid. After replacing solenoid, go to step 16 .
Check for carbon release into the EVAP system. Repair as necessary. After repairs, go to step 16 .
Replace EVAP vent solenoid. After replacing solenoid, go to next step.
Turn ignition on. Using scan tool, command EVAP vent solenoid on. Using EVAP diagnostic station, pressurize EVAP system to 15 in. H2O. Move rotary switch in diagnostic station to HOLD and observe EVAP pressure gauge. If EVAP pressure decreases to less than 10 in. Hg within 2 minutes, repeat step 3 . If EVAP pressure does not decrease, system is okay.

Check for the following

Cracked or punctured EVAP canister.
Damaged or disconnected source vacuum line, EVAP purge line, vent hose, for fuel tank vapor line.
Poor connection at PCM.
Inspect harness connectors for backed-out terminals, improper mating, broken lock, damaged terminals, or poor wire connection.
Check for intermittent in circuit.
Check for kinked, pinched or plugged vacuum lines to EVAP purge or fuel tank vapor line. Also check for restrictions.
Faulty or damaged evaporative canister.

DTC P0440: EVAP SYSTEM (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Evaporative (EVAP) emission system includes following components: fuel tank, EVAP vent solenoid, fuel tank pressure sensor, fuel pipes and hoses, vapor lines, fuel cap, EVAP emission canister, purge lines, and EVAP purge solenoid.

Conditions for setting DTC are: no misfire, fuel trim, injector control circuit, AIR, EGR, VSS, HO2S, TP, MAP, MAF, ECT or IAT DTCs set, battery voltage 5-18 volts, BARO pressure greater than 75 kPa, fuel level 15-85 percent of full capacity for at least 10 seconds continuously, ECT and IAT at start-up is 40-86°F (4-30°C), and ECT not greater than 46°C (8°C) or less than 36°F (2°C) at start-up

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if DTCs P0442, P0443, P0446, P0449, P0452, P0453, P0462, P0463 or P1441 is set. If any of these DTCs are set, diagnose affected DTCs. If no other DTCs are set, go to next step.
Inspect EVAP system for loose, incorrect, defective or missing fuel tank cap. Check for damaged EVAP system component, check service port for a missing dust cap or for a loose/damaged Schrader valve. Repair as necessary. After repairs, go to step 18 . If no problems were found, go to next step.
Ensure battery voltage is 10.5-17.5 volts, fuel level is 3-15 gallons, and engine temperature is less than 70°F (14°C). Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Reinstall fuel cap. Read and Record FAILURE RECORDS data for DTC P0440. Clear DTCs. Using scan tool, command EVAP vent solenoid ON (closed). Connect EVAP pressure/purge diagnostic station to EVAP service port. Using diagnostic station, attempt to pressurize EVAP system to 5 in. H2O. If specified pressure is achieved, fault is not present. If specified pressure is not achieved, go to next step.
Turn ignition off. Remove vacuum source connection from EVAP purge solenoid valve. Connect vacuum gauge directly to vacuum source. DO NOT tee gauge into line. Start and operate engine at idle. If vacuum reading is 12 in. Hg or greater, go to next step. If vacuum reading is not 12 in. Hg or greater, go to step 12 .
Turn ignition off. Reconnect vacuum source to EVAP purge solenoid valve. Connect vacuum gauge directly to EVAP purge solenoid valve. Start and operate engine at idle. Using scan tool, command EVAP purge solenoid valve to 100 percent purge. If vacuum gauge reads 12 in. Hg or greater, go to next step. If vacuum gauge does not read 12 in. Hg or greater, go to step 13 .
Turn ignition off. Disconnect fuel tank vapor and EVAP purge line from EVAP vapor canister. Plug canister fitting for fuel tank vapor line. Connect a hand-held vacuum pump to EVAP purge line canister fitting. Turn ignition on. Using scan tool, command EVAP vent valve ON (closed). Using vacuum pump, apply 5 in. Hg. If specified vacuum can be obtained and held, go to step 10 . If specified vacuum cannot be obtained or held, go to next step.
Leave system connected as in previous step. Disconnect vent line at EVAP vent valve. Plug vent line. Using vacuum pump, apply 5 in. Hg. If specified vacuum can be obtained and held, go to step 14 . If specified vacuum cannot be obtained or held, go to next step.
Inspect EVAP vent line from canister to EVAP vent valve for leaks. Replace as necessary. After repairs, go to step 18 . If no leaks were found, go to step 15 .
Turn ignition off. Remove plug and hand-held vacuum pump. Reconnect EVAP vapor canister purge and tank vent lines. Connect EVAP Pressure/Purge Diagnostic Station (J-14113) to EVAP system service port. Using scan tool, command EVAP vent valve closed. Continuously attempt to pressurize EVAP system. Using Ultrasonic Leak Detector (J-41416), locate and repair EVAP system leak. After repairs, go to step 18 . If no leaks were found, go to next step.
Check EVAP system for restrictions. Repair as necessary. After repairs, go to step 18 . If no problems were found, go to step 16 .
Repair vacuum source to EVAP purge solenoid valve. After repairs, go to step 18 .
Replace EVAP purge solenoid valve. After replacing solenoid valve, go to step 18 .
Replace EVAP vent valve. After replacing EVAP vent valve, go to step 18 .
Replace EVAP canister. After EVAP replacing canister, go to step 18 .
Relieve all system pressure. Using scan tool, use PURGE/SEAL function to turn on EVAP purge solenoid valve to varying levels with engine running and quickly seal system with scan tool. While system is sealed, compare EVAP pressure/purge diagnostic station's vacuum gauge to vacuum shown on scan tool from EVAP fuel tank pressure sensor. Allow system to stabilize. If both values indicate the same amount (plus or minus 2 in. Hg) of vacuum in EVAP system, go to step 3 . If both values are not the same (plus or minus 2 in. Hg), go to next step.
Replace EVAP pressure sensor. After replacing sensor, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this diagnostic test ran and passed, go to next step. If scan tool does not indicate that this diagnostic test ran and passed, go to step 2 .
Using scan tool, select CAPTURED INFO function. Check if any undiagnosed DTCs are displayed. Diagnose affected DTCs. If no additional DTCs are displayed, system is okay.

Check for missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings, cracks or punctures in EVAP canister, damaged or disconnected source vacuum line, EVAP purge line, vent hose or fuel tank vapor line. Check for faulty connections at VCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection or damaged harness. Inspect wiring harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0440: EVAP SYSTEM (3.8L "C", "F", "G", "H" & "W" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions required to set DTC are

No IAT, MAP, ODM, or TP sensor DTCs set.
Start-up ECT is 40-86°F (4-30C°).
Start-up ECT is not greater than 14°F (8°C) greater than start-up IAT.
Start-up IAT is 40-86°F (4-30°C).
Start-up IAT is not greater than 4°F (2°C) greater than start-up ECT.
Fuel tank level 15-85 full.
BARO is greater than 10.7 psi (0.75 kg/cm 2 )
System voltage 8-16 volts.
EVAP system unable to achieve or maintain vacuum during diagnostic test.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P1655 or P1675 is set, diagnose affected DTCs before proceeding. If DTCs are not set, go to next step.
Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays zero in. H2O, go to next step. If scan tool does not display zero in. H2O, repair faulty fuel tank pressure sensor circuit.
Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Reinstall fuel cap. Read and record FAILURE RECORDS data for DTC P0440. Clear DTCs. Using scan tool, command EVAP vent solenoid ON (closed). Connect EVAP pressure/purge diagnostic station to EVAP service port. Using EVAP pressure/purge diagnostic station, attempt to pressurize EVAP system to 5 in. H2O. If specified pressure is achieved, go to next step. If specified pressure is not achieved, to step 6 .
Maintain EVAP system pressure at 5 in. H2O. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays 5 in. H2O, go to step 8 . If scan tool does not display 5 in. H2O, go to step 7 .
Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand-held vacuum pump to EVAP purge line fitting at EVAP canister. Ensure EVAP vent solenoid is still commanded ON (closed). Attempt to apply 5 in. Hg vacuum to EVAP canister. If vacuum is maintained as specified, go to step 11 . If vacuum cannot be maintained as specified, go to step 10 .
Check fuel tank vapor line and EVAP purge line for restriction. If restriction is found, repair as necessary and go to step 16 . If no restriction is found, repair faulty fuel tank sensor circuit.
Disconnect vacuum source line and plug vacuum source fitting at EVAP purge solenoid. Using scan tool, select and activate SYSTEM PERF. Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 5 in. H2O. Observe pressure gauge on EVAP pressure/purge diagnostic station while removing plug from vacuum source fitting line at EVAP purge solenoid. If fuel tank vacuum decreases to zero in. H2O within 15 seconds, go to next step. If vacuum does not decrease as specified, go to step 13 .
Connect EVAP pressure/purge diagnostic station vacuum gauge to vacuum source line. Start engine. Run engine speed to greater than 2000 RPM while observing vacuum gauge. If vacuum is greater than 15 in. Hg, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vacuum is not greater than 15 in. Hg, go to step 14 .
Check if vent hose is disconnected or damaged. Check EVAP canister for damage. Repair as necessary. After repairs, go to step 16 . If no problem is found, go to step 15 .
Check for missing or faulty fuel cap. Check for disconnected or leaking fuel tank vapor line. Check for disconnected or damaged EVAP purge line. Repair as necessary and go to step 16 . If no problem is found, go to next step.
Using scan tool, command EVAP vent solenoid ON (closed). Connect EVAP pressure/purge diagnostic station to EVAP service port. Continuously attempt to pressurize EVAP system by leaving control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41413), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of fuel tank. After repairs, go to step 16 .
Replace EVAP purge solenoid. After replacing purge solenoid, go to step 16 .
Locate and repair cause of no source vacuum to EVAP purge solenoid. After repairs, go to step 16 .
Replace EVAP vent solenoid. After replacing solenoid, go to next step.
Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid ON (closed). Using EVAP pressure/purge diagnostic station pressurize EVAP system to 15 in. H2O. Monitor EVAP pressure/purge diagnostic station pressure gauge. Turn EVAP pressure/purge diagnostic station rotary switch to HOLD position. If pressure decreases to less than 10 in. H2O within 2 minutes, return to step 3 . If pressure does not decrease as specified, repair is complete.

Check following items

For missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings.
For cracks or punctures in EVAP canister.
For damaged or disconnected source vacuum line, EVAP purge line, vent hose or fuel tank vapor line.
For faulty connections at PCM. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
For damaged harness. Inspect wiring harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0440: EVAP SYSTEM (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM will test the EVAP system for the following conditions

Large and small leaks (P0440 and P0442).
Excess vacuum (P0446).
Purge flow during non-commanded conditions (P1441).
Fuel pressure and level sensor faults (P0452, P0453, P0461, P0462 and P0463).
EVAP purge and vent valve faults (P1645 and P1646).

PCM monitors the amount of vacuum in EVAP system by monitoring the fuel tank pressure sensor. For this DTC, PCM turns on both the EVAP purge and vent valves when conditions for setting this DTC are met. Engine vacuum is applied to closed EVAP system, checking whether vacuum can develop in EVAP system. Failure to develop vacuum may result from a large leak or from restriction. DTC will set after 2 consecutive failures during test.

DTC will set when EVAP system cannot develop vacuum.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Using scan tool, check if DTCs P0442, P0446, P0452, P0453, P0461, P0462, P0463, P1441, P1645 and P1646 are present. If any of these DTCs are present, diagnose affected DTCs first. If none of these DTCs are present, go to next step.
Check for loose, incorrect, defective or missing fuel filler cap. Check for misrouted, kinked or damaged EVAP system purge lines. Repair as necessary. If no problems were found, go to next step.
Ensure battery voltage is 10.5-17.5 volts, fuel level 1.8-16.6 gallons, and engine temperature at 37-95°F (4-35°C). Using scan tool, record data stored when DTC was set. Clear DTCs. Using scan tool, perform SERVICE BAY TEST for EVAP system. If vehicle passes service bay test, fault is intermittent. If vehicle does not pass the service bay test, go to next step.
Turn ignition off. Disconnect vacuum source from EVAP purge solenoid. Connect a vacuum gauge directly to vacuum source. Start and operate engine at idle. If vacuum reading is 12 in. Hg or greater, go to next step. If vacuum reading is not 12 in. Hg or greater, go to step 12 .
Turn ignition off. Reconnect vacuum source to EVAP purge solenoid. Connect vacuum gauge directly to purge connection of EVAP purge valve. Start and idle engine. Using scan tool, command EVAP purge solenoid to 100 percent purge. If vacuum gauge reading is 12 in. Hg or greater, go to next step. If vacuum gauge reading is not 12 in. Hg or greater, go to step 13 .
Turn ignition off. Disconnect fuel tank vapor and EVAP purge line from EVAP vapor canister. Plug fuel tank vapor line fitting at canister. Connect a hand-held vacuum pump to EVAP purge line fitting at canister. Apply 5 in. Hg to canister. If vacuum can be obtained and held, go to step 10 . If vacuum cannot be obtained and held, go to next step.
Disconnect and plug vent line at EVAP vent valve. Apply 5 in. Hg. If vacuum can be obtained and held, go to step 14 . If vacuum cannot be obtained and held, go to next step.
Inspect EVAP vent line from canister to vent valve for leaks. Replace if necessary. If line is okay, go to step 15 .
Install EVAP Pressure/Purge Diagnostic Station (J-41413) and Ultrasonic Leak Detector (J-41416). Ensure gauges on test equipment is zeroed before starting test. Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP vapor canister purge and tank vent lines. Connect diagnostic station to EVAP system service port. Using scan tool, command EVAP vent valve closed. Continuously attempt to pressurize EVAP system by leaving EVAP Pressure/Purge Diagnostic Station control knob to PRESSURIZE position. Using ultrasonic leak detector, locate EVAP system leak. Repair as necessary. If leak is not present, go to next step.
Check EVAP system for restrictions. Repair as necessary. If no restriction is found, go to step 16 .
Repair vacuum source to EVAP purge solenoid valve.
Check EVAP purge solenoid valve and purge line for carbon contamination. Replace EVAP purge solenoid valve.
Replace EVAP vent valve.
Replace EVAP vapor canister.
Relieve all system pressure. Using scan tool, use Purge/Seal function to turn EVAP purge solenoid valve on to varying vacuum levels with engine running and quickly seal system with scan tool. Leaving EVAP purge solenoid valve on for higher percents or longer times will allow a higher amount of vacuum to develop. A maximum of 12 in. H2O of vacuum can be applied to EVAP system using scan tool. While system is sealed, compare EVAP pressure/purge diagnostic station's vacuum gauge to vacuum shown on scan tool from the EVAP fuel tank pressure sensor. Allow a few seconds for system to stabilize. If both values are within 2 in. H2O of each other, repeat step 2 . If both values are not within 2 in. H2O of each other, go to next step.
Replace EVAP pressure sensor.

An accurate indication of fuel level is required for PCM to properly pass or fail this DTC. Always diagnose fuel level sensor DTCs before performing this DTC test. Always check for fuel level sensor DTCs stored as history.

Perform physical inspection of EVAP system. Check the following items

Loose, missing, defective, or incorrect fuel tank cap.
Incorrectly routed or defective EVAP system vacuum and vapor lines.
A malfunctioning or damaged EVAP vapor canister.
Check for charcoal release from EVAP vapor canister.

DTC P0440: EVAP SYSTEM (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions for setting DTC

No ECT, HO2S, IAT, MAP, TP or VSS sensor DTCs set.
DTC P0125 not active.
No fuel level related DTCs set.
Fuel tank level 12.5-87.5 percent.
System voltage 10-17 volts.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if DTCs P0446, P0452 or P0453 is set. If any of these DTCs are set, diagnose affected DTCs. If no other DTCs are set, go to next step.
Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK VACUUM. If scan tool displays zero in. H2O, go to next step. If scan tool does not display zero in. H2O, repair faulty fuel tank sensor circuit.
Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Reinstall fuel cap. Read and Record FAILURE RECORDS data for DTC P0440. Clear DTCs. Using scan tool, command EVAP vent solenoid ON (closed). Connect EVAP pressure/purge diagnostic station to EVAP service port. Using diagnostic station, attempt to pressurize EVAP system to 5 in. H2O. If specified pressure is achieved, go to next step. If specified pressure is not achieved, go to step 6 .
Maintain EVAP system pressure at 5 in. H2O. Using scan tool, read FUEL TANK VACUUM. If scan tool displays 5 in. H2O, go to step 9 . If scan tool does not display 5 in. H2O, go to step 8 .
Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand-held vacuum pump to EVAP purge line fitting at EVAP canister. Ensure EVAP vent solenoid is still commanded ON (closed). Attempt to apply 5 in. Hg to EVAP canister. If vacuum is maintained as specified, go to step 12 . If vacuum cannot be maintained as specified, go to next step.
Leave system connected as in previous step. Disconnect and plug vent valve hose. Using a hand-held vacuum pump, apply 5 in. Hg. If vacuum can be obtained and held, go to step 17 . If vacuum cannot be obtained or held, go to step 11 .
Disconnect fuel tank vapor line from canister. Attempt to pressurize EVAP system using EVAP Pressure/Purge Diagnostic Station (J-41413). Start engine. Monitor pressure on diagnostic station gauge. If 5 in. H2O can be obtained and held, go to step 18 . If 5 in. H2O cannot be obtained or held, go to step 15 .
Disconnect purge line from canister. Connect vacuum gauge to service port of diagnostic station. Start engine. Command EVAP solenoid valve to 100 percent. If vacuum reading is 12 in. Hg or greater, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vacuum reading is not 12 in. Hg, go to next step.
Disconnect purge line from purge solenoid valve. Start engine. Using scan tool, command EVAP purge solenoid purge solenoid ON (100 percent). If vacuum reading is 12 in. Hg or greater, go to step 14 . If vacuum reading is not 12 in. Hg or greater, go to step 16 .
Check if vent hose is disconnected or damaged. Check EVAP canister for damage. Repair as necessary. After repairs, go to step 19 . If no problem is found, go to step 18 .
Check for missing or faulty fuel filler cap. Check for disconnected, leaking or damaged fuel tank vapor line or EVAP purge line. Repair as necessary. After repairs, go to step 19 . If no problem is found, go to next step.
Using scan tool, command EVAP vent solenoid ON (closed). With EVAP pressure/purge diagnostic station connected to EVAP service port, continuously attempt to pressurize EVAP system to 15 in. H2O by leaving diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41413), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. Repair leak as necessary. After repairs, go to step 19 .
Repair restriction in EVAP purge line. After repairs, go to step 19 .
Repair restriction in fuel tank vapor line. After repairs, go to step 19 .
Replace EVAP purge solenoid valve. After replacing EVAP solenoid valve, go to step 19 .
Replace EVAP vent valve. After replacing EVAP vent valve, go to step 19 .
Replace EVAP canister. After EVAP replacing canister, go to next step.
Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid ON (closed). Using diagnostic station, pressurize EVAP system to 15 in. H2O. Monitor EVAP diagnostic station pressure gauge. Turn diagnostic station rotary switch to HOLD position. If pressure decreases to less than 10 in. H2O within 2 minutes, system is okay. If pressure does not decrease to less than 10 in. H2O within 2 minutes, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Perform SERVICE BAY TEST for EVAP system. After performing test, go to next step.
Using scan tool, select Read and Record INFO, REVIEW INFO function. Check if any undiagnosed DTCs are displayed. Diagnose affected DTCs. If no additional DTCs are displayed, system is okay.

Check following items

For missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings.
For cracks or punctures in EVAP canister.
For damaged or disconnected source vacuum line, EVAP purge line, vent hose or fuel tank vapor line.
For faulty connections at VCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
For damaged harness. Inspect wiring harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0440: EVAP SYSTEM (4.3L "L", "M", "S" & "T" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions required to set DTC are

No ECT, HO2S, IAT, MAP, TP or VSS sensor DTCs set.
DTC P0125 not active.
No fuel level related DTCs set.
Fuel tank level 12.5-87.5 percent.
System voltage 10-17 volts.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if DTCs P0446, P0452 or P0453 is set. If any of these DTCs are set, diagnose affected DTCs. If no other DTCs are set, go to next step.
Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK VACUUM. If scan tool displays zero in. H2O, go to next step. If scan tool does not display zero in. H2O, repair faulty fuel tank sensor circuit.
Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Reinstall fuel cap. Read and Record FAILURE RECORDS data for DTC P0440. Clear DTCs. Using scan tool, command EVAP vent solenoid ON (closed). Connect EVAP pressure/purge diagnostic station to EVAP service port. Using diagnostic station, attempt to pressurize EVAP system to 5 in. H2O. If specified pressure is achieved, go to next step. If specified pressure is not achieved, go to step 6 .
Maintain EVAP system pressure at 5 in. H2O. Using scan tool, read FUEL TANK VACUUM. If scan tool displays 5 in. H2O, go to step 9 . If scan tool does not display 5 in. H2O, go to step 8 .
Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand-held vacuum pump to EVAP purge line fitting at EVAP canister. Ensure EVAP vent solenoid is still commanded ON (closed). Attempt to apply 5 in. Hg to EVAP canister. If vacuum is maintained as specified, go to step 12 . If vacuum cannot be maintained as specified, go to next step.
Leave system connected as in previous step. Disconnect and plug vent valve hose. Using a hand-held vacuum pump, apply 5 in. Hg. If vacuum can be obtained and held, go to step 17 . If vacuum cannot be obtained or held, go to step 11 .
Disconnect fuel tank vapor line from canister. Attempt to pressurize EVAP system using EVAP Pressure/Purge Diagnostic Station (J-41413). Start engine. Monitor pressure on diagnostic station gauge. If 5 in. H2O can be obtained and held, go to step 18 . If 5 in. H2O cannot be obtained or held, go to step 15 .
Disconnect purge line from canister. Connect vacuum gauge to service port of diagnostic station. Start engine. Command EVAP solenoid valve to 100 percent. If vacuum reading is 12 in. Hg or greater, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vacuum reading is not 12 in. Hg or greater, go to next step.
Disconnect purge line from purge solenoid valve. Start engine. Using scan tool, command EVAP purge solenoid purge solenoid ON (100 percent). If vacuum reading is 12 in. Hg or greater, go to step 14 . If vacuum reading is not 12 in. Hg or greater, go to step 16 .
Check if vent hose is disconnected or damaged. Check EVAP canister for damage. Repair as necessary. After repairs, go to step 19 . If no problem is found, go to step 18 .
Check for missing or faulty fuel filler cap. Check for disconnected, leaking or damaged fuel tank vapor line or EVAP purge line. Repair as necessary. After repairs, go to step 19 . If no problem is found, go to next step.
Using scan tool, command EVAP vent solenoid ON (closed). With EVAP pressure/purge diagnostic station connected to EVAP service port, continuously attempt to pressurize EVAP system to 15 in. H2O by leaving diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41413), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. Repair leak as necessary. After repairs, go to step 19 .
Repair restriction in EVAP purge line. After repairs, go to step 19 .
Repair restriction in fuel tank vapor line. After repairs, go to step 19 .
Replace EVAP purge solenoid valve. After replacing EVAP solenoid valve, go to step 19 .
Replace EVAP vent valve. After replacing EVAP vent valve, go to step 19 .
Replace EVAP canister. After replacing EVAP canister, go to next step.
Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid ON (closed). Using diagnostic station, pressurize EVAP system to 15 in. H2O. Monitor EVAP diagnostic station pressure gauge. Turn diagnostic station rotary switch to HOLD position. If pressure decreases to less than 10 in. H2O within 2 minutes, system is okay. If pressure does not decrease to less than 10 in. H2O within 2 minutes, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Perform SERVICE BAY TEST for EVAP system. After performing test, go to next step.
Using scan tool, select Read and Record INFO, REVIEW INFO function. Check if any undiagnosed DTCs are displayed. Diagnose affected DTCs. If no additional DTCs are displayed, system is okay.

