Engine Control System - Tests W/codes - DTC p0704-p1272

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 P0704: CLUTCH SWITCH CIRCUIT (3.8L "F" BODY)

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

Circuit Description

Clutch Anticipate (CA) switch input allows PCM to adjust IAC when M/T clutch is disengaged. PCM does this to avoid possible RPM flare caused by sudden change in engine load.

Conditions required to set DTC are: vehicle speed is greater than zero MPH, vehicle in gear, CA switch input is not grounded (clutch disengaged) or changes in vehicle speed to engine speed ratio indicate greater than 20 gear changes have occurred. CA switch state has not changed.

Diagnostic Procedures

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, observe CLUTCH PEDAL SWITCH state. If scan tool displays RELEASED, go to next step. If scan tool does not display RELEASED, go to step 6 .
Depress clutch pedal. If scan tool displays APPLIED, go to «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272__diagnostic-aids) . If scan tool does not display APPLIED, go to next step.
Disconnect CA switch harness connector. If scan tool displays APPLIED, go to step 13 . If scan tool does not display APPLIED, go to next step.
Turn ignition off. Disconnect PCM harness connector. Connect a test light between battery voltage and PCM harness connector CA switch input circuit. If test light illuminates, go to step 9 . If test light does not illuminate, go to step 15 .
Disconnect clutch pedal switch connector. Connect test light between battery voltage and CA switch harness connector ground circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Connect a fused jumper wire between CA switch harness connector input and ground circuits. If the scan tool now displays RELEASED, go to step 11 . If scan tool does not display RELEASED, go to next step.
Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Check clutch input circuit for open or short to voltage between PCM and CA switch. Repair as necessary. After repairs, go to step 16 . If no problem is found, go to step 14 .
Locate and repair short to ground in clutch pedal input circuit. After repairs, go to step 16 .
Locate and repair open in CA switch ground circuit. After repairs, go to step 16 .
Check CA switch adjustment. Adjust as necessary. After adjustments, go to step 16 . If adjustment was not necessary, go to next step.
Check for faulty connection or faulty CA switch. Repair as necessary. After repairs, go to step 16 . If connection is okay, go to next step.
Replace clutch pedal switch. After replacing switch, go to step 16 .
Check for faulty connection at PCM. Repair as necessary. After repairs, go to step 16 . If connection is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Turn ignition on, engine off. Using scan tool, observe CLUTCH PEDAL SWITCH state. If scan tool displays RELEASED, go to next step. If scan tool does not display RELEASED, return to step 6 .
Depress clutch pedal. If scan tool displays APPLIED, repair is complete. If scan tool does not display APPLIED, return to step 4 .

Diagnostic Aids

Check for faulty connections or damaged harness. Observe scan tool CA switch display while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P0704: CLUTCH SWITCH CIRCUIT (4.3L "S" & "T" SERIES)

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

DTC determines if transmission clutch switch has failed by looking for a clutch switch transition within a range from zero MPH to some higher speed. DTC will set when no VSS DTCs are set, vehicle speed currently is zero MPH, vehicle speed has been greater than 40 MPH and brake switch not currently pressed.

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. Install scan tool. Turn ignition on, with engine off. Using scan tool, display CLUTCH SWITCH parameter. Engage and disengage clutch several times. If scan tool display indicates change when clutch is engaged and disengaged, go to step 7 . If scan tool display does not indicate change when clutch is engaged and disengaged, go to next step.
Check if brake fuse is open. If fuse is open, go to step 8 . If fuse is okay, go to next step.
Turn ignition off. Disconnect clutch switch connector. Connect a jumper wire between ignition feed circuit and signal circuit of clutch switch connector. Turn ignition on, with engine off. Using scan tool, check if clutch switch is on. If scan tool indicates clutch switch is on, go to next step. If scan tool indicates clutch switch is off, go to step 6 .
Remove jumper wire from clutch switch connector. Using scan tool, check if clutch switch is off. If scan tool indicates clutch switch is off, go to step 11 . If scan tool indicates clutch switch is on, go to step 9 .
Check for open in signal circuit. If a problem is found, go to step 12 . If no problem is found, go to step 10 .
DTC is intermittent. Check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, see appropriate TROUBLE SHOOTING - NO CODES article.
Check and repair conditions that caused fuse to blow. Replace fuse. After replacing fuse, go to step 14 .
Check for short to battery voltage in signal circuit. If a problem is found, go to step 12 . If no problem is found, go to step 13 .
Check for poor connections at VCM connector. If a problem is found, go to step 12 . If connections are okay, go to step 13 .
Replace clutch switch. After replacing switch, go to step 14 .
Repair as necessary. After repairs, go to step 14 .
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 P0704: CLUTCH SWITCH CIRCUIT (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

Clutch switch is a normally closed switch. When switch is closed, ignition voltage is sent to PCM. When switch is open, voltage input to PCM should go low. This diagnostic determines if clutch switch has failed by looking for clutch switch transition within a range from zero to 24 MPH.

DTC will set when vehicle speed goes from zero to greater than 24 MPH and back to zero MPH for 2 seconds without the PCM detecting clutch transition and condition occurring 7 times before diagnostic reports a fault.

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, read clutch switch status. Turn ignition on, with engine off. Engage and release clutch pedal several times. If scan tool display changes when clutch is engaged and released, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If scan tool display does not change, go to next step.
Check clutch switch adjustment. Adjust if necessary. After adjustment, go to step 14 . If adjustment is not necessary, go to next step.
Turn ignition off. Disconnect clutch switch connector. Using a DVOM, check voltage between ground and clutch pedal switch ignition feed circuit. If battery voltage is present, go to next step. If battery voltage is not present, go to step 11 .
Turn ignition off. Disconnect clutch switch connector. Connect a fused jumper wire between clutch switch connector ignition feed and signal circuits. If scan tool displays RELEASED, go to step 8 . If scan tool does not display RELEASED, go to next step.
Turn ignition off. Disconnect PCM harness connector C1. Using DVOM, check continuity of clutch pedal signal circuit. If continuity exists, go to next step. If continuity does not exist, go to step 10 .
Check continuity between ground and clutch pedal signal circuit. If continuity exists, go to step 10 . If continuity does not exist, go to step 9 .
Check for poor connections/terminal tension at clutch switch connector. Repair as necessary. After repairs, go to step 14 . If connection or terminal tension is okay, go to step 12 .
Check for poor connections/terminal tension at PCM connector. Repair as necessary. After repairs, to step 14 . If connection or terminal tension is okay, go to step 13 .
Repair clutch switch signal feed circuit. After repairs, go to step 14 .
Repair clutch pedal switch ignition feed circuit. After repairs, go to step 14 .
Replace clutch pedal switch. After replacing switch, 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.

Check harness connector terminals for poor connection, improper contact, poor terminals, 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 P0704: CLUTCH SWITCH CIRCUIT (5.0L, 5.7L & 7.4L "C", "K" & "P" SERIES)

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

DTC determines if transmission clutch switch has failed by looking for a clutch switch transition within a range from zero MPH to some higher speed.

Conditions for setting DTC are: no VSS DTCs set, vehicle speed is greater than 40 MPH or no clutch transition is detected.

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. Install scan tool. Turn ignition on, with engine off. Using scan tool, display clutch switch parameter. Engage and disengage clutch several times. If scan tool display changes when clutch is engaged and disengaged, go to next step. If scan tool display does not change when clutch is engaged and disengaged, go to step 4 .
DTC is intermittent. Check 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-p0704-p1272) .
Check if brake fuse is blown. If fuse if blown, go to step 8 . If fuse is okay, go to next step.
Turn ignition off. Disconnect clutch switch connector. Connect a jumper wire between ignition feed circuit and signal circuit of clutch switch connector. Turn ignition on, with engine off. Using scan tool, check if clutch switch is on. If scan tool indicates that clutch switch is on, go to next step. If scan tool does not indicate that clutch switch is on, go to step 7 .
Remove jumper wire from clutch switch connector. Using scan tool, check if clutch switch is off. If scan tool indicates that clutch switch is off, go to step 11 . If scan tool does not indicate that clutch switch is off, go to step 9 .
Check for short to ground in brake fuse circuit. If problem is found, go to step 12 . If circuit is okay, go to step 10 .
Check brake fuse circuit for short to ground. Repair as necessary. Replace fuse. After repairs, go to step 14 .
Check for short to battery voltage on clutch switch signal circuit. If problem is found, go to step 12 . If circuit is okay, go to step 13 .
Check for poor connections in clutch signal circuit at VCM connector. If a problem is found, go to step 14 . If connection is okay, go to step 13 .
Replace clutch switch. After replacing switch, go to step 14 .
Repair as necessary. After repairs, go to step 14 .
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.

Disconnect and inspect VCM connector. Inspect for damaged pins, corrosion and loose wires. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation. Reviewing FAILURE RECORDS, vehicle mileage since diagnostic test last failed may help determine how often condition that caused DTC to be set occurs.

DTC P0704: CLUTCH SWITCH CIRCUIT (5.7L "F" BODY)

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

Clutch switch is a normally closed switch. With clutch pedal released (circuit closed), PCM senses low voltage. With clutch pedal depressed (circuit open), PCM senses high voltage. This diagnostic determines if clutch switch has failed by monitoring voltage transitions on clutch switch circuit.

DTC will set when there is no VSS DTCs set and vehicle speed changes from zero MPH to greater than 24 MPH and back to zero MPH for 2 seconds without PCM detecting a voltage transition on clutch switch circuit. This must occur 7 times before diagnostic will report a fault.

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, monitor clutch pedal position switch parameter. Depress and release clutch pedal several times. If scan tool indicates a change in switch state as pedal is actuated, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If scan tool does not indicate a change in switch state, go to next step.
Check clutch pedal adjustment. Adjust as necessary. After adjustment, go to step 14 . If no adjustment is necessary, go to next step.
Turn ignition off. Disconnect clutch pedal position switch harness connector. Turn ignition on, with engine off. Check voltage between ground and clutch pedal position signal circuit at harness connector. If battery voltage is present, go to next step. If battery voltage is not present, go to step 6 .
Using a fused jumper wire, jumper clutch pedal position switch terminals together at harness connector. If scan tool displays CLUTCH SWITCH RELEASED, go to step 9 . If scan tool does not display CLUTCH SWITCH RELEASED, go to step 8 .
Check for continuity between ground and clutch pedal signal circuit. If continuity exists, go to step 11 . If continuity does not exist, go to next step.
Turn ignition off. Disconnect PCM harness connector C1. Check for continuity in clutch pedal position signal circuit. If continuity exists, go to step 10 . If continuity does not exist, go to step 11 .
Check for continuity between ground and clutch pedal position signal circuit. If continuity exists, go to next step. If continuity does not exist, go to step 12 .
Check for poor connections at clutch pedal position switch. Repair as necessary. After repairs, go to step 15 . If connections are okay, go to step 13 .
Check for poor connections at PCM. Repair as necessary. After repairs, go to step 15 . If connections are okay, go to step 14 .
Repair clutch pedal position switch signal circuit. After repairs, go to step 15 .
Repair clutch pedal position switch ignition feed circuit. After repairs, go to step 15 .
Replace clutch pedal position switch. After replacing switch, 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.

DTC P0704: CLUTCH SWITCH CIRCUIT (5.7L "Y" BODY)

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

Clutch switch is a normally closed switch. With clutch pedal released (circuit closed), PCM senses ignition voltage. With clutch pedal depressed (circuit open), PCM senses zero voltage. This diagnostic determines if clutch switch has failed by monitoring voltage transitions on clutch switch circuit.

DTC will set when there are no VSS DTCs set and vehicle speed changes from zero MPH to greater than 24 MPH and back to zero MPH for 2 seconds without PCM detecting a voltage transition on clutch switch circuit. This must occur 7 times before diagnostic will report a fault.

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, read clutch switch status. Depress and release clutch pedal several times. If scan tool display changes when clutch pedal is depressed and released, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If scan tool display does not change, go to next step.
Check clutch switch adjustment. Adjust if necessary. After adjustment, go to step 15 . If adjustment is not necessary, go to next step.
Turn ignition off. Disconnect clutch switch connector. Connect a fused jumper wire between clutch switch harness connector terminals. Turn ignition on. If scan tool displays RELEASED, go to next step. If scan tool does not display RELEASED, go to step 6 .
Remove jumper wire. If scan tool displays DEPRESSED, go to step 8 . If scan tool does not display DEPRESSED, go to step 7 .
Connect a test light between ground and ignition feed circuit at clutch switch connector. If test light illuminates, go to step 9 . If test light does not illuminate, go to step 10 .
Check clutch switch signal circuit for short to battery voltage. If a short is found, go to step 13 . If no short is found, go to step 14 .
Check for poor connections/terminal tension at clutch switch connector. If a problem is found, go to step 13 . If connection or terminal tension is okay, go to step 11 .
Check for open in clutch switch signal circuit. If circuit is open, go to step 13 . If circuit is okay, go to step 12 .
Repair open in clutch switch ignition feed circuit. After repairs, go to step 15 .
Replace clutch switch. After repairs, go to step 15 .
Check for poor connections/terminal tension at PCM harness connector. If a problem is found, go to next step. If connections/terminal tension is okay, go to step 14 .
Repair as necessary. 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.

DTC P0705: TRANSMISSION RANGE SWITCH CIRCUIT (2.2L "J" BODY, 2.2L "S" SERIES & 2.4L "J" & "N" BODIES)

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

Transmission range switch is a multi-signal switch that sends a signal indicating gear selection to Powertrain Control Module (PCM). Transmission range switch uses 4 circuits to pull 4 PCM voltage low in various combinations to indicate each gear range. Voltage level of circuits is represented as LOW (grounded) or HIGH (open). The 4 states displayed represents decoder P, A, B and C inputs.

Conditions for setting DTC are: PCM recognizes an invalid PRNDL parameter, vehicle speed greater than 5 MPH and conditions are met for a period longer 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, with engine off. Observe scan tool and move gear selector through all gear selections. If INVALID is indicated in any range, go to next step. If INVALID is not indicated in any range, go to step 10.
Compare scan tool values with transmission range switch valid input combination values. (Scheme 26) If all circuits are indicated as HI, go to next step. If all circuits are not indicated as HI, go to step 5.
Check transmission range switch ground circuit for an open or poor connection. Repair as necessary. After repairs, go to step 10. If circuit is okay, go to next step.
Move gear selector through all ranges and note which circuit does not correspond with transmission range switch valid input combination values. (Scheme 26) Disconnect transmission range switch connector. Connect a jumper wire between ground and circuit with incorrect value. If jumpered circuit changes from a HI value to a LO value, go to step 8. If jumpered circuit does not change from a HI value to a LO value, go to next step.
Check affected 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.
Check for poor connection at PCM connector. Repair as necessary. After repair is completed, go to step 10. If circuit is okay, go to step 9.
Replace defective transmission range switch. After replacing switch, go to step 10.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, 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 which was set. 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.

Scheme 26

Monitor scan tool while moving related connectors and wiring harness. Whenever a fault is detected, scan data will change from HI to LO or from LO to HI. Moving gear selector slowly through each gear while monitoring scan tool may also help isolate the problem.

DTC P0705: TRANSAXLE RANGE SWITCH CIRCUIT (3.1L "N" & "W" BODIES)

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

Transaxle range switch is a multi-signal switch that sends a signal indicating gear selection to Powertrain Control Module (PCM). Transaxle range switch uses 4 circuits to pull PCM voltage low in various combinations to indicate each gear range. Voltage level of circuits is represented as "X" (high voltage) or "O" (low voltage).

Conditions for setting DTC are: PCM recognizes an invalid PRNDL parameter and vehicle speed is greater than 5 MPH.

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. Place transaxle gear selector in Park. Using scan tool, observe TRANS RANGE PABC display. Compare scan tool values with transaxle range switch valid input combination values. (Scheme 27) In Park, if all values are as specified, go to next step. If any value is not as specified, go to step 4.
Observe TRANS RANGE PABC display and move gear selector through all gear selections. Compare scan tool values with transaxle range switch valid input combination values. If all values are as specified, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272). If any value is not as specified, go to step 10.
If all TRANS RANGE PABC values are indicated as "X" (high voltage), go to next step. If all values are not indicated as "X", go to step 7.
Check if transaxle range switch is disconnected. Repair as necessary. After repairs, go to step 17. If switch is not disconnected, go to next step.
Check transaxle range switch ground circuit for an open or poor connection. Repair as necessary. After repairs, go to step 17. If circuit is okay, go to step 13.
If all TRANS RANGE PABC values are indicated as "O" (low voltage), go to next step. If all values are not indicated as "O", go to step 10.
Disconnect transaxle range switch connector. Observe TRANS RANGE PABC display. If all TRANS RANGE PABC values are indicated as "O" (low voltage), go to next step. If all values are not indicated as "O", go to step 14.
Turn ignition off. Disconnect PCM connector. Check transaxle range switch wiring for pinched wires or short to ground. Repair as necessary. After repairs, go to step 17. If wiring is okay, go to step 16.
Check for crossed wires in transaxle range switch connector. Repair as necessary. After repairs, go to step 17. If connector is wired properly, go to next step.
Turn ignition off. Disconnect transaxle range switch and PCM connectors. Turn ignition on. Check for an open, short to ground or short to voltage in circuit that caused incorrect value reading in step 3. Repair as necessary. After repairs, go to step 17. If no problem is found, go to next step.
Reconnect transaxle range switch connector. Connect a test light between positive battery terminal and circuit terminal that caused incorrect value reading in step 3. Observe and note state of test light while moving gear selector through all gears. Compare test light state in each gear selection with transaxle range switch valid input combination values. If test light is on when value should be "O" and off when value should be "X", go to step 15. If test light state is not as specified, go to next step.
Check for poor terminal connections at transaxle range switch connectors. Repair as necessary. After repairs, go to step 17. If terminal connections are okay, go to next step.
Replace defective transaxle range switch. After repairs, go to step 17.
Disconnect and inspect PCM connector for damaged pins, corrosion and loose wires. After repairs, go to step 17. If terminal connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Observe TRANS RANGE PABC display and move gear selector through all gear selections. Compare scan tool values with transaxle range switch valid input combination values. If all values are as specified, repair is complete. If any of the value is not as specified, repeat step 2.

Scheme 27

Disconnect and inspect PCM connector. Inspect for damaged pins, corrosion and loose wires. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation. Reviewing FAILURE RECORDS vehicle mileage since diagnostic test last failed may help determine how often condition that caused DTC to be set occurs.

DTC P0705: TRANSAXLE RANGE SWITCH CIRCUIT (3.4L "N" BODY)

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

Conditions for setting DTC are: PCM recognizes an invalid PRNDL parameter, vehicle speed is greater than 5 MPH and conditions met for longer 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, with engine off. Install scan tool. Move transaxle gear selector through all ranges while observing scan tool. If scan tool displays INVALID in any of the ranges, go to next step. If scan tool does not display INVALID in any of the ranges, go to step 10.
Compare scan tool values with transaxle range switch valid input combination values. (Scheme 27) If all circuits are indicated as HI, go to next step. If not all of the circuits are indicated as HI, go to step 5.
Check transaxle range switch ground circuit for open or poor connection. Repair as necessary. After repairs, go to step 10. If repairs were not necessary, go to next step.
Move gear selector through all of the ranges and record which circuits did not correspond with values in table. (Scheme 27) Disconnect transaxle range switch harness connector. Using a jumper wire, jumper circuit with incorrect value to ground. If value changes from HI to LO, go to step 8. If value does not change from HI to LO, go to next step.
Check affected circuit for open or short to ground. Repair as necessary. After repairs, go to step 10. If circuit is okay, go to next step.
Check for poor electrical connection at PCM. Repair as necessary. After repairs, go to step 10. If connection is okay, go to step 9.
Replace transaxle range switch. After repairs, go to step 10.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, 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 which was set. 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.
Using scan tool, check for any undiagnosed DTCs. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P0705: TRANSAXLE RANGE SWITCH CIRCUIT (3.8L "C", "G", "H" & "W" BODIES)

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

Transaxle Range Switch (TRS) is part of Park/Neutral Position (PNP) switch. Inputs from TRS indicate to PCM which position is selected by gear selector lever. PCM uses this information for ignition timing, EVAP canister purge, EGR and IAC valve operation.

Combination of 4 TRS input states determine PCM commanded shift pattern. Input voltage level at PCM is high when TRS is open, and low when TRS is closed. A problem which causes PCM to detect an invalid transaxle range input combination for more than 10 seconds will set this DTC.

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. Place gear selector in Park. Using scan tool, read TR PABC display. If scan tool displays P=O A=O B=X C=X, go to next step. If display is not as specified, go to step 4 .
Observe scan tool display while placing gear selector in each gear position. Record TR PABC status for each gear position. Compare scan tool display for each gear position. See «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. If scan tool display matches table entries for each gear selected, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If scan tool display does not match table entries, go to step 10 .
If scan tool displays P=X A=X B=X C=X, go to next step. If display is not as specified, go to step 7 .
Check if TRS 4-pin harness connector is disconnected or damaged. Repair as necessary. After repairs, go to step 17 . If no problem is found, go to next step.
Check for open in TRS 7-pin harness connector ground circuit. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 13 .
If scan tool displays P=O A=O B=O C=O, go to next step. If display is not as specified, return to step 3 .
Disconnect TRS 4-pin harness connector. If scan tool displays P=O A=O B=O C=O, go to next step. If display is not as specified, go to step 14 .
Turn ignition off. Disconnect PCM harness connector. Check TRS input circuit for being pinched or shorted to ground. Repair as necessary. After repairs, go to step 17 . If no problem is found, go to step 16 .
Ensure wires in TRS 4-pin harness connector are not crossed. Repair as necessary. After repairs, go to step 17 . If no problem is found, go to next step.
Turn ignition off. Disconnect PCM and TRS harness connectors. Turn ignition on. Check for open, short to ground or short to voltage in circuit which caused incorrect TRS input combination. Repair as necessary. After repairs, go to step 17 . If no problem is found, go to next step.
Reconnect TRS. Connect a test light between battery voltage and TRS circuit which caused incorrect TRS input combination at PCM. Observe and record state of test light while selecting each gear position. Compare state of test light in each gear position. See «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. If test light illuminates when input state should be "O" and off when input state should equal "X", go to step 15 . If test light illuminates as specified, go to next step.
Check for faulty connection at TRS 4-pin and 7-pin connectors. Repair as necessary. After repairs, go to step 17 . If no problem is found, go to next step.
Replace TRS. After replacing switch, go to step 17 .
Check for faulty connection at PCM. Repair as necessary. After repairs, go to step 17 . If no problem is found, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Clear DTCs. Observe scan tool display while placing gear selector in each gear position. Record TR PABC status for each gear position. Compare scan tool display for each gear position. See «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. If scan tool display matches table entries for each gear selected, repair is complete. If scan tool display does not match table entries, return to step 2 .

Gear Selector Position	Scan Tool TR PABC Display
Park	P=O A=O B=X C=X
Reverse	P=X A=O B=O C=X
Neutral	P=O A=X B=O C=X
Drive 4	P=X A=X B=O C=O
Drive 3	P=O A=O B=O C=O
Drive 2	P=X A=O B=X C=O
Drive 1	P=O A=X B=X C=O

TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS

Check for faulty connections or damaged harness. Observe scan tool TR PABC display while moving all related harness and connectors. A change in scan tool display indicates fault location.