Check following items

For missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings.
For cracks or punctures in EVAP canister.
For damaged or disconnected source vacuum line, EVAP purge line, vent hose or fuel tank vapor line.
For faulty connections at VCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
For damaged harness. Inspect wiring harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0440: EVAP SYSTEM (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM tests the EVAP system for large and small leaks, excess vacuum, purge flow during non-commanded conditions, fuel level and fuel pressure sensor faults, and EVAP purge and vent valve faults.

PCM monitors the fuel tank pressure sensor in order to determine the level of vacuum/pressure in EVAP system. PCM commands both EVAP purge solenoid and EVAP vent valve on when conditions for running this DTC are met in order to apply engine vacuum to EVAP system.

PCM commands EVAP purge solenoid off once system has reached a predetermined level of vacuum. This test checks if vacuum can be achieved in EVAP system. Failure to develop a vacuum may be caused by a large leak or restriction. This DTC sets after twice failing this test. DTC will set when EVAP cannot develop a vacuum greater than a predetermined value.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other EVAP system DTCs are stored as history DTC, diagnose applicable DTC. If other EVAP system related DTCs are not present, go to next step.
Check EVAP system for loose, incorrect, defective or missing fuel tank filler cap. Check for improperly routed, kinked or damaged EVAP system purge lines or damaged EVAP system component. Repair or replace as necessary. After repairs, go to step 21 . If repairs were not necessary, go to next step.
Using scan tool, perform EVAP system SERVICE BAY TEST. If vehicle passes test, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vehicle fails test, go to next step.
Using scan tool, clear DTCs. Turn ignition off. Remove EVAP purge line from solenoid valve. Connect a hand-held vacuum pump to EVAP solenoid valve vacuum port. Apply 10 in. Hg to vacuum port. If vacuum is obtained and held, go to next step. If vacuum cannot be obtained or does not hold, go to step 15 .
Turn ignition off. Install vacuum gauge to EVAP canister side of EVAP purge solenoid valve. Using scan tool, command EVAP purge solenoid 50 percent. If vacuum gauge reads 12 in. Hg or greater, go to step 8 . If vacuum gauge does not read 12 in. Hg or greater, go to next step.
Turn ignition off. Remove EVAP purge solenoid valve from intake manifold. Connect vacuum gauge to vacuum source. Start and operate engine at idle. If vacuum gauge reads 12 in. Hg or greater, go to step 15 . If vacuum gauge does not read 12 in. Hg or greater, go to step 14 .
Turn ignition off. Disconnect and plug EVAP purge line from EVAP canister (line from EVAP purge solenoid valve). Connect a hand-held vacuum pump to EVAP purge line from EVAP purge solenoid valve. Apply 5 in. Hg to purge solenoid valve. If specified vacuum can be obtained and held, go to next step. If specified vacuum cannot be obtained and held, go to step 18 .
Turn ignition off. Disconnect fuel tank vapor line from EVAP canister. Plug EVAP canister port for fuel tank vapor line. Connect vacuum pump to EVAP purge port on EVAP canister. Turn ignition on. Using scan tool, command EVAP vent valve ON (closed). Using vacuum pump, attempt to apply 5 in. Hg. If specified vacuum can be obtained and held, go to step 12 . If specified vacuum cannot be obtained or held, go to next step.
Leave system connected as in step 7 . Disconnect vent line at EVAP vent valve. Plug vent line. Apply 15 in. Hg to vent valve. If specified vacuum can be obtained and held, go to step 16 . If specified vacuum cannot be obtained or held, go to next step.
Inspect EVAP vent line from canister to EVAP vent valve for leaks or missing/damaged "O" rings. Repair or replace as necessary. After repairs, go to step 21 . If no problems were found, go to step 17 .
Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP canister purge and vent valve lines. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP system service port. Ensure gauges are zeroed on diagnostic station. Using scan tool, command EVAP vent solenoid ON (closed). Continuously attempt to pressurize EVAP system by leaving EVAP pressure/purge diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41416), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. After repairs, go to step 21 . If no leaks are present, go to next step.
Check EVAP system for restrictions. Repair as necessary. After repairs, go to step 21 . If no restrictions were found, go to step 19 .
Locate and repair leak at vacuum source to EVAP purge solenoid valve. After repairs, go to step 21 .
Check EVAP purge solenoid valve and purge line for carbon contamination. Replace EVAP purge solenoid valve. After replacing solenoid valve, go to step 21 .
Replace EVAP vent valve. After replacing vent valve, go to step 21 .
Replace EVAP vapor canister. After replacing vapor canister, go to step 21 .
Repair EVAP line from EVAP purge solenoid valve to canister. After repairs, go to step 21 .
With EVAP system pressurized, compare EVAP pressure/purge diagnostic station pressure gauge reading to fuel tank pressure sensor reading on scan tool. Also, compare reading with system depressurized. If fuel tank pressure sensor indicate the actual amount of pressure in EVAP system, go to step 3 . If fuel tank pressure sensor pressure does not indicate the actual amount of pressure in EVAP system, go to next step.
Replace fuel tank pressure sensor. After replacing sensor, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter this DTC. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step 2 .
Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

An accurate indication of fuel level is required for PCM to properly pass or fail this DTC. Always diagnose fuel level sensor DTCs first.

Ensure that battery voltage is 10.5-17.5 volts, fuel level 15-85 percent of full capacity, engine temperature 38-95°F (3.5-35°C). Check for loose, missing, defective or incorrect fuel tank cap, incorrectly routed or defective EVAP system vacuum and vapor lines, malfunctioning or damaged vapor canister.

DTC P0440: EVAP SYSTEM (5.7L "F" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM tests the EVAP system for the following

Large and small leaks.
Excess vacuum.
Purge flow during non-commanded conditions.
Fuel level and fuel pressure sensor faults.
EVAP purge and vent valve faults.

Conditions for setting DTC

DTCs P0107, P0108, P0112, P0113, P0121, P0122, P0123, P0420, P0430, P0500, P0502, P0503, P1111, P1112, P1114, P1115 and HO2S related DTCs not set.
Ignition voltage 10-17 volts.
BARO pressure greater than 75 kPa.
Fuel level 15-85 percent of full capacity.
ECT and IAT 39-86°F (4-30°C).
Start-up engine coolant and intake air temperatures within 16°F (9°C) of each other.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other EVAP system DTCs are stored as history DTC, diagnose applicable DTC. If other EVAP system related DTCs are not present, go to next step.
Check EVAP system for loose, incorrect, defective or missing fuel tank filler cap. Check for improperly routed, kinked or damaged EVAP system purge lines or damaged EVAP system component. Repair or replace as necessary. After repairs, go to step 18 . If repairs were not necessary, go to next step.
Using scan tool, perform EVAP system SERVICE BAY TEST. If vehicle passes test, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vehicle fails test, go to next step.
Turn ignition off. Remove EVAP purge solenoid valve from intake manifold. Install a vacuum gauge to vacuum source. Start and operate engine at idle. If vacuum reading is 12 in. Hg or greater, go to next step. If vacuum reading is not 12 in. Hg or greater, go to step 12 .
Turn ignition off. Install vacuum gauge to EVAP canister side of EVAP purge solenoid valve. Start and operate engine at idle. Using scan tool, command EVAP vent solenoid 100 percent. If vacuum gauge reads 12 in. Hg or greater, go to next step. If vacuum gauge does not read 12 in. Hg or greater, go to step 13 .
Turn ignition off. Disconnect fuel tank vapor and EVAP purge line from EVAP canister. Plug canister fitting for fuel vapor line. Connect a hand-held vacuum pump to EVAP purge line on canister. Turn ignition on. Using scan tool, command EVAP vent valve on (closed). Using vacuum pump, apply 5 in. Hg. If specified vacuum can be obtained and held, go to step 10 . If vacuum cannot be obtained or held, go to next step.
Disconnect vent line at EVAP vent valve. Plug vent line. Apply 5 in. Hg using vacuum pump. If vacuum can be obtained and held, go to step 14 . If vacuum cannot be obtained or held, go to next step.
Check EVAP vent line from canister to EVAP vent valve for leaks. Repair as necessary. After repairs, go to step 18 . If leak is not present, go to step 15 .
Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP canister purge and vent valve lines. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP system service port. Ensure gauges are zeroed on diagnostic station. Using scan tool, command EVAP vent solenoid ON (closed). Continuously attempt to pressurize EVAP system by leaving EVAP pressure/purge diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41416), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. After repairs, go to step 18 . If leaks are not present, go to next step.
Check EVAP system for restrictions. Repair as necessary. After repairs, go to step 18 . If no restrictions are found, go to step 16 .
Locate and repair leak at vacuum source to EVAP purge solenoid valve. After repairs, go to step 18 .
Check EVAP purge solenoid valve and purge line for carbon contamination. Replace EVAP purge solenoid valve. After replacing solenoid valve, go to step 18 .
Replace EVAP vent valve. After replacing vent valve, go to step 18 .
Replace EVAP vapor canister. After replacing vapor canister, go to step 18 .
With EVAP system pressurized, compare EVAP pressure/purge diagnostic station pressure gauge reading to fuel tank pressure sensor reading on scan tool. Also, compare reading with system depressurized. If fuel tank pressure sensor indicate the actual amount of pressure in EVAP system, repeat step 13 . If fuel tank pressure sensor pressure does not indicate the actual amount of pressure in EVAP system, go to next step.
Replace fuel tank pressure sensor. After replacing sensor, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter DTC P0440. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step 2 .
Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

An accurate indication of fuel level is required for PCM to properly pass or fail this DTC. Always diagnose fuel level sensor DTCs first.

Check following items

Battery voltage 10.5-17.5 volts.
Fuel level 15-85 percent of full capacity.
Engine temperature 38-95°F (3.5-35°C).
Loose, missing, defective or incorrect fuel tank cap.
Incorrectly routed or defective EVAP system vacuum and vapor lines.
Malfunctioning or damaged vapor canister.

DTC P0440: EVAP SYSTEM (5.7L "Y" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM tests the EVAP system for large and small leaks, excess vacuum, purge flow during non-commanded conditions, fuel level and fuel pressure sensor faults, and EVAP purge and vent valve faults.

For duplication of DTC, ensure

DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0125, P0420, P0430, P0500, P0502, P0503, P0562, P0563, P1120, P1220, P1221, and HO2S related DTCs are not set.
Ignition voltage is 10-18 volts.
BARO pressure is greater than 75 kPa.
Fuel level is 15-85 percent of full capacity.
ECT and IAT is 39-86°F (4-30°C).
Start-up engine coolant and intake air temperatures are within 16°F (9°C) of each other.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any fuel level sensor or EVAP system DTCs are present, go to applicable DTC. If no fuel level sensor or EVAP system DTCs are present, go to next step.
Inspect EVAP system for the following conditions: Loose, incorrect, defective or missing fuel filler cap. Improperly routed, kinked or damaged EVAP system chassis purge line from vacuum source in engine compartment. Damaged EVAP purge solenoid valve. Improperly routed, kinked or damaged EVAP system chassis purge line from EVAP purge solenoid valve to EVAP canister. Leaking fuel tank vent valve. Repair EVAP system as necessary. After repairs, go to step 21 . If EVAP system is okay, go to next step.
Using scan tool, perform EVAP system SERVICE BAY TEST. If test passes (scan tool indicates 0.7-2.5 volts), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If test does not pass, go to next step.
Turn ignition off. Remove EVAP purge line from canister side of EVAP purge solenoid valve. Connect vacuum gauge to canister side of EVAP purge solenoid valve. Start engine and allow it to idle. Using scan tool, command EVAP purge solenoid valve to 50 percent. If vacuum displayed on gauge is 12 in. Hg or greater, go to step 7 . If vacuum displayed on gauge is not 12 in. Hg or greater, go to next step.
Turn ignition off. Disconnect vacuum source from EVAP purge solenoid valve. Connect vacuum gauge to EVAP purge solenoid valve vacuum source. Start engine and allow it to idle. If vacuum displayed on gauge is 12 in. Hg or greater, go to step 16 . If vacuum displayed on gauge is not 12 in. Hg or greater, go to step 15 .
Turn ignition off. Remove vacuum gauge and reconnect EVAP purge line. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP system service port located on left side of intake manifold, near EVAP purge solenoid valve. Using scan tool, command EVAP vent valve on (closed). Continuously attempt to pressurize EVAP system by leaving EVAP pressure/purge diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41416), attempt to locate EVAP system leak. Repair as necessary. After repairs, go to step 21 . If no leaks are found, go to next step.
Check EVAP system for restrictions. Repair as necessary. After repairs, go to step 21 . If no problem is found, go to next step.
With EVAP system pressurized, compare EVAP pressure/purge diagnostic station pressure gauge reading to fuel tank pressure sensor reading on scan tool. Also compare readings with system depressurized. If scan tool value indicates actual EVAP system pressure, go to next step. If scan tool does not indicate actual EVAP system pressure, go to step 19 .
Turn ignition off. Remove EVAP purge line from canister side of EVAP purge solenoid valve and plug hose end. Disconnect chassis EVAP purge pipe (aluminum/plastic coating) at EVAP canister nylon purge pipe. Connect hand-held vacuum pump to chassis EVAP purge line. Attempt to apply 5 in. Hg vacuum. If vacuum can be obtained and held, go to next step. If vacuum can not be obtained or held, go to step 20 .
Disconnect vapor and EVAP purge lines from EVAP canister. Plug canister fitting for vapor line. Connect hand-held vacuum pump to EVAP purge fitting on EVAP canister. Turn ignition on, with engine off. Using scan tool, command vent valve on (closed). Attempt to apply 5 in. Hg vacuum to EVAP canister. If vacuum can be obtained and held, go to step 14 . If vacuum can not be obtained or held, go to next step.
Leave system connected as in previous step. Disconnect vent line at EVAP vent valve. Plug vent line at EVAP vent valve. Using hand-held vacuum pump, attempt to apply 5 in. Hg vacuum to EVAP canister. If vacuum can be obtained and held, go to step 17 . If vacuum can not be obtained or held, go to next step.
Check line from EVAP canister to vent valve for any defects. Repair as necessary. After repairs, go to step 21 . If no problems are found, go to step 18 .
Remove fuel tanks. Remove tank-to-tank pipe from fuel tank vent valve quick connector and EVAP canister. Reassemble removed fuel tanks and EVAP system components on bench. Plug fuel tank vent valve pipe. Plug all remaining openings necessary for leak testing. Apply soap solution to fuel tanks and all connections. Pressurize fuel tank assembly at fuel tank fill hose to 1.5 psi (0.11 kg/cm 2 ). Air bubbles will indicate leak. Repair as necessary. After repairs, go to step 21 .
Repair vacuum source to EVAP purge solenoid valve. After repairs, go to step 21 .
Replace EVAP purge solenoid valve. After repairs, go to step 21 .
Replace EVAP vent valve. After repairs, go to step 21 .
Replace EVAP vapor canister. After repairs, go to step 21 .
Replace fuel tank pressure sensor. After repairs, go to step 21 .
Replace chassis EVAP pipe as necessary. After repairs, go to next step.
Using scan tool, perform EVAP system SERVICE BAY TEST. If test passes, go to next step. If test does not pass, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

An accurate indication of fuel level is required for PCM to properly pass or fail this DTC. Always diagnose fuel level sensor DTCs first.

Ensure battery voltage is 10.5-18.0 volts, fuel level is 15-85 percent of full capacity, and engine temperature is 38-95°F (3.5-35°C). Check for loose, missing, defective or incorrect fuel tank cap, incorrectly routed or defective EVAP system vacuum and vapor lines, malfunctioning or damaged vapor canister.

DTC P0442: EVAP SYSTEM-SMALL LEAK DETECTED (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

After a calibrated vacuum level is achieved, EVAP canister purge valve is turned off, sealing the system. A leak is detected by monitoring for a decrease in vacuum level over a calibrated period of time, while keeping all other variables constant.

Conditions for setting this DTC

DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0133, P0134 and P1144 are not set.
BARO is greater than 80.8 kPa.
Both ECT and IAT 14-122°F (10-50°C) at engine start-up.
ECT and IAT are within 10 degrees of each other at start-up.
Fuel tank level 15-85 percent.
Engine run time is greater than 2 seconds.
TP sensor between 9-35 percent.
Vacuum decay slope is greater than a calibrated amount during test. Decay slope is proportional to fuel level.

Connect scan tool. Turn ignition on, engine off. Using scan tool, view malfunction history. If DTC P0452, P0453 or P0460 is set, diagnose affected DTC. If DTCs are not present, go to next step.
Using scan tool, select SPECIAL TEST function and run SERVICE BAY TEST. If test indicates PASS, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If test does not indicate PASS, go to next step.
Use EVAP pressure/purge diagnostic station and ultrasound leak detector to locate and repair leak. After repairs, run SERVICE BAY TEST to verify repair.

Check for missing or leaking "O" rings at fuel vapor line connections or fuel sender. Check for cracked or damaged EVAP canister, damaged source vacuum line, EVAP purge line and hose, or fuel tank vapor line. Check for poor connections, terminals, locks at PCM harness connection. Use EVAP pressure/purge diagnostic station and ultrasound leak detector to locate leak.

DTC P0442: EVAP CONTROL SYSTEM-SMALL LEAK DETECTED (2.2L "J" BODY & "S" SERIES & 2.4L "J" & "N" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Evaporative leak detection strategy is based on applying vacuum to EVAP system and monitoring vacuum decay. Powertrain Control Module (PCM) monitors vacuum level by means of fuel tank vacuum sensor input. At a predetermined time, EVAP purge solenoid and EVAP vent solenoid are turned on. This allows engine vacuum to draw a small vacuum on entire EVAP system. After desired vacuum level has been achieved, EVAP purge solenoid is turned off, sealing the system. If a small leak is detected, a DTC P0442 will set.

Conditions for setting this DTC are as follows

DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134 and P1133 not set.
BARO is greater than 75 kPa.
ECT and IAT is 41-84°F (5-29°C) at engine start-up.
IAT not greater than 2°F (1°C) of ECT at engine start-up.
ECT not greater than 12°F (7°C) of IAT at engine start-up.
Fuel tank level is 26-74 percent.
TP angle is 9-35 percent.
EVAP solenoid is enabled.
EVAP system is unable to achieve or maintain vacuum during diagnostic test. Amount of vacuum decay will vary with fuel level.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P0452, P0453 or P0460 is also set, go to that DTC first. If these DTCs are not set, go to next step.
Turn ignition on, with engine off. Using scan tool, command EVAP canister purge and vent valve solenoids on and off. If purge and vent solenoids click on and off, go to next step. If purge and/or vent solenoid does not click, perform PCM diagnosis. See appropriate SYSTEM & COMPONENT TESTING article.
Turn ignition off. Disconnect purge line from fuel tank at EVAP canister. Turn ignition on, engine off. Using scan tool, check fuel tank pressure sensor value. If fuel tank pressure is zero mm Hg, go to step 6 . If fuel tank pressure is not zero mm Hg, go to next step.
Check EVAP purge line from fuel tank to EVAP canister for pinched, kinked or plugged line. Repair as necessary. After repairs, go to step 14 . If line is okay, diagnose using DTC P0452 or P0453 diagnostic tests.
Reconnect all disconnected EVAP hardware. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Using scan tool, command EVAP vent valve on (closed). Pressurize EVAP system to 12 mm Hg using EVAP pressure/purge diagnostic station and place switch in HOLD position. Observe fuel tank pressure on scan tool. If fuel tank pressure is 10 mm Hg, go to next step. If fuel tank pressure is not 10 mm Hg, diagnose using DTC P0452 or P0453 diagnostic tests.
Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid on (closed). Pressurize EVAP system to 15 in. H2O using EVAP Pressure/Purge Diagnostic Station (J-41413). Switch rotary switch to HOLD position and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 9 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to next step.
Turn ignition off. Install Fuel Tank Cap Adapter (J-41415-40). Turn ignition on, engine off. Using scan tool, command EVAP SYSTEM SEAL on. Pressurize EVAP system to 15 in. H2O. Monitor pressure on EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 12 . If pressure does not drop to less than 10 in. H2O within 2 minutes, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank vapor line and EVAP purge line from EVAP canister. Block fuel tank vapor line fitting on canister. Connect a hand-held vacuum pump to EVAP purge line fitting on canister. Ensure EVAP vent solenoid is still commanded on (closed). Attempt to apply vacuum to canister. If 5 in. Hg can be maintained, go to step 12 . If 5 in. Hg cannot be maintained, go to next step.
Check for disconnected or damaged vent hose, or damaged EVAP canister. Repair or replace as necessary. After repairs, go to step 13 . If no problems were found, go to next step.
Replace EVAP vent solenoid. After replacing EVAP vent solenoid, go to step 13 .
Check for faulty fuel cap, leaking filler neck, leaking vapor or purge lines. Repair as necessary. Reconnect all EVAP hardware previously disconnected. Command EVAP vent solenoid on (closed) using scan tool. With EVAP Pressure/Purge Diagnostic Station (J-41413) connected to EVAP system, leave control knob in PRESSURIZED position. Using Ultrasonic Leak Detector (J-41416), locate and repair leak in EVAP system. Fuel tank might have to be partially lowered to be able to check tank connections. After repairs, go to next step.
Pressurize EVAP system to 15 in. H2O using EVAP purge/pressure diagnostic station. Set switch to HOLD position. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 3 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to next step.
Using scan tool, select DTC, CLEAR INFO. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that the diagnostic ran and passed, go to next step. If scan tool does not indicate that the diagnostic ran and passed, repeat step 3 .
Check if additional DTCs are set. If additional DTCs are set, go to applicable DTC test. If no additional DTCs are set, system is okay.

Check for missing or damaged "O" rings at EVAP canister fuel vapor fittings and purge line fittings. Check for cracked EVAP canister. Check for damaged or disconnected vacuum source hose, EVAP purge hose, vent hose or fuel tank vapor hose. Check PCM connector for poor terminal connections. Check for damaged EVAP related wiring harness.

DTC P0442: EVAP SYSTEM-SMALL LEAK DETECTED (3.0L "V" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

During specific operating conditions, ECM performs various tests on Evaporative Emission (EVAP) system. System tests consist of the following series of events.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P0441 or P0446 is also set, diagnose affected DTC first. If either DTCs are not set, go to next step.
Check for disconnected, kinked or deteriorated hoses/lines. Check loose hose connections, missing or loose fuel tank filler cap. Repair as necessary. After repairs, go to step 23 . If no problems were found, go to next step.
Disconnect manifold vacuum source at purge valve. Install vacuum gauge to manifold vacuum source line. Start engine. Operate engine at greater than 2000 RPM and observe vacuum gauge. If vacuum gauge reading is 15 in. Hg, go to next step. If vacuum gauge reading is not 15 in. Hg, go to step 16 .
Turn ignition off. Remove fuel filler cap. Turn ignition on, engine off. Using scan tool, observe fuel tank pressure reading. If scan tool reads -1 to 1 in. H2O, go to next step. If scan tool does not read -1 to 1 in. H2O, diagnose using DTC P0450 diagnostics.
Using EVAP Pressure/Purge Diagnostic Station (J-41413), connect diagnostic station to EVAP service port. Reinstall fuel filler cap. Disconnect ECM harness connector. Remove main relay. Using a fused jumper wire, connect jumper between battery voltage and ignition circuit in relay harness connector terminal. Using another fused jumper wire, ground EVAP vent valve control circuit in ECM harness connector (to close vent). Pressurize EVAP system using EVAP pressure/purge diagnostic station. Monitor pressure using gauge in diagnostic station. If 15 in. H2O can be achieved, go to next step. If 15 in. H2O cannot be achieved, diagnose using DTC P0455 diagnostics.
Maintain system pressure at 15 in. H2O. Observe fuel tank pressure on scan tool. If fuel tank pressure is at 15 in. H2O or greater than 11 in. H2O, go to next step. If fuel tank pressure is not 15 in. H2O or not greater than 11 in. H2O, diagnose using DTC P0450 diagnostics.
Switch rotary switch on diagnostic station to HOLD position and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not drop to less than 10 in. H2O, no problem is found. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect and plug fuel tank vapor line at canister. Restore system pressure to 15 in. H2O. Set rotary switch on diagnostic station to HOLD position and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not drop to less than 10 in. H2O within 2 minutes, go to step 14 .
Disconnect and plug purge line at canister. Restore system pressure to 15 in. H2O. Set rotary switch on diagnostic station to HOLD position and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not drop to less than 10 in. H2O within 2 minutes, go to step 17 .
Disconnect and plug vent line at vent valve. Restore system pressure to 15 in. H2O. Set rotary switch on diagnostic station to HOLD position and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not drop to less than 10 in. H2O within 2 minutes, go to step 18 .
Disconnect and plug vent line at canister. Restore system pressure to 15 in. H2O. Set rotary switch on diagnostic station to HOLD position and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not drop to less than 10 in. H2O within 2 minutes, go to step 20 .
Disconnect and plug purge line at canister. Restore system pressure to 15 in. H2O. Set rotary switch on diagnostic station to HOLD position and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 21 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to step 19 .
Reconnect fuel tank vapor line at canister. Disconnect and plug fuel tank vapor line at fuel tank. Restore system pressure to 15 in. H2O. Set rotary switch on diagnostic station to HOLD position and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 22 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to next step.
Reconnect fuel tank-to canister vapor line at fuel tank. Continuously attempt to pressurize EVAP system by leaving diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41416), check fuel tank for leaks at seams, filler pipe, sending unit and tank pressure sensor. Repair as necessary. After repairs or after checking for leaks, go to step 23 .
Check for damaged vacuum source line, blocked or restricted vacuum port, or for low vacuum. Repair as necessary. After repairs, go to step 23 .
Replace purge valve. Check for contamination causing purge valve to fail. After replacing valve, go to step 23 .
Replace vent valve. After replacing valve, go to step 23 .
Replace EVAP canister. After replacing canister, go to step 23 .
Replace vent line. After replacing line, go to step 23 .
Replace vent-to-canister purge line. After replacing purge line, go to step 23 .
Replace vent-to-canister vapor line. After replacing vapor line, go to next step.
Pressurize EVAP system to 15 in. H2O using EVAP Pressure/Purge Diagnostic Station (J-41413). Monitor pressure using gauge on diagnostic station. Switch rotary switch on diagnostic station to HOLD position. Observe pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 6 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to next step.
Using scan tool, select DTC, CLEAR INFO. Operate vehicle within the conditions for setting this DTC. Check for DTCs. If DTC P0442 is set, repeat step 5 . If DTC P0442 is not set, go to next step.
If additional undiagnosed DTCs are set, go to applicable DTC test. If no additional DTCs are set, system is okay.

Check for missing or faulty fuel filler cap. Check for disconnected, damaged, pinched or blocked vapor lines or hoses. Check for damaged EVAP canister or purge valve. Check for leaking fuel sender assembly "O" ring or leaking fuel tank or fuel filler neck.

DTC P0442: EVAP CONTROL SYSTEM-SMALL LEAK DETECTED (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Evaporative (EVAP) emission system includes the following components, fuel tank, EVAP vent solenoid, fuel tank pressure sensor, fuel pipes and hoses, fuel cap, EVAP lines, EVAP canister and EVAP purge solenoid.

The evaporative leak detection diagnostic strategy is based on applying vacuum to EVAP system and monitoring vacuum decay. PCM monitors vacuum level through the fuel tank pressure sensor input. At a given time, the EVAP purge solenoid and EVAP vent solenoid are turned on, allowing engine vacuum to draw a small vacuum on the entire evaporative emission system. After desired vacuum level has been achieved, the EVAP purge solenoid is turned off, sealing the system. A leak is detected by monitoring for a decrease in vacuum level over a given time period, all other variables remaining constant. A small leak in the system will cause DTC to set.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if DTC P1665 or P1676 is also set. If any of DTCs is present, diagnose affected DTCs. If DTCs are not present, go to next step.
Turn ignition off. Remove fuel filler cap. Turn ignition on. Using scan tool, observe fuel tank pressure. If fuel tank pressure is zero in. H2O, go to next step. If fuel tank pressure in not zero in. H2O, diagnose evaporative system.
Replace fuel filler cap. Using scan tool, capture FAILURE RECORD data for DTC P0440 and clear DTC. Command EVAP vent solenoid on. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Pressurize EVAP system using diagnostic station. Monitor pressure on EVAP pressure gauge on diagnostic station. If pressure is 5 in. H2O, go to next step. If pressure is not 5 in. H2O, go to step 6 .
Turn ignition on, with engine off. Using scan tool, command EVAP vent solenoid on. Using diagnostic station, pressurize EVAP system to 15 in. H2O and monitor pressure on EVAP pressure gauge on diagnostic station. Move rotary switch on diagnostic station to HOLD position. If EVAP pressure decreases to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not decrease as specified, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank vapor line and EVAP purge line from EVAP canister. Block canister fitting for fuel tank pressure line. Connect a hand-held vacuum pump to canister fitting for EVAP purge line. Ensure that EVAP vent solenoid is still commanded on. Apply vacuum to EVAP canister. If vacuum can be maintained at 5 in. Hg, go to step 9 . If vacuum cannot be maintained at 5 in. Hg, go to next step.
Check for disconnected or damaged vent hose. Check for damaged EVAP canister. Repair as necessary. After repairs, go to step 11 . If no problems were found, go to next step.
Replace EVAP purge solenoid. After replacing EVAP solenoid, go to step 11 .
Check for faulty or missing fuel filler cap. Check for disconnected or leaking fuel tank vapor line. Check for disconnected or damaged EVAP purge line. If problem is found, repair as necessary. After repairs, go to step 11 . If no problems were found, go to next step.
Using scan tool, command EVAP vent solenoid on. Continuously attempt to pressurize the EVAP system by leaving the EVAP diagnostic station control knob in the pressurized position. Using the Ultrasonic Leak Detector (J-41416), locate and repair leak in EVAP system. After repairs, go to next step.
Turn ignition on. Using scan tool, command EVAP vent solenoid on. Using EVAP diagnostic station, pressurize EVAP system to 15 in. H2O. Move rotary switch in diagnostic station to HOLD position and observe EVAP pressure gauge. If EVAP pressure decreases to less than 10 in. Hg within 2 minutes, repeat step 3 . If EVAP pressure does not decrease, system is okay.

Check for the following

Cranked and punctured EVAP canister.
Damaged or disconnected source vacuum line, EVAP purge line, vent hose, for fuel tank vapor line.
Poor connection at PCM.
Inspect harness connectors for backed-out terminals, improper mating, broken lock, damaged terminals, or poor wire connection.
Check for intermittent in circuit.
Check for kinked, pinched or plugged vacuum lines to EVAP purge or fuel tank vapor line. Also check for restrictions.
Faulty or damaged evaporative canister.

DTC P0442: EVAP SYSTEM-SMALL LEAK DETECTED (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM will test EVAP system for large and small leaks, excess vacuum, purge flow during non-commanded conditions, fuel pressure and fuel level sensor faults, EVAP purge and vent valve faults.

This DTC will set if there is no misfire, fuel trim, injector control circuit, AIR, EGR, VSS, HO2S, TP, MAP, MAF, ECT or IAT DTCs are set. Battery voltage is 5-18 volts. BARO pressure greater than 75 kPa. Fuel level 15-85 percent of full capacity. ECT and IAT is 39-86°F (4-30°C). Start-up ECT and IAT within 16°F (9°C) of each other. Vacuum in EVAP system decays (leaks) at too fast a rate.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Using scan tool, check if other EVAP system related DTCs (DTC P0440, P0443, P0446, P0449, P0452, P0453, P0462, P0463 or P1441) are set as history DTC. If DTCs are present, diagnose affected DTCs. If DTCs are not present, go to next step.
Check for loose, incorrect, defective or missing fuel filler cap. Check for misrouted, kinked or damaged EVAP system purge lines. Repair as necessary. After repairs, go to step 15 . If no problems were found, go to next step.
Using scan tool, perform SERVICE BAY TEST for EVAP system. If vehicle passes service bay test, fault is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vehicle does not pass the service bay test, go to next step.
Turn ignition off. Disconnect EVAP purge line from EVAP purge solenoid valve. Connect a hand-held vacuum pump to purge connection of EVAP purge solenoid valve. Using vacuum pump, apply vacuum. If 12 in. Hg of vacuum can be obtained and held, go to next step. If 12 in. Hg of vacuum cannot be obtained or held, go to step 10 .
Turn ignition off. Reconnect EVAP purge solenoid valve lines. Disconnect fuel tank vapor and EVAP purge line from EVAP vapor canister. Plug canister fitting for fuel tank vapor line. Connect a hand-held vacuum pump to EVAP purge line canister fitting. Turn ignition on. Using scan tool, command EVAP vent valve closed. Using vacuum pump, apply vacuum. If 5 in. Hg of vacuum can be obtained and held, go to step 9 . If vacuum cannot be obtained and held, go to next step.
Leave system connected. Disconnect vent line at EVAP vent valve. Plug vent line. Using vacuum pump, apply vacuum. If 5 in. Hg of vacuum can be obtained and held, go to step 11 . If vacuum cannot be obtained and held, go to next step.
Inspect EVAP vent line from canister to vent valve for leaks. Replace as necessary. After repairs, go to step 15 . If vent line is okay, go to step 12 .
Install EVAP Pressure/Purge Diagnostic Station (J-41413) and Ultrasonic Leak Detector (J-41416). Ensure gauges on test equipment is zeroed before starting test. Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP vapor canister purge and tank vent lines. Connect diagnostic station to EVAP system service port. Using scan tool, command EVAP vent valve closed. Continuously attempt to pressurize EVAP system by leaving EVAP Pressure/Purge Diagnostic Station control knob to PRESSURIZE position. Using ultrasonic leak detector, locate EVAP system leak. Repair as necessary. After repairs, go to step 15 . If leak is not present, go to step 13 .
Check EVAP purge solenoid valve and purge line for carbon contamination. Replace EVAP purge solenoid valve. After replacing solenoid valve, go to step 15 .
Replace EVAP vent valve. After replacing vent valve, go to step 15 .
Replace EVAP vapor canister. After replacing vapor canister, go to step 15 .
Relieve all system pressure. Using scan tool, use Purge/Seal function to turn EVAP purge solenoid valve on to varying vacuum levels with engine running and quickly seal system with scan tool. While system is sealed, compare EVAP pressure/purge diagnostic station's vacuum gauge to vacuum shown on scan tool from the EVAP fuel tank pressure sensor. If fuel tank pressure sensor indicates actual amount of pressure in EVAP system, go to step 3 . If fuel tank pressure sensor does not indicate actual amount of pressure in EVAP system, go to next step.
Replace fuel tank pressure sensor. After replacing sensor, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter DTC P0442. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step 2 .
Using scan tool, review CAPTURED INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

Perform physical inspection of EVAP system. Ensure that battery voltage is 10.5-17.5 volts, fuel level 15-85 percent of full capacity, ECT 38-95°F (3.5-35°C). Check for loose, missing, defective, or incorrect fuel tank cap, incorrectly routed or defective EVAP system vacuum and vapor lines. Check for malfunctioning or damaged EVAP vapor canister or for charcoal release from EVAP vapor canister.

DTC P0442: EVAP SYSTEM-SMALL LEAK DETECTED (3.8L "C", "F", "G", "H" & "W" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions required to set DTC are

No IAT, MAP, ODM, or TP sensor DTCs set.
DTC P0440 test passed.
Vacuum decay condition indicating a small leak is detected during diagnostic test.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If other DTCs are set, diagnose affected DTCs before proceeding. If DTCs are not set, go to next step.
Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays zero in. H2O go to next step. If scan tool does not display zero in. H2O, repair faulty fuel tank sensor circuit.
Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Reinstall fuel cap. Read and record FAILURE RECORDS data for DTC P0442. Clear DTCs. Connect EVAP pressure/purge diagnostic station to EVAP service port. Using scan tool, command EVAP vent solenoid ON (closed). Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 5 in. H2O. If specified pressure is achieved, go to next step. If specified pressure is not achieved, repair faulty fuel tank sensor circuit.
Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid ON (closed). Using EVAP pressure/purge diagnostic station pressurize EVAP system to 15 in. H2O. Monitor EVAP pressure/purge diagnostic station pressure gauge. Turn EVAP pressure/purge diagnostic station rotary switch to HOLD position. If pressure decreases to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not decrease as specified, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand-held vacuum pump to EVAP purge line fitting at EVAP canister. Ensure EVAP vent solenoid is still commanded ON (closed). Attempt to apply 5 in. Hg to EVAP canister. If vacuum is maintained as specified, go to step 9 . If vacuum cannot be maintained as specified, go to next step.
Check if vent hose is disconnected or damaged. Check EVAP canister for damage. Repair as necessary. After repairs, go to step 11 . If no problem is found, go to next step.
Replace EVAP vent solenoid. After replacing solenoid, go to step 11 .
Check for missing or faulty fuel filler cap. Check for disconnected, leaking or damaged fuel tank vapor line or EVAP purge line. Repair as necessary. After repairs, go to step 11 . If no problem is found, go to next step.
Using scan tool, command EVAP vent solenoid on (closed). With EVAP pressure/purge diagnostic station connected to EVAP service port, attempt to pressurize EVAP system by leaving diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41416), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. After performing OBD system check, go to next step.
Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid on (closed). Using EVAP pressure/purge diagnostic station pressurize EVAP system to 15 in. H2O. Monitor diagnostic station pressure gauge. Turn EVAP pressure/purge diagnostic station rotary switch to HOLD position. If pressure decreases to less than 10 in. H2O within 2 minutes, repeat step 3 . If pressure does not decrease to less than 10 in. H2O within 2 minutes, repair is complete.

Check for the following items

For missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings.
For cracks or punctures in EVAP canister.
For damaged or disconnected source vacuum line, EVAP purge line, vent hose or fuel tank vapor line.
For faulty connections at PCM. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
For damaged harness. Inspect wiring harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0442: EVAP SYSTEM-SMALL LEAK DETECTED (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM will test EVAP system for the following conditions

Large and small leaks (P0440 and P0442).
Excess vacuum (P0446).
Purge flow during non-commanded conditions (P1441).
Fuel pressure and level sensor faults (P0452, P0453, P0461, P0462 and P0463).
EVAP purge and vent valve faults (P1645 and P1646).

PCM monitors the amount of vacuum in EVAP system by monitoring the fuel tank pressure sensor. For this DTC, PCM turns on both the EVAP purge and vent valves when conditions for setting this DTC are met. Engine vacuum is applied to closed EVAP system, checking whether vacuum can develop in EVAP system. DTC will set after 2 consecutive failures during test.

DTC will set when EVAP system cannot develop vacuum.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Using scan tool, check if DTCs P0440, P0446, P0452, P0453, P0461, P0462, P0463, P1441, P1645 and P1646 are present. If any of these DTCs are present, diagnose affected DTCs first. If any of these DTCs are not present, go to next step.
Check for loose, incorrect, defective or missing fuel filler cap. Check for misrouted, kinked or damaged EVAP system purge lines. Repair as necessary. If no problems were found, go to next step.
Ensure battery voltage is 10.5-17.5 volts, fuel level 1.8-16.6 gallons, and engine temperature at 37-95°F (4-35°C). Using scan tool, record data stored when DTC was set. Clear DTCs. Using scan tool, perform SERVICE BAY TEST for EVAP system. If vehicle passes service bay test, fault is intermittent. If vehicle does not pass the service bay test, go to next step.
Turn ignition off. Disconnect EVAP purge line from EVAP purge solenoid valve. Connect a hand-held vacuum pump to purge connection of EVAP purge solenoid valve. Using vacuum pump, apply vacuum. If 12 in. Hg of vacuum can be obtained and held, go to next step. If 12 in. Hg of vacuum cannot be obtained or held, go to step 10 .
Turn ignition off. Reconnect EVAP purge solenoid valve lines. Disconnect fuel tank vapor and EVAP purge line from EVAP vapor canister. Plug canister fitting for fuel tank vapor line. Connect a hand-held vacuum pump to EVAP purge line canister fitting. Turn ignition on. Using scan tool, command EVAP vent valve closed. Using vacuum pump, apply vacuum. If 5 in. Hg of vacuum can be obtained and held, go to step 9 . If vacuum cannot be obtained and held, go to next step.
Leave system connected. Disconnect vent line at EVAP vent valve. Plug vent line. Using vacuum pump, apply vacuum. If 5 in. Hg of vacuum can be obtained and held, go to step 11 . If vacuum cannot be obtained and held, go to next step.
Inspect EVAP vent line from canister to vent valve for leaks. Replace if necessary. If vent line is okay, go to step 12 .
Install EVAP Pressure/Purge Diagnostic Station (J-41413) and Ultrasonic Leak Detector (J-41416). Ensure gauges on test equipment is zeroed before starting test. Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP vapor canister purge and tank vent lines. Connect diagnostic station to EVAP system service port. Using scan tool, command EVAP vent valve closed. Continuously attempt to pressurize EVAP system by leaving EVAP Pressure/Purge Diagnostic Station control knob to PRESSURIZE position. Using ultrasonic leak detector, locate EVAP system leak. Repair as necessary. If leak is not present, go to step 13 .
Check EVAP purge solenoid valve and purge line for carbon contamination. Replace EVAP purge solenoid valve.
Replace EVAP vent valve.
Replace EVAP vapor canister.
Relieve all system pressure. Using scan tool, use Purge/Seal function to turn EVAP purge solenoid valve on to varying vacuum levels with engine running and quickly seal system with scan tool. Leaving EVAP purge solenoid valve on for higher percents or longer times will allow a higher amount of vacuum to develop. A maximum of 12 in. H2O of vacuum can be applied to EVAP system using scan tool. While system is sealed, compare EVAP pressure/purge diagnostic station's vacuum gauge to vacuum shown on scan tool from the EVAP fuel tank pressure sensor. Allow a few seconds for system to stabilize. If both values are within 2 in. H2O of each other, repeat step 3 . If both values are not within 2 in. H2O of each other, go to next step.
Replace EVAP pressure sensor.

Perform physical inspection of EVAP system. Check the following items

Loose, missing, defective, or incorrect fuel tank cap.
Incorrectly routed or defective EVAP system vacuum and vapor lines.
A malfunctioning or damaged EVAP vapor canister.
Check for charcoal release from EVAP vapor canister.

DTC P0442: EVAP SYSTEM-SMALL LEAK DETECTED (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EVAP emission system includes the following components: fuel tank, EVAP vent solenoid, fuel tank pressure sensor, fuel pipes and hoses, vapor lines, fuel cap, EVAP emission canister, purge lines, and EVAP purge solenoid.