DTC P0705: TRANSMISSION RANGE SWITCH CIRCUIT (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

Transmission is equipped Park/Neutral Position (PNP) switch and back-up switch. This switch incorporates a transmission range selector switch. There are 4 inputs (PRND ABCP) to the switch, which are switches to ground. These switches have a unique switch pattern. The PCM uses the combination of the switch patterns in order to determine the gear selected by the driver.

This diagnostic monitors the 4 inputs in order to determine what gear position the transmission is in. When PCM detects that an illegal range has occurred for 10 seconds, this 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, with engine off. Using scan tool, monitor PRND ABCP display while placing gear selector in each gear position. If scan tool displays INVALID in any range, go to next step. If scan tool does not display INVALID in any range, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Compare scan tool display for each gear position. See «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. If scan tool displays all circuits as OFF, go to next step. If scan tool does not display all circuits as OFF, go to step 5 .
Check for open or poor connection in PNP switch ground circuit. If problem is found, go to step 11 . If no problem is found, go to next step.
Move gear selector through all ranges and note which circuit does not correspond. See «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. Disconnect TRS connector. Connect a fused jumper wire between ground and circuit with incorrect value. If jumpered circuit status changes, go to step 8 . If jumpered circuit status does not change, go to next step.
Check affected circuit for an open or short to ground. Repair as necessary. After repairs, go to step 11 . If circuit is okay, go to next step.
Check for poor connection at PCM connector. Repair as necessary. After repairs, go to step 11 . If connection is okay, go to step 10 .
Check for poor connection at PNP switch connector. Repair as necessary. After repairs, go to step 11 . If connection is okay, go to next step.
Replace PNP switch. After replacing switch, go to step 11 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, 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 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.

Gear Selector Position	(1) Scan Tool PRND ABCP Display
Park (P)	A=O B=X C=X P=O
Reverse (R)	A=O B=O C=X P=X
Neutral (N)	A=X B=O C=X P=O
Drive 4 (OD)	A=X B=O C=O P=X
Drive 3 (3)	A=O B=O C=O P=0
Drive 2 (2)	A=O B=X C=O P=X
Drive 1 (1)	A=X B=X C=O P=0
(1) O equals ON, X equals OFF.

(1)	O equals ON, X equals OFF.

TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS

An intermittent problem can be caused by misrouted harness, rubbed through wire insulation or broken wire inside insulation. Monitor scan tool while moving related connectors and wiring harness. Whenever a fault is detected, scan data will change from ON to OFF or from OFF to ON. Moving gear selector slowly through each gear while monitoring scan tool may also help isolate problem.

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 P0706: TRANSAXLE RANGE SWITCH PERFORMANCE (3.1L "N" & "W" BODIES & 3.4L "N" BODY)

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

Combination of 4 TRS input states determine PCM commanded shift pattern. Input voltage level at PCM is high when TRS is open, and low when TRS is closed. If PCM detects engine start-up in any gear other than Park or Neutral, DTC P0706 is set.

Conditions for setting DTC are: system voltage is greater than 9 volts, TRS inputs indicate a gear position other than Park or Neutral during start-up and conditions are present for longer than 5 consecutive start-ups.

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 P0705 is also set, diagnose DTC P0705 before proceeding. If DTC is not set, go to next step.
Turn ignition on. Place gear selector in Park. Using scan tool, read TRANS RANGE display. If scan tool displays P-N, go to next step. If scan tool does not display P-N, go to step 5 .
Place gear selector in Neutral. Read scan tool TRANS RANGE display. If scan tool displays P-N, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If scan tool does not display P-N, go to next step.
Read scan tool TR PABC display. If scan tool displays P=O A=O B=O C=O, go to next step. If display is not as specified, go to step 10 .
Disconnect TRS 4-pin harness connector. If scan tool displays P=O A=O B=O C=O, go to next step. If display is not as specified, go to step 8 .
Turn ignition off. Disconnect PCM. Check TRS input circuit for being pinched or shorted to ground. If a problem is found, repair as necessary. After repairs, go to step 12 . If no problem is found, go to step 11 .
Attempt to adjust PNP/TRS switch. Read scan tool TRANS RANGE display with Park and Neutral selected. If scan tool displays P-N, go to step 12 . If scan tool does not display P-N, go to next step.
Ensure wires in TRS 4-pin harness connector are not crossed. If a problem is found, repair as necessary. After repairs, go to step 12 . If no problem is found, go to next step.
Replace TRS. After replacing switch, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Clear DTCs. Observe scan tool display while placing gear selector in each gear position. Record TR PABC status for each gear position. Compare scan tool display for each gear position. See «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. If scan tool display matches table entries for each gear selected, repair is complete. If scan tool display does not match table entries, return to step 3 .

Gear Selector Position	Scan Tool TR PABC Display
Park	P=O A=O B=X C=X
Reverse	P=X A=O B=O C=X
Neutral	P=O A=X B=O C=X
Drive 4	P=X A=X B=O C=O
Drive 3	P=O A=O B=O C=O
Drive 2	P=X A=O B=X C=O
Drive 1	P=O A=X B=X C=O

TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS

Adjust PNP switch.

DTC P0706: TRANSAXLE RANGE SYSTEM PERFORMANCE (3.8L "C", "G", "H" & "W" BODIES)

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

Conditions for setting DTC are: system voltage is greater than 9 volts, TRS inputs indicate a gear position other than Park or Neutral during start-up and conditions are present longer than 3 consecutive start-ups.

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 P0705 is also set, diagnose DTC P0705 before proceeding. If DTC is not set, go to next step.
Turn ignition on. Place gear selector in Park. Using scan tool, read TRANS RANGE display. If scan tool displays P-N, go to next step. If scan tool does not display P-N, go to step 5 .
Place gear selector in Neutral. Read scan tool TRANS RANGE display. If scan tool displays P-N, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If scan tool does not display P-N, go to next step.
Read scan tool TR PABC display. If scan tool displays P=O A=O B=O C=O, go to next step. If display is not as specified, go to step 10 .
Disconnect TRS 4-pin harness connector. If scan tool displays P=O A=O B=O C=O, go to next step. If display is not as specified, go to step 8 .
Turn ignition off. Disconnect PCM harness connector. Check TRS input circuit for being pinched or shorted to ground. Repair as necessary. After repairs, go to step 12 . If no problem is found, go to step 11 .
Attempt to adjust PNP/TRS switch. Read scan tool TRANS RANGE display with Park and Neutral selected. If scan tool displays P-N, go to step 12 . If scan tool does not display P-N, go to next step.
Ensure wires in TRS 4-pin harness connector are not crossed. Repair as necessary. After repairs, go to step 12 . If no problem is found, go to next step.
Replace TRS. After replacing switch, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Clear DTCs. Observe scan tool display while placing gear selector in each gear position. Record TR PABC status for each gear position. Compare scan tool display for each gear position. See «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. If scan tool display matches table entries for each gear selected, repair is complete. If scan tool display does not match table entries, return to step 3 .

Gear Selector Position	Scan Tool TR PABC Display
Park	P=O A=O B=X C=X
Reverse	P=X A=O B=O C=X
Neutral	P=O A=X B=O C=X
Drive 4	P=X A=X B=O C=O
Drive 3	P=O A=O B=O C=O
Drive 2	P=X A=O B=X C=O
Drive 1	P=O A=X B=X C=O

TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS

Check for faulty connections or damaged harness. Observe scan tool TR PABC display while moving all related harness and connectors. A change in scan tool display indicates fault location.

DTC P0706: TRANSMISSION RANGE SWITCH PERFORMANCE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

This diagnostic monitors the 4 inputs in order to determine what gear position the transmission is in. When PCM detects that an illegal range has occurred for 10 seconds, this 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, with engine off. Using scan tool, monitor PRND ABCP display while placing gear selector in each gear position. If scan tool displays INVALID in any range, go to next step. If scan tool does not display INVALID in any range, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Compare scan tool display for each gear position. See «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. If scan tool displays all circuits as OFF, go to next step. If scan tool does not display all circuits as OFF, go to step 5 .
Check for open or poor connection in PNP switch ground circuit. If problem is found, go to step 11 . If no problem is found, go to next step.
Move gear selector through all ranges and note which circuit does not correspond with «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. Disconnect TRS connector. Connect a fused jumper wire between ground and circuit with incorrect value. If jumpered circuit status changes, go to step 8 . If jumpered circuit status does not change, go to next step.
Check affected circuit for an open or short to ground. Repair as necessary. After repairs, go to step 11 . If circuit is okay, go to next step.
Check for poor connection at PCM connector. Repair as necessary. After repairs, go to step 11 . If connection is okay, go to step 10 .
Check for poor connection at PNP switch connector. Repair as necessary. After repairs, go to step 11 . If connection is okay, go to next step.
Replace PNP switch. After replacing switch, go to step 11 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, 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 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.

Gear Selector Position	(1) Scan Tool PRND ABCP Display
Park (P)	A=O B=X C=X P=O
Reverse (R)	A=O B=O C=X P=X
Neutral (N)	A=X B=O C=X P=O
Drive 4 (OD)	A=X B=O C=O P=X
Drive 3 (3)	A=O B=O C=O P=0
Drive 2 (2)	A=O B=X C=O P=X
Drive 1 (1)	A=X B=X C=O P=0
(1) O equals ON, X equals OFF.

(1)	O equals ON, X equals OFF.

TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS

DTC P0706: TRANSMISSION RANGE SWITCH PERFORMANCE (5.7L "Y" BODY)

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

Transaxle Range Switch (TRS) is part of Park/Neutral Position (PNP) switch. Combination of 4 TRS input states determine PCM commanded shift pattern. A problem which causes PCM to detect an invalid transaxle range input combination will set DTC P0706.

Conditions for setting DTC are: system voltage is greater than 8 volts, PCM detects TRS indicates a range other than Park or Neutral when engine is started and diagnostic fails 2 out of 4 tests.

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 PRND ABCP display while placing gear selector in each gear position. If scan tool displays INVALID in any range, go to next step. If scan tool does not display INVALID in any range, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Compare scan tool display for each gear position with «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. If scan tool displays all circuits as OFF, go to next step. If scan tool does not display all circuits as OFF, go to step 5 .
Check for open or poor connection in PNP switch ground circuit. If problem is found, go to step 10 . If no problem is found, go to next step.
Move gear selector through all ranges and note which circuit does not correspond with «TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) table. Disconnect TRS connector. Connect a fused jumper wire between ground and circuit with incorrect value. If jumpered circuit status changes, go to step 8 . If jumpered circuit status does not change, go to next step.
Check affected 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.
Check for poor connection at PCM connector. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to step 9 .
Replace PNP switch. After replacing switch, go to step 10 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, 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 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.

Gear Selector Position	(1) Scan Tool PRND ABCP Display
Park (P)	A=O B=X C=X P=O
Reverse (R)	A=O B=O C=X P=X
Neutral (N)	A=X B=O C=X P=O
Drive 4 (OD)	A=X B=O C=O P=X
Drive 3 (3)	A=O B=O C=O P=0
Drive 2 (2)	A=O B=X C=O P=X
Drive 1 (1)	A=X B=X C=O P=0
(1) O equals ON, X equals OFF.

(1)	O equals ON, X equals OFF.

TRANSAXLE RANGE SWITCH VALID INPUT COMBINATIONS

DTC P0801: REVERSE INHIBIT SOLENOID 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 Reverse Inhibit (RI) 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.

Conditions for setting DTC are: engine speed greater than 600 RPM, ignition voltage is 6-16 volts, PCM detects commanded state of driver and actual state does not match and 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 RI 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 a DVOM set 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.75 amp (but not zero), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If current draw is not less than.75 amp, go to next step.
Turn ignition off. Disconnect RI solenoid harness connector. Check resistance from solenoid 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. Disconnect RI solenoid connector. Connect test light between terminals in 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.
Connect test light to ground and probe ignition feed circuit in RI 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 RI solenoid connector. Disconnect PCM harness connector containing solenoid control circuit. Turn ignition on. Connect a fused jumper wire between to ground and PCM harness side connector, solenoid control circuit. If solenoid operates, go to step 9 . If solenoid does not operate, go to step 10 .
Check connections at RI solenoid. Repair as necessary. After repairs, go to step 14 . If solenoid 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 RI solenoid control circuit. After repairs, go to step 14 .
Repair faulty RI solenoid ignition feed circuit. After repairs, go to step 14 .
Replace RI solenoid. After replacing solenoid, 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 P0803: SKIP SHIFT SOLENOID CONTROL CIRCUIT (5.7L "F" BODY) OR 1-4 UPSHIFT SOLENOID CONTROL CIRCUIT (5.7L "Y" BODY)

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

Ignition voltage is supplied directly to 2nd gear block out or skip shift solenoid 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.

Conditions for setting DTC are: engine speed is greater than 600 RPM, ignition voltage is greater than 6 volts but less than 16 volts, PCM detects commanded state of driver and actual state do not match and 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 2nd gear block out ("F" Body) or 1-4 upshift ("Y" Body) 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 a DVOM set 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.75 amp (but not zero), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If current draw is not as specified, go to next step.
Turn ignition off. Disconnect solenoid connector. Check resistance between solenoid control circuit in PCM harness connector to ground. If resistance is infinite, go to step 12 . If resistance reading is not infinite, go to step 10 .
Turn ignition off. Disconnect solenoid connector. Connect test light between terminals in 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.
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 11 .
Turn ignition off. Reconnect solenoid connector. Disconnect PCM harness connector containing solenoid control circuit. Turn ignition on. Connect a fused jumper wire between to ground and PCM connector (harness side), 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 solenoid 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 solenoid control circuit. After repairs, go to step 14 .
Repair faulty solenoid ignition feed circuit. After repairs are complete, go to step 14 .
Replace solenoid. After replacing solenoid, 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 P0804: 1-4 UPSHIFT LIGHT CONTROL CIRCUIT (5.7L "Y" BODY)

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

Voltage is supplied directly to 1-4 upshift light. PCM controls shift light signal by grounding this 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.

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 1-4 upshift light ("Y" Body) on and off. If light turns on and off as commanded, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If light does not turn on or off when commanded, go to next step.
Turn ignition off. Disconnect PCM harness connector containing shift light control circuit. Turn ignition on. If shift light is off, go to next step. If shift light is on, go to step 5 .
Connect a fused jumper wire between ground and shift light control circuit at PCM connector (harness side). If shift light is on, go to step 6 . If shift light is not on, go to step 7 .
Repair short to ground in shift light control circuit. After repairs, go to step 9 .
Check connections at PCM. Repair as necessary. After repairs, go to step 9 . If connections are okay, go to step 8 .
Check for faulty shift light bulb, open ignition feed circuit to bulb, or shift light control circuit open or shorted to battery voltage. Repair as necessary. After repairs, go to step 9 .
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.

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 1-4 upshift lights 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 P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

Manifold Absolute Pressure (MAP) sensor measures changes in intake manifold pressure (vacuum). A low voltage signal, 2 volts, is sent to PCM on 5-volt reference circuit at closed throttle (high vacuum). A high voltage signal, 4 volts is sent at wide open throttle (low vacuum). DTC will set when MAP sensor intermittently indicates MAP voltage is greater than 4.2 volts.

Conditions for setting this DTC are: no TP sensor DTCs set, engine has been running for predetermined time determined by start-up ECT, TP angle less than 2 percent and engine speed is less than 900 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0108 is also set, diagnose DTC P0108 before proceeding. If DTC is not set, go to next step.
If DTC P1111, P1115, and/or P1121 is also set, go to step 6 . If none of these DTCs are set, go to next step.
Check for faulty sensor ground circuit terminal at MAP sensor. If problem is found, go to step 9 . If no problem is found, go to next step.
Check MAP signal circuit between MAP sensor harness connector and PCM for intermittent short to voltage. If a problem is found, go to step 10 . If no problem is found, go to step 8 .
Check for intermittent short to voltage on 5-volt reference circuit between PCM and MAP, EGR and TP sensors. If a problem is found, go to step 10 . If no problem is found, go to next step.
Check for faulty ground circuit terminal connection at PCM. If problem is found, go to step 9 . If no problem is found, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. If a problem is found, go to step 10 . If no problem is found, go to «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal. After repairs, go to step 11 .
Locate and repair intermittent open/short circuit. After repairs, go to next step.
Read and record FAILURE RECORDS data for DTC P1106. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Observe MAP display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.5L "W" BODY)

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

Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure. PCM supplies 5-volt reference, ground and signal circuit to MAP sensor. MAP sensor provides a signal to the PCM relative to pressure changes in intake manifold pressure (vacuum). A low voltage signal, about 2 volts, is sent to PCM on signal circuit at closed throttle (high vacuum) idle. A high voltage signal, about 4 volts or greater, is sent at wide open throttle (low vacuum).

DTC will set when there is no TP sensor related DTC set, ignition is on and throttle angle is steady at less than 2 percent if engine speed is less than 900 RPM and MAP sensor intermittently indicates a voltage greater than 4.2 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0108 is also set, diagnose DTC P0108 before proceeding. If DTC P0108 is not set, go to next step.
If DTC P1111, P1115, and/or P1121 is also set, go to step 6 . If these DTCs are not set, go to next step.
Check for faulty sensor ground circuit terminal at MAP sensor. If problem is found, go to step 9 . If no problem is found, go to next step.
Check MAP signal circuit between MAP sensor harness connector and PCM for intermittent short to voltage. If a problem is found, go to step 10 . If no problem is found, go to step 8 .
Check for intermittent short to voltage on 5-volt reference circuit between PCM and MAP, EGR and TP sensor. If a problem is found, go to step 10 . If no problem is found, go to next step.
Check for faulty ground circuit terminal connection at PCM. If problem is found, go to step 9 . If no problem is found, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. If a problem is found, go to step 10 . If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal. After repairs, go to step 11 .
Locate and repair intermittent open/short circuit. After repairs, go to next step.
Read and record FAILURE RECORDS data for DTC P1106. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURED INFO feature. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

Check for faulty connections or damaged harness. Observe scan tool MAP display while moving all related harness and connectors. A change in scan tool display indicates fault location.

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

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

Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure. PCM supplies 5-volt reference and ground for MAP sensor. MAP sensor provides a signal to the PCM relative to pressure changes in intake manifold pressure (vacuum). A low voltage signal, about 2 volts on VIN K or 1.5-2.5 volts on VIN 1, is sent to PCM on signal circuit at closed throttle (high vacuum) idle. A high voltage signal, about 4 volts or greater on both engines, is sent at wide open throttle (low vacuum).

Conditions for setting DTC are: no TP sensor DTCs set, ignition on, TP ANGLE steady and less than 5 percent with engine speed less than 1000 RPM, or steady and less than 10 percent with engine speed greater than 1000 RPM. MAP sensor intermittently indicates MAP greater than 12.8 psi (0.90 kg/cm 2 ).

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, select LAST TST FAIL. Record any other failed DTCs. If DTC P0108 is also set, diagnose DTC P0108 before proceeding. If DTC is not set, go to next step.
If DTC P1111, P1115, and/or P1121 is also set, go to step 6 . If none of these DTCs are set, go to next step.
Check for faulty sensor ground circuit terminal at MAP sensor. If problem is found, go to step 9 . If no problem is found, go to next step.
Check MAP signal circuit between MAP sensor harness connector and PCM for intermittent short to voltage. If a problem is found, go to step 10 . If no problem is found, go to step 8 .
Check for intermittent short to voltage on 5-volt reference circuit between PCM and MAP, EGR and TP sensors. If a problem is found, go to step 10 . If no problem is found, go to next step.
Check for faulty ground circuit terminal connection at PCM. If problem is found, go to step 9 . If no problem is found, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. If a problem is found, go to step 10 . If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal. After repairs, go to step 11 .
Locate and repair intermittent open/short circuit. After repairs, go to next step.
Read and record FAILURE RECORDS data for DTC P1106. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Observe scan tool MAP display while moving all related harness and connectors. A change in scan tool display indicates fault location.

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

MAP sensor changes resistance based upon manifold vacuum. PCM provides a 5-volt reference and ground signal and monitors a signal circuit. MAP sensor signal varies between ground and 5 volts as manifold vacuum varies. As MAP decreases, voltage decreases (low engine load, high vacuum). As MAP increases, voltage increases (high engine load, low vacuum). PCM uses MAP sensor value as an indicator of engine load. DTC will set when PCM detects a MAP sensor value that is too high.

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, verify if DTC P0106 or P0108 is also present. If these DTCs are present, diagnose affected DTC(s) first. If these DTCs are not present, go to next step.
Turn ignition off. Disconnect MAP sensor harness connector. Check harness connector terminals. Repair as necessary. If terminals are okay, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector C1. Check MAP sensor circuit terminals at PCM harness connector. Repair as necessary. If terminals are okay, go to next step.
Disconnect MAP sensor connector. Check all sensor terminals. Repair as necessary. If terminals are okay, go to next step.
Check MAP sensor 5-volt reference and signal circuits for intermittent short to voltage. Also, check for open MAP sensor ground circuit. Repair as necessary. If circuits are okay, fault is not present. Diagnose using DTC P0106 test.

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L "C" & "K" SERIES)

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

Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure (vacuum). A 5-volt reference is applied to sensor. A variable resistor moves in relation to manifold pressure and a voltage signal is returned to VCM through MAP signal circuit. Voltage signal varies from 1.0-1.5 volts at closed throttle to 4.0-4.5 volts at wide open throttle (low vacuum). VCM utilizes MAP signal and throttle position to determine fuel delivery.

DTC will set if VCM detects an intermittent high MAP sensor voltage after a calibrated amount of time.

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 vacuum gauge. Start engine. If engine idle is unstable, incorrect, or if manifold vacuum at idle is less than 15 in. Hg, repair problem before proceeding with this test. If engine idle and vacuum reading is normal, monitor MAP sensor voltage at idle using a scan tool. If MAP sensor voltage is greater than 4.6 volts, go to next step. If MAP sensor voltage is not greater than 4.6 volts, go to step 4 .
Check for other DTCs set. If other DTCs are set, diagnose affected DTCs. If no other DTCs are set, go to next step.
Turn ignition off. Disconnect MAP sensor connector. Check MAP sensor terminals and harness connector. If connector or terminals are faulty, go to step 7 . If connector or terminals are okay, go to next step.
Disconnect VCM harness connectors C2 and C3. Check VCM terminals and harness connector. If connector or terminals are faulty, go to step 7 . If connector or terminals are okay, go to next step.
Reconnect VCM and MAP sensor harness connectors. Start engine. Using scan tool, check for open or short to voltage in MAP sensor signal or ground circuit while moving/wiggling harness in various locations. If scan tool reading fluctuates greater than 0.5 volt, go to next step. If scan tool reading does not fluctuate greater than 0.5 volt, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair circuit or terminals 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.

An intermittent ground in MAP signal circuit or 5-volt reference circuit will result in DTC P1106 setting. With ignition on and engine off, manifold pressure is equal to atmospheric pressure with signal voltage high. VCM uses information as an indication of vehicle altitude.

To test accuracy of a suspect sensor, compare reading with a known-good vehicle. Reading should be within 0.4 volt. An intermittent may be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation.

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L "L", "M", "S" & "T" SERIES)

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

DTC will set if VCM detects an intermittent high MAP sensor voltage after a calibrated amount of time.

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 vacuum gauge. Start engine. If engine idle is unstable, incorrect, or if manifold vacuum at idle is less than 15 in. Hg, repair problem before proceeding with this test. If engine idle and vacuum reading is normal, monitor MAP sensor voltage at idle using a scan tool. If MAP sensor voltage is greater than 4.4 volts, go DTC P0108 test. If MAP sensor voltage is not greater than 4.4 volts, go to next step.
Turn ignition off. Disconnect MAP sensor connector. Check MAP sensor terminals and harness connector. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Disconnect VCM harness connectors C2 and C3. Check VCM terminals and harness connector. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Reconnect VCM and MAP sensor harness connectors. Start engine. Using scan tool, check for open or short to voltage in MAP sensor signal or ground circuit while moving/wiggling harness in various locations. If scan tool reading fluctuates greater than 0.5 volt, go to next step. If scan tool reading does not fluctuate greater than 0.5 volt, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair circuit or terminals 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.