Conditions for setting DTC

No ECT, HO2S, IAT, MAP, ODM, TP or VSS sensor DTCs set.
DTC P0125 not active.
Fuel level 12.5-87.5 percent.
Vacuum decay for a period of at least 15 seconds.
Vacuum less than 7 in. H2O for less than 25 seconds.
Vacuum greater than 0.1 in. H2O for longer than 35 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if DTC P0446, P0452 or P0453 is set. If any of this DTC is set, diagnose affected DTC. If DTCs are not set, go to next step.
Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK VACUUM. If scan tool displays zero in. H2O go to next step. If scan tool does not display zero in. H2O, repair faulty fuel tank sensor circuit.
Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Reinstall fuel cap. Read and Record FAILURE RECORDS data for this DTC. Clear DTCs. Using scan tool, command EVAP vent valve on (closed). Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Using diagnostic station, pressurize EVAP system to 15 in. H2O. Monitor pressure on diagnostic station gauge. If pressure decreases to less than 10 in. H2O, go to next step. If pressure does not decrease to less than 10 in. H2O, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand vacuum pump to EVAP purge line fitting at EVAP canister. Ensure EVAP vent solenoid is still commanded ON (closed). Attempt to apply 5 in. Hg to EVAP canister. If vacuum is maintained as specified, go to step 10 . If vacuum cannot be maintained as specified, go to next step.
Leave system connected as in previous step. Disconnect and plug vent hose at vent valve. Using a hand-held vacuum pump, apply 5 in. Hg. If vacuum can be obtained and held, go to step 8 . If vacuum cannot be obtained or held, go to next step.
Check vent hose for leak. Repair as necessary. After repairs, go to step 12 . If hose is okay, go to step 9 .
Replace EVAP vent valve. After replacing vent valve, go to step 12 .
Replace EVAP canister. After replacing canister, go to step 12 .
Check for missing or faulty fuel cap. Check for disconnected or leaking fuel tank vapor line. Check for disconnected or damaged EVAP purge line. Repair as necessary. After repairs, go to step 12 . If no problem is found, go to next step.
Using scan tool, command EVAP vent solenoid on (closed). With EVAP pressure/purge diagnostic station connected to EVAP service port, attempt to pressurize EVAP system to 15 in. H2O by leaving EVAP pressure/purge diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41413), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. After repairs, go to next step.
Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid on (closed). Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 15 in. H2O. Monitor diagnostic station pressure gauge. Turn the diagnostic station rotary switch to HOLD position. If pressure decreases to less than 10 in H2O within 2 minutes, repeat step 2 . If pressure does not decrease as specified, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Using scan tool, perform SERVICE BAY TEST for EVAP system. After performing test, go to next step.
Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

Check following items

For missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings.
For cracks or punctures in EVAP canister.
For damaged or disconnected source vacuum line, EVAP purge line, vacuum line, EVAP purge line, vent hose or fuel tank vapor line.
For faulty connections at VCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
For damaged harness. Inspect wiring harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0442: EVAP SYSTEM-SMALL LEAK DETECTED (4.3L "L", "M", "S" & "T" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions required to set DTC are

No ECT, IAT, MAP, TP or VSS sensor DTCs set.
DTC P0125 not active.
Fuel level 12.5-87.5 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if DTC P0446, P0452 or P0453 is set. If any of these DTCs are set, diagnose affected DTC. If DTCs are not set, go to next step.
Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK VACUUM. If scan tool displays zero in. H2O go to next step. If scan tool does not display zero in. H2O, repair faulty fuel tank sensor circuit.
Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Reinstall fuel cap. Read and Record FAILURE RECORDS data for this DTC. Clear DTCs. Using scan tool, command EVAP vent valve on (closed). Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Using diagnostic station, pressurize EVAP system to 15 in. H2O. Monitor pressure on diagnostic station gauge. If pressure decreases to less than 10 in. H2O, go to next step. If pressure does not decrease to less than 10 in. H2O, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand vacuum pump to EVAP purge line fitting at EVAP canister. Ensure EVAP vent solenoid is still commanded ON (closed). Attempt to apply 5 in. Hg to EVAP canister. If vacuum is maintained as specified, go to step 10 . If vacuum cannot be maintained as specified, go to next step.
Leave system connected as in previous step. Disconnect and plug vent hose at vent valve. Using a hand-held vacuum pump, apply 5 in. Hg. If vacuum can be obtained and held, go to step 8 . If vacuum cannot be obtained or held, go to next step.
Check vent hose for leak. Repair as necessary. After repairs, go to step 12 . If hose is okay, go to step 9 .
Replace EVAP vent valve. After replacing vent valve, go to step 12 .
Replace EVAP canister. After replacing canister, go to step 12 .
Check for missing or faulty fuel cap. Check for disconnected or leaking fuel tank vapor line. Check for disconnected or damaged EVAP purge line. Repair as necessary. After repairs, go to step 12 . If no problem is found, go to next step.
Using scan tool, command EVAP vent solenoid on (closed). With EVAP pressure/purge diagnostic station connected to EVAP service port, attempt to pressurize EVAP system to 15 in. H2O by leaving EVAP pressure/purge diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41413), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. After repairs, go to next step.
Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid ON (closed). Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 15 in. H2O. Monitor EVAP diagnostic station pressure gauge. Turn EVAP diagnostic station rotary switch to HOLD position. If pressure decreases to less than 10 in H2O within 2 minutes, repeat step 2 . If pressure does not decrease as specified, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Using scan tool, perform SERVICE BAY TEST for EVAP system. After performing test, go to next step.
Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

Check following items

Missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings.
Cracks or punctures in EVAP canister.
Damaged or disconnected source vacuum line, EVAP purge line, vacuum line, EVAP purge line, vent hose or fuel tank vapor line.
Faulty connections at VCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
Damaged harness. Inspect wiring harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0442: EVAP SYSTEM-SMALL LEAK DETECTED (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM tests the EVAP system for large and small leaks, excess vacuum, purge flow during non-commanded conditions, fuel level and fuel pressure sensor faults, and EVAP purge and vent valve faults.

PCM commands EVAP purge solenoid off once system has reached a predetermined level of vacuum. This test checks if vacuum can be achieved in EVAP system. Failure to develop a vacuum may be caused by a large leak or restriction. This DTC sets after twice failing this test. DTC will set when vacuum in the EVAP system decays (leaks) at too fast a rate.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other EVAP system DTCs are stored as history DTC, diagnose applicable DTC. If other EVAP system related DTCs are not present, go to next step.
Check EVAP system for loose, incorrect, defective or missing fuel tank filler cap. Check for improperly routed, kinked or damaged EVAP system purge lines or damaged EVAP system component. Repair or replace as necessary. After repairs, go to step 21 . If repairs were not necessary, go to next step.
Using scan tool, perform EVAP system SERVICE BAY TEST. If vehicle passes test, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vehicle fails test, go to next step.
Using scan tool, clear DTCs. Turn ignition off. Remove EVAP purge line from solenoid valve. Connect a hand-held vacuum pump to EVAP solenoid valve vacuum port. Apply 10 in. Hg to vacuum port. If vacuum is obtained and held, go to next step. If vacuum cannot be obtained or does not hold, go to step 15 .
Turn ignition off. Install vacuum gauge to EVAP canister side of EVAP purge solenoid valve. Using scan tool, command EVAP purge solenoid 50 percent. If vacuum gauge reads 12 in. Hg or greater, go to step 8 . If vacuum gauge does not read 12 in. Hg or greater, go to next step.
Turn ignition off. Remove EVAP purge solenoid valve from intake manifold. Connect vacuum gauge to vacuum source. Start and operate engine at idle. If vacuum gauge reads 12 in. Hg or greater, go to step 15 . If vacuum gauge does not read 12 in. Hg or greater, go to step 14 .
Turn ignition off. Disconnect and plug EVAP purge line from EVAP canister (line from EVAP purge solenoid valve). Connect a hand-held vacuum pump to EVAP purge line from EVAP purge solenoid valve. Apply 5 in. Hg to purge solenoid valve. If specified vacuum can be obtained and held, go to next step. If specified vacuum cannot be obtained and held, go to step 18 .
Turn ignition off. Disconnect fuel tank vapor line from EVAP canister. Plug EVAP canister port for fuel tank vapor line. Connect vacuum pump to EVAP purge port on EVAP canister. Turn ignition on. Using scan tool, command EVAP vent valve ON (closed). Using vacuum pump, attempt to apply 5 in. Hg. If specified vacuum can be obtained and held, go to step 12 . If specified vacuum cannot be obtained or held, go to next step.
Leave system connected as in step 7 . Disconnect vent line at EVAP vent valve. Plug vent line. Apply 15 in. Hg to vent valve. If specified vacuum can be obtained and held, go to step 16 . If specified vacuum cannot be obtained or held, go to next step.
Inspect EVAP vent line from canister to EVAP vent valve for leaks or missing/damaged "O" rings. Repair or replace as necessary. After repairs, go to step 21 . If no problems were found, go to step 17 .
Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP canister purge and vent valve lines. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP system service port. Ensure gauges are zeroed on diagnostic station. Using scan tool, command EVAP vent solenoid ON (closed). Continuously attempt to pressurize EVAP system by leaving EVAP pressure/purge diagnostic station control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41416), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. After repairs, go to step 21 . If no leaks are present, go to next step.
Check EVAP system for restrictions. Repair as necessary. After repairs, go to step 21 . If no restrictions were found, go to step 19 .
Locate and repair leak at vacuum source to EVAP purge solenoid valve. After repairs, go to step 21 .
Check EVAP purge solenoid valve and purge line for carbon contamination. Replace EVAP purge solenoid valve. After replacing solenoid valve, go to step 21 .
Replace EVAP vent valve. After replacing vent valve, go to step 21 .
Replace EVAP vapor canister. After replacing vapor canister, go to step 21 .
Repair EVAP line from EVAP purge solenoid valve to canister. After repairs, go to step 21 .
With EVAP system pressurized, compare EVAP pressure/purge diagnostic station pressure gauge reading to fuel tank pressure sensor reading on scan tool. Also, compare reading with system depressurized. If fuel tank pressure sensor indicate the actual amount of pressure in EVAP system, go to step 3 . If fuel tank pressure sensor pressure does not indicate the actual amount of pressure in EVAP system, go to next step.
Replace fuel tank pressure sensor. After replacing sensor, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter this DTC. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step 2 .
Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

An accurate indication of fuel level is required for PCM to properly pass or fail this DTC. Always diagnose fuel level sensor DTCs first.

DTC P0442: EVAP SYSTEM-SMALL LEAK DETECTED (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM will test EVAP system for the following conditions

Large and small leaks.
Excess vacuum.
Purge flow during non-commanded conditions.
Fuel pressure and fuel level sensor faults.
EVAP purge and vent valve faults.

Conditions for setting this DTC

DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0420, P0430, P0500, P0502, P0503, P0562, P0563, P1111, P1112, P1114, P1115, P1120, P1121, and HO2S related DTCs.
BARO pressure greater than 75 kPa.
Fuel level 15-85 percent of full capacity.
ECT and IAT is 39-86°F (4-30°C).
Start-up ECT and IAT within 16°F (9°C) of each other.
Vacuum in EVAP system decays (leaks) at too fast a rate.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Using scan tool, check if other EVAP system related DTCs are set as history DTC. If DTCs are present, diagnose affected DTCs. If DTCs are not present, go to next step.
Check for loose, incorrect, defective or missing fuel filler cap. Check for misrouted, kinked or damaged EVAP system purge lines. Repair as necessary. After repairs, go to step 15 . If no problems were found, go to next step.
Using scan tool, perform SERVICE BAY TEST for EVAP system. If vehicle passes service bay test, fault is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vehicle does not pass the service bay test, go to next step.
Turn ignition off. Disconnect EVAP purge line from EVAP purge solenoid valve. Connect a hand-held vacuum pump to purge connection of EVAP purge solenoid valve. Using vacuum pump, apply vacuum. If 12 in. Hg of vacuum can be obtained and held, go to next step. If 12 in. Hg of vacuum cannot be obtained or held, go to step 10 .
Turn ignition off. Reconnect EVAP purge solenoid valve lines. Disconnect fuel tank vapor and EVAP purge line from EVAP vapor canister. Plug canister fitting for fuel tank vapor line. Connect a hand-held vacuum pump to EVAP purge line canister fitting. Turn ignition on. Using scan tool, command EVAP vent valve closed. Using vacuum pump, apply vacuum. If 5 in. Hg of vacuum can be obtained and held, go to step 9 . If vacuum cannot be obtained and held, go to next step.
Leave system connected. Disconnect vent line at EVAP vent valve. Plug vent line. Using vacuum pump, apply vacuum. If 5 in. Hg of vacuum can be obtained and held, go to step 11 . If vacuum cannot be obtained and held, go to next step.
Inspect EVAP vent line from canister to vent valve for leaks. Replace if necessary. After repairs, go to step 15 . If vent line is okay, go to step 12 .
Install EVAP Pressure/Purge Diagnostic Station (J-41413) and Ultrasonic Leak Detector (J-41416). Ensure gauges on test equipment is zeroed before starting test. Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP vapor canister purge and tank vent lines. Connect diagnostic station to EVAP system service port. Using scan tool, command EVAP vent valve closed. Continuously attempt to pressurize EVAP system by leaving EVAP Pressure/Purge Diagnostic Station control knob to PRESSURIZE position. Using ultrasonic leak detector, locate EVAP system leak. Repair as necessary. After repairs, go to step 15 . If leak is not present, go to step 13 .
Check EVAP purge solenoid valve and purge line for carbon contamination. Replace EVAP purge solenoid valve. After repairs, go to step 15 .
Replace EVAP vent valve. After repairs, go to step 15 .
Replace EVAP vapor canister. After repairs, go to step 15 .
Relieve all system pressure. Using scan tool, use Purge/Seal function to turn EVAP purge solenoid valve on to varying vacuum levels with engine running and quickly seal system with scan tool. While system is sealed, compare EVAP pressure/purge diagnostic station's vacuum gauge to vacuum shown on scan tool from the EVAP fuel tank pressure sensor. If fuel tank pressure sensor indicates actual amount of pressure in EVAP system, go to step 3 . If fuel tank pressure sensor does not indicate actual amount of pressure in EVAP system, go to next step.
Replace fuel tank pressure sensor. After repairs, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter DTC P0442. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step 2 .
Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

Perform physical inspection of EVAP system. Check the following items

Battery voltage between 10.5-17.5 volts.
Fuel level 15-85 percent of full capacity.
ECT 38-95°F (3.5-35°C).
Loose, missing, defective, or incorrect fuel tank cap.
Incorrectly routed or defective EVAP system vacuum and vapor lines.
A malfunctioning or damaged EVAP vapor canister.
Check for charcoal release from EVAP vapor canister.

DTC P0443: EVAP CANISTER PURGE SOLENOID CIRCUIT FAULT (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

The EVAP system draws stored fuel vapors from the charcoal canister. The canister purge solenoid is used to control flow of vapors from canister to intake manifold. PCM controls solenoid with a Pulse Width Modulated (PWM) signal. PCM uses a Generic Field Effect Transistor Driver (GFD) to control solenoid's ground when certain conditions have been met. The GFD driver has the capability to diagnose if circuit has opened or shorted.

DTC will set if feedback signal voltage is greater than 0.3 volt when solenoid is commanded on, or less than 7 volts when solenoid is commanded off.

Connect scan tool. Turn ignition on, engine off. Using scan tool, command EVAP canister purge solenoid on and off. If solenoid clicks on and off when commanded, go to next step. If solenoid does not click, go to step 3 .
Observe status of purge feedback. If scan tool status displays HIGH when commanded off or LOW when commanded on, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If scan tool display is not as indicated, check for short to ground in circuit between EVAP canister purge solenoid and PCM. Repair as necessary. If circuit is okay, replace PCM.
Check EGR fuse located in underhood fuse block. If fuse is okay, go to next step. If fuse is faulty, check for shorted circuit between fuse block and purge solenoid. Replace fuse.
Disconnect solenoid harness connector. Turn ignition on. Connect test light between harness terminals. If test light does not illuminate, go to next step. If test light illuminates, check for short in circuit between EVAP purge solenoid and PCM. Repair as necessary. If circuit is okay, replace PCM.
Using scan tool, command EVAP vent solenoid on. If test light illuminates, replace EVAP purge solenoid. If test light does not illuminate, go to next step.
Using test light connected to ground, probe EVAP purge solenoid harness connector terminal "A". If test light illuminates, check for open in circuit between solenoid and PCM. Repair as necessary. If circuit is okay, replace PCM. If test light does not illuminate, check for open between solenoid and fuse block.

An intermittent open or short in harness will cause DTC P0443 to set. Intermittent conditions can be detected by using scan tool and observing the purge feedback status. Status should be HIGH when solenoid is commanded off and LOW when solenoid is commanded on. Ensure terminal connections are tight. Solenoid resistance should be 19-31 ohms. Check EGR fuse in underhood fuse block.

DTC P0443: EVAP PURGE VALVE CONTROL (3.0L "V" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EVAP purge valve is supplied power via main relay (switched battery feed circuit). ECM controls valve by grounding control circuit via an internal driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by ECM. When ECM is commanding a component on, voltage of control circuit should be low (near zero volt). When ECM is commanding control circuit to component off, voltage should be high (near battery voltage). If fault detection circuit senses a voltage other than what is expected, this DTC will set.

ECM will monitor EVAP purge valve circuit for short to ground, short to voltage, open circuit, open component or an internally shorted or excessively low resistance on EVAP purge valve circuit. When ECM detects any of these malfunctions, this DTC will set and affected driver will be disabled. ECM will continue to test circuit and if fault disappears, driver will be reactivated.

For duplication of DTC, a short to ground, open, or short to battery voltage must be detected on control circuit.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command purge valve on and off. If purge valve turns on and off with each command, go to next step. If purge valve does not turn on and off with each command, go to step 5 .
Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Jumper main relay control circuit to ground. Using DVOM on 10-amp scale, measure current between ground and valve control circuit at ECM harness connector for 2 minutes. If current draw is 0.1-0.75 amp, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not 0.1-0.75 amp, go to next step.
Turn ignition off. Disconnect valve connector. Using DVOM, check resistance between ground and valve control circuit at ECM harness connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 9 .
Turn ignition off. Disconnect valve connector. Connect test light between valve harness connector terminals. Turn ignition on. Using scan tool, command valve on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
With test light connected to ground, probe valve harness connector switched battery feed circuit. If test light is on, go to next step. If test light is off, go to step 10 .
Turn ignition off. Reconnect valve connector. Disconnect ECM harness connector located in engine compartment relay center. Jumper main relay control circuit to ground. Using a fused jumper wire connected to ground, probe valve control circuit at ECM harness connector. If valve operates, go to step 12 . If valve does not operate, go to step 9 .
Check connections at valve. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 11 .
Repair valve control circuit. After repairs, go to step 14 .
Repair switched battery feed circuit to purge valve. After repairs, go to step 14 .
Replace purge valve. After replacing valve, go to step 14 .
Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 14 . If connections and terminals are okay, go to next step.
Replace ECM. New ECM must be programmed with theft deterrent module frequency code currently on vehicle. After replacing ECM, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0443 is set, go to step 2 . If DTC P0443 is not set, go to next step.
If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.

Check for damaged wiring harness. If harness appears to be okay, observe scan tool while moving related connectors and wiring harnesses. A change in scan tool display may help to locate fault.

DTC P0443: EVAP PURGE SOLENOID VALVE CONTROL CIRCUIT (3.1L "W" BODY & 3.4L "U" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM uses an output driver module to control ground (control) circuit to EVAP purge solenoid valve. Output driver module is also used by PCM to diagnose the output of this circuit. If an improper voltage level has been detected on EVAP purge solenoid valve control circuit for 30 seconds or more, DTC will set. For duplication of DTC, ensure ignition is on.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, increase and decrease purge solenoid up and down. If solenoid responds as commanded, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If solenoid does not respond as commanded, go to next step.
Turn ignition off. Disconnect purge solenoid. Turn ignition on, with engine off. Using a test light connected to ground, probe purge solenoid ignition feed circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Connect test light between purge solenoid ignition feed and ground circuits. Using scan tool, command purge solenoid on and off. If test light turns on and off, go to step 8 . If test light does not turn on and off, go to next step.
If test light remains illuminated, go to step 7 . If test light remains off, go to next step.
Check purge solenoid for an open or short to voltage. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
Check purge solenoid control circuit for a short to ground. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
Check for faulty purge solenoid connections. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
Check for faulty PCM connections. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
Repair purge solenoid ignition feed circuit. After repairs, go to step 13 .
Replace purge solenoid. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Operate vehicle under conditions required to set DTC. Check for DTCs. If DTC P0443 is set, go to step 2 . If no DTCs are set, system is okay.

Intermittent can be caused by poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Check connectors for backed-out terminals, improper mating, broken lock, damaged terminal or poor terminal to wire connection.

DTC P0443: EVAP PURGE VALVE CONTROL (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Ignition voltage is supplied directly to EVAP purge solenoid valve. PCM controls valve by grounding control circuit via an internal driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by PCM. When PCM is commanding a component on, voltage of control circuit should be low (near zero volt). When PCM is commanding control circuit to component off, voltage should be high (near battery voltage). If fault detection circuit senses a voltage other than what is expected, this DTC will set.

PCM will monitor EVAP purge valve circuit for short to ground, short to voltage, open circuit, open component or an internally shorted or excessively low resistance on EVAP purge valve circuit. When PCM detects any of these malfunctions, this DTC will set and affected driver will be disabled. PCM will continue to test circuit and if fault disappears, driver will be reactivated.

This DTC will set when there is short to ground, open, or short to battery voltage detected on control circuit and the condition is present for at least 30 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command purge solenoid valve on and off. If purge valve turns on and off with each command, go to next step. If purge valve does not turn on and off with each command, go to step 5 .
Turn ignition off. Disconnect PCM harness connector. Using DVOM on 10-amp scale, measure current between ground and valve control circuit at PCM harness connector for 2 minutes. If current draw is 0.1-0.75 amp, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not 0.1-0.75 amp, go to next step.
Turn ignition off. Disconnect solenoid valve connector. Using DVOM, check resistance between ground and valve control circuit at ECM harness connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 9 .
Turn ignition off. Disconnect solenoid valve connector. Connect test light between valve harness connector terminals. Turn ignition on. Using scan tool, command valve on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
With test light connected to ground, probe valve harness connector switched battery feed circuit. If test light is on, go to next step. If test light is off, go to step 10 .
Turn ignition off. Reconnect solenoid valve connector. Disconnect PCM harness connector. Jumper main relay control circuit to ground. Using a fused jumper wire connected to ground, probe valve control circuit at PCM harness connector. If solenoid valve operates, go to step 12 . If solenoid valve does not operate, go to step 9 .
Check connections at solenoid valve. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 11 .
Repair EVAP purge solenoid valve control circuit. After repairs, go to step 14 .
Repair switched battery feed circuit to EVAP purge solenoid purge valve. After repairs, go to step 14 .
Replace EVAP purge solenoid valve. After replacing solenoid valve, go to step 14 .
Check for poor connections and terminal tension at PCM harness connector. Repair as necessary. After repairs, go to step 14 . If connections and terminals are okay, go to next step.
Replace PCM. New PCM must be programmed with theft deterrent module frequency code currently on vehicle. After replacing PCM, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0443 is set, go to step 2 . If DTC P0443 is not set, go to next step.
Using scan tool, review CAPTURED INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTC. If no other DTCs are present, system is okay.

Check for misrouted wiring harness. Inspect harness to ensure that it is not routed too close to high voltage wires (spark plug wires) or too close to high current devices (generator, motors, solenoids). Check for damaged wiring harness. If harness appears to be okay, observe scan tool while moving related connectors and wiring harnesses. A change in scan tool display may help to locate fault.

DTC P0443: EVAP PURGE SOLENOID CONTROL CIRCUIT (3.8L "C", "F", "G" & "W" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

This DTC will set when there is short to ground, open, or short to battery voltage detected on control circuit and the condition is present for at least 30 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, increase and decrease purge solenoid up and down. If solenoid responds as commanded, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If solenoid does not respond as commanded, go to next step.
Turn ignition off. Disconnect purge solenoid. Turn ignition on, with engine off. Using a test light connected to ground, probe purge solenoid ignition feed circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Connect test light between purge solenoid ignition feed and ground circuits. Using scan tool, command purge solenoid on and off. If test light turns on and off, go to step 8 . If test light does not turn on and off, go to next step.
If test light remains illuminated, go to step 7 . If test light remains off, go to next step.
Check purge solenoid for an open or short to voltage. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
Check purge solenoid control circuit for a short to ground. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
Check for faulty purge solenoid connections. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
Check for faulty PCM connections. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
Repair purge solenoid ignition feed circuit. After repairs, go to step 13 .
Replace purge solenoid. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Operate vehicle under conditions required to set DTC. Check for DTCs. If DTC P0443 is set, go to step 2 . If no DTCs are set, system is okay.

DTC P0443: EVAP PURGE SOLENOID CONTROL CIRCUIT (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Ignition voltage is supplied directly to EVAP canister purge solenoid. PCM controls solenoid by grounding control circuit through an internal switch called a driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by PCM.

When PCM is commanding a component on, voltage of control circuit should be low (near zero volts). When PCM is commanding control circuit to a component off, voltage potential of circuit should be high (near battery voltage). If fault detection circuit senses a voltage other than what is expected, fault line status will change, causing DTC to set.

DTC will set when PCM detects that the commanded state of the driver and actual state of the control circuit do not match and this condition is present for a minimum of 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command EVAP solenoid on and off. If solenoid turns on and off as commanded, go to next step. If solenoid does not turn on or off when commanded, go to step 5 .
Turn ignition off. Disconnect PCM harness connector C2. Connect a fused jumper wire to control circuit at PCM harness connector. Turn ignition on, with engine off. Using DVOM, set DVOM to 40-amp scale. Check current draw from solenoid control circuit in PCM harness connector to ground for 2 minutes. If current draw is less than 0.75 amp (but not zero), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not less than 0.75 amp, go to next step.
Turn ignition off. Disconnect EVAP solenoid. Using DVOM, check resistance from solenoid control circuit in PCM harness connector and ground. If resistance is not infinite, go to step 12 . If resistance is infinite, go to step 10 .
Turn ignition off. Disconnect EVAP solenoid. Connect test light between solenoid harness connector terminals. Warm engine to normal operating temperature. Operate engine at idle. Using scan tool, command solenoid on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
Connect test light ground and probe ignition feed circuit in solenoid harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Turn ignition off. Reconnect EVAP solenoid. Disconnect PCM harness connector. Turn ignition on. Connect a fused jumper wire between ground and PCM harness connector, solenoid control circuit. If solenoid operates, go to step 9 . If solenoid does not operate, go to step 10 .
Check connections at EVAP solenoid. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 12 .
Check connections at PCM. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
Repair faulty EVAP solenoid control circuit. After repairs, go to step 14 .
Repair faulty EVAP solenoid ignition feed circuit. After repairs, go to step 14 .
Replace EVAP solenoid. After replacing solenoid, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0443: EVAP PURGE SOLENOID CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

DTC will set when the following conditions are present

Engine speed greater than 600 RPM.
Ignition voltage 6-16 volts.
PCM detects commanded state of driver and actual state do not match.
Conditions met for 10 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command EVAP solenoid on and off. If solenoid turns on and off as commanded, go to next step. If solenoid does not turn on or off when commanded, go to step 5 .
Turn ignition off. Disconnect PCM harness connector containing solenoid control circuit. Turn ignition on. Using DVOM, set DVOM to 10-amp scale. Check current from solenoid control circuit in PCM harness connector to ground for 2 minutes. If current draw is less than 0.75 amp (but not zero), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not less than 0.75 amp, go to next step.
Turn ignition off. Disconnect EVAP solenoid. Using DVOM, check resistance from solenoid control circuit in PCM harness connector and ground. If resistance is not infinite, go to step 12 . If resistance is infinite, go to step 10 .
Turn ignition off. Disconnect EVAP solenoid. Connect test light between solenoid harness connectors. Turn ignition on. Using scan tool, command solenoid on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
Connect test light ground and probe ignition feed circuit in solenoid harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Turn ignition off. Reconnect EVAP solenoid. Disconnect PCM harness connector containing solenoid control circuit. Turn ignition on. Connect a fused jumper wire between ground and PCM connector (harness side), solenoid control circuit. If solenoid operates, go to step 9 . If solenoid does not operate, go to step 10 .
Check connections at EVAP solenoid. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 12 .
Check connections at PCM. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
Repair faulty EVAP solenoid control circuit. After repairs, go to step 14 .
Repair faulty EVAP solenoid ignition feed circuit. After repairs, go to step 14 .
Replace EVAP solenoid. After replacing solenoid, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0443. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0446: EVAP SYSTEM CANISTER VENT BLOCKED (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

After a calibrated vacuum level is achieved, EVAP canister purge valve is turned off, sealing the system. A restricted or blocked EVAP canister path is detected by opening or releasing the vent solenoid and monitoring for a rapid change in pressure from the pressure sensor. With EVAP vent solenoid open, any vacuum in the system should release rapidly unless path is blocked. A blockage can be caused by the following conditions

Faulty EVAP vent solenoid.
Plugged, kinked or pinched vent hose.
Shorted EVAP vent solenoid driver circuit (should set P0448).
Plugged EVAP canister.

Conditions for setting this DTC

DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0133, P0134 and P1144 are not set.
BARO is greater than 80.8 kPa.
Both ECT and IAT 14-122°F (10-50°C) at engine start-up.
ECT and IAT are within 10 degrees of each other at start-up.
Fuel tank level 15-85 percent.
Engine run time is greater than 2 seconds.
TP sensor 9-35 percent.
EVAP canister purge solenoid is at 50 percent PWM with 60 seconds of start engine run time.
EVAP system is unable to release vacuum when diagnostic test is run.

Connect scan tool. Turn ignition on, engine off. Using scan tool, view malfunction history DTCs. If DTC P0443 or P0449 is present, diagnose affected DTC. If DTCs are not present, go to next step.
Using scan tool, command both the canister purge solenoid and EVAP vent solenoid on and off. If both solenoids click when commanded on and off, go to next step. If either or both solenoids does not click when commanded on and off, go to step 4 .
Using scan tool, run SERVICE BAY test. If test indicates PASS, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If test does not indicate PASS, check for a kinked or pinched vent solenoid hose. Repair as necessary. If hose is okay, replace vent solenoid.
Disconnect harness connector to affected solenoid. Using a test light, connect test light between harness connector terminals. Turn ignition on, engine off. If test light does not illuminate, go to next step. If test light illuminates, check control circuit for short to ground. Repair as necessary. If circuit is okay, replace faulty PCM.
Using scan tool, command solenoid on. If test light illuminates, replace solenoid. If test light does not illuminate, connect test light between ground and source circuit. If test light does not illuminate, repair open in source circuit. If test light illuminates, check for open in control circuit or faulty terminal connection. Repair as necessary. If circuit or terminal connection is okay, replace PCM.

Check for missing or leaking "O" rings at fuel vapor line connections or fuel sender. Check for cracked or damaged EVAP canister. Check for damaged source vacuum line, EVAP purge line, EVAP vent hose or fuel tank vapor line. Check for poor connections at PCM. Use EVAP pressure/purge diagnostic station and ultrasound leak detector to locate leak.

DTC P0446: EVAP SYSTEM CANISTER VENT BLOCKED (2.2L "J" BODY & "S" SERIES & 2.4L "J" & "N" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

With EVAP vent solenoid open, any vacuum in system should decrease quickly unless vent path is blocked.

Conditions required to test for DTC are

DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134 and P1133 not set.
BARO is greater than 75 kPa.
ECT and IAT temperature 41-84°F (5-29°C) at engine start-up.
IAT is not greater than 2°F (1°C) of ECT at engine start-up.
ECT is not greater than 12°F (7°C) of IAT at engine start-up.
Fuel tank level is 26-74 percent.
TP angle is 9-35 percent.
EVAP system is unable to achieve or maintain vacuum during diagnostic test. The amount of decay will vary with fuel level.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P0452, P0453 or P0460 is also set, diagnose affected DTC first. If these DTCs are not set, go to next step.
Turn ignition on, with engine off. Using scan tool, command EVAP canister purge and vent valve solenoids on and off. If purge and vent solenoids click on and off, go to next step. If purge and/or vent solenoid does not click, perform PCM diagnosis. See appropriate SYSTEM & COMPONENT TESTING article.
Turn ignition off. Disconnect purge line from fuel tank at EVAP canister. Turn ignition on, engine off. Using scan tool, check fuel tank pressure sensor value. If fuel tank pressure is zero mm Hg, go to step 6 . If fuel tank pressure is not zero mm Hg, go to next step.
Check EVAP purge line from fuel tank to EVAP canister for pinched, kinked or plugged line. Repair or replace as necessary. After repairs, go to step 14 . If line is okay, diagnose using DTC P0452 or P0453 diagnostic tests.
Reconnect all disconnected EVAP hardware. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Using scan tool, command EVAP vent valve on (closed). Pressurize EVAP system to 5 in. H2O using diagnostic station. Observe fuel tank pressure on scan tool. If fuel tank pressure is 12 mm Hg, go to next step. If fuel tank pressure is not 12 mm Hg, diagnose using DTC P0452 or P0453 tests.
Maintain EVAP pressure at 5 in. H2O. Command EVAP vent solenoid off (open) while observing EVAP pressure gauge. If EVAP pressure return line is zero in. H2O within 5 seconds, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If EVAP pressure return line is not zero in. H2O within 5 seconds, go to next step.
Disconnect large vent hose from EVAP canister marked AIR. Switch rotary switch on diagnostic station to PURGE position. Start and warm engine to normal operating temperature. Observe vacuum gauge for 5 seconds while holding engine speed to 2500 RPM. If vacuum reading remains less than 10 in. H2O, go to next step. If vacuum reading does not remain less than 10 in. Hg, go to step 11 .
Check for kinked, pinched or blocked EVAP vent hose between EVAP canister and EVAP vent solenoid. Repair as necessary. After repairs, go to step 12 . If hose is okay, go to next step.
Replace EVAP vent solenoid. After replacing solenoid, go to step 12 .
Replace EVAP canister. After replacing canister, go to next step.
Reconnect all disconnected EVAP hardware. Turn ignition on, with engine off. Using scan tool, command EVAP vent solenoid on (closed). Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 5 in. H2O. Set rotary switch on pressure/purge diagnostic station to HOLD position. Observe EVAP pressure gauge. If pressure decreases to zero in. H2O within 5 seconds, go to next step. If pressure does not decrease to zero in. H2O within 5 seconds, repeat step 3 .
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 3 .
Using scan tool, check for additional undiagnosed DTCs. If additional DTCs are set, diagnose applicable DTCs. If no additional DTCs are set, system is okay.

Check for kinked, pinched or plugged vent hose between EVAP canister and EVAP vent solenoid. Check PCM connector for poor terminal connections. Check for damaged EVAP related wiring harness.

DTC P0446: EVAP VENT VALVE CONTROL (3.0L "V" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EVAP vent valve is supplied power via main relay (switched battery feed circuit). ECM controls valve by grounding control circuit via an internal driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by ECM. When ECM is commanding a component on, voltage of control circuit should be low (near zero volt). When ECM is commanding control circuit to component off, voltage should be high (near battery voltage). If fault detection circuit senses a voltage other than what is expected, this DTC will set.

ECM will monitor EVAP vent valve circuit for short to ground, short to voltage, open circuit, open component or an internally shorted or excessively low resistance on EVAP valve circuit. When ECM detects any of these malfunctions, this DTC will set and affected driver will be disabled. ECM will continue to test circuit and if fault disappears, driver will be reactivated.

For duplication of DTC, a short to ground, open, or short to battery voltage must be detected on control circuit.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command vent valve on and off. If vent valve turns on and off with each command, go to next step. If vent valve does not turn on and off with each command, go to step 5 .
Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Jumper main relay control circuit to ground. Using DVOM on 10-amp scale, measure current between ground and valve control circuit at ECM harness connector for 2 minutes. If current draw is 0.1-0.75 amp, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not 0.1-0.75 amp, go to next step.
Turn ignition off. Disconnect valve connector. Using DVOM, check resistance between ground and valve control circuit at ECM harness connector. If resistance is infinite, go to step 11 . If resistance is not infinite, go to step 9 .
Turn ignition off. Disconnect valve connector. Connect test light between valve harness connector terminals. Turn ignition on. Using scan tool, command valve on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
With test light connected to ground, probe valve harness connector switched battery feed circuit. If test light is on, go to next step. If test light is off, go to step 10 .
Turn ignition off. Reconnect valve connector. Disconnect ECM harness connector located in engine compartment relay center. Jumper main relay control circuit to ground. Using a fused jumper wire connected to ground, probe valve control circuit at ECM harness connector. If valve operates, go to step 12 . If valve does not operate, go to step 9 .
Check connections at valve. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 11 .
Repair valve control circuit. After repairs, go to step 14 .
Repair switched battery feed circuit to vent valve. After repairs, go to step 14 .
Replace vent valve. After replacing valve, go to step 14 .
Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 14 . If connections and terminals are okay, go to next step.
Replace ECM. New ECM must be programmed with theft deterrent module frequency code currently on vehicle. After replacing ECM, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0446 is set, go to step 2 . If DTC P0446 is not set, go to next step.
If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.

Check for damaged wiring harness. If harness appears to be okay, observe scan tool while moving related connectors and wiring harnesses. A change in scan tool display may help to locate fault.

DTC P0446: EVAP CANISTER VENT BLOCKED (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

A restricted or blocked EVAP vent path is detected by monitoring fuel tank pressure during normal operation (EVAP vent solenoid open, EVAP purge solenoid normal). With the EVAP vent solenoid open, vacuum level in the system should be very low, unless the vent path is blocked. A blockage can be caused by the following conditions

Faulty EVAP vent solenoid (stuck closed).
Plugged, kinked or pinched vent hose.
Shorted EVAP vent solenoid driver circuit.
Plugged evaporative canister.

An incorrect fuel tank pressure sensor signal is detected by monitoring fuel tank pressure when ignition is first turned on during a cold start. If fuel tank pressure signal is out of range, EVAP diagnostic will not be able to detect leaks. If any of the conditions described are present, DTC P0446 will set.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if DTC P1676 is also set. If DTC P1676 is present, diagnose DTC first. If DTC P1676 is not present, go to next step.
Turn ignition on. Using scan tool, capture FAILURE RECORD data for DTC P0446 and clear DTC. Turn ignition off. Remove fuel filler cap. Using scan tool, observe fuel tank pressure on scan tool. If fuel tank pressure is zero in. Hg, go to next step. If fuel tank pressure is not zero in. Hg, diagnose EVAP control system.
Replace fuel filler cap. Using scan tool, command EVAP vent solenoid on. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Pressurize EVAP system using diagnostic station. Monitor pressure on EVAP pressure gauge on diagnostic station. If pressure is 5 in. H2O, go to next step. If pressure is not 5 in. H2O, diagnose EVAP control system.
Maintain EVAP pressure at 5 in. H2O. Using scan tool, command EVAP vent solenoid off (open) while observing EVAP pressure gauge on diagnostic station. If EVAP pressure changes to zero in. H2O within 5 seconds, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If pressure does not change, go to next step.
Disconnect large vent hose (marked AIR) from EVAP canister. Move rotary on diagnostic station to PURGE position. Start and operate engine to normal operating temperature. Using scan tool, command purge solenoid on (open). Monitor vacuum gauge on diagnostic station for 5 seconds while holding engine speed at 2500 RPM. If vacuum remains less than -45 in. H2O, go to next step. If vacuum does not remain less than -45 in. H2O, go to step 9 .
Check for disconnected, kinked or damaged vent hose between EVAP canister and vent solenoid. Repair as necessary. After repairs, go to step 10 . If no problems were found, go to next step.
Replace EVAP vent solenoid. After replacing solenoid, go to step 10 .
Replace EVAP canister. After replacing canister, go to next step.
Using scan tool, command EVAP vent solenoid on. Pressurize the EVAP system to 5 in. H2O. Move rotary switch in diagnostic station to HOLD and observe EVAP pressure gauge. Command EVAP vent solenoid off (open). Observe EVAP pressure on gauge. If EVAP pressure decreases to zero in. H2O within 5 seconds, system is okay. If EVAP pressure does not decrease, repeat step 3 .

Check for the following

Poor connection at PCM.
Inspect harness connectors for backed-out terminals, improper mating, broken lock, damaged terminals, or poor wire connection.
Check for intermittent, open or shorted circuit.
Check for kinked, pinched or plugged vent hose.

DTC P0446: EVAP SYSTEM CANISTER VENT BLOCKED (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM will test the EVAP system for large and small leaks (DTC P0440 and P0442), excess vacuum (P0446), purge flow during non-commanded conditions (P1441), fuel pressure sensor and fuel level faults (P0452, P0453, P0462 and P0463), and EVAP purge and vent valve faults (P0443 and P0449).

DTC will set when EVAP system exceeds a vacuum threshold or if there is too much system vacuum present at the start of this test.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P0449 is also set, diagnose DTC P0449 before proceeding. If DTC P0449 is not set, check EVAP system for improperly routed, kinked or damaged EVAP purge and tank vent lines. Repair as necessary. After repairs, go to step 15 . If no problems were found, go to next step.
Turn ignition off. Remove fuel filler cap. Wait 30 seconds, then replace filler cap. Turn ignition on, with engine off. Using scan tool, monitor EVAP fuel tank pressure sensor display. If scan tool displays -10 in. H2O or less, go to next step. If scan tool does not display -10 in. H2O or less, go to step 10 .
Start and operate engine at idle. Using scan tool, select EVAP PURGE/SEAL function. Command enough EVAP purge to obtain -10 in. H2O, then seal the system. While monitoring EVAP fuel tank pressure sensor display, command EVAP vent valve OPEN (press Exit). If pressure sensor reading drops to near zero when zero percent EVAP purge is commanded and vent valve opened, fault is not present. If pressure reading does not drop to near zero when zero percent EVAP purge is commanded and vent valve opened, go to next step.
Turn ignition off. Disconnect fuel tank vapor and EVAP purge lines from EVAP vapor canister. Plug canister fitting for fuel tank vapor line. Connect a hand-held vacuum pump to EVAP purge line canister fitting. Turn ignition on, with engine off. Using scan tool, command EVAP vent valve ON (closed). Using vacuum pump, apply and hold 5 in. Hg. Command EVAP vent valve OFF (open). If vacuum drops when vent valve is opened, go to step 8 . If vacuum does not drop when vent is opened, go to next step.
Leave system connected as in previous step. Disconnect and plug vent line at EVAP vent valve. Using vacuum pump, apply 5 in. Hg. Monitor vacuum pump gauge as plug from vent line is removed. If vacuum drops, go to step 11 . If vacuum does not drop, go to next step.
Check EVAP vent line from EVAP vent valve for restrictions. Replace as necessary. After repairs, go to step 10 . If no problem is found, go to step 12 .
Check fuel tank vapor line for restriction. Replace as necessary. After replacing vapor line, go to step 15 . If vapor line is okay, go to next step.
Turn ignition off. Remove plug and vacuum pump. Reconnect EVAP vapor canister purge and vent lines. Connect EVAP pressure/purge diagnostic station to EVAP system service port. Operate engine. Using scan tool, select Purge/Seal function to command EVAP vent solenoid ON to varying vacuum levels with engine running and quickly seal the system using scan tool. Compare EVAP pressure/purge diagnostic station's vacuum gauge and scan tool's reading. If both readings are within plus or minus 2 in. Hg of each other, go to step 2 . If both readings are not within plus or minus 2 in. Hg of each other, go to step 13 .
Turn ignition off. Disconnect EVAP fuel tank pressure sensor harness connector. Disconnect PCM harness connector C1. Using a DVOM, check resistance of sensor ground circuit between PCM harness connector and EVAP fuel tank pressure sensor harness connector. If resistance is 5 ohms or less, go to step 13 . If resistance is not 5 ohms or less, go to step 14 .
Replace EVAP vent valve. After replacing vent valve, go to step 15 .
Replace EVAP vapor canister. After replacing vapor canister, go to step 15 .
Replace EVAP fuel tank pressure sensor. After replacing sensor, go to step 15 .
Repair open in EVAP fuel tank pressure sensor ground circuit. After repairs, go to next step.
Using scan tool, select DTC and CLEAR DTC INFO functions. Clear DTCs. Operate vehicle within conditions required to set DTC. If scan tool displays that this test ran and passed, go to next step. If scan tool does not display that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

Check for missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings. Check for kinked, pinched or plugged vent hose. Check for faulty connections at PCM. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection or for damaged harness. Inspect wiring harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0446: EVAP SYSTEM CANISTER VENT BLOCKED (3.8L "C", "F", "G", "H" & "W" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions required to set DTC are

No IAT, MAP, ODM, or TP sensor DTCs set.
Start-up ECT is 40-86°F (4-30°C).
Start-up ECT is not greater than 14°F (8°C), but greater than start-up IAT.
Start-up IAT is 40-86°F (4-30°C).
Start-up IAT is not greater than 4°F (2°C), but greater than start-up ECT.
Fuel tank level 15-85 percent.
BARO greater than 75 kPa.
Fuel tank pressure NOT -1.5 to 1.5 in. H2O when ignition is turned on.

No IAT, MAP, ODM, or TP sensor DTCs set.
DTC P0442 test passed.
Normal EVAP system operation is commanded (EVAP vent solenoid open, EVAP purge solenoid normal).
Fuel tank pressure less than -10 in. H2O.
Conditions present for 30 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P1675 is also set, diagnose DTC P1675 before proceeding. If DTC is not set, go to next step.
Turn ignition on. Read and record FAILURE RECORDS data for DTC P0446. Clear DTCs. Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays zero in. H2O, go to next step. If scan tool does not display zero in. H2O, repair faulty fuel tank sensor circuit.
Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Reinstall fuel cap. Using scan tool, command EVAP vent solenoid ON (closed). Connect EVAP pressure/purge diagnostic station to EVAP service port. Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 5 in. H2O. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays 5 in. H2O, go to next step. If scan tool does not display 5 in. H2O, repair faulty fuel tank sensor circuit.
Maintain EVAP system pressure at 5 in. H2O. Using scan tool, command EVAP vent solenoid OFF (open). Monitor EVAP pressure/purge diagnostic station pressure gauge. If pressure decreases to zero in. H2O within 5 seconds, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If pressure does not decrease as specified, go to next step.
Disconnect vent hose, marked AIR, from EVAP canister. Switch EVAP pressure/purge diagnostic station rotary switch to PURGE. Start engine and allow it to reach operating temperature. Monitor vacuum gauge for 5 seconds while holding engine speed at 2500 RPM. If vacuum remains at less than 30 in. H2O, go to next step. If vacuum does not remain as specified, go to step 9 .
Check if vent hose is between EVAP canister and EVAP solenoid is kinked, pinched or blocked. Repair as necessary. After repairs, go to step 10 . If no problem is found, go to next step.
Replace EVAP vent solenoid. After replacing solenoid, go to step 10 .
Replace EVAP canister. After replacing canister, go to next step.
Using scan tool, command EVAP vent solenoid ON (closed). With EVAP pressure/purge diagnostic station connected to EVAP service port, pressurize EVAP system to 5 in. H2O. Switch EVAP pressure/purge diagnostic station rotary switch to HOLD. Using scan tool, command EVAP vent solenoid OFF (open). If pressure decreases to zero in. H2O within 5 seconds, repair is complete. If pressure does not decrease as specified, return to step 3 .

Check following items

For missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings. Check for kinked, pinched or plugged vent hose.
For faulty connections at PCM. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
For damaged harness. Inspect wiring harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0446: EVAP SYSTEM CANISTER VENT BLOCKED (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM will test EVAP system for the following conditions

Large and small leaks (P0440 and P0442).
Excess vacuum (P0446).
Purge flow during non-commanded conditions (P1441).
Fuel pressure and level sensor faults (P0452, P0453, P0461, P0462 and P0463).
EVAP purge and vent valve faults (P1645 and P1646).