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH 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.

Conditions for setting DTC are: no TP sensor DTCs set, throttle position is 0.4 percent or less with engine speed greater than 1200 RPM, throttle position 20 percent or less when engine speed is greater than 1200 RPM and MAP voltage is greater than 4.4 volts for a calibrated number of times.

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 engine idle is unstable, incorrect, or if manifold vacuum at idle is less than 15 in. Hg, repair as necessary. Using scan tool. With engine at idle, monitor MAP sensor voltage. If MAP sensor voltage is greater than 4.4 volts, go to DTC P0108 test. If MAP sensor voltage is not greater than 4.4 volts, go to next step.
Turn ignition off. Disconnect MAP sensor harness connector. Inspect harness connectors and terminals. If a problem is found, go to step 6 . If no problem is found, go to next step.
Disconnect VCM harness connectors. Inspect connectors and terminals. If problem is found, go to step 6 . If not problem is found, go to next step.
Reconnect VCM and MAP sensor harness connectors. Start engine. Using scan tool, monitor for open or short to voltage in MAP sensor signal or ground circuits by wiggling/moving harness in various locations. If MAP sensor voltage fluctuates greater than 0.5 volt, go to next step. If MAP sensor voltage does not fluctuate greater than 0.5 volt, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair circuit 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.

To test accuracy of a suspect sensor, compare reading with a known-good vehicle. Reading should be 3.6-4.9 volts. If DTC is intermittent, see appropriate TROUBLE SHOOTING - NO CODES article. To check for intermittent connection, disconnect sensor from bracket and twist sensor by hand. Output changes greater than.1 volt indicates a poor connection or connector. If okay, replace sensor. Ensure electrical connection remains securely connected. If sensor is removed from intake manifold, sensor-to-manifold seal must be replaced.

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT 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.

Manifold Absolute Pressure (MAP) sensor measures changes in intake manifold pressure (vacuum). A low voltage signal (2 volts) is sent to PCM on 5-volt reference circuit at closed throttle (high vacuum). A high voltage signal (4 volts) is sent at wide open throttle (low vacuum).

Conditions required to set DTC are, no TP sensor DTCs set, engine is running, TP angle greater than zero percent with engine speed less than 1000 RPM, TP angle greater than 5 percent with engine speed greater than 1000 RPM and MAP sensor intermittently indicating MAP voltage less than 0.1 volt.

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, select LAST TST FAIL. Record any other failed DTCs. If DTC P0107 is also set, diagnose DTC P0107 before proceeding. If DTC is not set, go to next step.
If DTC P1122 is also set, go to step 6 . If DTC P1122 is not set, go to next step.
Check for faulty 5-volt reference or signal circuit connection at MAP sensor. Repair as necessary. After repairs, go to step 9 . If circuit or connection is okay, go to next step.
Check signal circuit between MAP sensor and PCM connector for intermittent open or short to ground. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to step 8 .
Check for intermittent short to ground on 5-volt reference circuit between PCM and EGR valve, MAP and TP sensors. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty 5-volt reference circuit connection at PCM. If faulty connection is found, go to step 9 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in 5-volt reference circuit. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal(s). After replacing terminals, go to step 11 .
Repair circuit as necessary. After repairs, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Observe MAP display on scan tool MAP while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.5L "W" BODY)

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

DTC will set when there is no TP sensor related DTC set, ignition is on and throttle angle is steady at greater than 6 percent if engine speed is greater than 1000 RPM and MAP sensor intermittently indicates a voltage less than 0.1 volt.

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, select LAST TST FAIL. Record any other failed DTCs. If DTC P0107 is also set, diagnose DTC P0107 before proceeding. If DTC P0107 is not set, go to next step.
If DTC P1122 is also set, go to step 6 . If these DTCs are not set, go to next step.
Check for faulty sensor ground circuit terminal at MAP sensor. If problem is found, go to step 9 . If no problem is found, go to next step.
Check MAP signal circuit between MAP sensor harness connector and PCM for intermittent short to voltage. If a problem is found, go to step 10 . If no problem is found, go to step 8 .
Check for intermittent short to voltage on 5-volt reference circuit between PCM and MAP, EGR and TP sensor. If a problem is found, go to step 10 . If no problem is found, go to next step.
Check for faulty ground circuit terminal connection at PCM. If problem is found, go to step 9 . If no problem is found, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. If a problem is found, go to step 10 . If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal. After repairs, go to step 11 .
Locate and repair intermittent open/short circuit. After repairs, go to next step.
Read and record FAILURE RECORDS data for this DTC. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURED INFO feature. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

Check for faulty connections or damaged harness. Observe scan tool MAP display while moving all related harness and connectors. A change in scan tool display indicates fault location.

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

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

DTC will set when MAP sensor indicates a signal voltage intermittently less than 0.1 volt for longer 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0107 is also set, diagnose DTC P0107 before proceeding. If DTC is not set, go to next step.
If DTC P1122 is also set, go to step 6 . If DTC is not set, go to next step.
Check for faulty 5-volt reference or signal circuit connection at MAP sensor. If a problem is found, go to step 9 . If no problem is found, go to next step.
Check signal circuit between MAP sensor and PCM for intermittent open or short to ground. If problem is found, go to step 10 . If no problem is found, go to step 8 .
Check for intermittent short to ground on 5-volt reference circuit between PCM and EGR valve, MAP and TP sensors. If a problem is found, go to step 10 . If no problem is found, go to next step.
Check for faulty 5-volt reference circuit connection at PCM. If faulty connection is found, go to step 9 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in 5-volt reference circuit. If a problem is found, go to step 10 . If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal(s). After replacing terminals, go to step 11 .
Repair circuit as necessary. After repairs, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P1107. If scan tool displays DTC P1107 FAILED THIS IGN, return to step 2 . If scan tool does not display DTC P1107 FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Observe scan tool MAP display while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

MAP sensor changes resistance based upon manifold vacuum. PCM provides a 5-volt reference and ground signal. MAP sensor signal varies between one and 5 volts as manifold vacuum varies. As MAP decreases, voltage decreases (low engine load, high vacuum). As MAP increases, voltage increases (high engine load, low vacuum). PCM uses MAP sensor value as an indicator of engine load. DTC will set when PCM detects a MAP sensor value that is too low.

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, verify if DTC P0106 or P0107 is also present. If DTCs are present, diagnose affected DTC(s) first. If DTCs are not present, go to next step.
Turn ignition off. Disconnect harness connector to MAP sensor. Check harness connector terminals. Repair as necessary. If terminals are okay, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector C1. Check MAP sensor circuit terminals at PCM harness connector. Repair as necessary. If terminals are okay, go to next step.
Disconnect MAP sensor harness connector. Check all sensor terminals. Repair as necessary. If terminals are okay, go to next step.
Check MAP sensor 5-volt reference and signal circuits for intermittent short to voltage. Also, check for open MAP sensor ground circuit. Repair as necessary. If circuits are okay, fault is not present. Diagnose using DTC P0106 test.

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

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

Manifold Absolute Pressure (MAP) sensor measures changes in intake manifold pressure (vacuum). A low voltage signal (1.0-1.5 volts) is sent to VCM on 5-volt reference circuit at closed throttle (high vacuum). A high voltage signal (4.0-4.5 volts) is sent at wide open throttle (low vacuum).

DTC will set when MAP sensor voltage is less than.04 volt for a calibrated number of 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 vacuum gauge. Start engine. If engine idle is unstable, incorrect, or if manifold vacuum at idle is less than 15 in. Hg, repair problem before proceeding with this test. If engine idles and vacuum reading is normal, monitor MAP sensor voltage at idle using a scan tool. If MAP sensor voltage is less than 0.4 volt, go DTC P0107 test. If MAP sensor voltage is not less than 0.4 volt, go to next step.
Turn ignition off. Disconnect MAP sensor harness connector. Check MAP sensor terminals and harness connector. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Disconnect VCM harness connectors C2 and C3. Check VCM terminals and harness connector. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Reconnect VCM and MAP sensor harness connectors. Start engine. Using scan tool, check for open or short to voltage in MAP sensor signal or ground circuit while moving/wiggling harness in various locations. If scan tool reading fluctuates greater than 0.5 volt, go to next step. If scan tool reading does not fluctuate greater than 0.5 volt, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair circuit or terminals 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.

Check MAP sensor signal and 5-volt reference circuits for intermittent open condition.

With ignition on and engine off, MAP signal is equal to atmospheric pressure with signal voltage high. This information is used by VCM as an indication of altitude. Comparison of this reading with a known-good vehicle with same sensor is a way to check accuracy of suspect sensor. Reading should be within 0.4 volt.

Disconnect sensor from bracket and twist sensor by hand to check for intermittents. Output changes greater than 0.1 volt indicate a faulty sensor connection.

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT 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.

Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure (vacuum). A 5-volt reference voltage is applied to sensor. A variable resistor moves in relation to manifold pressure and a voltage signal is returned to VCM through MAP signal circuit. Voltage signal varies from 1.0-1.5 volts at closed throttle to 4.0-4.5 volts at wide open throttle (low vacuum). VCM utilizes MAP signal and throttle position to determine fuel delivery.

DTC will set when there are no TP sensor DTCs set, engine is running, TP is at least zero percent when engine speed is not greater than 1000 RPM (800 RPM on 7.4L) or TP is at least 12.5 percent when engine speed is greater than 1000 RPM (800 RPM on 7.4L) and MAP sensor voltage is less than.04 volt.

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. With engine idling, monitor MAP sensor voltage using scan tool. If MAP sensor voltage is less than.5 volt, go to next step. If MAP sensor voltage is not less than.5 volt, go to step 5 .
Turn ignition off. Disconnect MAP sensor connector. Connect a jumper wire between 5-volt reference circuit and signal circuit of MAP sensor connector. Turn ignition on. Monitor MAP sensor voltage using scan tool. If MAP sensor voltage is greater than 4.7 volts, go to step 6 . If MAP sensor voltage is not greater than 4.7 volts, go to next step.
Turn ignition off. Remove jumper wire. Using test light, probe MAP sensor connector signal circuit to battery voltage. Turn ignition on. Monitor MAP sensor voltage using scan tool. If MAP sensor voltage is greater than 4.7 volts, go to step 9 . If MAP sensor voltage is not greater than 4.7 volts, go to step 7 .
DTC is intermittent. Check if additional DTCs are set. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If any additional DTCs are set, go to applicable DTC test.
Check for poor connection at MAP sensor. If a problem is found, go to step 12 . If connection is okay, go to step 11 .
Check for open in MAP signal circuit. If circuit is open, go to step 12 . If circuit is okay, go to next step.
Check for short to ground in MAP signal circuit. If circuit is shorted, go to step 12 . If circuit is okay, go to step 13 .
Check for open in MAP 5-volt reference circuit. If circuit is open, go to step 12 . If circuit is okay, go to next step.
Check for short to ground in MAP 5-volt reference circuit. If circuit is shorted, go to step 12 . If circuit is okay, go to step 13 .
Replace MAP sensor. After replacing sensor, go to step 14 .
Repair circuit as necessary. After repairs, go to step 14 .
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.

An intermittent open in MAP signal circuit or 5-volt reference circuit will result in DTC P1107 setting. With ignition on and engine off, manifold pressure is equal to atmospheric pressure with signal voltage high. VCM uses information as an indication of vehicle altitude.

To test accuracy of a suspect sensor, compare reading with a known-good sensor/vehicle. Reading should be 3.6-4.9 volts. If DTC is intermittent, see appropriate TROUBLE SHOOTING - NO CODES article. To check for intermittent connection, disconnect sensor from bracket and twist sensor by hand. Output changes greater than.1 volt indicates a poor connection or connector. If okay, replace sensor. Ensure electrical connection remains securely connected. If sensor is removed from intake manifold, sensor-to-manifold seal must be replaced.

DTC P1108: BARO-TO-MAP SENSOR CIRCUIT COMPARISON TOO HIGH (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

MAP sensor changes resistance based upon manifold vacuum. PCM provides a 5-volt reference and ground signal. MAP sensor signal varies between ground and 5 volts as manifold vacuum varies. As MAP decreases, voltage decreases (low engine load, high vacuum). As MAP increases, voltage increases (high engine load, low vacuum). PCM uses MAP sensor value as an indicator of engine load.

This test monitors the MAP signal by comparing the reading to calculated BARO. If the values of the MAP signal and the calculated BARO are too close together at idle, 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.
Start and idle engine. Using scan tool, select ENGINE 1 and note MAP and BARO displays. Subtract MAP value from BARO value. If difference between BARO and MAP value is 11 kPa or less, go to next step. If difference is greater than 11 kPa, fault is not present. Diagnose using DTC P0106 tests.
Connect vacuum gauge at MAP sensor port. With engine at idle, if vacuum is 14 in. Hg or greater, go to next step. If vacuum is not greater than 14 in. Hg, go to step 14 .
Turn engine off. Disconnect MAP sensor harness connector. Turn ignition to LOCK position. Note MAP display on scan tool. If MAP sensor display reads 16 kPa or less, go to next step. If MAP sensor display does not read 16 kPa or less, go to step 7 .
Check voltage between ground and MAP sensor ground circuit at MAP sensor harness connector terminal. If voltage reading is greater than.5 volt, go to step 12 . If voltage reading is not greater than.5 volt, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition to LOCK position, then disconnect PCM harness connector C1 and MAP sensor harness connector terminals. Using DVOM, check resistance of MAP sensor ground circuit between PCM harness connector and MAP harness connector terminals. If resistance is 5 ohms or less, go to step 11 . If resistance is not 5 ohms or less, go to step 9 .
Store fluid life index as indicated on scan tool. Turn ignition to LOCK position and wait 30 seconds, then disconnect PCM harness connector C1 and MAP sensor harness connector terminals. Using DVOM, check voltage between chassis ground and MAP sensor ground circuit at MAP sensor harness connector terminal "B". If voltage reading is.5 volt or less, go to step 10 . If voltage reading is not.5 volt or less, go to next step.
Repair short to voltage in MAP sensor signal circuit.
Repair open in MAP sensor ground circuit.
Check terminal contact to MAP sensor at PCM harness connector C1. Repair as necessary. If terminal contact is okay, go to step 15 .
Repair terminal contact MAP sensor harness connector. Repair as necessary. If terminal contact is okay, go to step 13 .
Repair short to voltage in MAP sensor 5-volt reference circuit.
Replace MAP sensor.
Check and repair causes of intake manifold vacuum leaks or low engine vacuum.
Replace PCM. Program replacement PCM using required equipment.

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

Intake Air Temperature (IAT) sensor is a thermistor. PCM applies and reads a 5-volt reference signal to sensor. When air is cold, sensor resistance is high and PCM will measure a high signal voltage. If air is warm, sensor resistance is low causing PCM to measure low voltage.

Conditions required to set DTC are, vehicle speed less than 35 MPH, IAT signal voltage intermittently indicates IAT less than -38°F (-39°C) and conditions present up to 3 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0113 is also set, diagnose DTC P0113 before proceeding. If DTC is not set, go to next step.
If DTC P1106, P1115, and/or P1121 is also set, go to step 6 . If these DTCs are not set, go to next step.
Check for faulty sensor ground circuit terminal at IAT sensor. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty signal circuit connection at IAT sensor. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Check IAT signal circuit between IAT sensor connector and PCM for intermittent open. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check IAT signal circuit between IAT sensor harness connector and PCM for intermittent short to voltage. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty ground circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. 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-p0704-p1272) .
Read and record FAILURE RECORDS data for DTC P1111. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Observe IAT display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.5L "W" BODY)

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

DTC will set when there is no ECT, MAF or VSS sensor DTCs set, engine running longer than 3 minutes, ECT greater than 140°F (60°C), vehicle speed less than 35 MPH and IAT intermittently less than -38°F (-39°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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0113 is also set, diagnose DTC P0113 before proceeding. If DTC is not set, go to next step.
If DTC P1106, P1115 and/or P1121 is also set, go to step 6 . If DTC P1106, P1115 and/or P1121 is not set, go to next step.
Check for faulty sensor ground circuit terminal at IAT sensor. Repair as necessary. After repairs, go to step 10 . If no problem is found, go to next step.
Check for faulty signal circuit connection at IAT sensor. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Check IAT signal circuit between IAT sensor connector and PCM for intermittent open. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check IAT signal circuit between IAT sensor harness connector and PCM for intermittent short to voltage. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty ground circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 10 . If no problem is found, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. Repair as necessary. After repairs, go to next step. If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Read and record FAILURE RECORDS data for this DTC. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are displayed, go to appropriate DTC test.

Check for faulty connections or damaged harness. Observe scan tool IAT display while moving all related harnesses and connectors. A change in scan tool display indicates fault location. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (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, vehicle speed less than 35 MPH, IAT signal voltage intermittently indicates IAT less than -38°F (-39°C) and conditions present up to 3 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0113 is also set, diagnose DTC P0113 before proceeding. If DTC P0113 is not set, go to next step.
If DTC P1106, P1115, and/or P1121 is also set, go to step 6 . If these DTCs are not set, go to next step.
Check for faulty sensor ground circuit terminal at IAT sensor. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty signal circuit connection at IAT sensor. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Check IAT signal circuit between IAT sensor connector and PCM for intermittent open. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check IAT signal circuit between IAT sensor harness connector and PCM for intermittent short to voltage. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty ground circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. 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-p0704-p1272) .
Read and record FAILURE RECORDS data for this DTC. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

Intake Air Temperature (IAT) sensor is a thermistor that varies resistance based on temperature. Low temperature will result in high signal voltage. If IAT reading is -31°F (-35°C) or lower when coolant temperature is greater than the IAT, 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 DTC P0111 or P0113 is also present. If either DTC is present, diagnose affected DTCs first. If these DTCs are not present, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition on and wait 30 seconds, then disconnect PCM harness connectors C1 and C2. Check terminals to IAT sensor at PCM harness connectors C1 and C2. Repair as necessary. If terminal contacts are okay, go to next step.
Disconnect and check IAT sensor harness connector. Repair as necessary. If terminal contacts are okay, go to next step.
Check IAT sensor signal circuit for short to ground. Repair as necessary. If circuit is okay, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .

If fault is not present, check PCM grounds. If a faulty sensor is suspected, check sensor resistance. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article. Replace sensor as necessary.

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

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

Intake Air Temperature (IAT) sensor is a thermistor. VCM applies and reads a 5-volt reference signal to sensor. When air is cold, sensor resistance is high and VCM will measure a high signal voltage. If air is warm, sensor resistance is low causing VCM to measure low voltage.

DTC will set when VCM detects an intermittent high IAT voltage while engine is running.

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, read IAT sensor voltage. If voltage reading is greater than 4.9 volts, go DTC P0113 test. If voltage reading is not greater than 4.9 volts, go to next step.
Turn ignition off. Disconnect IAT sensor harness connector. Check sensor harness connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Disconnect VCM harness connectors C2 and C3. Check connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Reconnect VCM harness connectors. Turn ignition, with engine off. Using scan tool, check for intermittent open or short in IAT sensor signal or ground circuits while moving/wiggling sensor harness. If scan tool voltage reading fluctuates, go to next step. If scan tool voltage reading does not fluctuate, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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 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 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 at IAT sensor and at VCM. Observe scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH 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.

Intake Air Temperature (IAT) sensor is a thermistor located in fresh air duct to throttle body. It is used to monitor temperature of air entering throttle body. VCM supplies 5 volts to sensor. When air is cool, sensor resistance will be high and VCM will sense a high voltage signal. When air is warm, sensor resistance will be low and VCM will sense a low voltage signal.

DTC will set when IAT voltage is greater than 4.9 volts 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.
Turn ignition on, with engine off. Using scan tool, monitor IAT sensor voltage. If scan tool voltage reading is greater than 4.9 volts, go to DTC P0113 test. If scan tool voltage reading is not greater than 4.9 volts, go to next step.
Turn engine off. Disconnect IAT sensor harness connector. Check IAT sensor harness connector and terminals. If a problem is found, go to step 6 . If no problem is found, go to next step.
Disconnect VCM harness connector terminals. Check terminals and connectors. If a problem is found, go to step 6 . If no problem is found, go to next step.
Reconnect VCM and IAT sensor harness connectors. Turn ignition on, with engine off. Using scan tool, check for intermittent open or short to voltage in IAT sensor ground or signal voltage while moving/wiggling harness in various locations. If IAT sensor voltage on scan tool fluctuates, go to next step. If IAT sensor voltage on scan tool does not fluctuate, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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.

Scan tool indicates temperature of ambient air entering throttle body. Air temperature should be very close to temperature of outside air and should gradually rise as engine warms and underhood temperature increases. If DTC P1111 is set, problem is intermittent. Check for poor connections at IAT sensor and VCM by wiggling wiring harness and monitoring IAT temperature or voltage on scan tool. Check for poor connection at point where scan tool display changed. Also, check for a skewed or mis-scaled sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

Intake Air Temperature (IAT) sensor is a thermistor which changes resistance based on temperature. IAT is located in air intake passage of engine air induction system. IAT sensor has a signal and ground circuit. PCM applies a voltage (about 5 volts) on signal circuit to sensor and monitors changes in this voltage caused by changes in resistance of sensor to determine intake temperature.

When intake air is cold, sensor resistance is high and PCM signal voltage is only pulled down a small amount through sensor ground. When intake air is warm, sensor resistance is low and PCM signal voltage is pulled down a greater amount. This causes PCM to sense a low signal voltage (high temperature). When signal voltage is higher than normal operating range, DTC will set. Conditions for setting DTC are: intake air temperature is less than -31°F (-35°C) and condition exists for a total of one second during a 20 second period.

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, with engine off. Using scan tool, monitor FAILED THIS IGNITION under DTC status for DTC P0113. If DTC P0113 failed this ignition cycle, diagnose DTC P0113. If DTC P0113 did not fail this ignition cycle, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes while moving related harness connectors, go to step 6 . If sensor value does not change while moving connectors, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harnesses. If sensor value changes abruptly, go to step 7 . If sensor value does not change, 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 step 8 . 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-p0704-p1272) .
Repair damaged connectors or terminals. After repairs, go to step 9 .
Repair circuit as necessary. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If circuits are okay, replace sensor/component. After repairs, 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.

If other DTCs are present that share same ground and/or 5-volt reference circuit, check for faulty connections or faulty wiring. If engine has been allowed to sit overnight, engine coolant temperature (ECT) and intake air temperature (IAT) sensor values should display within a few degrees of each other. If temperature value is not within 5°F (3°C), check IAT sensor resistance. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (5.7L "F" & "Y" BODIES)

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

Conditions for setting DTC are: DTCs P0102, P0103, P0117, P0118, P0500, P0502 or P0503 not set, engine operating greater than 100 seconds, engine coolant temperature greater than 32°F (0°C), IAT less than -31°F (-35°C), vehicle speed less than 7 MPH and MAF less than 15 gm/sec.

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, with engine off. Using scan tool, monitor FAILED THIS IGNITION under DTC status for DTC P0113. If DTC P0113 failed this ignition cycle, diagnose DTC. If DTC does not fail this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes while moving related harness connectors, go to step 6 . If sensor value does not change while moving connectors, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harnesses. If sensor value changes abruptly, go to step 7 . If sensor value does not change, 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 P1111. If scan tool indicates that this test failed this ignition, go to step 8 . 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-p0704-p1272) .
Repair damaged connectors or terminals. After repairs, go to step 9 .
Repair faulty wiring. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If circuits are okay, replace sensor/component. After repairs, 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 P1112: INTAKE PLENUM SWITCHOVER VALVE CIRCUIT (3.0L "V" BODY)

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

Multi-Ram system uses variable air induction tuning to achieve maximum performance and efficiency over entire operating range of engine. System consists of 2 main components. Intake manifold contains intake plenum switchover valve. This vacuum operated valve is essentially a moveable divider that changes airflow characteristics of intake manifold. Vacuum to valve is controlled by an ECM controlled solenoid valve.

Intake resonance switchover valve is located in air intake duct assembly in front of engine. This vacuum operated valve is also a moveable divider that changes tuning of air intake system. Vacuum to valve is controlled by ECM controlled solenoid valve. By opening and closing these valves independently in different combinations, 4 different air flow configurations can be created, each optimized to a particular set of engine operating conditions.

Both solenoid valves are supplied power via main relay (switched battery feed circuit). Both solenoid valves have a control circuit to ECM. ECM controls a 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, control circuit voltage should be low (near zero volts). When ECM is commanding control circuit to a component off, circuit 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 circuit for short to ground, short to voltage, open or an internally shorted or excessively low resistance in 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.

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 valve on and off. If valve turns on and off with each command, go to next step. If valve 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 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-p0704-p1272) . If current draw is not 0.1-0.75 amp, go to next step.
Turn ignition off. Disconnect switchover 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 switchover 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 switched battery feed circuit at valve harness connector. 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 solenoid operates, go to step 12 . If solenoid 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 valve. After repairs, go to step 14 .
Replace 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 P1112 is set, go to step 2 . If DTC P1112 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 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.

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "U" SERIES)

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

Conditions for setting DTC are: vehicle speed greater than 25 MPH, IAT sensor voltage intermittently less than 0.14 volt and conditions present for up to 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0112 is also set, diagnose DTC P0112 before proceeding. If DTC is not set, go to next step.
Check IAT signal circuit between IAT sensor harness connector and PCM for intermittent short to ground. Repair as necessary. After repairs, go to next step. If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Read and record FAILURE RECORDS data for DTC P1112. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.5L "W" BODY)

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

DTC will set when there is not ECT sensor, MAF sensor or VSS related DTCs are present, vehicle speed greater than 25 MPH, IAT sensor voltage intermittently indicates an intake air temperature greater than 274°F (134°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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0112 is also set, diagnose DTC P0112 before proceeding. If DTC is not set, go to next step.
Check IAT signal circuit between IAT sensor harness connector and PCM for intermittent short to ground. Repair as necessary. After repairs, go to next step. If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Read and record FAILURE RECORDS data for this DTC. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURED INFO function. If any diagnosed DTCs are displayed, go to appropriate DTC test.

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT 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 are: no ECT, MAF, or VSS sensor DTCs set, vehicle speed greater than 25 MPH, engine running longer than 10 seconds and IAT sensor voltage intermittently less than 0.14 volt.

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, select LAST TST FAIL. Record any other failed DTCs. If DTC P0112 is also set, diagnose DTC P0112 before proceeding. If DTC is not set, go to next step.
Check IAT signal circuit between IAT sensor harness connector and PCM for intermittent short to ground. Repair as necessary. After repairs, go to next step. If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Read and record FAILURE RECORDS data for DTC P1112. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool indicates that this test failed in this ignition, return to step 2 . If scan tool does not indicate that this test failed in this ignition, system is okay.

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

Intake Air Temperature (IAT) sensor is a thermistor that varies resistance based on temperature. High temperature will result in low signal voltage. If IAT reading is 304°F (151°C) or greater when coolant temperature is less than 230°F (110°C), 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 DTC P0111 or P0112 is also present. If either DTC is present, diagnose affected DTCs first. If these DTCs are not present, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition on and wait 30 seconds, then disconnect PCM harness connectors C1 and C2. Check terminals to IAT sensor at PCM harness connectors C1 and C2. Repair as necessary. If terminal contacts are okay, go to next step.
Disconnect and check IAT sensor harness connector. Repair as necessary. If terminal contacts are okay, go to next step.
Check IAT sensor signal circuit for short to ground. Repair as necessary. If circuit is okay, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .

If fault is not present, check PCM grounds. If a faulty sensor is suspected, check sensor resistance. Replace sensor as necessary.

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

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

DTC will set when VCM detects an intermittent low IAT voltage while engine is running and vehicle speed exceeds 2 MPH.

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, read IAT sensor voltage. If voltage reading is less than 0.25 volt, go to DTC P0112 test. If voltage reading is not less than 0.25 volt, go to next step.
Turn engine off. Disconnect IAT sensor harness connector. Check IAT sensor harness connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Disconnect VCM harness connectors C2 and C3. Check connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Reconnect VCM harness connectors. Turn ignition, with engine off. Using scan tool, check for intermittent open or short in IAT sensor signal or ground circuits while moving/wiggling sensor harness. If scan tool voltage reading fluctuates, go to next step. If scan tool voltage reading does not fluctuate, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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 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 Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT 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.

Conditions for setting DTC are: no VSS DTCs set, vehicle speed is greater than 2 MPH, engine run time is greater than 100 seconds and IAT voltage less than.25 volt 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.
Install scan tool. Turn ignition on, with engine off. Monitor IAT sensor voltage on scan tool. If voltage reading is less than.25 volt, go to DTC P0112 test. If voltage reading is not less than.25 volt, go to next step.
Turn engine off. Disconnect IAT sensor harness connector. Check IAT sensor harness connector and terminals. If a problem is found, go to step 6 . If no problem is found, go to next step.
Disconnect VCM harness connectors. Check harness connectors and terminals. If a problem is found, go to step 6 . If no problem is found, go to next step.
Reconnect VCM and IAT harness connectors. Turn ignition on, with engine off. Using scan tool, check for intermittent short to ground in IAT sensor signal circuit by wiggling/moving harness in various locations. If IAT sensor voltage on scan tool fluctuates, go to next step. If IAT sensor voltage on scan tool does not fluctuate, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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.

Scan tool indicates temperature of ambient air entering throttle body. Air temperature should be very close to temperature of outside air and should gradually rise as engine warms and underhood temperature increases. If DTC P1112 is set, problem is intermittent. Check for short to ground in IAT signal circuit by wiggling wiring harness at various locations and monitoring IAT temperature or voltage on scan tool. Check for short to ground at point where scan tool display changed. Also, check for a skewed or mis-scaled sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

When intake air is cold, sensor resistance is high and PCM signal voltage is only pulled down a small amount through sensor ground. When intake air is warm, sensor resistance is low and PCM signal voltage is pulled down a greater amount. This causes PCM to sense a low signal voltage (high temperature). When signal voltage is lower than normal operating range, DTC will set. Conditions for setting DTC are: intake air temperature is greater than 282°F (139°C) and condition exists for a total of one second during a 20 second period.

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, with engine off. Using scan tool, monitor FAILED THIS IGNITION under DTC status for DTC P0112. If DTC P0112 failed this ignition cycle, diagnose DTC P0112. If DTC P0112 did not fail this ignition cycle, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes while moving related harness connectors, go to step 6 . If sensor value does not change while moving connectors, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harnesses. If sensor value changes abruptly, go to step 7 . If sensor value does not change, 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 step 8 . 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-p0704-p1272) .
Repair damaged connectors or terminals. After repairs, go to step 9 .
Repair circuit as necessary. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If circuits are okay, replace sensor/component. After repairs, 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 P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (5.7L "F" & "Y" BODIES)

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

When intake air is cold, sensor resistance is high and PCM signal voltage is only pulled down a small amount through sensor ground. When intake air is warm, sensor resistance is low and PCM signal voltage is pulled down a greater amount. This causes PCM to sense a low signal voltage (high temperature). When PCM senses a signal voltage higher than normal operating range, DTC will set.

Conditions for setting DTC are: DTCs P0102, P0103, P0117, P0118, P0500, P0502 or P0503 not set, engine run time is greater than 100 seconds, vehicle speed at least 25 MPH, ECT greater than 32°F (0°C), IAT is less than -31°F (-35°C) and intermittent condition exists for a total of one second during a 20 second time period.

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, with engine off. Using scan tool, monitor FAILED THIS IGNITION under DTC status for DTC P0112. If DTC P0112 failed this ignition cycle, diagnose DTC. If DTC does not fail this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes while moving connectors, go to step 6 . If sensor value does not change while moving connectors, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harnesses. If sensor value changes abruptly, go to step 7 . If sensor value does not change, 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 step 8 . 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-p0704-p1272) .
Repair damaged connectors or terminals. After repairs, go to step 9 .
Repair faulty wiring. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If circuits are okay, replace sensor/component. After repairs, 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 P1113: INTAKE RESONANCE SWITCHOVER VALVE CIRCUIT (3.0L "V" BODY)

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.
Turn ignition on, with engine off. Using scan tool, command switchover valve on and off. If valve turns on and off with each command, go to next step. If valve 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 switchover 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-p0704-p1272) . If current draw is not 0.1-0.75 amp, go to next step.
Turn ignition off. Disconnect switchover 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 switchover 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 switched battery feed circuit at valve harness connector. If test light is on, go to next step. If test light is off, go to step 10 .
Turn ignition off. Reconnect switchover valve 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 valve 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 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 switchover valve. After repairs, go to step 14 .
Replace switchover 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 P1113 is set, go to step 2 . If DTC P1113 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 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 switched harness. Ensure IAT sensor electrical connector and intake resonance switchover valve electrical connectors are not switched. This can cause IAT sensor reading to remain constant. Allow vehicle to idle a few minutes. Using scan tool, observe IAT sensor.

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 P1114: ECT SENSOR CIRCUIT INTERMITTENT 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.

Engine Coolant Temperature (ECT) sensor is a thermistor that varies resistance based on temperature. As temperature of sensor increases, resistance decreases. High temperature will result in a low signal voltage. DTC will set when PCM sees an ECT sensor voltage intermittently less than 1.5 volt.

Conditions for setting DTC are: engine running, ECT sensor signal is intermittently greater than 282°F (139°C) and conditions present for greater than 15 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0117 is also set, diagnose DTC P0117 before proceeding. If DTC is not set, go to next step.
Check ECT signal circuit between ECT sensor harness connector and PCM for intermittent short to ground. Repair as necessary. After repairs, go to next step. If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Read and record FAILURE RECORDS data for DTC P1114. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Observe ECT display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location. Check for skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.5L "W" BODY)

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

Conditions for setting DTC are: ECT sensor intermittently indicates a coolant temperature of less than 9°F (-13°C) and engine has been running for longer than 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0117 is also set, diagnose DTC P0117 before proceeding. If DTC is not set, go to next step.
Check ECT signal circuit between ECT sensor harness connector and PCM for intermittent short to ground. Repair as necessary. After repairs, go to next step. If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Read and record FAILURE RECORDS data for this DTC. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are displayed, go to appropriate DTC test.

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT 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 are: engine running for 3 seconds, ECT voltage intermittently less than 0.74 volt and ECT sensor intermittently indicates ECT greater than 237°F (114°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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0117 is also set, diagnose DTC P0117 before proceeding. If DTC is not set, go to next step.
Check ECT signal circuit between ECT sensor harness connector and PCM for intermittent short to ground. Repair as necessary. After repairs, go to next step. If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Read and record FAILURE RECORDS data for DTC P1114. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool indicates that this test failed this ignition, return to step 2 . If scan tool does not indicates that this test failed this ignition, system is okay.

Check for faulty connections or damaged harness. Observe scan tool IAT display while moving all related harnesses and connectors. A change in scan tool display indicates fault location. Check for skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

Engine Coolant Temperature (ECT) sensor is a thermistor that varies resistance based on temperature. High temperature will result in low signal voltage. If ECT reading is 304°F (151°C) or greater, 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 DTC P0116 or P0117 is also present. If either DTC is present, diagnose affected DTC first. If these DTCs are not present, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition on and wait 30 seconds, then disconnect PCM harness connectors C1 and C2. Check ECT sensor circuit terminals at PCM harness connectors C1 and C2. Repair as necessary. If terminal contacts are okay, go to next step.
Disconnect and check ECT sensor harness connector. Repair as necessary. If terminal contacts are okay, go to next step.
Check ECT sensor signal circuit for short to ground. Repair as necessary. If circuit is okay, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .

If fault is not present, check PCM grounds. If a faulty sensor is suspected, check for skewed ECT sensor.

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

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

Engine Coolant Temperature (ECT) sensor is a thermistor that varies resistance based on temperature. As temperature of sensor increases, resistance decreases. High temperature will result in a low signal voltage. DTC will set when VCM sees an ECT sensor voltage of less than 0.82 volt with engine running for 5 seconds.

DTC will set when VCM detects an intermittent low ECT voltage while engine is running and run time exceeds 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, read ECT sensor voltage. If voltage reading is less than 0.25 volt, go to DTC P0117. If voltage reading is not less than 0.25 volt, go to next step.
Turn engine off. Disconnect ECT sensor harness connector. Check sensor connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Disconnect VCM harness connectors C2 and C3. Check VCM connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Reconnect ECT and VCM harness connectors. Turn ignition on, with engine off. Using scan tool, check for intermittent short to ground in ECT sensor signal circuit while moving/wiggling harness. If scan tool voltage reading fluctuates, go to next step. If scan tool voltage reading does not fluctuate, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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 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 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 short to ground in ECT sensor harness connector 5-volt reference circuit. Observe scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

Check for skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT 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.

Engine Coolant Temperature (ECT) sensor is a thermistor located in intake manifold cooling system passage used to monitor engine coolant temperature. VCM supplies 5 volts to sensor. When engine coolant is cool, sensor resistance will be high and VCM will sense a high voltage signal. When engine coolant is warm, sensor resistance will be low and VCM will sense a low voltage signal.

DTC will set when engine is running and ECT voltage is less than.25 volt 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.
Install scan tool. Turn ignition on, with engine off. Monitor ECT sensor voltage on scan tool. If voltage reading is less than.25 volt, go to DTC P0117 test. If voltage reading is not less than.25 volt, go to next step.
Turn engine off. Disconnect ECT sensor harness connector. Check ECT sensor harness connector and terminals. If a problem is found, go to step 6 . If no problem is found, go to next step.
Disconnect VCM harness connectors. Check harness connectors and terminals. If a problem is found, go to step 6 . If no problem is found, go to next step.
Reconnect VCM and ECT harness connectors. Turn ignition on, with engine off. Using scan tool, check for intermittent short to ground in ECT sensor signal circuit by wiggling/moving harness in various locations. If ECT sensor voltage on scan tool fluctuates, go to next step. If ECT sensor voltage on scan tool does not fluctuate, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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.

Scan tool displays engine temperature in degrees centigrade. After engine is started, temperature should steadily rise to about 90°C then stabilize when thermostat opens. A poor connection or open in 5-volt reference circuit or ground circuit will cause DTC P0117 to set. A skewed or mis-scaled sensor could cause poor driveability conditions. Check for skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

Engine Coolant Temperature (ECT) sensor is a thermistor which changes resistance based on temperature. ECT sensor is mounted on left front of cylinder head. ECT sensor has a signal and ground circuit. PCM applies a voltage (about 5 volts) on signal circuit to sensor and monitors changes in this voltage caused by changes in resistance of sensor to coolant temperature.

When coolant is cold, sensor resistance is high and PCM signal voltage is only pulled down a small amount through sensor ground. When coolant is warm, sensor resistance is low and PCM signal voltage is pulled down a greater amount. This causes PCM to sense a low signal voltage (high temperature). DTC will set when PCM senses a signal voltage lower than normal operating range of sensor or when ECT is greater than 282°F (139°C) and intermittent condition exists for a total of one second during a 20 second time period.

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, with engine off. Using scan tool, monitor FAILED THIS IGNITION under DTC status for DTC P0117. If DTC P0117 failed this ignition cycle, diagnose DTC P0117. If DTC P0117 did not fail this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes while moving connectors at component and PCM, go to step 6 . If sensor value does not change while moving connectors, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harnesses. If sensor value changes abruptly, go to step 7 . If sensor value does not change, 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 step 8 . 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-p0704-p1272) .
Repair damaged connectors or terminals. After repairs, go to step 9 .
Repair circuit as necessary. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If circuits are okay, replace sensor/component. After repairs, 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.

And intermittent DTC can be caused by Electromagnetic Interference (EMI). Inspect related circuits for being too close to secondary ignition wires and generator.

If other DTCs are present that share same ground and/or 5-volt reference circuit, check for faulty connections or faulty wiring.

If engine has been allowed to sit overnight, engine coolant temperature (ECT) and intake air temperature (IAT) sensor values should display within a few degrees of each other. If temperature value is not within 5°F (3°C), check for skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (5.7L "F" & "Y" BODIES)

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

When coolant is cold, sensor resistance is high and PCM signal voltage is only pulled down a small amount through sensor ground. When coolant is warm, sensor resistance is low and PCM signal voltage is pulled down a greater amount. This causes PCM to sense a low signal voltage (high temperature). DTC will set when PCM senses a signal voltage higher than normal operating range (1.5-2.0 volts) and engine operating at greater than 10 seconds and PCM indicates ECT is greater than 282°F (139°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.
Turn ignition off, with engine off. Using scan tool, monitor FAILED THIS IGNITION under DTC status for DTC P0118. If DTC P0118 failed this ignition cycle, diagnose DTC. If DTC does not fail this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes while moving connectors at component and PCM, go to step 6 . If sensor value does not change while moving connectors, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harnesses. If sensor value changes abruptly, go to step 7 . If sensor value does not change, 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 P1114. If scan tool indicates that this test failed this ignition, go to step 8 . 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-p0704-p1272) .
Repair damaged connectors or terminals. After repairs, go to step 9 .
Repair faulty wiring. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If circuits are okay, replace sensor/component. After repairs, 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.

And intermittent DTC can be caused by Electromagnetic Interference (EMI). Inspect related circuits for being too close to secondary ignition wires and generator.

If other DTCs are present that share same ground and/or 5-volt reference circuit, check for faulty connections or faulty wiring.

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

Engine Coolant Temperature (ECT) sensor is a thermistor or a variable resistor, that varies resistance based on temperature. As temperature of sensor increases, resistance decreases. High temperature will result in a low signal voltage. DTC will set when PCM sees an ECT sensor voltage intermittently greater than 2 volts.

DTC will set when engine is running, ECT sensor signal voltage is intermittently greater than 4.8 volts and conditions are present for greater than 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0118 is also set, diagnose DTC P0118 before proceeding. If DTC is not set, go to next step.
If DTC P1106, P1111, and/or P1121 is also set, go to step 8 . If none of these DTCs are set, go to next step.
Check for faulty sensor ground circuit terminal at ECT sensor. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty signal circuit connection at ECT sensor. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Check ECT signal circuit between ECT sensor harness connector and PCM for intermittent open. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check ECT signal circuit between ECT sensor harness connector and PCM for intermittent short to voltage. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty ground circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. Repair as necessary. After repairs, go to next step. If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Read and record FAILURE RECORDS data for DTC P1115. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.5L "W" BODY)

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

DTC will set when engine has been running for longer than 15 seconds and ECT sensor intermittently indicates a coolant temperature greater than 274°F (134°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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0118 is also set, diagnose DTC P0118 before proceeding. If DTC P0118 is not set, go to next step.
If DTC P1106, P1111, and/or P1121 is also set, go to step 8 . If DTC P0116, P1111, and/or P1121 is not set, go to next step.
Check for faulty sensor ground circuit terminal at ECT sensor. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty signal circuit connection at ECT sensor. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Check ECT signal circuit between ECT sensor harness connector and PCM for intermittent open. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check ECT signal circuit between ECT sensor harness connector and PCM for intermittent short to voltage. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty ground circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. Repair as necessary. After repairs, go to next step. If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Read and record FAILURE RECORDS data for this DTC. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are displayed, go to appropriate DTC test.

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

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

Engine Coolant Temperature (ECT) sensor is a thermistor, that varies resistance based on temperature. As temperature of sensor increases, resistance decreases. High temperature will result in a low signal voltage. DTC will set when PCM sees an ECT sensor voltage intermittently greater than 4.8 volts and engine is running for 3 seconds, ECT voltage intermittently greater than 4.8 volts and ECT sensor intermittently indicates ECT at less than -29°F (-34°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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0118 is also set, diagnose DTC P0118 before proceeding. If DTC is not set, go to next step.
If DTC P1106, P1111, and/or P1121 is also set, go to step 8 . If any of these DTCs are not set, go to next step.
Check for faulty sensor ground circuit terminal at ECT sensor. Repair as necessary. After repairs, go to step 10 . If ground circuit terminal is okay, go to next step.
Check for faulty signal circuit connection at ECT sensor. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Check ECT signal circuit between ECT sensor and PCM connector for intermittent open. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check ECT signal circuit between ECT sensor and PCM for intermittent short to voltage. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty ground circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 10 . If no problem is found, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. 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-p0704-p1272) .
Read and record FAILURE RECORDS data for DTC P1115. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool indicates that this test failed in this ignition, return to step 2 . If scan tool does not indicate that this test failed in this ignition, repair is complete.

Check for faulty connections or damaged harness. Observe scan tool ECT display while moving all related harnesses and connectors. A change in scan tool display indicates fault location. Check for skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

Engine Coolant Temperature (ECT) sensor is a thermistor or a variable resistor that varies resistance based on temperature. High temperature will result in low signal voltage. If ECT reading is less than -36°F (-38°C) when IAT reading is greater than 23°F (-5°C) or vehicle is running long enough for coolant temperature to increase to greater than -36°F (-38°C), 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 DTC P0116 or P0118 is also present. If either DTC is present, diagnose affected DTC first. If these DTCs are not present, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition on and wait 30 seconds, then disconnect PCM harness connectors C1 and C2. Check ECT sensor circuit terminals at PCM harness connectors C1 and C2. Repair as necessary. If terminal contacts are okay, go to next step.
Disconnect and check ECT sensor harness connector. Repair as necessary. If terminal contacts are okay, go to next step.
Check ECT sensor signal and ground circuits for open or short to voltage. Repair as necessary. If circuit is okay, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .

If fault is not present, check PCM grounds. Check for skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

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

Engine Coolant Temperature (ECT) sensor is a thermistor or a variable resistor, that varies resistance based on temperature. As temperature of sensor increases, resistance decreases. Low temperature will result in a high signal voltage. DTC will set when VCM sees an ECT sensor voltage of greater than 5 volts.

DTC will set when VCM detects an intermittent high ECT voltage while engine is running and run time exceeds 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, read ECT sensor voltage. If voltage reading is greater than 4.9 volts, go to DTC P0118. If voltage reading is not greater than 4.9 volts, go to next step.
Turn engine off. Turn ignition on. Disconnect ECT sensor harness connector. Check ECT sensor connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Turn ignition off. Disconnect VCM harness connectors C2 and C3. Check connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Reconnect ECT sensor and VCM harness connectors. Turn ignition on, with engine off. Using scan tool, check for an intermittent open or short to voltage in ECT sensor signal or ground circuit by moving/wiggling harness at various locations. If scan tool voltage reading fluctuates, go to next step. If scan tool voltage reading does not fluctuate, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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 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 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 open in 5-volt reference and ground circuits. Check for skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

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

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH 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.