DTC will set when EVAP system cannot develop vacuum.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check for improperly routed, kinked or damaged EVAP purge and tank vent lines. Check for damaged EVAP system component(s). Repair or replace as necessary. If no problems were found, go to next step.
Turn ignition off. Remove fuel filler cap. Wait 30 seconds and then replace fuel cap. Turn ignition on, engine off. Using scan tool, monitor EVAP fuel tank pressure sensor display. If scan tool reading is -10 in. H2O or less, go to next step. If scan tool reading is not -10 in. H2O or less, go to step 10 .
Start and operate engine at idle. Using scan tool, select EVAP purge/seal function. While monitoring EVAP fuel tank pressure sensor display, command EVAP purge to obtain -10 in. H2O. While monitoring EVAP fuel tank pressure sensor display, command EVAP vent valve open (pressing EXIT). If EVAP fuel tank pressure sensor quickly drops to near zero in. H2O when zero percent EVAP purge is commanded and vent valve is opened, fault is not present. If reading is not as specified, go to next step.
Turn ignition off. Disconnect fuel tank vapor and EVAP purge lines from EVAP vapor canister. Plug canister fitting for fuel tank vapor line. Connect a hand-held vacuum pump to EVAP purge line canister fitting. Using vacuum pump, apply 5 in. Hg. While monitoring vacuum pump gauge, command EVAP vent valve off (open). If vacuum drops when vent valve is opened, go to step 8 . If vacuum does not drop when valve is opened, go to next step.
Leave system connected. Disconnect vent line at EVAP vent valve. Plug vent line. Using vacuum pump, apply 5 in. Hg. While monitoring vacuum pump gauge, remove plug from vent line. If vacuum drops when plug is removed, go to step 11 . If vacuum does not drop when plug is removed, go to next step.
Inspect EVAP vent line from canister to vent valve for restrictions. Replace vent line if necessary. If vent line is okay, go to step 12 .
Check fuel tank vapor line for restriction. Replace vapor line is necessary. If vapor line is okay, go to next step.
Install EVAP Pressure/Purge Diagnostic Station (J-41413) and Ultrasonic Leak Detector (J-41416). Ensure gauges on test equipment is zeroed before starting test. Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP vapor canister purge and tank vent lines. Connect diagnostic station to EVAP system service port. Operate vehicle until EVAP purge solenoid valve can be commanded on with scan tool. Use Purge/Seal function on scan tool to turn EVAP purge solenoid valve on to varying vacuum levels with engine running and quickly seal system with scan tool. Leaving EVAP purge solenoid valve on for higher percents or longer times will allow a higher amount of vacuum to develop. A maximum of -14 in. H2O of vacuum can be applied to EVAP system using scan tool. While system is sealed, compare EVAP pressure/purge diagnostic station's vacuum gauge to vacuum shown on scan tool from the EVAP fuel tank pressure sensor. Allow a few seconds for system to stabilize. If both values are within ±2 in. H2O, repeat step 2 . If both values are not within ±2 in. H2O, go to step 13 .
Turn ignition off. Disconnect EVAP fuel tank pressure sensor harness connector. Disconnect PCM harness connector C1. Using DVOM, check resistance of sensor ground circuit between PCM connector and EVAP fuel tank pressure sensor. If resistance is 5 ohms or less, go to step 13 . If resistance is not 5 ohms or less, go to step 14 .
Replace EVAP vent valve.
Replace EVAP vapor canister.
Replace EVAP fuel tank pressure sensor.
Repair open in EVAP fuel tank pressure sensor ground circuit.

Perform physical inspection of EVAP system. Check the following items

Loose, missing, defective, or incorrect fuel tank cap.
Incorrectly routed/defective EVAP system vacuum and vapor lines.
Stuck closed EVAP vent valve.
Restricted or blocked EVAP system hose.
Restricted or stuck closed fuel tank rollover valve.
A malfunctioning or damaged EVAP vapor canister.
Check for charcoal release from EVAP vapor canister.

DTC P0446: EVAP CANISTER VENT VALVE PERFORMANCE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

VCM monitors performance of EVAP system by applying a predetermined level of vacuum to EVAP system, then monitors the vacuum decay rate. VCM sets this DTC if vacuum decay rate is greater than a predetermined value.

Conditions for setting DTC

No ECT, HO2S, IAT, MAP, TP or VSS DTCs set.
DTC P0125 not active.
ECT and IAT greater than 39°F (4°C) but less than 86°F (30°C).
BARO pressure greater than 73 kPa.
Excess vacuum present in EVAP system.
Fuel level greater than 10-85 percent of full tank.
System voltage greater than 10 volts but less than 17 volts.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, observe fuel tank pressure. If fuel tank pressure is -1 to 1 in. H2O, go to next step. If fuel tank pressure is not -1 to 1 in. H2O, diagnose fuel tank pressure sensor. See appropriate SYSTEM & COMPONENT TESTING article.
Install fuel filler cap. Install EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Ensure gauges on test equipment is zeroed before starting test. Using scan tool, command EVAP vent valve closed. Attempt to pressurize EVAP system to 5 in. H2O using diagnostic station. Monitor pressure using gauge on diagnostic station. If scan tool indicates that fuel tank pressure is -1 to 1 in. H2O, go to next step. If scan tool does not indicate that fuel tank pressure is -1 to 1 in. Hg, diagnose EVAP control system. See appropriate SYSTEM & COMPONENT TESTING article.
Maintain EVAP pressure at 5 in. H2O. Using scan tool, command EVAP vent valve off (open). If EVAP pressure returns to -1 to 1 in. H2O within 10 seconds, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If EVAP pressure does not return to -1 to 1 in. H2O within 10 seconds, go to next step.
Switch rotary switch on diagnostic station to RELEASE PRESSURE position. Disconnect vent hose from EVAP canister. Disconnect fuel tank vapor line and EVAP purge line from EVAP canister. Block fuel tank vapor line fitting at EVAP canister. Connect a hand-held vacuum pump to EVAP purge line fitting on EVAP canister. Apply 5 in. Hg. If 5 in. Hg can be obtained and held, go to step 11 . If vacuum cannot be obtained or held, go to next step.
Check for kinked, pinched or blocked vent hose between EVAP canister and vent valve. Repair as necessary. After repairs, go to step 13 . If vent hose is okay, go to next step.
Turn ignition off. Disconnect vent valve connector. Turn ignition on, engine off. Connect a test light between battery voltage and vent valve connector terminal "A". If test light illuminates, go to next step. If test light does not illuminate, go to step 12 .
Turn ignition off. Disconnect VCM harness connector. Connect test light between battery voltage and EVAP vent valve connector terminal "A". If test light illuminates, go to next step. If test light does not illuminate, go to step 12 .
Repair short to ground in EVAP vent control circuit. After repairs, go to step 13 .
Replace EVAP vent valve. After replacing valve, go to step 13 .
Check EVAP vapor canister. After replacing canister, go to step 13 .
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, command EVAP vent valve on (closed). Using diagnostic station, pressurize EVAP system to 5 in. H2O. Using scan tool, command EVAP vent valve off (open). Observe gauge on diagnostic station. If EVAP pressure returns to zero in. H2O within 10 seconds, go to next step. If EVAP pressure does not return to zero in. H2O, repeat step 2 .
Using scan tool, select DTC, CLEAR INFO function. Perform SERVICE BAY TEST for EVAP system. After performing test, go to next step.
Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

Perform physical inspection of EVAP system. Check the following items

Battery voltage 10.5-17.5 volts.
Fuel level 15-85 percent of full capacity.
ECT 38-95°F (3.5-35°C).
Loose, missing, defective, or incorrect fuel tank cap.
Incorrectly routed or defective EVAP system vacuum and vapor lines.
A malfunctioning or damaged EVAP vapor canister.
Check for charcoal release from EVAP vapor canister.

DTC P0446: EVAP SYSTEM VENT VALVE PERFORMANCE (4.3L "L", "M", "S" & "T" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Conditions for setting DTC are

No ECT, HO2S, IAT, MAP, TP or VSS sensor DTCs set.
DTC P0125 not active.
ECT and IAT 39-86°F (4-30°C).
Start-up IAT not greater than 14.9°F (8.3°C) than start-up ECT.
BARO greater than 72.5 kPa.
Excess vacuum present in EVAP system.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays zero in. H2O, go to next step. If scan tool does not display zero in. H2O, perform fuel tank sensor circuit diagnosis. See appropriate BASIC DIAGNOSTIC PROCEDURES article.
Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Reinstall fuel cap. Using scan tool, command EVAP vent solenoid ON (closed). Connect EVAP pressure/purge diagnostic station to EVAP service port. Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 5 in. H2O. Using scan tool, read FUEL TANK VACUUM. If scan tool displays 5 in. H2O, go to next step. If scan tool does not display 5 in. H2O, repair faulty fuel tank sensor circuit.
Maintain EVAP system pressure at 5 in. H2O. Using scan tool, command EVAP vent solenoid OFF (open). Monitor EVAP pressure/purge diagnostic station pressure gauge. If pressure decreases to zero in H2O within 5 seconds, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If pressure does not decrease as specified, go to next step.
Disconnect vent and fuel tank vapor hose from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Switch EVAP pressure/purge diagnostic station rotary switch to RELEASE position. Connect a hand-held vacuum pump to EVAP purge line fitting on EVAP canister. Apply 5 in. Hg. If specified vacuum can be obtained, go to step 11 . If specified vacuum cannot be obtained, go to next step.
Check if vent hose is between EVAP canister and EVAP solenoid is kinked, pinched or blocked. If a problem is found, repair as necessary. After repairs, go to step 13 . If no problem is found, go to next step.
Turn ignition off. Disconnect vent valve harness connector. Turn ignition on, engine off. Using a test light connected to battery voltage, probe harness connector terminal "A". If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Turn ignition off. Disconnect VCM harness connector. Connect test light between battery voltage and EVAP vent valve harness connector terminal "A". If test light does not illuminate, go to next step. If test light does not illuminate, go to step 12 .
Repair short to ground in EVAP vent valve control circuit. After repairs, go to step 13 .
Replace EVAP vent valve. After replacing EVAP vent valve, go to step 13 .
Replace EVAP canister. After replacing EVAP canister, go to step 13 .
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, command EVAP vent solenoid ON (closed). With EVAP pressure/purge diagnostic station connected to EVAP service port, pressurize EVAP system to 5 in. H2O. Switch EVAP pressure/purge diagnostic station rotary switch to HOLD. Using scan tool, command EVAP vent solenoid OFF (open). If pressure decreases to zero in H2O within 5 seconds, go to next step. If pressure does not decrease as specified, repeat step 2 .
Using scan tool, select DTC and CLEAR DTC INFO functions. Clear DTCs. Perform EVAP SERVICE BAY TEST. After performing service bay test, go to next step.
Check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, system is okay.

Check following items

For missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings.
For faulty connections at VCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
For damaged harness. Inspect wiring harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0446: EVAP SYSTEM VENT VALVE PERFORMANCE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

DTC will set when EVAP vacuum decay rate is greater that a predetermined value and condition is present for greater than 2 seconds or when vacuum present in EVAP system is greater that a predetermined value and condition is present for greater than 4 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays zero in. Hg, go to next step. If scan tool does not display zero in. Hg, perform fuel tank sensor circuit diagnosis. See DTC P0453 test.
Inspect for improperly routed, kinked or damaged EVAP purge and tank vent lines. Repair as necessary. After repairs, go to step 13 . If repairs were not necessary, go to next step.
Ensure battery voltage is 10.5-17.5 volts, fuel level is 15-85 percent of full capacity and engine temperature is between 38-95°F (4-35°C). Check for loose, missing, defective or incorrect fuel tank cap. Check for incorrectly routed or defective EVAP system vacuum and vapor lines. Check for malfunctioning or damaged vapor canister or for charcoal release from canister. Using scan tool, perform EVAP system SERVICE BAY TEST. If system passed the test, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If system did not pass the test, go to next step.
Clear DTCs using scan tool. Turn ignition off. Disconnect fuel tank vapor and EVAP purge lines from EVAP vapor canister. Plug canister port for fuel tank vapor line. Connect a hand-held vacuum pump to EVAP purge line canister fitting. Turn ignition on, with engine off. Using scan tool, command EVAP vent valve ON (closed). Using vacuum pump, apply 5 in. Hg. Command EVAP vent valve OFF (open). Monitor vacuum pump gauge. If vacuum drops when vent valve is opened, go to step 8 . If vacuum does not drop when vent valve is opened, go to next step.
Leave system connected as in step 5 . Disconnect and plug vent line at EVAP vent valve. Using vacuum pump, apply 5 in. Hg. Remove plug from vent line. Monitor vacuum pump gauge. If vacuum drops when vent line is unplugged, go to step 10 . If vacuum does not drop when vent line is unplugged, go to next step.
Inspect EVAP vent line from canister to vent valve for restrictions. Repair as necessary. After repairs, go to step 13 . If restriction is not found, go to step 11 .
Inspect fuel tank vapor line for restriction. Repair as necessary. After repairs, go to step 13 . If restriction is not found, go to next step.
Install EVAP Pressure/Purge Diagnostic Station (J-41413). Ensure gauges on test equipment is zeroed before starting test. Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP vapor canister purge and tank vent lines. Connect diagnostic station to EVAP system service port. Turn ignition on, with engine off. Using scan tool, command EVAP vent valve closed. Using Pressure/Purge Diagnostic Station, pressurize EVAP system. Allow system to stabilize (on scan tool) and then rotate diagnostic station's selector to OFF/HOLD position. Compare diagnostic station's pressure gauge and fuel tank pressure on scan tool. If fuel tank pressure sensor indicates actual amount of pressure in EVAP system, go to step 4 . If fuel tank pressure sensor does not indicates the actual amount of vacuum in EVAP system, go to step 12 .
Replace EVAP vent valve. After replacing EVAP vent valve, go to step 13 .
Replace EVAP canister. After replacing EVAP canister, go to step 13 .
Replace fuel tank pressure sensor. After replacing pressure sensor, go to next step.
Using scan tool, select DTC and CLEAR DTC INFO functions. Clear DTCs. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO and REVIEW INFO function. If any undiagnosed DTCs are set, go to appropriate DTC test.

Check for missing or damaged "O" rings at EVAP canister fuel vapor and purge line fittings, check for faulty connections at PCM, inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Check for damaged harness to EVAP vent solenoid, EVAP purge solenoid, and fuel tank pressure sensor for intermittent open or short.

DTC P0446: EVAP CANISTER VENT BLOCKED (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM monitors performance of EVAP system by applying a predetermined level of vacuum to EVAP system, then monitors the vacuum decay rate. PCM sets this DTC if vacuum decay rate is greater than a predetermined value.

DTC will set when the following conditions are present

DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0420, P0430, P0452, P0453, P0500, P0502, P0503, P0562, P0563, P1111, P1112, P1114, P1115, P1120, P1121, or H2OS related DTCs are not set.
Ignition voltage is 10-18 volts.
BARO pressure is greater than 75 kPa.
Fuel level is 15-85 percent of full capacity.
ECT and IAT are 39-86°F (4-30°C).
Start-up ECT and IAT are within 16°F (9°C) of each other.
EVAP vacuum decay rate is greater than predetermined value.
Vacuum present in EVAP system is greater than predetermined value.
Conditions present for more than 4 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check for loose, incorrect, defective or missing fuel filler cap. Check for misrouted, kinked or damaged EVAP system purge lines. Repair as necessary. After repairs, go to step 12 . If no problems were found, go to next step.
Using scan tool, perform SERVICE BAY TEST for EVAP system. If vehicle passes service bay test, fault is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If vehicle does not pass the service bay test, go to next step.
Turn ignition off. Reconnect EVAP purge solenoid valve lines. Disconnect fuel tank vapor and EVAP purge line from EVAP vapor canister. Plug canister fitting for fuel tank vapor line. Connect a hand-held vacuum pump to EVAP purge line canister fitting. Turn ignition on. Using scan tool, command EVAP vent valve closed. Using vacuum pump, apply vacuum. If 5 in. Hg of vacuum can be obtained and held, go to step 7 . If vacuum cannot be obtained and held, go to next step.
Leave system connected. Disconnect vent line at EVAP vent valve. Plug vent line. Using vacuum pump, apply vacuum. If 5 in. Hg of vacuum can be obtained and held, go to step 9 . If vacuum cannot be obtained and held, go to next step.
Check EVAP vent line from canister to EVAP vent valve for restrictions. Repair as necessary. After repairs, go to step 12 . If vent line is okay, go to step 10 .
Check fuel vapor line for restriction. Repair as necessary. After repairs, go to step 12 . If vapor line is okay, go to next step.
Install EVAP Pressure/Purge Diagnostic Station (J-41413) and Ultrasonic Leak Detector (J-41416). Ensure gauges on test equipment is zeroed before starting test. Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP vapor canister purge and tank vent lines. Connect diagnostic station to EVAP system service port. Using scan tool, command EVAP vent valve closed. Continuously attempt to pressurize EVAP system by leaving EVAP Pressure/Purge Diagnostic Station control knob to PRESSURIZE position. If fuel tank pressure sensor indicates the actual amount of vacuum in EVAP system, go to step 3 . If fuel tank pressure sensor does not indicate actual amount of vacuum in EVAP system, go to step 11 .
Replace EVAP vent valve. After replacing valve, go to step 12 .
Replace EVAP vapor canister. After replacing canister, go to step 12 .
Replace fuel tank pressure sensor. After replacing sensor, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter DTC P0442. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step 2 .
Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

Perform physical inspection of EVAP system. Check the following items

Battery voltage 10.5-18.0 volts.
Fuel level 15-85 percent of full capacity.
ECT 38-95°F (3.5-35°C).
Loose, missing, defective, or incorrect fuel tank cap.
Incorrectly routed or defective EVAP system vacuum and vapor lines.
A malfunctioning or damaged EVAP vapor canister.
Check for charcoal release from EVAP vapor canister.

DTC P0449: EVAP SYSTEM VENT SOLENOID CIRCUIT FAULT (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM supplies ground to energize (open) the EVAP solenoid, allowing vacuum to purge the canister. The ground is Pulse Width Modulated (PWM), pulse on and off several times per second, to control flow of purge vapors from the canister. A feedback detection circuit in PCM monitors circuit for proper operation. When solenoid is commanded on, PCM feedback should be low, and when commanded off, should be high. If feedback is not low or high as expected, DTC P0449 will be set.

PCM continually monitors the vent solenoid circuit. DTC will set when, solenoid is commanded on and feedback voltage is greater than 3 volts, or solenoid is commanded off and feedback voltage is less than 7 volts.

Connect scan tool. Turn ignition on, engine off. Using scan tool, command EVAP canister vent solenoid on and off. If solenoid clicks when commanded, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If solenoid does not click, go to next step.
Check IGN 1 fuse located in passenger compartment fuse block. If fuse is okay, go to next step. If fuse is faulty, check circuit between EVAP canister vent solenoid and fuse block. Repair as necessary. If circuit is okay, replace solenoid. Replace fuse.
Disconnect EVAP canister vent solenoid harness connector. Turn ignition on. Connect test light between solenoid terminals. If test light does not illuminate, go to next step. If test light illuminates, check for short in circuit between EVAP canister vent solenoid and PCM. Repair as necessary. If circuit is okay, replace PCM.
Using scan tool, command EVAP vent solenoid on. If test light illuminates, replace EVAP vent solenoid. If test light does not illuminate, go to next step.
Turn ignition on. Using test light connected to ground, probe EVAP canister vent solenoid harness connector terminal "A". If test light illuminates, go to next step. If test light does not illuminate, repair open in circuit between solenoid and fuse block.
Check for open in circuit between EVAP canister vent solenoid harness connector "B" and PCM. Repair as necessary. If circuit is okay, check harness connector to PCM. If connector is okay, replace PCM.

An intermittent open or short in harness will cause DTC P0449 to set. Check harness connectors and terminals. EVAP vent solenoid resistance should be 15-35 ohms. Check IGN fuse in passenger compartment fuse block.

DTC P0449: EVAP VENT SOLENOID VALVE CONTROL CIRCUIT (3.1L "W" BODY & 3.4L "U" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM uses an output driver module to control ground (control) circuit to EVAP vent solenoid valve. Output driver module is also used by PCM to diagnose the output of this circuit. If an improper voltage level has been detected on EVAP vent solenoid valve control circuit for 30 seconds or more, DTC will set. For duplication of DTC, ensure ignition is on.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command vent solenoid on and off. If solenoid responds as commanded, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If solenoid does not respond as commanded, go to next step.
Turn ignition off. Disconnect vent solenoid. Turn ignition on, with engine off. Using a test light connected to ground, probe vent solenoid ignition feed circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Connect test light between vent solenoid ignition feed and ground circuits. Using scan tool, command vent solenoid on and off. If test light turns on and off, go to step 8 . If test light does not turn on and off, go to next step.
If test light remains illuminated, go to step 7 . If test light remains off, go to next step.
Check vent solenoid control circuit for an open or short to voltage. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
Check vent solenoid control circuit for a short to ground. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
Check for faulty vent solenoid connections. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
Check for faulty PCM connections. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
Repair vent solenoid ignition feed circuit. After repairs, go to step 13 .
Replace vent solenoid. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Operate vehicle under conditions required to set DTC. Check for DTCs. If DTC P0449 is set, go to step 2 . If no DTCs are set, system is okay.

DTC P0449: EVAP VENT SOLENOID VALVE CONTROL CIRCUIT (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Ignition voltage is supplied directly to EVAP vent valve relay coil. PCM controls solenoid by grounding control circuit through an internal switch called a driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by PCM.

DTC will set when engine speed is greater than 80 RPM, ignition voltage 9-18 volts, PCM detects commanded state of driver and actual state does not match or a short to ground, open circuit, or a short to battery voltage is detected on control circuit and these conditions are met for 30 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command solenoid on and off. If solenoid turns on and off as commanded, go to next step. If solenoid does not turn on or off when commanded, go to step 5 .
Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Using DVOM in 10-amp scale, check current from solenoid control circuit in PCM harness connector to ground for 2 minutes. If current draw is less than 0.1-0.75 amp, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not less than 0.1-0.75 amp, go to next step.
Turn ignition off. Disconnect solenoid connector. Using DVOM, check resistance from solenoid control circuit in PCM harness connector and ground. If resistance is not infinite, go to step 11 . If resistance is infinite, go to step 9 .
Turn ignition off. Disconnect solenoid connector. Connect test light between solenoid harness connectors. Turn ignition on. Using scan tool, command solenoid on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
Connect test light to ground and probe ignition feed circuit in solenoid harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Turn ignition off. Reconnect solenoid harness connector. Disconnect PCM harness connector. Turn ignition on. Connect a fused jumper wire between ground and PCM harness connector, solenoid control circuit. If solenoid operates, go to step 12 . If solenoid does not operate when energized, go to step 9 .
Check connections at solenoid. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 11 .
Repair solenoid control circuit. After repairs, go to step 14 .
Repair ignition feed circuit to solenoid. After repairs, go to step 14 .
Replace solenoid. After replacing solenoid, go to step 14 .
Check for poor connections/terminals at PCM harness connector. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0449. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0449: EVAP CANISTER VENT SOLENOID VALVE CONTROL CIRCUIT (3.8L "C", "F", "G" & "W" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Ignition voltage is supplied directly to EVAP vent valve solenoid. PCM controls solenoid by grounding control circuit through an internal switch called a driver. Primary function of driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by PCM.