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. Turn ignition on, with engine off. Monitor ECT sensor voltage on scan tool. If voltage reading is greater than 4.9 volts, go to DTC P0118 test. If voltage reading is not greater than 4.9 volts, go to next step.
Turn engine off. Disconnect ECT sensor harness connector. Check ECT sensor harness connector and terminals. If a problem is found, go to step 6 . If no problem is found, go to next step.
Disconnect VCM harness connectors. Check harness connectors and terminals. If a problem is found, go to step 6 . If no problem is found, go to next step.
Reconnect VCM and ECT harness connectors. Turn ignition on, with engine off. Using scan tool, check for intermittent short to ground in ECT sensor signal circuit by wiggling/moving harness in various locations. If ECT sensor voltage on scan tool fluctuates, go to next step. If ECT sensor voltage on scan tool does not fluctuate, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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.

Check harness routing for short to ground in 5-volt reference circuit. Scan tool displays engine temperature in degrees centigrade. After engine is started, temperature should steadily rise to about 90°C then stabilize when thermostat opens. A skewed or mis-scaled sensor could cause poor driveability conditions. Check ECT sensor resistance. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

When coolant is cold, sensor resistance is high and PCM signal voltage is only pulled down a small amount through sensor ground. When coolant is warm, sensor resistance is low and PCM signal voltage is pulled down a greater amount. This causes PCM to sense a low signal voltage (high temperature). DTC will set when PCM senses a signal voltage greater than normal operating range of sensor and ECT is less than -31°F (-35°C) and intermittent condition exists for a total of one second during a 20 second time period.

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, with engine off. Using scan tool, monitor FAILED THIS IGNITION under DTC status for DTC P0118. If DTC P0118 failed this ignition cycle, diagnose DTC P0118. If DTC P0118 did not fail this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes while moving connectors at component and PCM, go to step 6 . If sensor value does not change while moving connectors, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harnesses. If sensor value changes abruptly, go to step 7 . If sensor value does not change, 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 step 8 . 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-p0704-p1272) .
Repair damaged connectors or terminals. After repairs, go to step 9 .
Repair circuit as necessary. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If circuits are okay, replace sensor/component. After repairs, 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.

And intermittent DTC can be caused by Electromagnetic Interference (EMI). Inspect related circuits for being too close to secondary ignition wires and generator.

If other DTCs are present that share same ground and/or 5-volt reference circuit, check for faulty connections or faulty wiring.

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (5.7L "F" & "Y" BODIES)

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

Engine Coolant Temperature (ECT) sensor is a thermistor which changes resistance based on temperature. ECT sensor is located on front of left cylinder head. ECT sensor has a signal and ground circuit. PCM applies a voltage (about 5 volts) on signal circuit to sensor and monitors changes in this voltage caused by changes in resistance of sensor to coolant temperature.

When coolant is cold, sensor resistance is high and PCM signal voltage is pulled down a small amount through sensor ground. When coolant is warm, sensor resistance is low and PCM signal voltage is pulled down a greater amount. This causes PCM to sense a low signal voltage (high temperature). DTC will set when PCM senses a signal voltage higher than normal operating range (1.5-2.0 volts) and engine is operating for greater than 60 seconds and PCM indicates ECT is less than -31°F (-35°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.
Turn ignition off, with engine off. Using scan tool, monitor FAILED THIS IGNITION under DTC status for DTC P0117. If DTC P0117 failed this ignition cycle, diagnose DTC. If DTC does not fail this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes while moving/wiggling related connectors, go to step 6 . If sensor value does not change while moving/wiggling connectors, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harnesses. If sensor value changes abruptly, go to step 7 . If sensor value does not change, 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 step 8 . 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-p0704-p1272) .
Repair damaged connectors or terminals. After repairs, go to step 9 .
Repair faulty wiring. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If circuits are okay, replace sensor/component. After repairs, 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 P1115. 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.

And intermittent DTC can be caused by Electromagnetic Interference (EMI). Inspect related circuits for being too close to secondary ignition wires and generator.

If other DTCs that are present share same ground and/or 5-volt reference circuit, check for faulty connections or faulty wiring.

If engine has been allowed to sit overnight, engine coolant temperature (ECT) and intake air temperature (IAT) sensor values should display within a few degrees of each other. If temperature value is not within 5°F (3°C), check for a skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P1120: TP SENSOR NO. 1 CIRCUIT (3.8L "F" BODY)

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

Throttle Position (TP) sensor is mounted on throttle body/Throttle Actuator Control (TAC) assembly. Sensor is actually 2 individual TP sensors within one housing. Two separate signal, ground and reference circuits are used in order to connect TP sensor assembly and TAC module. TP sensor No. 1 signal voltage increases as throttle opens. The signal circuit for TP sensor is pulled up to reference voltage.

DTC will set when TP sensor No. 1 voltage is less than 0.34 volt or greater than 4.4 volts and condition is 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. NOTE: If scan tool indicates NO and DTC P1515 or P1516 are not set, go to next step.
Using scan tool, observe TP sensor disagree parameter. If scan tool indicates YES, go to next step. If scan tool does not indicate YES, go to DTC P1515 or P1516 test.
Using scan tool, observe TP sensor No. 1 voltage while depressing throttle to WOT, then releasing it. If sensor voltage remains at or about one volt throughout the throttle travel, go to next step. If sensor voltage does not remain at or about one volt throughout the throttle travel, go to step 5 .
Check ELEC THROT CONT and TCS BATT fuses. If either fuse is open, go to step 15 . If fuses are okay, go to step 19 .
Turn ignition off for 15 seconds. Turn ignition on, with engine off. Using scan tool, select DTC option and FAILED THIS IGNITION option. Move/wiggle harness and related connectors while monitoring scan tool. If movement caused DTC to set, go to step 20 . If movement did not cause DTC to set, go to next step.
Turn ignition off. Disconnect TAC harness connector. Using DVOM, check resistance between reference and return circuits at TAC harness connector. If resistance is 4500-5500 ohms, go to next step. If resistance is not 4500-5500 ohms, go to step 29 .
Turn ignition on. Check voltage between ground and signal circuit at TAC harness connector. If voltage reading is 3.9-4.6 volts, go to next step. If voltage reading is not 3.9-4.6 volts, go to step 10 .
Check voltage between ground and reference circuit at TAC harness connector. If voltage reading is 3.9-4.6 volts, go to next step. If voltage reading is not 3.9-4.6 volts, go to step 12 .
Turn ignition off. Check resistance between TP sensors No. 1 and 2 ground circuits in TAC harness connector. If resistance is 0-5 ohms, go to step 28 . If resistance is not 0-5 ohms, go to step 14 .
Turn ignition off. Leave TAC harness connector disconnected. Disconnect TAC module harness connector. Turn ignition on, with engine off. Check voltage between ground and signal circuit in TAC module harness connector. If any voltage is present, go to step 21 . If no voltage is present, go to next step.
Check signal circuit for short to ground. If circuit is faulty, go to step 22 . If circuit is okay, go to step 16 .
Turn ignition off. Leave TAC harness connector disconnected. Disconnect TAC module harness connector. Turn ignition on, with engine off. Check voltage between ground and reference circuit in TAC module harness connector. If any voltage is present, go to step 24 . If no voltage is present, go to next step.
Check reference circuit for short to ground. If circuit is faulty, go to step 25 . If circuit is okay, go to step 17 .
Turn ignition off. Leave TAC harness connector disconnected. Disconnect TAC module harness connector. Check for open in ground circuit. If circuit is open, go to step 18 . If circuit is okay, go to step 26 .
Repair short to ground in TAC module battery feed or ignition feed circuits. After repairs, go to step 32 .
Check harness for continuity between signal circuit and all other circuits at TAC module harness connector. If any of the circuits indicate continuity, go to step 20 . If any of the circuits does not indicate continuity, go to step 23 .
Check harness for continuity between reference circuit and all other circuits at TAC module harness connector. If any of the circuits indicate continuity, go to step 20 . If any of the circuits does not indicate continuity, go to step 27 .
Check harness for continuity between ground circuit and all other circuits at TAC module harness connector. If any of the circuits indicate continuity, go to step 20 . If any of the circuits does not indicate continuity, go to step 30 .
Repair open/high resistance in TAC module battery feed or ignition feed circuits. After repairs, go to step 32 .
Repair harness or connections as necessary. After repairs, go to step 32 .
Repair short to voltage in signal circuit. After repairs, go to step 32 .
Repair short to ground in signal circuit. After repairs, go to step 32 .
Check for open/high resistance in signal circuit. Repair as necessary. After repairs, go to step 32 . If circuit is okay, go to step 30 .
Repair short to voltage in reference circuit. After repairs, go to step 32 .
Repair short to ground in reference circuit. After repairs, go to step 32 .
Check for open/high resistance in ground circuit. Repair as necessary. After repairs, go to step 32 . If circuit is okay, go to step 30 .
Check for open/high resistance in reference circuit. Repair as necessary. After repairs, go to step 32 . If circuit is okay, go to step 30 .
Check for poor connection in TAC harness connector. Repair as necessary. After repairs, go to step 32 . If circuit is okay, go to next step.
Replace throttle body/TAC assembly. After replacing throttle body, go to step 32 .
Check for poor connection at TAC module harness connector. If connection is faulty, go to step 32 . If connection is okay, go to next step.
Replace TAC module. After replacing module, 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 that 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, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

An intermittent problem can be caused by poor connections, corrosion, mis-routed harness, broken wire inside insulation or rubbed-through wire insulation. Check connectors for signs of water intrusion, causing multiple DTCs to set and no circuit or component problems can be located.

DTC P1120: TP SENSOR NO. 1 CIRCUIT (5.7L "Y" BODY)

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

The Throttle Position (TP) sensor is a potentiometer, mounted on side of Air Control Valve assembly (throttle body). TP sensor is actually 2 sensors within one housing.

TP sensor No. 1 signal voltage increases as throttle opens from, less than 1.1 volt at zero percent throttle to greater than 3.7 volts at 100 percent throttle. TP sensor No. 2 signal voltage decreases from greater than 3.9 volts at zero percent throttle to less than 1.2 volt at 100 percent throttle.

Signal circuit for TP sensor No. 1 is pulled up to 5 volts and signal circuit for TP sensor No. 2 is pulled to ground through Throttle Actuator Control (TAC) module.

Conditions for setting DTC are: DTCs P0606, P1517 or P1518 not set, ignition switch in CRANK or RUN position, ignition voltage greater than 5.23 volts, TP sensor No. 1 voltage less than.13 volt or greater than 4.87 volts and 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.
If DTC P1515 or P1516 is also present, diagnose affected DTC first. If DTCs are not present, go to next step.
Remove duct from throttle body assembly. Disconnect throttle actuator motor connector. Manually close throttle blade while monitoring scan tool TP SENSOR NO. 1 voltage display. If voltage reading is.13-.67 volt, go to next step. If voltage reading is not as specified, go to step 7 .
Manually rotate throttle blade to wide open throttle. If voltage reading is 4.09-4.87 volts, go to next step. If voltage reading is not 4.09-4.87 volts, go to step 7 .
Reconnect throttle actuator motor connector. Turn ignition off for 15 seconds. Turn ignition on, with engine off. Using scan tool, select DTC function, then enter DTC P1120. Monitor scan tool while moving wiring harness and related connectors. If scan tool indicates this test failed this ignition, go to step 22 . If scan tool does not indicate that this test failed this ignition, go to next step.
While monitoring scan tool, fully open and close throttle. If scan tool indicates this test failed this ignition, go to step 32 . 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-p0704-p1272) .
Disconnect TP sensor connector. Using DVOM, check voltage between battery ground and TP sensor No. 1 signal circuit. If voltage reading is 3.94-6.06 volts, go to step 12 . If voltage reading is not 3.94-6.06 volts, go to next step.
Turn ignition off. Leave TP sensor disconnected. Disconnect Throttle Actuator Control (TAC) module connector containing TP sensor circuits. Turn ignition on, with engine off. Using DVOM, check voltage between battery ground and TP sensor No. 1 signal circuit connector. If any voltage is present, go to step 26 . If no voltage is present, go to next step.
Using DVOM, check continuity of TP sensor No. 1 signal circuit. If continuity exists, go to next step. If continuity does not exist, go to step 27 .
Check for continuity between battery ground and TP sensor No. 1 signal circuit. If continuity exists, go to step 28 . If continuity does not exist, go to next step.
Check for continuity between TP sensor No. 1 signal circuit and all other circuits in both TAC module harness connectors. If continuity exists between any circuit(s), go to step 30 . If continuity does not exist between any circuit, go to step 33 .
Using DVOM, check voltage between battery ground and TP sensor No. 1 5-volt reference circuit. If voltage reading is 3.94-6.06 volts, go to step 17 . If voltage reading is not 3.94-6.06 volts, go to next step.
Turn ignition off. Leave TP sensor disconnected. Disconnect Throttle Actuator Control (TAC) module connector containing TP sensor circuits. Turn ignition on, with engine off. Using DVOM, check voltage between battery ground and TP sensor No. 1 5-volt reference circuit connector. If any voltage is present, go to step 23 . If no voltage is present, go to next step.
Using DVOM, check continuity of TP sensor No. 1 5-volt reference circuit. If continuity exists, go to next step. If continuity does not exist, go to step 24 .
Check for continuity between battery ground and TP sensor No. 1 5-volt reference circuit. If continuity exists, go to step 25 . If continuity does not exist, go to next step.
Check for continuity between TP sensor No. 1 5-volt reference circuit and all other circuits in both TAC module harness connectors. If continuity exists between any circuit(s), go to step 30 . If continuity does not exist between any circuit, go to step 33 .
Using DVOM, check resistance between battery ground and TP sensor No. 1 ground circuit. If resistance is 0-5 ohms, go to step 19 . If resistance is not 0-5 ohms, go to next step.
Turn ignition off. Leave TP sensor disconnected. Disconnect Throttle Actuator Control (TAC) module connector containing TP sensor circuits. Check continuity of TP sensor No. 1 ground circuit. If continuity exists, go to step 33 . If continuity does not exist, go to step 29 .
Using scan tool, monitor TP sensor No. 1 voltage. Connect a fused jumper wire between TP sensor No. 1 signal and ground circuits. If voltage reading is zero volts, go to next step. If voltage reading is not zero volts, go to step 34 .
Reconnect TAC module connector containing APP sensor circuits. Using scan tool, monitor APP sensor No. 1, No. 2 and No. 3 voltages. Connect a fused jumper wire between TP sensor No. 1 connector, signal and ground circuits. If any voltage is affected when signal circuit is grounded, go to next step. If voltage is not affected, go to step 31 .
Turn ignition off. Disconnect Throttle Actuator Control (TAC) module connector. Check continuity of TP sensor No. 1 signal circuit and all other circuits in both TAC module connectors. If continuity exists between any circuit(s), go to step 30 . If continuity does not exist between any circuit, go to step 34 .
Repair harness and connectors as necessary. After repairs, go to step 35 .
Repair short to voltage in 5-volt reference circuit. After repairs, go to step 35 .
Repair open 5-volt reference circuit. After repairs, go to step 35 .
Repair short to ground in 5-volt reference circuit. After repairs, go to step 35 .
Repair short to voltage in signal circuit. After repairs, go to step 35 .
Repair open signal circuit. After repairs, go to step 35 .
Repair short to ground in signal circuit. After repairs, go to step 35 .
Repair open ground circuit. After repairs, go to step 35 .
Repair circuit(s) shorted together. After repairs, go to step 35 .
Check for poor terminal connections at TP sensor harness connector. Repair or replace terminals. After repairs, go to step 35 . If terminals are okay, go to next step.
Replace throttle body assembly. After replacing throttle body, go to step 35 .
Check for poor terminal connections at TAC module harness connector. Repair or replace terminals. After repairs, go to step 35 . If terminals are okay, go to next step.
Replace TAC module. After replacing module, 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 that 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, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. If other DTCs are set that share same ground and/or 5-volt reference circuit, check for faulty connections or wiring. PCM 5-volt reference circuits are internally connected within PCM.

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

Throttle Position (TP) sensor measures amount of throttle opening. PCM uses TP sensor information for fuel delivery calculations. TP sensor readings during acceleration are much higher than those during deceleration or idle. DTC will set if PCM senses TP sensor voltage intermittently greater than 4.7 volts with engine running and TP signal voltage is intermittently greater than 4.7 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0123 is also set, diagnose DTC P0123 before proceeding. If DTC is not set, go to next step.
If DTC P1106, P1111, and/or P1115 is also set, go to step 6 . If any of these DTCs are not set, go to next step.
Check for faulty sensor ground circuit terminal at TP sensor. Repair as necessary. After repairs, go to step 9 . If circuit is okay, go to next step.
Check TP signal circuit between TP sensor harness connector and PCM for intermittent short to voltage. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to step 8 .
Check for intermittent short to voltage on 5-volt reference circuit between PCM and MAP, EGR and TP sensors. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty ground circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 9 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. Repair as necessary. After repairs, go to step 10 . If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal. After replacing terminals, go to step 11 .
Locate and repair intermittent open/short circuit. After repairs, go to next step.
Read and record FAILURE RECORDS data for DTC P1121. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Observe TP SENSOR display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.5L "W" BODY)

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

Throttle Position (TP) sensor measures amount of throttle opening. PCM uses TP sensor information for fuel delivery calculations. TP sensor readings during acceleration are much higher than those during deceleration or idle. DTC P1121 sets if PCM senses TP sensor voltage intermittently greater than 4.7 volts.

DTC will set when ignition is on and TP sensor intermittently indicates a throttle position signal greater than 4.9 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0123 is also set, diagnose DTC P0123 before proceeding. If DTC is not set, go to next step.
If DTC P1106, P1111 and/or P1115 is also set, go to step 6 . If any of these DTCs are not set, go to next step.
Check for faulty sensor ground circuit terminal at TP sensor. Repair as necessary. After repairs, go to step 9 . If circuit is okay, go to next step.
Check TP signal circuit between TP sensor harness connector and PCM for intermittent short to voltage. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to step 8 .
Check for intermittent short to voltage on 5-volt reference circuit between PCM and MAP, EGR and TP sensors. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty ground circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 9 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. Repair as necessary. After repairs, go to step 10 . If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal. After replacing terminals, go to step 11 .
Locate and repair intermittent open/short circuit. After repairs, go to next step.
Read and record FAILURE RECORDS data for this DTC. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are displayed, go to appropriate DTC test.

Check for faulty connections or damaged harness. Observe TP SENSOR display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.8L "C", "G", "H" & "W" BODIES)

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

Throttle Position (TP) sensor measures amount of throttle opening. PCM uses TP sensor information for fuel delivery calculations. TP sensor readings during acceleration are much higher than those during deceleration or idle. DTC P1121 sets if PCM senses TP sensor voltage is intermittently greater than 4.7 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0123 is also set, diagnose DTC P0123 before proceeding. If DTC is not set, go to next step.
If DTC P1106, P1111, and/or P1115 is also set, go to step 6 . If these DTCs are set, go to next step.
Check for faulty sensor ground circuit terminal at TP sensor. If problem is found, go to step 9 . If no problem is found, go to next step.
Check TP signal circuit between TP sensor harness connector and PCM for intermittent short to voltage. If a problem is found, go to step 10 . If no problem is found, go to step 8 .
Check for intermittent short to voltage on 5-volt reference circuit between PCM and MAP, EGR and TP sensors. If a problem is found, go to step 10 . If no problem is found, go to next step.
Check for faulty ground circuit terminal connection at PCM. If problem is found, go to step 9 . If no problem is found, go to next step.
Check for intermittent open or faulty splice in sensor ground circuit. If a problem is found, go to step 10 . If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal. After repairs, go to step 11 .
Locate and repair intermittent open/short circuit and go to next step.
Read and record FAILURE RECORDS data for DTC P1121. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P1121 FAILED THIS IGN, return to step 2 . If scan tool does not display DTC P1121 FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Observe scan tool TP display while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

Throttle Position (TP) sensor is a potentiometer. At low throttle angle, the TP sensor signal voltage is low. PCM uses TP sensor information to determine idle, Wide Open Throttle (WOT), deceleration enleanment and acceleration enrichment. DTC will set when PCM detects a TP sensor signal that is 4.96 volts or greater, which is not possible under normal 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.
Turn ignition on. Using scan tool, check if DTC P0120 or P0123 is also present. If either DTC is present, diagnose affected DTC first. If these DTCs are not present, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition on and wait 30 seconds, then disconnect PCM harness connector C1. Check TP sensor circuit terminals at PCM harness connector C1. Repair as necessary. If terminal contacts are okay, go to next step.
Disconnect and check TP sensor harness connector. Repair as necessary. If terminal contacts are okay, go to next step.
Check for open in TP sensor ground circuit. Check for short to voltage in TP sensor 5-volt reference and signal circuits. Repair as necessary. If circuits are okay, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .

If fault is not present, check PCM grounds.

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

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

Throttle Position (TP) sensor measures amount of throttle opening. VCM uses TP sensor information for fuel delivery calculations. TP sensor readings during acceleration are much higher than those during deceleration or idle. DTC will set when VCM detects an intermittent high TP sensor voltage while engine is running.

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.
Verify that throttle is closed. Turn ignition on, with engine off. Using scan tool, monitor TP signal voltage. If voltage reading is greater than 4.7 volts, go to DTC P0123 test. If voltage reading is not greater than 4.7 volts, go to next step.
Turn ignition off. Disconnect TP sensor harness connector. Check TP sensor harness connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Disconnect VCM harness connectors C2 and C3. Check harness connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Reconnect VCM and TP sensor harness connectors. Turn ignition on, with engine off. Using scan tool, check for intermittent open or short on TP sensor signal or ground circuit while moving/wiggling harness in various locations. If scan tool voltage reading increases, go to next step. If scan tool voltage reading does not increase, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272__dtc-p1121-tp-sensor-circuit-intermittent) .
Repair 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 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 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 and repair throttle plate sticking or excessive deposits on throttle plate or throttle bore. Check TP sensor harness connector ground circuit for open, and signal circuit for short to ground. TP sensor signal voltage should be less than 1.25 volt with throttle closed, and greater than 4.5 volts at wide open throttle.

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

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH 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.

Throttle Position (TP) sensor provides a voltage signal that changes relative to throttle opening. Signal voltage varies from about.5 volt at idle to about 4.5 volts at Wide Open Throttle (WOT). TP sensor signal is one of the most important inputs used by VCM for fuel control and most VCM control outputs. DTC will set when engine is running and TP sensor voltage is greater than 4.7 volts 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.
Ensure throttle is closed. Turn ignition on, with throttle closed. Using scan tool, monitor TP sensor voltage. If TP sensor voltage is greater than 4.7 volts, go to DTC P0123 test. If TP sensor voltage is not greater than 4.7 volts, go to next step.
Turn ignition off. Disconnect TP sensor connector. Check harness connector and terminals. If problem is found, go to step 6 . If no problem is found, go to next step.
Disconnect VCM harness connectors. Check harness connector and terminals. If problem is found, go to step 6 . If no problem is found, go to next step.
Reconnect VCM and TP sensor harness connectors. Turn ignition on, with engine off. Using scan tool, check for intermittent open or short to voltage in TP sensor signal or ground circuit while moving/wiggling harness at various locations. If TP sensor voltage on scan tool fluctuates, go to next step. If TP sensor voltage on scan tool does not fluctuate, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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.

Scan tool displays throttle position in volts. Voltage should be.45-.85 volt with throttle closed and ignition on or at idle. Voltage should steadily increase as throttle is moved toward WOT. Scan tool throttle angle percentage will display as zero percent being closed throttle and 100 percent being WOT. While depressing accelerator pedal with ignition on, engine off, TP signal voltage should vary from less than 1.25 volts with throttle closed to greater than 4.5 volts with WOT. If DTC is intermittent, see appropriate TROUBLE SHOOTING - NO CODES article.

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

Throttle Position (TP) sensor is a potentiometer, mounted on side of throttle body. TP sensor voltage signal changes relative to throttle blade angle. This signal voltage is one of most important inputs used by PCM. TP sensor has a 5-volt reference, ground and a signal circuit.

TP sensor signal voltage should be about 0.6 volt at idle and 4 volts or greater at wide open throttle. PCM compares actual throttle position from TP sensor to a predicted throttle position value. Predicted value is calculated from engine speed and other inputs. If PCM detects predicted throttle position is greater than actual TP sensor value, DTC will set. DTC will under these following conditions, TP sensor voltage is greater than 4.75 volts and intermittent condition exists for a total of one second during a 20 second time period.

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, monitor FAILED THIS IGNITION under DTC status for DTC P0123. If scan tool indicates that DTC P0123 failed this ignition cycle, diagnose DTC. If scan tool does not indicate that DTC P0123 failed this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes abruptly while moving related connectors, go to step 6 . If sensor value does not change, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harness. If sensor value changes abruptly while moving related harnesses, go to step 7 . If sensor value does not change, 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 step 8 . 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-p0704-p1272) .
Repair damaged connectors/terminals. After repairs, go to step 9 .
Repair circuit. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If all circuits check okay, replace sensor/components. After repairs, 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 that set 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, diagnose affected DTCs.

An intermittent DTC can be caused by Electromagnetic Interference (EMI). Inspect related circuits for being too close to secondary ignition wires and generator.

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (5.7L "F" BODY)

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

TP sensor signal voltage should be about 0.6 volt at idle and 4 volts or more at wide open throttle. PCM compares actual throttle position from TP sensor to a predicted throttle position value. Predicted value is calculated from engine speed and other inputs. DTC will set when PCM detects predicted throttle position is greater than actual TP sensor value and ignition switch is in RUN position, TP sensor voltage greater than 4.8 volts and conditions are present for 3.5 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.
Turn ignition on, with engine off. Using scan tool, monitor FAILED THIS IGNITION under DTC status for DTC P0123. If scan tool indicates that DTC P0123 failed this ignition cycle, diagnose DTC. If scan tool does not indicate that DTC P0123 failed this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes abruptly while moving related connectors, go to step 6 . If sensor value does not change, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harness. If sensor value changes abruptly while moving related harnesses, go to step 7 . If sensor value does not change, 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 step 8 . 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-p0704-p1272) .
Repair damaged connectors/terminals. After repairs, go to step 9 .
Repair faulty wiring/harness. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If all circuits check okay, replace sensor/components. After repairs, 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 P1121. Operate vehicle within conditions that set 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, diagnose affected DTCs.

An intermittent DTC can be caused by Electromagnetic Interference (EMI). Inspect related circuits for being too close to secondary ignition wires and generator.

DTC P1122: TP SENSOR CIRCUIT INTERMITTENT 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.

Throttle Position (TP) sensor measures amount of throttle opening. PCM uses TP sensor information for fuel delivery calculations. TP sensor readings during acceleration are much higher than those during deceleration or idle. DTC will set if PCM senses TP sensor voltage is intermittently less than 0.16 volt with engine running.

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, select LAST TST FAIL. Record any other failed DTCs. If DTC P0122 is also set, diagnose DTC P0122 before proceeding. If DTC is not set, go to next step.
If DTC P1107 is also set, go to step 6 . If DTC is not set, go to next step.
Check for faulty 5-volt reference or signal circuit connection at TP sensor. Repair as necessary. After repairs, go to step 9 . If circuit is okay, go to next step.
Check signal circuit between TP sensor and PCM for intermittent open or short to ground. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to step 8 .
Check for intermittent short to ground on 5-volt reference circuit between PCM and EGR valve, MAP and TP sensors. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty 5-volt reference circuit connection at PCM. Repair as necessary. After repairs, go to step 9 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in 5-volt reference circuit. Repair as necessary. After repairs, go to step 10 . If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal(s). After repairs, go to step 11 .
Repair circuit as necessary. After repairs, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Observe TP SENSOR display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P1122: TP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.5L "W" BODY)

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

Throttle Position (TP) sensor measures amount of throttle opening. PCM uses TP sensor information for fuel delivery calculations. TP sensor readings during acceleration are much higher than those during deceleration or idle. DTC will sets if PCM senses TP sensor voltage intermittently less than 0.16 volt.

DTC will run when ignition is on and when TP sensor intermittently indicates a throttle position signal less than 0.1 volt.

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, select LAST TST FAIL. Record any other failed DTCs. If DTC P0122 is also set, diagnose DTC P0122 before proceeding. If DTC P0122 is not set, go to next step.
If DTC P1107 is also set, go to step 6 . If DTC is not set, go to next step.
Check for faulty 5-volt reference or signal circuit connection at TP sensor. Repair as necessary. After repairs, go to step 9 . If circuit is okay, go to next step.
Check signal circuit between TP sensor and PCM for intermittent open or short to ground. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to step 8 .
Check for intermittent short to ground on 5-volt reference circuit between PCM and EGR valve, MAP and TP sensors. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
Check for faulty 5-volt reference circuit connection at PCM. Repair as necessary. After repairs, go to step 9 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in 5-volt reference circuit. Repair as necessary. After repairs, go to step 10 . If circuit is okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal(s) for 5-volt reference "A" circuit and/or TP signal circuit. After repairs, go to step 11 .
Repair circuit as necessary. After repairs, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are displayed, go to appropriate DTC test.

Check for faulty connections or damaged harness. Observe TP SENSOR display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P1122: TP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.8L "C", "G", "H" & "W" BODIES)

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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If DTC P0122 is also set, diagnose DTC P0122 before proceeding. If DTC is not set, go to next step.
If DTC P1107 is also set, go to step 6 . If DTC is not set, go to next step.
Check for faulty 5-volt reference or signal circuit connection at TP sensor. If a problem is found, go to step 9 . If no problem is found, go to next step.
Check signal circuit between TP sensor and PCM for intermittent open or short to ground. If problem is found, go to step 10 . If no problem is found, go to step 8 .
Check for intermittent short to ground on 5-volt reference circuit between PCM and EGR valve, MAP and TP sensors. If a problem is found, go to step 10 . If no problem is found, go to next step.
Check for faulty 5-volt reference circuit connection at PCM. If faulty connection is found, go to step 9 . If connection is okay, go to next step.
Check for intermittent open or faulty splice in 5-volt reference circuit. If a problem is found, go to step 10 . If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Replace faulty connector terminal(s). After repairs, go to step 11 .
Repair circuit as necessary. After repairs, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P1122. If scan tool displays DTC P1122 FAILED THIS IGN, return to step 2 . If scan tool does not display DTC P1122 FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Observe scan tool TP display while moving all related harness and connectors. A change in scan tool display indicates fault location.

DTC P1122: TP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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.
Turn ignition on. Using scan tool, check if DTC P0120 or P0123 is also present. If either DTC is present, diagnose affected DTC first. If these DTCs are not present, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition on and wait 30 seconds, then disconnect PCM harness connector C1. Check TP sensor circuit terminals at PCM harness connector C1. Repair as necessary. If terminal contacts are okay, go to next step.
Disconnect and check TP sensor harness connector. Repair as necessary. If terminal contacts are okay, go to next step.
Check for open or short to ground in TP sensor 5-volt reference and signal circuits. Repair as necessary. If circuits are okay, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .

If fault is not present, check PCM grounds.

DTC P1122: TP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" 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.
Verify that throttle is closed. Turn ignition on, with engine off. Using scan tool, monitor TP signal voltage. If voltage reading is less than 0.25 volt, go to DTC P0122 test. If voltage reading is not less than 0.25 volt, go to next step.
Turn ignition off. Disconnect TP sensor harness connector. Check TP sensor harness connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Disconnect VCM harness connectors C2 and C3. Check harness connector and terminals. If connector or terminals are faulty, go to step 6 . If connector or terminals are okay, go to next step.
Reconnect VCM and TP sensor harness connectors. Turn ignition on, with engine off. Using scan tool, check for intermittent open or short on TP sensor signal or ground circuit while moving/wiggling harness in various locations. If scan tool voltage reading increases, go to next step. If scan tool voltage reading does not increase, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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 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 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 and repair throttle plate sticking or excessive deposits on throttle plate or throttle bore, TP sensor harness connector 5-volt reference circuit for open or short to ground. TP signal voltage reading on scan tool should be about 0.5 volt with throttle closed and greater than 4.5 volts at wide open throttle.

DTC P1122: TP SENSOR CIRCUIT INTERMITTENT 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.

Throttle Position (TP) sensor provides a voltage signal that changes relative to throttle opening. Signal voltage varies from about.5 volt at idle to about 4.5 volts at Wide Open Throttle (WOT). TP sensor signal is one of the most important inputs used by VCM for fuel control and most VCM control outputs. DTC will set when engine has been running for greater than 5 seconds and TP sensor voltage is less than.25 volt 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.
Ensure throttle is closed. Turn ignition on, with throttle closed. Using scan tool, monitor TP sensor voltage. If TP sensor voltage is less than.25 volt, go to DTC P0122 test. If TP sensor voltage is not less than.25 volt, go to next step.
Turn ignition off. Disconnect TP sensor connector. Check harness connector and terminals. If problem is found, go to step 6 . If no problem is found, go to next step.
Disconnect VCM harness connectors. Check harness connector and terminals. If problem is found, go to step 6 . If no problem is found, go to next step.
Reconnect VCM and TP sensor harness connectors. Turn ignition on, with engine off. Using scan tool, check for intermittent open or short to ground in TP sensor signal or 5-volt reference circuit while moving/wiggling harness at various locations. If TP sensor voltage on scan tool fluctuates, go to next step. If TP sensor voltage on scan tool does not fluctuate, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Repair 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.

Scan tool displays throttle position in volts. Voltage should be.45-.85 volt with throttle closed and ignition on or at idle. An open or short to ground in 5-volt reference circuit or TP signal circuit will cause DTC to set. If DTC is intermittent, see appropriate TROUBLE SHOOTING - NO CODES article. While depressing accelerator pedal with engine stopped and ignition on, TP signal voltage should vary from less than 1.25 volts with throttle closed to greater than 4.5 volts with WOT.

DTC P1122: TP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

TP sensor signal voltage should be about 0.6 volt at idle and 4 volts or greater at wide open throttle. PCM compares actual throttle position from TP sensor to a predicted throttle position value. Predicted value is calculated from engine speed and other inputs. DTC will set when PCM detects predicted throttle position is lower than actual TP sensor value or TP sensor voltage is less than.2 volt and intermittent condition exists for a total of one second during a 20 second time period.

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, monitor FAILED THIS IGNITION under DTC status for DTC P0122. If scan tool indicates that DTC P0122 failed this ignition cycle, diagnose DTC. If scan tool does not indicate that DTC P0122 failed this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes abruptly while moving related connectors, go to step 6 . If sensor value does not change, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harness. If sensor value changes abruptly while moving related harnesses, go to step 7 . If sensor value does not change, 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 step 7 . 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-p0704-p1272) .
Repair damaged connectors/terminals. After repairs, go to step 9 .
Repair circuit. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If all circuits check okay, replace sensor/components. After repairs, 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 that set 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, diagnose affected DTCs.

An intermittent DTC can be caused by Electromagnetic Interference (EMI). Inspect related circuits for being too close to secondary ignition wires and generator.

DTC P1122: TP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (5.7L "F" BODY)

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

TP sensor signal voltage should be about 0.6 volt at idle and 4 volts or more at wide open throttle. PCM compares actual throttle position from TP sensor to a predicted throttle position value. Predicted value is calculated from engine speed and other inputs. DTC will set when PCM detects predicted throttle position is less than actual TP sensor value or TP sensor voltage is less than.2 volt for.3 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, with engine off. Using scan tool, monitor FAILED THIS IGNITION under DTC status for DTC P0122. If scan tool indicates that DTC P0122 failed this ignition cycle, diagnose DTC. If scan tool does not indicate that DTC P0122 failed this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, observe affected sensor value while moving related harness connectors (at component and PCM). If sensor value changes abruptly while moving related connectors, go to step 6 . If sensor value does not change, go to next step.
Using scan tool, observe affected sensor value while moving related wiring harness. If sensor value changes abruptly while moving related harnesses, go to step 7 . If sensor value does not change, 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 P1122. If scan tool indicates that this test failed this ignition, go to step 8 . 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-p0704-p1272) .
Repair damaged connectors/terminals. After repairs, go to step 9 .
Repair faulty wiring/harness. After repairs, go to step 9 .
Reinspect all related circuits and connectors. If all circuits check okay, replace sensor/components. After repairs, 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 that set 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, diagnose affected DTC(s).

An intermittent DTC can be caused by Electromagnetic Interference (EMI). Inspect related circuits for being too close to secondary ignition wires and generator.

DTC P1125: APP SYSTEM (3.0L "V" BODY)

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

This DTC will run when battery voltage is greater than 7 volts. DTC will set when DTCs P1275 and P1280 are not set. ECM sill not illuminate MIL when DTC is set. DTC clears after 40 consecutive warm-up cycles in which no failures are reported by this diagnostic and/or other non-essential related diagnostic. DTC will clear when battery is disconnected or cleared by scan tool.

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 P1275 or P1280 is set, diagnose affected DTC(s). If no other DTC is set, 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 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, check for any undiagnosed DTC. Diagnose affected DTCs. If no additional DTCs are set, system is okay.

DTC P1125: APP SYSTEM (3.8L "F" BODY & 5.7L "Y" BODY)

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

Accelerator Pedal Position (APP) module provides a voltage signal that changes relative to accelerator pedal position. There are 3 sensors located within the APP module and are scaled differently.

DTC will set when following conditions are present: 2 or more APP sensors are out of range or all 3 APP sensors disagree, or one APP sensor out of range and the other 2 sensors disagree and 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.
This DTC indicates that 2 or more APP sensor DTCs are set. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTC(s).

An intermittent DTC can be caused by Electromagnetic Interference (EMI). Inspect related circuits for being too close to secondary ignition wires and generator.

DTC P1133: O2S INSUFFICIENT SWITCHING SENSOR 1 (2.2L "J" BODY, 2.2L "S" SERIES & 2.4L "J" & "N" BODIES)

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

Powertrain Control Module (PCM) continuously monitors Oxygen Sensor 1 (O2S 1) activity for 100 seconds. During the monitor period, PCM counts number of times than O2S 1 switches from rich-to-lean and from lean-to-rich. If total number of switches is less than calibrated value, a DTC P1133 will set.

DTC will set under the following conditions: DTC(s) P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300-P0304, P0341, P0404, P0506, P0507, P0601 and P0602 not set, engine speed 1600-2600 RPM, TP sensor angle 9-20 percent. EVAP emission control system commanded open for greater than 36 percent Pulse Width Modulated (PWM), purge learned memory greater than 191 and conditions are present for at least 100 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 other DTCs are present, diagnose affected DTCs. If no other DTCs are present, go to next step.
Start engine. Ensure engine is at normal operating temperature. Operate vehicle within the conditions required for setting this DTC. Using scan tool, monitor LEAN/RICH transition and note number of switches. Also, note number of RICH/LEAN transitions. If transition is 30-40 on A/T or 10-15 on M/T vehicles, go to next step. If transition is not 30-40 on A/T or 10-15 on M/T vehicles, go to step 18 .
Inspect for proper O2S 1 installation, check O2S 1 connector and wiring for corrosion or damage or check O2S 1 ground circuit. Repair as necessary. After repairs, go to step 9 . If no problems were found, go to next step.
Check exhaust manifold for leaks. Repair as necessary. After repairs, repeat step 3 . If exhaust is okay, go to next step.
Disconnect O2S 1 connector. Turn ignition on. Using scan tool, monitor O2S 1 voltage. If voltage reading is 407-509 mV, go to next step. If voltage reading is not 407-509 mV, go to step 10 .
Connect a jumper wire between ground and signal circuit terminal at O2S 1 harness connector. If voltage reading is less than 200 mV, go to next step. If voltage reading is not less than 200 mV, go to step 11 .
Replace oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After repairs, go to step 17 .
Repair wiring or terminal as necessary. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor. After repairs, go to step 17 .
Repair short to ground in O2S 1 signal circuit. After repairs, go to step 17 .
Remove jumper wire. Check voltage between ground and signal circuit at O2S 1 harness connector. If voltage reading is greater than 407 mV, go to next step. If voltage reading is not greater than 407 mV, go to step 13 .
Turn ignition off. Disconnect PCM harness connectors. Check resistance between ground and O2S 1 ground circuit at PCM connector. If resistance is less than 5 ohms, go to step 14 . If resistance is not less than 5 ohms, repair open in ground circuit. After repairs, go to step 17 .
Turn ignition off. Disconnect PCM harness connectors. Check resistance of signal circuit between O2S 1 harness connector and PCM connector. If resistance is less than 5 ohms, go to step 15 . If resistance is not less 5 ohms, repair open in sensor signal circuit. After repairs, go to step 17 .
Check O2S 1 ground circuit terminal connection at PCM connector. Repair or replace terminal as necessary. After repairs, go to step 17 . If ground circuit terminal is okay, go to step 16 .
Check O2S 1 signal circuit terminal connection at PCM connector. Repair or replace terminal as necessary. After repairs, go to step 17 . If ground circuit terminal 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 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 P1133. 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, go to «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .

Check if fuel pressure is too high. PCM can compensate for some increase; however, if fuel pressure is too high, DTC will set. Check for leaking injector(s) or faulty fuel pressure regulator. See appropriate SYSTEM & COMPONENT TESTING article.

Check EVAP system for fuel saturation. Disconnect MAP sensor harness connector and see if rich condition is corrected. If rich condition is corrected, check for faulty MAP sensor. Check for oxygen sensor silicone contamination. Check TP sensor. See appropriate SYSTEM & COMPONENT TESTING article.

DTC P1133: HO2S INSUFFICIENT SWITCHING SENSOR 1 (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 Heated Oxygen Sensor (HO2S) activity for 100 seconds. PCM determines if HO2S 1 is functioning properly by counting number of HO2S 1 Lean/Rich (L/R) and Rich/Lean (R/L) switches. If PCM determines that HO2S 1 did not switch enough times, DTC 1133 is 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If any DTC other than P1133 or P1134 sets, diagnose affected DTC before proceeding. If no other DTC sets, start engine and allow it to idle. Operate vehicle within conditions required to set DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P1133 FAILED THIS IGN, go to next step. If scan tool does not display DTC P1133 FAILED THIS IGN, go to «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks. If exhaust leak is found, repair as necessary. After repairs, go to step 11 . If no exhaust leak is found, go to next step.
Visually inspect HO2S 1 for secure installation or corrosion on terminals. Check terminal tension at HO2S 1 and PCM. Check for damaged wiring. If a problem is found, go to step 8 . If no problem is found, go to next step.
Disconnect HO2S 1 harness connector. Connect a jumper wire between HO2S 1 harness connector ground circuit and chassis ground. Using scan tool, read HO2S 1 voltage. If voltage reading is about 0.45 volt, go to next step. If voltage reading is not about 0.45 volt, go to step 9 .
Connect a jumper wire between HO2S 1 harness connector signal and ground circuits, and chassis ground. If voltage reading is less than 0.3 volt, go to next step. If voltage reading is not less than 0.3 volt, go to step 10 .
Repair condition causing fuel, sealant, oil or coolant contamination. Replace affected HO2S. After replacing sensor, go to step 11 .
Repair condition as necessary. After repairs, go to step 11 .
Repair open HO2S 1 ground circuit or HO2S 1 signal circuit shorted to ground. After repairs, go to step 11 .
Repair open HO2S 1 signal circuit or faulty PCM connections as necessary. After repairs, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

Check HO2S 1 heater circuits for intermittent faults. If HO2S 1 heater circuits are okay, replace HO2S 1.

DTC P1133: HO2S INSUFFICIENT SWITCHING SENSOR 1 (3.5L "W" BODY)

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

PCM monitors Heated Oxygen Sensor (HO2S) activity for 100 seconds. PCM determines if HO2S is functioning properly by counting number of times signal voltage crosses the rich-to-lean and lean-to-rich thresholds. A lean-to-rich condition is when voltage changes from less than 300 mV to greater than 600 mV. A rich-to-lean condition is when voltage changes from greater than 600 mV to less than 300 mV.

DTC will run if no active fuel trim, injector, misfire, AIR, CKP, ECT, EGR, EVAP, IAT, MAF, MAP, or TP sensor DTCs are present, DTC P0131, P0132 or P0135 not set, system voltage is greater than 9 volts, system is in closed-loop, engine running for at least 3 minutes, ECT greater than 167°F (75°C), engine speed greater 1000-3000 RPM, MAF 15-40 gm/s and these conditions are stable for 3 seconds.

DTC will set when PCM monitors HO2S switches fewer than 5 rich-to-lean and lean-to-rich condition.

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, clear DTCs. Reset fuel trim values. Start and operate engine to normal operating temperature. Using scan tool, monitor HO2S voltage for sensor that applies to this DTC. If HO2S voltage is fixed within 351-551 mV, go to step 4 . If HO2S voltage is not fixed within 351-551 mV, go to next step.
Visually inspect HO2S for water intrusion, open or short in circuit, inoperative HO2S heater, poor connector terminal contact, exhaust leak (within 12 inches upstream of sensor) or faulty HO2S. Repair as necessary. After repairs, go to step 17 . If no problems were found, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Turn ignition off. Disconnect harness connector to affected HO2S. Using a jumper wire, jumper HO2S low circuit to ground. Jumper HO2S high signal circuit to ground. Turn ignition on, with engine off. Using scan tool, monitor affected HO2S voltage. If voltage reading is 20 mV, go to step 7 . If voltage reading is not 20 mV, go to next step.
Turn ignition off. Remove jumper wires from HO2S terminals. Disconnect PCM harness connector containing the affected HO2S high and low circuits. Using a DVOM, check continuity of high and low circuits between HO2S harness connector and PCM harness connector terminals. If resistance on circuit(s) is less than 5 ohms, go to next step. If resistance on circuit(s) is not less than 5 ohms, go to step 9 .
Check for proper PCM connector terminal contact. Repair as necessary. After repairs, go to step 17 . If terminal contact is okay, go to step 16 .
Remove jumpers from HO2S terminals. Turn ignition on, with engine off. Using a test light, connect test light between HO2S heater ignition feed and heater ground circuit harness connector terminals. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Turn ignition off. Reconnect HO2S harness connector. Disconnect PCM harness connector containing the affected HO2S low circuit. Using a DVOM, check continuity of low circuit between HO2S harness connector and ground circuit terminals. If resistance is less than 500 ohms, go to step 12 . If resistance is not less than 500 ohms, go to step 11 .
Repair circuit with a high resistance. After repairs, go to step 17 .
Repair HO2S heater ignition or ground circuit. After repairs, go to step 17 .
Repair high resistance between HO2S low circuit and PCM ground circuit. After repairs, go to step 17 .
Check for exhaust leak upstream of suspect HO2S. Repair as necessary. After repairs, go to step 17 . If exhaust leak is not present, go to next step.
Allow engine to cool down to ambient temperature. Using DVOM, check resistance between HO2S low circuit terminal and PCM ground circuit terminal. If resistance is less than 500 ohms, go to step 15 . If resistance is not less than 500 ohms, go to next step.
Remove HO2S from exhaust. Clean HO2S mounting threads. Apply anti-seize compound to sensor threads. Install and tighten HO2S to 30 ft. lbs. (41 N.m). Using DVOM, check resistance between HO2S low circuit terminal and PCM ground circuit terminal. If resistance is less than 500 ohms, go to step 17 . If resistance is not less than 500 ohms, go to next step.
Replace HO2S sensor. After replacing sensor, go to step 17 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, clear DTC. Turn ignition off and wait 15 seconds. Start and 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 CAPTURED INFO function. If any undiagnosed DTCs are displayed, go to appropriate DTC test.