DTC will set when PCM detects that the commanded state of the driver and actual state of the control circuit do not match and condition is present for a minimum of 30 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command vent solenoid on and off. If solenoid responds as commanded, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If solenoid does not respond as commanded, go to next step.
Turn ignition off. Disconnect vent solenoid. Turn ignition on, with engine off. Using a test light connected to ground, probe vent solenoid ignition feed circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Connect test light between vent solenoid ignition feed and ground circuits. Using scan tool, command vent solenoid on and off. If test light turns on and off, go to step 8 . If test light does not turn on and off, go to next step.
If test light remains illuminated, go to step 7 . If test light remains off, go to next step.
Check vent solenoid control circuit for an open or short to voltage. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
Check vent solenoid control circuit for a short to ground. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
Check for faulty vent solenoid connections. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
Check for faulty PCM connections. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
Repair vent solenoid ignition feed circuit. After repairs, go to step 13 .
Replace vent solenoid. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Operate vehicle under conditions required to set DTC. Check for DTCs. If DTC P0449 is set, go to step 2 . If no DTCs are set, system is okay.

DTC P0449: EVAP CANISTER VENT SOLENOID VALVE CONTROL CIRCUIT (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

DTC will set when PCM detects that the commanded state of the driver and actual state of the control circuit do not match and condition is present for a minimum of 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, command solenoid on and off. If solenoid turns on and off as commanded, go to next step. If solenoid does not turn on or off when commanded, go to step 5 .
Turn ignition off. Disconnect PCM harness connector C2. Turn ignition on. Using DVOM, set DVOM to 40-amp scale. Check current from solenoid control circuit in PCM harness connector to ground for 2 minutes. If current draw is less than 0.75 amp (but not zero), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not less than 0.75 amp, go to next step.
Turn ignition off. Disconnect solenoid connector. Using DVOM, check resistance from solenoid control circuit in PCM harness connector and ground. If resistance is infinite, go to step 14 . If resistance is not infinite, go to step 15 .
Turn ignition off. Remove underhood electrical center housing side shield. Release and pivot electrical center up to access Blue 12-pin connector. Disconnect connector. Turn ignition on, with engine off. Using a test light connected to battery voltage, probe test light to pin "F" of male terminal connector. Using scan tool, command EVAP vent solenoid on and off. If test light illuminates when vent solenoid is commanded on and off, go to next step. If test light does not illuminate when vent solenoid is commanded on and off, go to step 8 .
Turn ignition off. Reconnect Blue 12-pin connector to underhood electrical center. Disconnect EVAP purge solenoid harness connector. Connect test light between solenoid harness connector terminals. Turn ignition on. Using scan tool, command EVAP purge solenoid on and off. If test light turns on and off when commanded, go to step 9 . If test light does not turn on and off when commanded, go to next step.
Connect test light to ground. Probe test light to ignition feed circuit on solenoid harness connector. If test light illuminates, go to step 12 . If test light does not illuminate, go to step 13 .
Turn ignition on. Reconnect Blue 12-pin connector to underhood electrical center. Disconnect PCM harness connector C2. Turn ignition on, with engine off. Using a fused jumper wire connected to ground, momentarily probe solenoid control circuit in PCM harness connector. If solenoid clicks when circuit is grounded and opened, go to step 10 . If solenoid does not click when circuit is grounded and opened, go to step 11 .
Check connections at solenoid. Repair as necessary. After repairs, go to step 19 . If connections are okay, go to step 14 .
Check connections at PCM. Repair as necessary. After repairs, go to step 19 . If connections are okay, go to step 18 .
Repair faulty solenoid control circuit between PCM and Blue 12-pin connector. After repairs, go to step 19 .
Repair faulty solenoid control circuit between solenoid and Blue 12-pin connector. After repairs, go to step 19 .
Repair faulty solenoid ignition feed circuit. After repairs, go to step 19 .
Replace EVAP vent solenoid. After replacing solenoid, go to step 19 .
Turn ignition off. Remove underhood electrical center housing side shield. Lift underhood electrical center up to access Blue 12-pin connector. Disconnect connector. Check resistance between ground and solenoid control circuit connector male terminal pin "F". If resistance is infinite, go to next step. If resistance is not infinite, go to step 17 .
Repair short to ground in EVAP solenoid control circuit between 12-pin connector and EVAP solenoid. After repairs, go to step 19 .
Repair short to ground in EVAP solenoid control circuit between PCM and 12-pin connector. After repairs, go to step 19 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0449: EVAP CANISTER VENT SOLENOID VALVE CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

DTC will set when the following conditions are present

Engine speed greater than 600 RPM.
Ignition voltage 6-16 volts.
PCM detects commanded state of driver and actual state do not match.
Conditions met for 10 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine and let idle at normal operating temperature. Using scan tool, command solenoid on and off. If solenoid turns on and off as commanded, go to next step. If solenoid does not turn on or off when commanded, go to step 5 .
Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Using DVOM, set DVOM to 10-amp scale. Check current from solenoid control circuit in PCM harness connector to ground for 2 minutes. If current draw is less than 0.75 amp (but not zero), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If current draw is not less than 0.75 amp, go to next step.
Turn ignition off. Disconnect solenoid connector. Using DVOM, check resistance from solenoid control circuit in PCM harness connector and ground. If resistance is infinite, go to step 12 . If resistance is not infinite, go to step 10 .
Turn ignition off. Disconnect solenoid connector. Connect test light between solenoid harness connectors. Turn ignition on. Using scan tool, command solenoid on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
Connect test light ground and probe ignition feed circuit in solenoid harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Turn ignition off. Reconnect solenoid harness connector. Disconnect PCM harness connector. Turn ignition on. Connect a fused jumper wire between ground and PCM harness connector, solenoid control circuit. If solenoid operates, go to step 9 . If solenoid does not operate when energized, go to step 10 .
Check connections at solenoid. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 12 .
Check connections at PCM. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
Repair faulty solenoid control circuit. After repairs, go to step 14 .
Repair faulty solenoid ignition feed circuit. After repairs, go to step 14 .
Replace solenoid. After replacing solenoid, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0449. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

DTC P0450: FUEL TANK PRESSURE SENSOR CIRCUIT (3.0L "V" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Fuel tank pressure sensor is mounted to sending unit at top of fuel tank. Sensor measures pressure changes within EVAP system. Sensor has a 5 volt reference, a ground and a signal circuit.

Sensor contains a diaphragm which changes resistance based on pressure. When EVAP system pressure is low (during purge), sensor output voltage is low. When EVAP system pressure is high, sensor output voltage is high. When ECM senses sensor signal voltage outside normal operating range of sensor, this DTC will set.

Conditions required to set DTC are

Tank pressure is more or less than 1.1 in. H2O for at least 5 seconds.
Tank pressure is greater than 0.4 H2O for at least 3 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Remove fuel cap. Using scan tool, monitor fuel tank pressure voltage. If voltage reading is 2.2-2.8 volts, go to next step. If voltage reading is not 2.2-2.8 volts, go to step 6 .
Zero gauges on EVAP Pressure/Purge Diagnostic Station (J-41413) prior to installation. Connect diagnostic station to EVAP service port. Reinstall fuel cap. Disconnect vent hose at EVAP vent valve and plug hose. Using diagnostic station, pressurize EVAP system to 15 in. H2O. Monitor pressure using gauge on EVAP pressure/purge diagnostic station. Using scan tool, monitor fuel tank pressure sensor voltage. If sensor voltage is 3.3-3.9 volts, go to next step. If sensor voltage is not 3.3-3.9 volts, go to step 6 .
Turn ignition on, with engine off. Wiggle fuel tank pressure sensor electrical connector, wiring harness and ECM harness connector while observing scan tool display. If voltage value displayed on scan tool changes when wiggling components, go to step 17 . If voltage value displayed on scan tool does not change when wiggling components, go to next step.
Turn ignition on, with engine off. Review FREEZE FRAME data for this DTC and note parameters. Clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Check for DTCs. If DTC P0450 is set, go to next step. If DTC P0450 is not set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank pressure sensor connector. Using DVOM, check voltage between ground and sensor harness connector signal circuit. If voltage reading is 4.7-5.3 volts, go to step 10 . If voltage reading is not 4.7-5.3 volts, go to next step.
Turn ignition off. Leave sensor disconnected. Disconnect ECM harness connector located in engine compartment relay center. Turn ignition on. Using DVOM, check voltage between ground and sensor harness connector signal circuit. If any voltage is present, go to step 21 . If no voltage is present, go to next step.
Using DVOM, check harness continuity of sensor signal circuit. If continuity exists, go to next step. If continuity does not exist, go to step 22 .
Using DVOM, check harness continuity between ground and sensor signal circuit. If continuity exists, go to step 23 . If continuity does not exist, go to step 27 .
Using DVOM, check voltage between ground and sensor harness connector 5-volt reference circuit. If voltage reading is 4.7-5.3 volts, go to step 14 . If voltage reading is not 4.7-5.3 volts, go to next step.
Turn ignition off. Leave sensor disconnected. Disconnect ECM harness connector located in engine compartment relay center. Turn ignition on. Using DVOM, check voltage between ground and sensor connector 5-volt reference circuit. If voltage is present, go to step 18 . If no voltage is present, go to next step.
Using DVOM, check harness continuity of sensor 5-volt reference circuit. If continuity exists, go to next step. If continuity does not exist, go to step 19 .
Using DVOM, check harness continuity between ground and sensor 5-volt reference circuit. If continuity is exists, go to step 20 . If continuity does not exist, go to step 27 .
Turn ignition off. Using DVOM, check resistance between ground and sensor harness connector ground circuit. If resistance is 0-5 ohms, go to step 16 . If resistance is not 0-5 ohms, go to next step.
Leave sensor disconnected. Disconnect ECM harness connector located in engine compartment relay center. Using DVOM, check harness continuity of sensor ground circuit. If continuity exists, go to step 27 . If continuity does not exist, go to step 24 .
Turn ignition on, with engine off. Using scan tool, monitor sensor voltage. Using a fused jumper wire, jumper sensor harness connector signal circuit to ground circuit. If scan tool display indicates zero volts, go to step 25 . If scan tool does not indicate zero volts, go to step 28 .
Repair harness and connections as necessary. After repairs, go to step 29 .
Repair short to voltage in 5-volt reference circuit. After repairs, go to step 29 .
Repair open or high resistance in 5-volt reference circuit. After repairs, go to step 29 .
Repair short to ground in 5-volt reference circuit. After repairs, go to step 29 .
Repair short to voltage in signal circuit. After repairs, go to step 29 .
Repair open or high resistance in signal circuit. After repairs, go to step 29 .
Repair short to ground in signal circuit. After repairs, go to step 29 .
Repair open or high resistance in ground circuit. After repairs, go to step 29 .
Check for poor connections and terminal tension at fuel tank pressure sensor harness connector. Repair as necessary. After repairs, go to step 29 . If connections and terminals are okay, go to next step.
Replace fuel tank pressure sensor. After replacing tank pressure sensor, go to step 29 .
Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 29 . If connections and terminals are okay, go to next step.
Replace ECM. New ECM must be programmed with theft deterrent module frequency code currently on vehicle. After replacing ECM, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0450 is set, go to step 2 . If DTC P0450 is not set, go to next step.
If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (1.9L SATURN)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Tank pressure sensor is a 3-wire gauge sensor that responds to changes in pressure in fuel tank. Sensor measures the difference between air pressure (or vacuum) in fuel tank and ambient/outside air pressure. When air pressure in fuel tank is equal to outside air pressure (fuel cap removed), output of sensor will measure 1.3-1.7 volts. DTC will set if signal voltage is less than 0.1 volt for greater than 3 seconds.

Connect scan tool. Turn ignition on, engine off. Remove fuel filler cap. Using scan tool, monitor fuel tank pressure voltage. If voltage reading is 1.3-1.7 volts, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If voltage reading is not 1.3-1.7 volts, go to next step.
Locate and disconnect 3-way instrument panel-body and engine-body harness connector (located behind left kick panel). Using a jumper wire, jumper PCM side of harness connector terminals "B" and "U". If tank pressure voltage is 4.5-5.5 volts, go to step 4 . If tank pressure voltage is not 4.5-5.5 volts, go to next step.
Using DVOM connected to ground, check voltage on harness connector terminal "U". If voltage reading is 4.5-5.5 volts, check for open or short in circuit to harness connector terminal "B". Repair as necessary. If circuit is okay, replace PCM. If voltage reading is not 4.5-5.5 volts, check for open or short to ground in circuit to harness connector terminal "U". Repair as necessary. If circuit is okay, replace PCM.
Reconnect harness connectors. If fuel tank pressure voltage is 1.3-1.7 volts, check for poor harness connector connection. Repair as necessary. If fuel tank pressure voltage is not 1.3-1.7 volts, go to next step.
Lower fuel tank and disconnect fuel tank pressure sensor harness connector. Jumper sensor harness connector terminals "B" and "C". If fuel tank pressure voltage reading is 4.5-5.5 volts, check for poor connection at sensor or faulty sensor. If fuel tank pressure voltage reading is not 4.5-5.5 volts, go to next step.
Check voltage between ground and fuel tank pressure sensor harness connector terminal "C". If voltage reading is 4.5-5.5 volts, check for open or short to ground in signal circuit to PCM. If voltage reading is not 4.5-5.5 volts, repair open or short to ground in 5-volt reference circuit between PCM and fuel tank air pressure sensor.

An intermittent open in the signal or 5-volt reference circuit or connectors will set DTC. Wiggle harnesses and connectors while monitoring tank pressure voltage. Review malfunction history data and attempt to reproduce the condition and fault.

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (2.2L "J" BODY & "S" SERIES & 2.4L "J" & "N" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM monitors fuel tank pressure sensor signal to detect vacuum decay and excess vacuum during the enhanced EVAP diagnostic. Fuel tank pressure sensor measures the difference between air pressure (or vacuum) in the tank and the outside air pressure. PCM applies 5-volt reference and ground to the sensor. Sensor will return a signal voltage between 0.2-4.0 volts. If PCM detects a fuel tank pressure sensor signal that is excessively low, DTC will set.

Conditions for setting DTC

Ignition on.
Fuel tank pressure sensor signal is less than 0.1 volt for greater than 25 seconds.
Conditions present for one second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, engine off. Monitor fuel tank pressure sensor voltage on scan tool. If scan tool reading is 0.20 volt or greater, go to next step. If scan tool reading is not 0.20 volt or greater, go to step 4 .
Turn ignition on, engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start and operate vehicle within conditions required for this DTC to run. If fuel tank pressure is greater than 0.20 volt, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) . If fuel tank pressure is not greater than 0.20 volt, go to next step.
Turn ignition off. Disconnect fuel tank pressure sensor connector. Turn ignition on, engine off. Check voltage between 5-volt reference voltage circuit and sensor ground circuit at fuel tank pressure sensor harness connector. If voltage reading is 5 volts, go to step 7 . If voltage reading is not 5 volts, go to next step.
Check 5-volt reference circuit for poor terminal connection at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
Check fuel tank pressure sensor 5-volt reference circuit between fuel tank pressure sensor and PCM for open, short to ground, or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Turn ignition off. Remove fuel filler cap. Using appropriate test adapter from Connector Test Adapter Kit (J-35616-A), connect jumper between terminal "A" of fuel pressure sensor and terminal "A" of harness connector. Jumper fuel pressure sensor terminal "C" to harness connector terminal "C". Turn ignition on, engine off. Check voltage between ground and fuel tank pressure sensor terminal "B". If voltage reading is 1.3-1.7 volts, go to next step. If voltage reading is not 1.3-1.7 volts, go to step 11 .
Check for poor terminal connections at fuel tank pressure sensor connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to next step.
Check fuel tank pressure signal circuit between sensor connector and PCM for open or short to ground. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
Check for poor terminal connection at fuel tank pressure sensor connector. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Replace fuel tank pressure sensor. After replacing sensor, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM monitors fuel tank pressure sensor signal to detect vacuum decay and excess vacuum during the enhanced EVAP diagnostic. Fuel tank pressure sensor measures the difference between air pressure (or vacuum) in the tank and the outside air pressure. PCM applies 5-volt reference and ground to the sensor. Sensor will return a signal voltage between 0.1-4.9 volts. If PCM detects a fuel tank pressure sensor signal that is excessively low, DTC will set.

Conditions for setting DTC

Ignition on.
Fuel tank pressure sensor signal is less than 0.3 volt.
Conditions present for one second.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, engine off. Monitor fuel tank pressure sensor voltage on scan tool. If scan tool reading is 0.30 volt or less, go to step 4 . If scan tool reading is not 0.30 volt or less, go to next step.
Turn ignition on, engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start and operate vehicle within conditions required for this DTC to run. Using scan tool, select DTC option, SPECIFIC DTC option, then enter this DTC. If scan tool indicates that this diagnostic failed this ignition cycle, go to next step. If scan tool does not indicate that this diagnostic failed this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank pressure sensor connector. Jumper fuel tank pressure sensor 5-volt reference circuit and signal circuit at harness connector. Using scan tool observe fuel tank pressure sensor voltage. If scan tool display reads 5 volts, go to step 8 . If scan tool display does not read 5 volts, go to next step.
Check voltage between 5-volt reference voltage circuit and sensor ground circuit at fuel tank pressure sensor harness connector. If voltage reading is 5 volts, go to step 9 . If voltage reading is not 5 volts, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check 5-volt reference circuit for poor connection at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
Check fuel tank pressure sensor 5-volt reference circuit between sensor and PCM for open, short to ground, or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Check for poor terminal connections at fuel tank pressure sensor connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
Turn ignition off. Disconnect PCM harness connector. Check fuel tank pressure signal circuit for poor connection at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
Check fuel tank pressure signal circuit between the fuel tank pressure sensor connector and PCM for an open, short to ground, or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Replace fuel tank pressure sensor. After replacing sensor, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (3.5L "W" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM monitors fuel tank pressure sensor signal to detect vacuum decay and excess vacuum during the enhanced EVAP diagnostic. Fuel tank pressure sensor measures the difference between air pressure (or vacuum) in the tank and the outside air pressure. PCM applies 5-volt reference and ground to the sensor. Sensor will return a signal voltage between 0.1-4.9 volts. If PCM detects a fuel tank pressure sensor signal that is excessively low, DTC will set.

DTC will set when fuel tank pressure sensor signal is less than 0.1 volt and condition is present for 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, engine off. Monitor fuel tank pressure sensor voltage on scan tool. If scan tool reading is 0.30 volt or less, go to step 4 . If scan tool reading is not 0.30 volt or less, go to next step.
Turn ignition on, engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start and operate vehicle within conditions required for this DTC to run. Using scan tool, select DTC option, SPECIFIC DTC option, then enter this DTC. If scan tool indicates that this diagnostic failed this ignition cycle, go to next step. If scan tool does not indicate that this diagnostic failed this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank pressure sensor connector. Jumper fuel tank pressure sensor 5-volt reference circuit and signal circuit at harness connector. Using scan tool observe fuel tank pressure sensor voltage. If scan tool display reads 5 volts, go to step 8 . If scan tool display does not read 5 volts, go to next step.
Check voltage between 5-volt reference voltage circuit and sensor ground circuit at fuel tank pressure sensor harness connector. If voltage reading is 5 volts, go to step 9 . If voltage reading is not 5 volts, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check 5-volt reference circuit for poor connection at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
Check fuel tank pressure sensor 5-volt reference circuit between sensor and PCM for open, short to ground, or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Check for poor terminal connections at fuel tank pressure sensor connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
Turn ignition off. Disconnect PCM harness connector. Check fuel tank pressure signal circuit for poor connection at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
Check fuel tank pressure signal circuit between the fuel tank pressure sensor connector and PCM for an open, short to ground, or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Replace fuel tank pressure sensor. After replacing sensor, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

PCM monitors fuel tank pressure sensor signal to detect vacuum decay and excess vacuum during the enhanced EVAP diagnostic. Fuel tank pressure sensor measures the difference between air pressure (or vacuum) in the tank and the outside air pressure. PCM applies 5-volt reference and ground to the sensor. Sensor will return a signal voltage between 0.1-4.9 volts. If PCM detects a fuel tank pressure sensor signal that is excessively low, DTC will set.

Conditions for setting DTC

Ignition on.
Fuel tank pressure sensor signal is less than 0.1 volt.
Conditions present for 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, engine off. Monitor fuel tank pressure sensor voltage on scan tool. If scan tool reading is 0.30 volt or less, go to step 4 . If scan tool reading is not 0.30 volt or less, go to next step.
Turn ignition on, engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start and operate vehicle within conditions required for this DTC to run. Using scan tool, select DTC option, SPECIFIC DTC option, then enter this DTC. If scan tool indicates that this diagnostic failed this ignition cycle, go to next step. If scan tool does not indicate that this diagnostic failed this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank pressure sensor connector. Jumper fuel tank pressure sensor 5-volt reference circuit and signal circuit at harness connector. Using scan tool observe fuel tank pressure sensor voltage. If scan tool display reads 5 volts, go to step 8 . If scan tool display does not read 5 volts, go to next step.
Check voltage between 5-volt reference voltage circuit and sensor ground circuit at fuel tank pressure sensor harness connector. If voltage reading is 5 volts, go to step 9 . If voltage reading is not 5 volts, go to next step.
Turn ignition off. Disconnect PCM harness connector. Check 5-volt reference circuit for poor connection at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
Check 5-volt reference circuit between fuel tank pressure sensor and PCM for open, short to ground, or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Check for poor terminal connections at fuel tank pressure sensor connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
Turn ignition off. Disconnect PCM harness connector. Check fuel tank pressure signal circuit for poor connection at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
Check fuel tank pressure signal circuit between the fuel tank pressure sensor connector and PCM for an open, short to ground, or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Replace fuel tank pressure sensor. After replacing sensor, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0443. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EVAP tank pressure sensor responds to changes in resistance based upon fuel tank pressure (or vacuum). Vacuum is considered negative pressure.

PCM provides a 5-volt reference and ground signal to sensor. Signal varies between ground and 5 volts as fuel tank pressure varies. As pressure decreases, voltage increases and vice-versa. PCM uses EVAP fuel tank pressure sensor values as an indicator of EVAP system efficiency.