Check HO2S heater operation. If HO2S heater operation is okay, replace HO2S.

DTC P1133: HO2S INSUFFICIENT SWITCHING SENSOR 1 (3.8L "C", "G", "H" & "W" BODIES)

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

Conditions for setting DTC are: PCM monitors fewer than 40 lean-to-rich and rich-to-lean switches for bank 1, sensor 1 HO2S, HO2S voltage remains between 300-600 mV and conditions are present for 2 minutes after "closed-loop" enable.

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, select LAST TST FAIL. Record any other failed DTCs. If any DTC other than P1133 or P1134 sets, diagnose affected DTC before proceeding. If no other DTC sets, start engine and allow it to idle. Operate vehicle within conditions required to set DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P1133 FAILED THIS IGN, go to next step. If scan tool does not display DTC P1133 FAILED THIS IGN, go to «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 11 . If no exhaust leak is found, go to next step.
Visually inspect HO2S 1 for secure installation or corrosion on terminals. Check terminal tension at HO2S 1 and PCM. Check for damaged wiring. If a problem is found, go to step 8 . If no problem is found, go to next step.
Disconnect HO2S 1 harness connector. Connect a jumper wire between HO2S 1 harness connector ground circuit and chassis ground. Using scan tool, read HO2S 1 voltage. If voltage reading is about 0.45 volt, go to next step. If voltage reading is not about 0.45 volt, go to step 9 .
Connect a jumper wire between HO2S 1 harness connector signal and ground circuits, and chassis ground. If voltage reading is less than 0.3 volt, go to next step. If voltage reading is not less than 0.3 volt, go to step 10 .
Repair condition causing fuel, sealant, oil or coolant contamination. Replace affected HO2S. After repairs, go to step 11 .
Repair condition as necessary. After repairs, go to step 11 .
Repair open HO2S 1 ground circuit or HO2S 1 signal circuit shorted to ground. After repairs, go to step 11 .
Repair open HO2S 1 signal circuit or faulty PCM connections as necessary. After repairs, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P1133. If scan tool displays DTC P1133 FAILED THIS IGN, return to step 2 . If scan tool does not display DTC P1133 FAILED THIS IGN, repair is complete.

Check HO2S 1 heater operation. If HO2S 1 heater operation is okay, replace HO2S 1.

DTC P1133: HO2S INSUFFICIENT SWITCHING BANK 1, SENSOR 1 (3.8L "F" BODY)

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

PCM monitors Heated Oxygen Sensor (HO2S) activity. PCM counts the number of times that the HO2S signal voltage crosses the rich-to-lean and lean-to-rich thresholds during a 100 second test period. If PCM determines that HO2S did not switch enough times, DTC will set.

A lean-to-rich switch is determined when HO2S voltage changes from less than 300 mV to greater than 600 mV. A rich-to-lean switch is determined when the HO2S voltage changes from greater than 600 mV to less than 300 mV.

DTC will set when PCM monitors fewer than 40 lean-to-rich and rich-to-lean switches for bank 1, sensor 1, HO2S voltage remains between 300-600 mV and conditions are present for 2 minutes after "closed-loop" enable.

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 vehicle within conditions required to set DTC. Using scan tool, monitor SPECIFIC DTC. If scan tool indicates that this DTC FAILED THIS IGN, go to next step. If scan tool does not indicate that this DTC FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1153 and/or P1154 failed, go to step 9 . If scan tool does not indicate that DTC P1153 and/or P1154 failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 16 . If no exhaust leak is found, go to next step.
Visually inspect HO2S for secure installation or corrosion on terminals. Check terminal tension at HO2S and PCM. Check for damaged wiring. If a problem is found, go to step 10 . If no problem is found, go to next step.
Disconnect HO2S harness connector. Connect a jumper wire between HO2S harness connector ground circuit and chassis ground. Using scan tool, monitor HO2S voltage. If voltage reading is 350-550 mV, go to next step. If voltage reading is not 350-550 mV, go to step 7 .
Connect jumper wire between HO2S harness connector signal circuit and chassis ground. Using scan tool, monitor HO2S voltage. If voltage reading is 350-550 mV, go to next step. If voltage reading is not 350-550 mV, go to step 11 .
Connect jumper wire between ground and HO2S signal and low circuits. Using scan tool, monitor HO2S reading. If voltage reading is less than 200 mV, go to step 14 . If voltage reading is not less than 200 mV, go to step 13 .
Replace affected HO2S. Ensure cause of contamination is corrected. After replacing sensor, go to step 16 .
Repair as necessary. After repairs, go to step 16 .
Repair short to ground in HO2S low circuit. After repairs, go to step 16 .
Repair condition causing fuel, sealant, oil or coolant contamination. Replace affected HO2S. After repairs, go to step 16 .
Check for open in HO2S low and signal circuits and faulty PCM connector. Repair as necessary. After repairs, go to step 16 .
Check for poor connections at HO2S. Repair as necessary. After repairs, go to step 16 . If connections are okay, go to next step.
Replace HO2S. After replacing sensor, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Check HO2S heater operation. If HO2S heater operation is okay, replace HO2S.

DTC P1133: HO2S INSUFFICIENT SWITCHING BANK 1, SENSOR 1 (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

PCM provides a 5-volt reference signal to the oxygen sensor. When oxygen sensor is cold, sensor signal voltage will be about 5 volts and PCM will keep the system in "open loop" operation. When oxygen sensor is warm, sensor will swing from rich-to-lean rapidly (one swing every 2 seconds), if PCM is in good control of air/fuel mixture. If oxygen sensor is slow to respond to changes in exhaust oxygen content, 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.
If you were sent here from another DTC, go to step 4 . If not, go to next step.
Using scan tool, check if other DTCs are present. If other DTCs are present, diagnose affected DTC(s) first. If no other DTCs are present, go to next step.
Start engine. Using scan tool, select ENGINE 1 and observe ECT display. Operate engine until temperature reaches 185°F (85°C). Note ENGINE SPEED and BNK 1 SEN 1 display. Operate engine at 1200-2000 RPM for about 2 minutes. After 2 minutes check if rear oxygen sensor voltage rapidly swings from less than.3 volt to greater than.6 volt. If oxygen sensor voltage is swinging as specified, go to next step. If oxygen sensor voltage is not swinging as specified, go to step 6 .
With engine running at 1200-2000 RPM, note scan tool display LOOP STATUS. If display indicates CLOSED, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If display does not indicate CLOSED, go to step 9 .
If rear oxygen sensor voltage remains between.3-.6 volt longer that it swings out of this range, go to step 9 . If oxygen sensor voltage swings, go to next step.
Check terminal contact at PCM harness connector C2. Repair as necessary. If terminal contact is okay, go to next step.
Check terminal contact at rear oxygen sensor connector. Repair as necessary. If harness connector is okay, go to next step.
Replace rear oxygen sensor. Check for possible sensor contamination, i.e. leaded fuel, incorrect gasket seal or over rich operation. If failure is caused by over rich condition, check fuel injection system. See appropriate BASIC DIAGNOSTIC PROCEDURES article.

If fault is not present, check PCM grounds. Never solder oxygen sensor wires.

DTC P1133: HO2S INSUFFICIENT SWITCHING BANK 1, SENSOR 1 (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

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

VCM provides about 0.45 volt reference to Heated Oxygen Sensor (HO2S). HO2S sensor signal voltage varies from about one volt when exhaust is rich to about 0.1 volt when exhaust is lean. VCM determines if HO2S is functioning properly by reading number of Lean/Rich (L/R) and Rich/Lean (R/L) switches. DTC will set when the number of L/R and R/L transitions within a 100 second sample period were less a calibrated number.

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 HO2S related DTC(s). If any other HO2S DTCs are set, go to step 4 . If no other HO2S DTCs are set, go to next step.
Check for PCM related DTCs. If other DTCs are set, diagnose affected DTC first. If no other DTCs are set, go to step 5 .
Repair cause of HO2S silicon contamination, leading, incorrect gasket sealer, rich fuel mixture or antifreeze contamination. Replace HO2S. After replacing sensor, go to next step 18 .
Using scan tool, store DTC information from VCM into scan tool. Clear DTC information from VCM. Start and warm engine to normal operating temperature. Operate engine under the conditions for setting this DTC. If this DTC ran and failed this ignition, go to step 7 . If this DTC did not run or did not fail this ignition, go to next step.
Check for exhaust system leak between engine and HO2S, poor HO2S terminal contact, improperly torqued HO2S, faulty HO2S, poor VCM connector terminal contact. Check HO2S high or low circuit for intermittent open or short, or excessive resistance. Check for contaminated HO2S. Repair as necessary. After repairs, go to step 18 . If no problems were found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks between engine and HO2S. Check HO2S and VCM connectors for proper terminal contact. Repair as necessary. After repairs, go to step 18 . If no problems were found, go to next step.
Turn ignition off. Disconnect affected HO2S harness connector. Using a jumper wire connected to ground, jumper HO2S low circuit terminal on harness connector. Using scan tool, monitor HO2S voltage. If scan tool voltage reading is 351-551 mV, go to next step. If scan tool voltage reading is not 351-551 mV, go to step 13 .
Jumper HO2S high signal circuit to ground. Monitor HO2S voltage. If scan tool voltage reading is 20 mV, go to next step. If scan tool voltage reading is not 20 mV, go to step 14 .
Remove jumper wire. Using a test light connected to chassis ground, probe HO2S heater ignition feed circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 15 .
Connect test light between HO2S heater ignition feed circuit and heater ground circuit on harness connector terminal. If test light illuminates, go to next step. If test light does not illuminate, go to step 16 .
Repair cause of HO2S contamination. Replace sensor. After replacing sensor, go to step 17 .
Check for short between HO2S high and low circuits or between HO2S high signal and ignition voltage source circuits. Repair as necessary. After repairs, go to step 18 . If circuits are okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check HO2S high and low signal circuits for an open or short in circuit. Repair as necessary. After repairs, go to step 18 .
Repair HO2S heater ignition feed circuit. After repairs, go to step 18 .
Repair HO2S heater ground circuit. After repairs, go to step 18 .
Replace HO2S. 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 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 HO2S heater operation. Never solder HO2S wire. An intermittent may be caused by poor connection, rubbed-through wire insulation or broken wire inside insulation.

DTC P1133: HO2S INSUFFICIENT SWITCHING BANK 1, SENSOR 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.

VCM supplies a voltage of about.45 volt between HO2S signal and HO2S ground circuits. HO2S varies voltage from about one volt with rich exhaust to.1 volt with lean exhaust. HO2S produces no voltage and acts as an open circuit when temperature is less than 600°F (360°C). An open sensor circuit or a cold sensor causes open loop operation.

HO2S heater provides for faster sensor warm-up allowing sensor to become active in a shorter period of time and remain active during long extended idle. DTC determines if HO2S is operating properly by monitoring number of lean/rich and rich/lean switches.

DTC will set when the number of lean-to-rich and rich-to-lean transitions within a 100 second sample period were less than a calibrated number.

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 any other HO2S related DTCs are set. If any other DTCs are set, go to step 4 . If no other DTCs are set, go to next step.
Check if any VCM related DTCs are set. If VCM DTCs are set, diagnose affected DTC(s). If no VCM DTCs are set, go to step 5 .
Replace affected HO2S. Repair cause of HO2S contamination. After replacing HO2S sensor, go to step 18 .
Using scan tool, store DTC information from VCM into scan tool. Clear DTCs from VCM. Reset fuel trim values. Start and operate engine to normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this DTC ran and failed this ignition, go to step 7 . If scan tool does not indicate that this DTC ran and failed this ignition, go to next step.
Problem may be intermittent. Check for exhaust leak between engine and HO2S, HO2S connector corrosion, improperly torqued sensor, inoperative HO2S heater or poor VCM harness connector terminal contact. Check for intermittent open or shorted circuit. If problem is found, repair as necessary. After repairs, go to step 18 . If no problems were found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks between engine and HO2S sensor. Check HO2S and VCM harness connectors for proper terminal contact. Repair as necessary. After repairs, go to step 18 . If no problems were found, go to next step.
Disconnect affected HO2S harness connector. Using a jumper wire, connect jumper between ground and HO2S low circuit at sensor harness connector. Turn ignition on, with engine off. Using scan tool, monitor voltage on affected HO2S. If voltage reading on scan tool is 351-551 mV, go to next step. If voltage reading on scan tool is not 351-551 mV, go to step 13 .
Connect jumper wire between ground and affected HO2S high signal circuit at sensor harness connector. Using scan tool, monitor voltage on affected HO2S. If voltage reading on scan tool is less than 20 mV, go to next step. If voltage reading on scan tool is not less than 20 mV, go to step 14 .
Remove jumper wire. Using a test light connected to engine ground, probe HO2S heater ignition feed circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 15 .
Connect test light between HO2S ground and HO2S heater ignition feed circuit on harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 16 .
Check cause of contamination causing HO2S to fail. Repair as necessary. After repairs, go to step 17 .
Check for short between HO2S high and low signal circuits or HO2S high signal and ignition voltage source. Repair as necessary. After repairs, go to step 18 . If circuits are okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check HO2S high and low signal circuit for open or high resistance. Repair as necessary. After repairs, go to step 18 .
Repair HO2S heater ignition feed circuit. After repairs, go to step 18 .
Repair HO2S heater ground circuit. After repairs, go to step 18 .
Replace HO2S. After replacing sensor, go to next step.
Using scan tool, reset fuel trim values. Start and warm engine to normal operating temperature. Operate vehicle within the 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 .

Never solder HO2S wires. Check for improperly installed or defective air intake duct, throttle body and intake manifold leaks, exhaust leaks, HO2S contamination, leaking vacuum hoses or contaminated fuel. An intermittent may be caused by poor connection, rubbed-through wire insulation or a broken wire inside insulation.

DTC P1133: HO2S INSUFFICIENT SWITCHING BANK 1, SENSOR 1 (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

PCM monitors Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this period, PCM counts number of times that HO2S switches from rich-to-lean and lean-to-rich. When PCM determines that HO2S does not switch enough times, DTC will set.

A lean-to-rich switch is determined when HO2S voltages changes from less than 300 mV to greater than 600 mV. A rich-to-lean switch is determined when HO2S voltage changes for greater than 600 mV to less than 300 mV. DTC will set when PCM determines that within 100 seconds the HO2S lean-to-rich and rich-to-lean switches are less than 10.

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. Using scan tool, monitor FAIL THIS IGN under DTC info. If scan tool indicates that DTC P1133 test failed this ignition cycle, go to next step. If scan tool does not indicate that DTC P1133 failed this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1153 test failed, go to step 8 . If scan tool does not indicate that DTC P1153 test failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 14 . If exhaust leak is not present, go to next step.
Ensure that HO2S is securely installed. Check for corrosion on terminals and terminal tension at sensor and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 14 . If circuits are okay, go to next step.
Disconnect HO2S. Connect a fused jumper wire between ground and HO2S low signal circuit at PCM harness connector. Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage. If HO2S voltage reading is 350-550 mV, go to next step. If HO2S voltage reading is 350-550 mV, go to step 10 .
Connect a fused jumper wire between ground and HO2S high and low signal circuits. Using scan tool, monitor voltage. If voltage reading is less than 200 mV, go to step 13 . If voltage reading is greater than 200 mV, go to next step.
Replace affected oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After replacing oxygen sensor, go to step 14 .
Remove jumper wire from HO2S low circuit. Check voltage between battery ground and HO2S low signal circuit. If voltage reading is about 5 volts, go to step 12 . If voltage reading is not about 5 volts, go to step 11 .
Repair high signal circuit for short to ground or voltage. After repairs, go to step 14 .
Repair open in sensor low signal circuit or faulty PCM connection. After repairs, go to step 14 .
Repair open in sensor high signal circuit or faulty PCM connection. After repairs, go to step 14 .
Replace affected HO2S. After replacing sensor, 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 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.

A malfunction in HO2S heater circuit will set DTC. Check circuit for intermittent open or faulty connectors. Oxygen supply inside HO2S is provided through wires.

Use of FREEZE FRAME and/or FAILURE RECORDS mode will aid in locating intermittent condition. If DTC cannot be duplicated, information in data can be useful in determining how many miles since DTC set. This mode can also be used to determine how many ignition cycles diagnostic reported a pass and/or fail condition. Operating vehicle within FREEZE FRAME conditions (RPM, load, vehicle speed, temperature, etc.) will isolate when DTC failed.

DTC P1133: HO2S INSUFFICIENT SWITCHING BANK 1, SENSOR 1 (5.7L "F" & "Y" BODIES)

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

A lean-to-rich switch is determined when HO2S voltages changes from less than 300 mV to greater than 600 mV. A rich-to-lean switch is determined when HO2S voltage changes from greater than 600 mV to less than 300 mV. DTC will set when PCM determines that within 100 seconds the HO2S lean-to-rich and rich-to-lean switches are less than 10.

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. Using scan tool, monitor FAIL THIS IGN under DTC info. If scan tool indicates that DTC P1133 test failed this ignition cycle, go to next step. If scan tool does not indicate that this test failed this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1153 test failed, go to step 8 . If scan tool does not indicate that DTC P1153 test failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 14. If exhaust leak is not present, go to next step.
Ensure that HO2S is securely installed. Check for corrosion on terminals and terminal tension at sensor and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 14. If no problems were found, go to next step.
Disconnect HO2S. Connect a fused jumper wire between ground and PCM connector (PCM side), HO2S low signal circuit. Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage. If HO2S voltage is within a range of 350-550 mV, go to next step. If HO2S voltage is not as specified, go to step 10 .
Connect a fused jumper wire between ground and HO2S high and low signal circuits. Using scan tool, monitor voltage. If voltage reading is less than 200 mV, go to step 13 . If voltage reading is greater than 200 mV, go to step 9 .
Replace affected oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After replacing oxygen sensor, go to step 14 .
Remove jumper wire from HO2S low circuit. Check voltage between battery ground and HO2S low signal circuit. If voltage reading is volts, go to step 12 . If voltage reading is not 5 volts, go to step 11 .
Repair short to ground or voltage in high signal circuit. After repairs, go to step 14 .
Repair open in sensor low signal circuit or faulty PCM connectors. After repairs, go to step 14 .
Repair open in sensor high signal circuit or faulty PCM connectors. After repairs, go to step 14 .
Replace HO2S. After replacing oxygen sensor, 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 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.

A malfunction in HO2S heater circuit will set DTC. Check circuit for intermittent open or faulty connectors. Oxygen supply inside HO2S is provided through wires.

DTC P1134: HO2S TRANSITION TIME RATIO SENSOR 1 (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

PCM reads Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this period, PCM counts the number of Lean/Rich (L/R) and Rich/Lean (R/L) switches.

With this information, an average time for all transitions can be determined. PCM then divides R/L average by L/R rich average to obtain a ratio. If HO2S ratio is not within range, DTC P1134 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If any DTC other than P1133 or P1134 sets, diagnose affected DTC before proceeding. If no other DTC sets, start engine and allow it to idle. Operate vehicle within conditions required to set DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P1134 FAILED THIS IGN, go to next step. If scan tool does not display DTC P1134 FAILED THIS IGN, go to «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks. If exhaust leak is found, repair as necessary. After repairs, go to step 11 . If no exhaust leak is found, go to next step.
Visually inspect HO2S 1 for secure installation or corrosion on terminals. Check terminal tension at HO2S 1 and PCM. Check for damaged wiring. If a problem is found, go to step 8 . If no problem is found, go to next step.
Disconnect HO2S 1 connector. Connect a jumper wire between HO2S 1 harness connector ground circuit and chassis ground. Using scan tool, read HO2S 1 voltage. If voltage reading is about 0.45 volt, go to next step. If voltage reading is not about 0.45 volt, go to step 9 .
Connect a jumper wire between HO2S 1 harness connector signal and ground circuits, and chassis ground. If voltage reading is less than 0.3 volt, go to step 11 . If voltage reading is not less than 0.3 volt, go to step 10 .
Repair condition causing fuel, sealant, oil or coolant contamination. Replace affected HO2S. After replacing sensor, go to step 11 .
Repair condition as necessary. After repairs, go to step 11 .
Repair open HO2S 1 ground circuit or HO2S 1 signal circuit shorted to ground. After repairs, go to step 11 .
Repair open HO2S 1 signal circuit or faulty PCM connections. After repairs, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.

Check HO2S 1 heater circuits for intermittent faults. If HO2S 1 heater circuits are okay, replace HO2S 1.

DTC P1134: HO2S TRANSITION TIME RATIO SENSOR 1 (3.5L "W" BODY)

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

PCM monitors the Heated Oxygen Sensor HO2S activity for 100 seconds. During this period, PCM counts the number of Lean/Rich (L/R) and Rich/Lean (R/L) switches. With this information, an average time for all transitions can be determined. PCM then divides R/L average by L/R rich average to obtain a ratio.

Conditions for setting DTC are: no active fuel trim, injector circuit, misfire, AIR, CKP, ECT, EGR, EVAP, IAT, MAF, MAP or TP sensor DTCs set. P0131, P0132 or P0135 not set, system voltage greater than 9 volts, system in closed-loop, engine running for at least 3.3 minutes, ECT greater than 167°F (75°C), engine speed 1000-3000 RPM, MAF 15-40 gm/s and these conditions stable for 3 seconds.

DTC will set when PCM detects degraded (slow) rich-to-lean or lean-to-rich response times for HO2S 1 or HO2S ratio is not within range.

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 P0140 is also set. If DTC P0140 is set, go to step 4 . If DTC P0140 is not set, go to next step.
Check if any other powertrain component DTCs are set. Diagnose affected DTC. If no other DTCs are set, go to step 5 .
Replace affected HO2S sensors. Ensure cause of contamination are repaired. After repairs, go to step 18 .
Using scan tool, store DTC information from PCM into scan tool. Clear DTC from PCM. Reset fuel trim values. Start and operate to normal operating temperature. Operate engine under conditions for running this DTC. Observe DTC status and verify that DTC runs. If this DTC ran and failed this ignition, go to step 7 . If this DTC did not ran and fail this ignition, go to next step.
DTC may have set by an exhaust system leak between engine and HO2S, poor HO2S connector terminal contact, water intrusion, improperly torqued sensor, inoperative HO2S heater, poor PCM terminal contact, or faulty HO2S high/low circuit. Repair as necessary. After repairs, go to step 18 . If no problems were found, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks between engine and HO2S. Check HO2S and PCM connectors for proper terminal contact. Repair as necessary. After repairs, go to step 18 . If connector terminal contacts are okay, go to next step.
Turn ignition off. Disconnect affected HO2S harness connector. Using a jumper wire, jumper HO2S low circuit harness connector terminal and a known-good ground. Turn ignition on, with engine off. Using scan tool, monitor voltage to affected HO2S. If voltage reading is 351-551 mV, go to next step. If voltage reading is not 351-551 mV, go to step 13 .
Jumper HO2S high signal circuit to ground. Using scan tool, monitor voltage to affected HO2S. If HO2S voltage is less than 20 mV, go to next step. If HO2S voltage is not less than 20 mV, go to step 14 .
Remove jumper wire from HO2S low circuit. Using a test light, connect test light between ground and HO2S heater ignition feed circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 15 .
Connect test light between HO2S heater ignition feed circuit and heater ground circuit terminals at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 16 .
Check contamination sources that caused HO2S to fail. Repair as necessary. After repairs, go to step 17 .
Check for faulty HO2S high signal circuit. Repair as necessary. After repairs, go to step 18 .
Check for open or high resistance in HO2S high signal or low signal circuits. Repair as necessary. After repairs, go to step 18 .
Repair HO2S heater ignition feed circuit. After repairs, go to step 18 .
Repair HO2S heater ground circuit. After repairs, go to step 18 .
Replace HO2S. After replacing sensor, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Turn ignition off. Wait 15 minutes then operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURED INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

Check HO2S 1 heater circuits for intermittent faults. If HO2S 1 heater circuits are okay, replace HO2S 1.