DTC will set when EVAP fuel tank pressure sensor signal goes low when signal line is shorted to ground, EVAP fuel tank pressure sensor is shorted internally or EVAP fuel tank pressure sensor reading has been 0.22 volts or less.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, view EVAP fuel tank pressure sensor display. If scan tool reading is 0.22 volt or less, go to next step. If scan tool reading is not 0.22 volt or less, fault is not present.
Turn ignition off. Disconnect EVAP fuel tank pressure sensor harness connector. Using a jumper wire, jumper 5-volt reference and sensor signal circuit. Turn ignition on. If scan tool reading is 4.8 volts or greater, go to step 13 . If scan tool reading is not 4.8 volts or greater, go to next step.
Disconnect jumper wire. Using DVOM, check voltage between ground and 5-volt reference circuit terminal. If voltage reading is 4.5 volts or greater, go to next step. If voltage reading is not 4.5 volts or greater, go to step 7 .
Using scan tool, record fluid life index. Turn ignition off. Wait 30 seconds then disconnect PCM harness connector C1. Check resistance between sensor signal and ground circuits. Check resistance between sensor signal circuit and a known-good engine ground. If resistance in both tests is 10,000 ohms or greater, go to next step. If resistance in both tests is not 10,000 ohms or greater, go to step 9 .
Check resistance of sensor signal circuit between PCM harness connector and EVAP fuel tank pressure sensor connector terminal. If resistance is 5 ohms or greater, go to step 10 . If resistance is not 5 ohms or greater, go to step 19 .
Using scan tool, record fluid life index. Turn ignition off. Wait 30 seconds then disconnect PCM harness connector C1. Check resistance between sensor 5-volt reference circuit and sensor ground circuit. Check resistance between sensor 5-volt reference circuit and a known-good engine ground. If resistance in both tests is 10,000 ohms or greater, go to next step. If resistance in both tests is not 10,000 ohms or greater, go to step 11 .
Check resistance of 5-volt reference circuit between EVAP tank fuel pressure sensor connector terminal and PCM connector terminal. If resistance is less than 5 ohms, go to step 15 . If resistance is not less than 5 ohms, go to step 11 .
Repair short to ground in EVAP fuel tank pressure sensor signal circuit or short between EVAP fuel tank pressure sensor signal and sensor ground.
Repair open in EVAP fuel tank pressure sensor signal circuit.
Repair open in EVAP fuel tank pressure sensor 5-volt reference circuit.
Repair short to ground in EVAP fuel tank pressure sensor 5-volt reference circuit, or short between 5-volt reference circuit and sensor ground circuit.
Check terminal contact at EVAP fuel tank pressure sensor. Repair as necessary. If terminal contact is okay, go to next step.
Replace EVAP fuel tank pressure sensor.
A short to ground may exist on another 5-volt reference circuit. Turn ignition off. Reconnect all sensor harness connectors. Disconnect PCM harness connector C1. Using DVOM, check resistance between 5-volt reference circuit and sensor ground circuit of TP sensor, EGR position sensor and MAP sensor. If resistance on any of the sensors is less than 10,000 ohms, go to step 17 . If resistance on any of the sensors is not less than 10,000 ohms, go to next step.
Check resistance between 5-volt reference circuit and a known-good ground of TP, EGR position and MAP sensors. If resistance on any of the sensors is less than 10,000 ohms, go to step 18 . If resistance on any of the sensors is not less than 10,000 ohms, go to step 19 .
Repair short to sensor ground on 5-volt reference circuit or replace shorted sensor on affected circuit.
Repair short to engine/body ground on 5-volt reference circuit on affected circuit.
Check terminal contact on PCM harness connector C1. Repair as necessary. If terminal contacts are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

EVAP fuel tank pressure sensor monitors a range from 7.5 in. H2O of pressure to -17.5 in. H2O of pressure (vacuum).

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Fuel tank pressure sensor responds to changes in fuel tank pressure (or vacuum). Vacuum is considered negative pressure. This information is used in order to detect vacuum decay or an excessive vacuum during EVAP diagnostic routine.

Fuel tank pressure sensor signal voltage to VCM varies from a minimum of about 0.1 volt with pressure in fuel tank to greater than 4.0 volts with high vacuum in fuel tank.

DTC will set when fuel tank pressure sensor voltage is less than 0.1 volt for greater than 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, engine off. Using scan tool, monitor fuel tank pressure sensor reading. If fuel tank pressure sensor value is within -1.0 to 1.0 in. H2O, go to next step. If fuel tank pressure sensor value is not within -1.0 to 1.0 in. H2O, go to step 4 .
DTC is intermittent. Check for additional DTCs set. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect fuel tank pressure sensor harness connector. Turn ignition on, engine off. Using DVOM, check voltage between fuel tank pressure sensor harness connector 5-volt reference voltage and ground circuit. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 6 .
Turn ignition off. Using jumper wires, connect jumper between fuel tank pressure sensor 5-volt reference circuit at harness connector to sensor terminal. Connect jumper between sensor ground circuit at harness connector to sensor terminal. Turn ignition on, engine off. Using DVOM, check voltage between ground and sensor signal circuit. If voltage reading is 1.3-2.0 volts, go to step 13 . If voltage reading is not 1.3-2.0 volts, go to step 11 .
Check for open in fuel tank pressure sensor 5-volt reference circuit. If circuit is open, go to step 15 . If circuit is okay, go to next step.
Check for short to ground in 5-volt reference circuit. If circuit is shorted, go to step 15 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor terminal contact at VCM. If problem is found, go to step 15 . If terminal connection is okay, go to next step.
Check for open in fuel tank pressure sensor ground circuit. If circuit is open, go to step 15 . If circuit is okay, go to next step.
Check sensor ground circuit for poor terminal connection at VCM. If problem is found, go to step 15 . If terminal connection is okay, go to step 16 .
Check fuel pressure sensor signal for short to ground. If circuit is shorted, go to step 15 . If circuit is okay, go to next step.
Check fuel pressure sensor signal terminal connection at VCM. If problem is found, go to step 15 . If terminal connection is okay, go to step 16 .
Check fuel tank pressure sensor for water intrusion, backed out terminal, improper terminal mating or poor terminal-to-wire connections. If problem is found, go to step 15 . If sensor connections are okay, go to next step.
Replace fuel tank pressure sensor. After replacing sensor, go to step 17 .
Repair circuit as necessary. After repairs, go to step 17 .
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Check for additional DTCs. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, system is okay.

Check for damaged harness or poor connection at VCM or fuel tank pressure sensor.

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (4.3L "L", "M", "S" & "T" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

Fuel tank pressure sensor signal voltage to VCM varies from a minimum of about 0.1 volt with pressure in fuel tank to greater than 4.0 volts with high vacuum in fuel tank.

DTC will set when fuel tank pressure sensor voltage is less than 0.1 volt for greater than 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, engine off. Using scan tool, monitor fuel tank pressure sensor reading. If fuel tank pressure sensor value is within -1.0 to 1.0 in. H2O, go to next step. If fuel tank pressure sensor value is not within -1.0 to 1.0 in. H2O, go to step 4 .
DTC is intermittent. Check for additional DTCs set. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off. Disconnect fuel tank pressure sensor harness connector. Turn ignition on, engine off. Using DVOM, check voltage between fuel tank pressure sensor harness connector 5-volt reference voltage and ground circuit. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 6 .
Turn ignition off. Using jumper wires, connect jumper between fuel tank pressure sensor 5-volt reference circuit at harness connector to sensor terminal. Connect jumper between sensor ground circuit at harness connector to sensor terminal. Turn ignition on, engine off. Using DVOM, check voltage between ground and sensor signal circuit. If voltage reading is 1.3-2.0 volts, go to step 13 . If voltage reading is not 1.3-2.0 volts, go to step 11 .
Check for open fuel tank pressure sensor in 5-volt reference circuit. If circuit is open, go to step 15 . If circuit is okay, go to next step.
Check for short to ground in 5-volt reference circuit. If circuit is shorted, go to step 15 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor terminal contact at VCM. If problem is found, go to step 15 . If terminal connection is okay, go to next step.
Check for open in fuel tank pressure sensor ground circuit. If circuit is open, go to step 15 . If circuit is okay, go to next step.
Check sensor ground circuit for poor terminal connection at VCM. If problem is found, go to step 15 . If terminal connection is okay, go to step 16 .
Check fuel pressure sensor signal for short to ground. If circuit is shorted, go to step 15 . If circuit is okay, go to next step.
Check fuel pressure sensor signal terminal connection at VCM. If problem is found, go to step 15 . If terminal connection is okay, go to step 16 .
Check fuel tank pressure sensor for water intrusion, backed out terminal, improper terminal mating or poor terminal-to-wire connections. If problem is found, go to step 15 . If sensor connections are okay, go to next step.
Replace fuel tank pressure sensor. After replacing sensor, go to step 17 .
Repair circuit as necessary. After repairs, go to step 17 .
Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Check for additional DTCs. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, system is okay.

Check for damaged harness or poor connection at VCM or fuel tank pressure sensor.

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EVAP tank pressure sensor responds to changes in resistance based upon fuel tank pressure (or vacuum). Vacuum is considered negative pressure.

PCM provides a 5-volt reference and ground signal to sensor. Signal varies between ground and 5 volts as fuel tank pressure varies. As pressure decreases, voltage increases and vice-versa. PCM uses fuel tank pressure sensor values as an indicator of EVAP system efficiency.

DTC will set when ignition switch in RUN position, fuel tank pressure sensor reading is 0.1 volt or less and all conditions present for greater than 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, monitor FAILED THIS IGNITION option under DTC INFO option. If scan tool indicates that DTC P1639 failed in this ignition cycle, diagnose DTC P1639. If scan tool does not indicate that DTC P1639 failed in this ignition cycle, go to next step.
Turn ignition off for 15 seconds. Turn ignition on, with engine off. Using scan tool, monitor fuel tank pressure sensor voltage. If sensor voltage reading is less than 0.10 volt, go to step 5 . If sensor voltage reading is not less than 0.10 volt, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start and operate vehicle within conditions required for this DTC to run. Using scan tool, select DTC option, SPECIFIC DTC option, then enter DTC P0452. If scan tool indicates that this diagnostic failed this ignition cycle, go to next step. If scan tool does not indicate that this diagnostic failed this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Turn ignition off for 15 seconds. Disconnect fuel tank pressure sensor connector. Jumper fuel tank pressure sensor 5-volt reference circuit and signal circuit at harness connector. Using scan tool, observe fuel tank pressure sensor voltage. If pressure sensor voltage reading is 5 volts, go to step 13 . If pressure sensor voltage reading is not 5 volts, go to next step.
Turn ignition off for 15 seconds. Disconnect fuel tank pressure sensor connector. Using a test light connected to battery voltage, probe test light to fuel tank pressure sensor signal circuit. Using scan tool, monitor fuel tank pressure sensor voltage. If pressure sensor voltage reading is 5 volts, go to step 7 . If pressure sensor voltage reading is not 5 volts, go to step 12 .
Turn ignition off. Disconnect PCM harness connector. Check fuel tank pressure sensor signal circuit between PCM and fuel tank pressure harness connector for open or short to ground. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to step 12 .
Disconnect PCM harness connector C1. Check 5-volt reference circuit between PCM and fuel tank pressure sensor harness connector for open circuit. If circuit is open, go to next step. If circuit is okay, go to step 11 .
Repair open in 5-volt reference circuit. After repairs, go to step 15 .
Repair open or grounded fuel tank pressure sensor signal circuit. After repairs, go to step 15 .
Check fuel tank pressure sensor signal circuit for poor connection at PCM harness connector. Repair as necessary. After repairs, go to step 15 . If connection is okay, go to step 14 .
Check fuel tank pressure sensor signal circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to step 14 .
Check fuel tank pressure sensor connections. Repair as necessary. If connections are okay, replace fuel tank pressure sensor. After replacing sensor, go to step 15 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (5.7L "F" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EVAP tank pressure sensor responds to changes in resistance based upon fuel tank pressure (or vacuum). Vacuum is considered negative pressure.

PCM provides a 5-volt reference and ground signal to sensor. Signal varies between ground and 5 volts as fuel tank pressure varies. As pressure decreases, voltage increases and vice-versa. PCM uses fuel tank pressure sensor values as an indicator of EVAP system efficiency.

DTC will set when ignition switch in RUN position, fuel tank pressure sensor reading is 0.1 volt or less and all conditions present for greater than 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, monitor FAILED THIS IGNITION option under DTC INFO option. If scan tool indicates that DTC P1639 failed in this ignition cycle, diagnose DTC P1639. If scan toll does not indicate that DTC P1639 failed in this ignition cycle, go to next step.
Monitor fuel tank pressure sensor voltage on scan tool. If scan tool reading is less than 0.10 volt, go to step 5 . If scan tool reading is not less than 0.10 volt, go to next step.
Turn ignition on, engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start and operate vehicle within conditions required for this DTC to run. Using scan tool, select DTC option, SPECIFIC DTC option, then enter DTC P0452. If scan tool indicates that this diagnostic failed this ignition cycle, go to next step. If scan tool does not indicate that this diagnostic failed this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Disconnect fuel tank pressure sensor jumper harness at body pass-through connector. Jumper fuel tank pressure sensor 5-volt reference circuit and signal circuit at harness connector. Using scan tool, observe fuel tank pressure sensor voltage. If voltage is about 5 volts, go to step 11 . If voltage is not about 5 volts, go to next step.
Using a test light connected to battery voltage, probe fuel tank pressure sensor signal circuit at harness connector. Observe sensor voltage on scan tool. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 9 .
Turn ignition off. Disconnect PCM harness connector C1. Check 5-volt reference circuit for open or short to ground. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor connection to PCM connector terminal. Repair as necessary. After repairs, go to step 19 . If connection is okay, go to step 18 .
Turn ignition off. Disconnect PCM harness connector C1. Check fuel tank pressure sensor signal circuit for open, short to ground or short to sensor ground. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to next step.
Check fuel tank pressure sensor signal circuit for poor connection at PCM harness connector. Repair as necessary. After repairs, go to step 19 . If connection is okay, go to step 18 .
Check for faulty connections at body harness pass-through connector. Repair as necessary. After repairs, go to step 19 . If connections are okay, go to next step.
Turn ignition off. Reconnect body pass-through connector. Lower fuel tank. Disconnect fuel tank pressure sensor. Turn ignition on, with engine off. Using a jumper wire, jumper 5-volt reference circuit and signal circuit together at fuel tank pressure sensor harness connector. Using scan tool, monitor fuel tank pressure sensor voltage. If voltage is about 5 volts, go to step 16 . If voltage is not about 5 volts, go to next step.
Measure voltage between ground and 5-volt reference circuit at fuel tank pressure sensor. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 15 .
Repair open or short to ground in fuel tank pressure sensor signal circuit. After repairs, go to step 19 .
Repair open or short to ground in fuel tank pressure sensor 5-volt reference circuit. After repairs, go to step 19 .
Check for faulty connections at fuel tank pressure sensor. Repair as necessary. After repairs, go to step 19 . If connections are okay, go to next step.
Replace fuel tank pressure sensor. After repairs, go to step 19 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE (5.7L "Y" BODY)

Note. For circuit reference, see appropriate wiring diagram in WIRING DIAGRAMS article.

EVAP tank pressure sensor responds to changes in resistance based upon fuel tank pressure (or vacuum). Vacuum is considered negative pressure.

PCM provides a 5-volt reference and ground signal to sensor. Signal varies between ground and 5 volts as fuel tank pressure varies. As pressure decreases, voltage increases and vice-versa. PCM uses fuel tank pressure sensor values as an indicator of EVAP system efficiency.

DTC will set when ignition switch in RUN position, fuel tank pressure sensor reading is 0.1 volt or less and all conditions present for greater than 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, monitor FAILED THIS IGNITION option under DTC INFO option. If scan tool indicates that DTCs P1635 and P1639 failed in this ignition cycle, diagnose DTCs P1635 and P1639. If scan tool does not indicate that DTCs P1635 and P1639 failed in this ignition cycle, go to next step.
Turn ignition on. Using scan tool, monitor FAILED THIS IGNITION option under DTC INFO option. If scan tool indicates that only DTC P1639 failed in this ignition cycle, diagnose DTC P1639. If scan tool does not indicate that only DTC P1639 failed in this ignition cycle, go to next step.
Using scan tool, monitor fuel tank pressure sensor voltage. If voltage is less than 0.10 volt, go to step 6 . If voltage is not less than 0.10 volt, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start and operate vehicle within conditions required for this DTC to run. Using scan tool, select DTC option, SPECIFIC DTC option, then enter DTC P0452. If scan tool indicates that this diagnostic failed this ignition cycle, go to next step. If scan tool does not indicate that this diagnostic failed this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0352-p0452) .
Remove left rear wheelhouse panel. Disconnect fuel tank pressure sensor harness connector. Using a fused jumper wire, jumper 5-volt reference circuit to signal circuit at fuel tank pressure sensor harness connector (PCM side). Using scan tool, monitor fuel tank pressure sensor voltage. If voltage is near 5 volts, go to next step. If voltage is not near 5 volts, go to step 8 .
Check for poor connections at fuel tank pressure sensor harness connector. Repair as necessary. After repairs, go to step 15 . If connections are okay, go to step 13 .
Using test light connected to battery positive, probe signal circuit at fuel tank pressure sensor harness connector. Using scan tool, monitor fuel tank pressure sensor voltage. If voltage is near 5 volts, go to next step. If voltage is not near 5 volts, go to step 11 .
Turn ignition off. Disconnect PCM harness connector C1. Check 5-volt reference circuit for an open or short to ground. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 15 . If connections are okay, go to step 14 .
Turn ignition off. Disconnect PCM harness connector C2. Check fuel tank pressure sensor signal circuit for an open, short to ground, or short to sensor ground circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
Check fuel tank pressure sensor signal circuit for poor connections at PCM. Repair as necessary. After repairs, go to step 15 . If connections are okay, go to step 14 .
Replace fuel tank pressure sensor. After repairs, go to step 15 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Engine Control System - Tests W/codes - DTC p0352-p0452 GMC Savana I

MODEL IDENTIFICATION

DTC P0352 &/OR P1352: IC CIRCUITS NO. 2 & 3 MALFUNCTION OR SHORTED (1.9L SATURN)

Circuit Description

Diagnostic Procedures

Diagnostic Aids

DTC P0352: IGNITION COIL NO. 2 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

DTC P0352: IGNITION COIL NO. 2 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

DTC P0353: IGNITION COIL NO. 3 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

DTC P0353: IGNITION COIL NO. 3 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

DTC P0354: IGNITION COIL NO. 4 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

DTC P0354: IGNITION COIL NO. 4 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

DTC P0355: IGNITION COIL NO. 4 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

DTC P0355: IGNITION COIL NO. 5 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

DTC P0356: IGNITION COIL NO. 6 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

DTC P0356: IGNITION COIL NO. 6 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

DTC P0357: IGNITION COIL NO. 7 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

DTC P0357: IGNITION COIL NO. 7 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

DTC P0358: IGNITION COIL NO. 8 CONTROL CIRCUIT (4.8L, 5.3L, 6.0L "C" & "K" SERIES)

DTC P0358: IGNITION COIL NO. 8 CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

DTC P0371: IGNITION CONTROL (IC) MODULE 24X REFERENCE CIRCUIT-TOO MANY PULSES (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0372: IGNITION CONTROL (IC) MODULE 24X REFERENCE CIRCUIT-MISSING PULSES (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0385: CRANKSHAFT POSITION (CKP) SENSOR "B" CIRCUIT (3.5L "W" BODY)

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (1.9L SATURN)

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (2.4L "N" BODY)

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (3.5L "W" BODY)

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P0401: EGR SYSTEM MALFUNCTION (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (4.3L "L", "M", "S" & "T" SERIES)

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0401: EGR SYSTEM-INSUFFICIENT FLOW (5.7L "F" BODY)

DTC P0403: EGR SOLENOID CONTROL CIRCUIT (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0403: EGR SOLENOID CONTROL CIRCUIT (3.5L "W" BODY)

DTC P0403: EGR SOLENOID CONTROL CIRCUIT (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P0404: EGR PINTLE POSITION ERROR (1.9L SATURN)

DTC P0404: EGR VALVE PINTLE POSITION OPEN (2.4L "N" BODY)

DTC P0404: EGR SYSTEM PERFORMANCE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0404: EGR SYSTEM PERFORMANCE (3.5L "W" BODY)

DTC P0404: EGR VALVE PINTLE STUCK CLOSED (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P0404: EGR SYSTEM PERFORMANCE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0404: EGR VALVE OPEN PINTLE POSITION (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

DTC P0404: EGR VALVE OPEN PINTLE POSITION (4.3L "L", "M", "S" & "T" SERIES)

DTC P0404: EGR VALVE OPEN PINTLE POSITION (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0404: EGR SYSTEM PERFORMANCE (5.7L "F" BODY)

DTC P0405: EGR FEEDBACK VOLTAGE OUT OF RANGE-OPEN/SHORTED (1.9L SATURN)

DTC P0405: EGR VALVE SENSOR SIGNAL CIRCUIT-LOW VOLTAGE (2.4L "N" BODY)

DTC P0405: EGR SENSOR CIRCUIT-LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0405: EGR SENSOR CIRCUIT-VOLTAGE OUT OF RANGE (3.5L "W" BODY)

DTC P0405: EGR PINTLE POSITION SENSOR CIRCUIT-LOW VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P0405: EGR VALVE SENSOR CIRCUIT-VOLTAGE OUT OF RANGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0405: EGR PINTLE POSITION CIRCUIT-LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

DTC P0405: EGR PINTLE POSITION CIRCUIT-LOW VOLTAGE (4.3L "L", "M", "S" & "T" SERIES)

DTC P0405: EGR PINTLE POSITION CIRCUIT-LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0405: EGR PINTLE POSITION CIRCUIT-LOW VOLTAGE (5.7L "F" BODY)

DTC P0410: AIR SYSTEM (1.9L SATURN)

DTC P0410: AIR SYSTEM (3.1L "N" BODY)

Conditions For Running DTC

Condition For Not Passing AIR Passive Test 1

Condition For Not Passing AIR Passive Test 2

Condition For Not Passing AIR Active Test

Condition For Setting DTC

Action Taken When DTC Sets

Conditions For Clearing MIL/DTC

Test Description

DTC P0410: AIR SYSTEM (3.5L "W" BODY)

DTC P0410: AIR INJECTION SYSTEM (4.3L "C", "K", "S" & "T" SERIES)

DTC P0410: AIR INJECTION SYSTEM (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0410: AIR INJECTION SYSTEM (5.0L, 5.7L & 7.4L "C" & "K" SERIES)

DTC P0410: AIR SYSTEM (5.7L "F" & "Y" BODIES)

DTC P0410: AIR SYSTEM (7.4L "G" BODY)

DTC P0411: AIR SYSTEM-NO FLOW DETECTED (3.0L "V" BODY)

DTC P0412: AIR SOLENOID VALVE CONTROL CIRCUIT (3.0L "V" BODY)

DTC P0412: AIR SOLENOID VALVE CONTROL CIRCUIT (3.5L "W" BODY)

DTC P0412: AIR SOLENOID RELAY CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

DTC P0418: AIR PUMP RELAY CONTROL CIRCUIT (3.0L "V" BODY)

DTC P0418: AIR PUMP RELAY CONTROL CIRCUIT (3.5L "W" BODY)

DTC P0418: SECONDARY AIR INJECTION (AIR) PUMP RELAY CONTROL CIRCUIT (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0418: AIR PUMP RELAY CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)