DTC P1134: HO2S TRANSITION TIME RATIO SENSOR 1 (3.8L "C", "G", "H" & "W" BODIES)

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

PCM reads Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this period, PCM counts the number of Lean/Rich (L/R) and Rich/Lean (R/L) switches. With this information, an average time for all transitions can be determined. PCM then divides R/L average by L/R rich average to obtain a ratio. If HO2S ratio is not within range, DTC P1134 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If any DTC other than P1133 or P1134 sets, diagnose affected DTC before proceeding. If no other DTC sets, start engine and allow it to idle. Operate vehicle within conditions required to set DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P1133 FAILED THIS IGN, go to next step. If scan tool does not display DTC P1133 FAILED THIS IGN, go to «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check if DTC P1153, P1154, P1155 and/or P1156 failed. If any of these DTCs are present, go to step 8 . If DTCs are not present, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, repeat step 2 . If no exhaust leak is found, go to next step.
Visually inspect HO2S 1 for secure installation or corrosion on terminals. Check terminal tension at HO2S 1 and PCM. Check for damaged wiring. If a problem is found, go to step 9 . If no problem is found, go to next step.
Disconnect HO2S 1 connector. Connect a jumper wire between HO2S 1 harness connector ground circuit and chassis ground. Using scan tool, read HO2S 1 voltage. If voltage reading is about 0.45 volt, go to next step. If voltage reading is not about 0.45 volt, go to step 10 .
Connect a jumper wire between HO2S 1 harness connector signal and ground circuits, and chassis ground. If voltage reading is less than 0.3 volt, go to next step. If voltage reading is not less than 0.3 volt, go to step 11 .
Repair condition causing fuel, sealant, oil or coolant contamination. Replace affected HO2S. After repairs, go to step 13 .
Repair condition as necessary. After repairs, go to step 13 .
Repair open HO2S 1 ground circuit or HO2S 1 signal circuit shorted to ground. After repairs, go to step 13 .
Repair open HO2S 1 signal circuit or faulty PCM connections as necessary. After repairs, go to step 13 .
Replace Bank 1 HO2S 1. After replacing sensor, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P1133. If scan tool displays DTC P1133 FAILED THIS IGN, return to step 2 . If scan tool does not display DTC P1133 FAILED THIS IGN, repair is complete.

Check HO2S 1 heater operation. If HO2S 1 heater operation is okay, replace HO2S 1.

DTC P1134: HO2S TRANSITION TIME RATIO SENSOR 1 (3.8L "F" BODY)

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

PCM monitors Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this period, PCM counts the number of Lean/Rich (L/R) and Rich/Lean (R/L) switches. With this information, an average time for all transitions can be determined. PCM then divides R/L average by L/R rich average to obtain a ratio. If HO2S ratio is not within range, DTC will set.

Conditions for setting DTC are: PCM detects that bank 1, sensor 1 transition time ratio is less than 0.4 and greater than 4 and condition is present for 2 minutes after "closed-loop" enable.

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.
Warm engine to normal operating temperature. Operate vehicle within conditions required to set this DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC failed this ignition, go to next step. If scan tool does not display that this DTC failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1153 and/or P1154 failed, go to step 8 . If scan tool does not indicate that DTC P1153 and/or P1154 failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 14 . If no exhaust leak is found, go to next step.
Visually inspect HO2S 1 for secure installation or corrosion on terminals. Check terminal tension at HO2S and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 14 . If no problem is found, go to next step.
Disconnect HO2S harness connector. Connect a jumper wire between HO2S harness connector low (ground) circuit and chassis ground. Using scan tool, monitor HO2S voltage. If voltage reading is 350-550 mV, go to next step. If voltage reading is not 350-550 mV, go to step 10 .
Connect a jumper wire between chassis ground and HO2S harness connector signal and low (ground) circuits. Using scan tool, monitor HO2S voltage. If voltage reading is less than 200 mV, go to step 13 . If voltage reading is not less than 200 mV, go to step 9 .
Repair condition causing fuel, sealant, oil or coolant contamination. Replace affected HO2S. After replacing sensor, go to step 14 .
Check voltage between ground and HO2S low circuit. If voltage reading is about 5 volts, go to step 12 . If voltage reading is not about 5 volts, go to step 11 .
Repair short to ground or short to voltage in HO2S signal circuit. After repairs, go to step 14 .
Repair open in HO2S low circuit or faulty PCM connections. After repairs, go to step 14 .
Repair open in HO2S signal circuit or faulty PCM connections. After repairs, go to step 14 .
Replace HO2S. After replacing sensor, go to next step.
Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURE INFO and REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

Check HO2S 1 heater operation. If HO2S 1 heater operation is okay, replace HO2S 1.

DTC P1134: HO2S TRANSITION TIME RATIO BANK 1, SENSOR 1 (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

This test is used in conjunction with the rear oxygen sensor slow response diagnostic test (DTC P0133). The ratio of the response times that was calculated are compared to calibrated limits. If the number of both lean-to-rich transitions (switches) and rich-to-lean transitions were both zero, then ratio will be set to zero. Otherwise, the ratio is calculated based on which average response time was 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.
Using scan tool, check if other DTC(s) are present. If other DTC(s) are present, diagnose affected DTC(s) first. If no other DTC(s) are present, go to next step.
Start engine. Using scan tool, select ENGINE 1 and observe ECT display. Operate engine until temperature reaches 185°F (85°C). Note ENGINE SPEED and BNK 1 SEN 1 display. Operate engine at 1200-2000 RPM for about 2 minutes. After 2 minutes, check if rear oxygen sensor voltage rapidly swings from less than.3 volt to greater than.6 volt. If oxygen sensor voltage is swinging as specified, go to next step. If oxygen sensor voltage is not swinging as specified, go to step 5 .
With engine running at 1200-2000 RPM, note scan tool display LOOP STATUS. If display indicates CLOSED, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If display does not indicate CLOSED, go to step 8 .
If rear oxygen sensor voltage remains between.3-.6 volt longer than it swings out of this range, go to step 8 . If oxygen sensor voltage does not remain within range, go to next step.
Check terminal contact at PCM harness connector C2. Repair as necessary. If terminal contact is okay, go to next step.
Check terminal contact at rear oxygen sensor connector. Repair as necessary. If harness connector is okay, go to next step.
Replace rear oxygen sensor. Check for possible sensor contamination (i.e., leaded fuel, incorrect gasket seal or over rich operation). If failure is caused by over rich condition, check fuel injection system. See appropriate BASIC DIAGNOSTIC PROCEDURES article.

If fault is not present. Check PCM grounds. Never solder oxygen sensor wires.

DTC P1134: HO2S TRANSITION TIME RATIO BANK 1, SENSOR 1 (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

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

VCM reads Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this period, VCM counts the number of Lean/Rich (L/R) and Rich/Lean (R/L) switches.

With this information, an average time for all transitions can be determined. VCM then divides R/L average by L/R rich average to obtain a ratio. If HO2S ratio is not within range or average transition time over a 100 second sample period, 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.
Check for HO2S related DTC(s). If any other HO2S DTCs are set, go to step 4 . If no other HO2S DTCs are set, go to next step.
Check for VCM related DTCs. If VCM DTCs are set, diagnose affected DTC(s) first. If no VCM DTCs are set, go to step 5 .
Repair cause of HO2S silicon contamination, leading, incorrect gasket sealer, rich fuel mixture or antifreeze contamination. Replace HO2S. After replacing sensor, go to next step 18 .
Using scan tool, store DTC information from VCM into scan tool. Clear DTC information from VCM. Start and warm engine to normal operating temperature. Operate engine under the conditions for setting this DTC. If this DTC ran and failed this ignition, go to step 7 . If this DTC did not run or did not fail this ignition, go to next step.
Check for exhaust system leak between engine and HO2S, poor HO2S terminal contact, improperly torqued HO2S, faulty HO2S, poor VCM connector terminal contact. Check HO2S high or low circuit for intermittent open or short, or excessive resistance. Check for contaminated HO2S. Repair as necessary. After repairs, go to step 18 . If no problems were found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks between engine and HO2S. Check HO2S and VCM connectors for proper terminal contact. Repair as necessary. After repairs, go to step 18 . If no problems were found, go to next step.
Turn ignition off. Disconnect affected HO2S harness connector. Using a jumper wire connected to ground, jumper HO2S low circuit terminal on harness connector. Using scan tool, monitor HO2S voltage. If scan tool voltage reading is 351-551 mV, go to next step. If scan tool voltage reading is not 351-551 mV, go to step 13 .
Jumper HO2S high signal circuit to ground. Monitor HO2S voltage. If scan tool voltage reading is 20 mV, go to next step. If scan tool voltage reading is not 20 mV, go to step 14 .
Remove jumper wire. Using a test light connected to chassis ground, probe HO2S heater ignition feed circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 15 .
Connect test light between HO2S heater ignition feed circuit and heater ground circuit on harness connector terminal. If test light illuminates, go to next step. If test light does not illuminate, go to step 16 .
Repair cause of HO2S contamination. Replace sensor. After replacing sensor, go to step 17 .
Check for short between HO2S high and low circuits or between HO2S high signal and ignition voltage source circuits. Repair as necessary. After repairs, go to step 18 . If circuits are okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check HO2S high and low signal circuits for an open or short in circuit. Repair as necessary. After repairs, go to step 18 .
Repair HO2S heater ignition feed circuit. After repairs, go to step 18 .
Repair HO2S heater ground circuit. After repairs, go to step 18 .
Replace HO2S. 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 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 P1134: HO2S TRANSITION TIME RATIO BANK 1, SENSOR 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.

This diagnostic test is used in conjunction with HO2S bank 1, sensor 1 slow response diagnostic test P0133. Ratio of response times that were calculated are compared to calibrated limits. If number of lean-to-rich and rich-to-lean transitions were zero, ratios will be set to zero. Otherwise, ratio is calculated based on which average response time was greater.

DTC will set when the average transition time over a 100 second sample period is not within a specified range.

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. Check if any other DTCs are set. If any other DTCs are set, go to applicable DTC test. If no other DTCs are set, go to next step.
Start engine and idle until normal operating temperature is reached. Observe engine coolant temperature using scan tool while operating engine at a steady speed of 1200-2000 RPM for 2 minutes. After 2 minutes, if HO2S bank 1, sensor 1 voltage rapidly swings greater than and less than.3-.6 volt, go to next step. After 2 minutes, if HO2S bank 1, sensor 1 voltage does not rapidly swing greater than and less than.3-.6 volt, go to step 5 .
Observe scan tool with engine running at 1200-2000 RPM. If scan tool indicates closed loop operation, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If scan tool does not indicate closed loop operation, go to step 8 .
If HO2S bank 1, sensor 1 voltage remains within.3-.6 volt longer than it swings outside of.3-.6 volt range, go to step 10 . If voltage does not remain within.3-.6 volt longer than it swing out of.3-.6 volt range, go to next step.
Check for poor connection at VCM connector. If a problem is found, go to step 10 . If no problem is found, go to next step.
Check for poor connection at HO2S bank 1, sensor 1. If a problem is found, go to step 10 . If no problem is found, go to next step.
Replace HO2S bank 1, sensor 1. After replacing HO2S sensor, go to step 10 .
Check leaded fuel, incorrect gasket sealer and over rich operation as possible causes of HO2S contamination. If a problem is found, go to next step. If no problem is found, go to step 11 .
Repair or replace 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 DTC(s) are displayed, go to applicable DTC test.

DTC P1134: HO2S TRANSITION TIME RATIO BANK 1, SENSOR 1 (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

PCM monitors Heated Oxygen Sensor (HO2S) activity. During this period, PCM counts number of times that HO2S switches from rich-to-lean and lean-to-rich. When PCM determines that HO2S does not switch enough times, DTC will set.

A lean-to-rich switch is determined when HO2S voltages changes from less than 300 mV to greater than 600 mV. A rich-to-lean switch is determined when HO2S voltage changes for greater than 600 mV to less than 300 mV. DTC will set when PCM determines that HO2S transition time ratio is not at expected 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 warm engine to normal operating temperature. Using scan tool, monitor FAIL THIS IGN under DTC info. If scan tool indicates that DTC P1134 test failed this ignition cycle, go to next step. If scan tool does not indicate that DTC P1134 failed this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1154 test failed, go to step 8 . If scan tool does not indicate that DTC P1154 test failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 14 . If exhaust leak is not present, go to next step.
Ensure that HO2S is securely installed. Check for corrosion on terminals and terminal tension at sensor and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 14 . If circuits are okay, go to next step.
Disconnect HO2S. Connect a fused jumper wire between ground and HO2S low signal circuit at PCM harness connector. Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage. If HO2S voltage reading is 350-550 mV, go to next step. If HO2S voltage reading is 350-550 mV, go to step 10 .
Connect a fused jumper wire between ground and HO2S high and low signal circuits. Using scan tool, monitor voltage. If voltage reading is less than 200 mV, go to step 13 . If voltage reading is greater than 200 mV, go to next step.
Replace affected oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After replacing oxygen sensor, go to step 14 .
Remove jumper wire from HO2S low circuit. Check voltage between battery ground and HO2S low signal circuit. If voltage reading is about 5 volts, go to step 12 . If voltage reading is not about 5 volts, go to step 11 .
Repair high signal circuit for short to ground or voltage. After repairs, go to step 14 .
Repair open in sensor low signal circuit or faulty PCM connection. After repairs, go to step 14 .
Repair open in sensor high signal circuit or faulty PCM connection. After repairs, go to step 14 .
Replace affected HO2S. After replacing sensor, 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 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.

A malfunction in HO2S heater circuit will set DTC. Check circuit for intermittent open or faulty connectors. Oxygen supply inside HO2S is provided through wires.

DTC P1134: HO2S TRANSITION TIME RATIO BANK 1, SENSOR 1 (5.7L "F" & "Y" BODIES)

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

PCM monitors Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this period, PCM counts number of times that HO2S switches from rich-to-lean and lean-to-rich and adds amount of time it took to complete all transitions.

With this information, an average time for all transitions can be determined. PCM then divides rich-to-lean average by lean-to-rich average to obtain a ratio. If HO2S ratio is not within range, 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.
Start and warm engine to normal operating temperature. Using scan tool, monitor FAIL THIS IGN under DTC info. If scan tool indicates that DTC P1134 test failed, go to next step. If scan tool does not indicate that this test failed, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1154 test failed, go to step 8 . If scan tool does not indicate that DTC P1154 test failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 14 . If exhaust leak is not present, go to next step.
Ensure that HO2S is securely installed. Check for corrosion on terminals and terminal tension at sensor and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 14 . If circuits are okay, go to next step.
Disconnect HO2S. Connect a fused jumper wire between ground and PCM connector (PCM side), HO2S low signal circuit. Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage. If HO2S voltage is within a range of 350-550 mV, go to next step. If HO2S voltage is not within a range of 350-550 mV, go to step 10 .
Connect a jumper wire between ground and HO2S high and low signal circuits (PCM side). Using scan tool, monitor voltage. If voltage reading is less than 200 mV, go to step 13 . If voltage reading is not less than 200 mV, go to step 9 .
Replace oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After replacing oxygen sensor, go to step 14 .
Remove jumper wire fro HO2S low circuit. Check voltage between battery ground and HO2S low signal circuit. If voltage reading is about 5 volts, go to step 12 . If voltage reading is not about 5 volts, go to step 11 .
Repair short to ground or voltage in high signal circuit. After repairs, go to step 14 .
Repair open in sensor low signal circuit or faulty PCM connectors. After repairs, go to step 14 .
Repair open in sensor high signal circuit or faulty PCM connectors. After repairs, go to step 14 .
Replace HO2S. After replacing oxygen sensor, 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 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 DTC(s) are displayed, go to applicable DTC test.

A malfunction in HO2S heater circuit will set DTC. Check circuit for intermittent open or faulty connectors. Oxygen supply inside HO2S is provided through wires.

DTC P1141: HO2S HEATER CIRCUIT BANK 1, SENSOR 2 (3.0L "V" BODY)

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

This DTC will run when battery voltage is greater than 9 volts. DTC will set when an internal fault is detected in Ignition Control (IC) system. ECM will illuminate MIL and records the operation conditions in the Freeze Frame on the second consecutive drive trip that the diagnostic runs and fails.

DTC will clear when ECM turns off MIL after 3 consecutive drive trips that the diagnostic runs and passes. A history DTC clears after 40 consecutive warm-up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic. DTC will also clear when battery is disconnected or cleared by scan tool.

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 fuse No. 43 (30-amp) located in ECM housing. If fuse is open, go to step 5 . If fuse is okay, go to next step.
Check bank 1 HO2S 2 heater control and ignition circuit for open or short to ground. If circuit is faulty, go to step 6 . If circuit is okay, go to next step.
Replace ECM. Program replacement ECM using required equipment and with frequency code of theft deterrent module that is currently on vehicle. After replacing ECM, go to step 7 .
Check circuit for short to ground. If circuit is shorted, go to next step.
Repair as necessary. After repairs, go to next step.
Using scan tool, clear DTCs. Operate vehicle within conditions required to set DTC. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC failed this ignition, return to step 2 . If scan tool does not display that this DTC failed this ignition, go to next step.
Using scan tool, select CAPTURE INFO and REVIEW INFO option. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

DTC P1153: HO2S INSUFFICIENT SWITCHING BANK 2, SENSOR 1 (3.8L "F" BODY)

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

PCM monitors Heated Oxygen Sensor (HO2S) activity for 100 seconds. PCM determines if HO2S is functioning properly by counting number of Lean/Rich (L/R) and Rich/Lean switches. If PCM determines that HO2S did not switch enough times, DTC will set.

Conditions for setting DTC are: PCM monitors fewer than 40 lean-to-rich and rich-to-lean switches for bank 2, HO2S 1, HO2S voltage remains between 300-600 mV and conditions are present for 2 minutes after "closed-loop" enable.

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.
Warm engine to normal operating temperature. Operate vehicle within conditions required to set this DTC. Using scan tool, read SPECIFIC DTC. If scan tool indicates that this DTC failed this ignition, go to next step. If scan tool does not indicate that this DTC failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1153 and/or P1154 test failed, go to step 9 . If scan tool does not indicate that DTC P1153 and/or P1154 test failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 16 . If no exhaust leak is found, go to next step.
Visually inspect HO2S for secure installation or corrosion on terminals. Check terminal tension at HO2S and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 10 . If circuit or terminals are okay, go to next step.
Disconnect HO2S harness connector. Connect a jumper wire between ground HO2S harness connector low circuit. Using scan tool, monitor HO2S voltage. If voltage reading is 350-550 mV, go to next step. If voltage reading is not 350-550 mV, go to step 12 .
Connect a jumper wire between ground and HO2S 2 harness connector signal circuit. Using scan tool, monitor HO2S voltage. If voltage reading is 350-550 mV, go to next step. If voltage reading is not 350-550 mV, go to step 11 .
Connect jumper between ground and HO2S harness connector signal and low circuits. If scan tool voltage reading is less than 200 mV, go to step 14 . If scan tool voltage is not less than 200 mV, go to step 13 .
Repair condition causing fuel, sealant, oil or coolant contamination. Replace affected HO2S. After replacing sensor, go to step 16 .
Repair as necessary. After repairs, go to step 16 .
Repair short to ground in HO2S low circuit. After repairs, go to step 16 .
Repair short to ground in HO2S signal circuit. After repairs, go to step 16 .
Check for open in HO2S signal and low circuits. Repair as necessary. After repairs, go to step 16 .
Check for poor connection at HO2S harness connector. Repair as necessary. After repairs, go to step 16 . If connections are okay, go to next step.
Replace HO2S 2. After replacing sensor, go to next step.
Using scan tool, clear DTCs. Operate vehicle within conditions required to set DTC. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC failed this ignition, return to step 2 . If scan tool does not display that this DTC failed this ignition, go to next step.
Using scan tool, select CAPTURE INFO and REVIEW INFO option. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

An malfunction in the HO2S heater ignition feed or ground circuit may cause DTC to set. Check HO2S heater circuit for intermittent faults or poor connections. If connections are okay and DTC continues to set, replace bank 2, HO2S 1.

DTC P1153: HO2S INSUFFICIENT SWITCHING BANK 2, SENSOR 1 (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

PCM provides a 5-volt reference signal to the oxygen sensor. When oxygen sensor is cold, sensor signal voltage will be about 5 volts and PCM will keep the system in "open loop" operation. When oxygen sensor is warm, 392°F (200°C), sensor will swing from rich-to-lean rapidly (one swing every 2 seconds), if PCM is in good control of air/fuel mixture. If oxygen sensor is slow to respond to changes in exhaust oxygen content, 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.
If you were sent here from another DTC, go to step 4 . If not, go to next step.
Using scan tool, check if other DTCs are present. If other DTCs are present, diagnose affected DTC(s) first. If no other DTCs are present, go to next step.
Start engine. Using scan tool, select ENGINE 1 and observe ECT display. Operate engine until temperature reaches 185°F (85°C). Note ENGINE SPEED and BNK 2 SEN 1 display. Operate engine at 1200-2000 RPM for about 2 minutes. After 2 minutes, check if pre-converter oxygen sensor voltage rapidly swings from less than.3 volt to greater than.6 volt. If oxygen sensor voltage is swinging as specified, go to next step. If oxygen sensor voltage is not swinging as specified, go to step 6 .
With engine running at 1200-2000 RPM, note scan tool display LOOP STATUS. If display indicates CLOSED, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If display does not indicate CLOSED, go to step 9 .
If pre-converter oxygen sensor voltage remains between.3-.6 volt longer that it swings out of this range, go to step 9 . If voltage does not remain between.3-.6 volt, go to next step.
Check terminal contact at PCM harness connector C2. Repair as necessary. If terminal contact is okay, go to next step.
Check terminal contact at pre-converter oxygen sensor connector. Repair as necessary. If harness connector is okay, go to next step.
Replace pre-converter oxygen sensor. Check for possible sensor contamination, i.e. leaded fuel, incorrect gasket seal or over rich operation. If failure is caused by over rich condition, check fuel injection system. See appropriate BASIC DIAGNOSTIC PROCEDURES article.

If fault is not present, check PCM grounds. Never solder oxygen sensor wires.

DTC P1153: HO2S INSUFFICIENT SWITCHING BANK 2, SENSOR 1 (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

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

DTC will set when the number of L/R and R/L transitions within a 100 second sample period are less than a calibrated number.

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 HO2S related DTC(s). If any other HO2S DTCs are set, go to step 4 . If no other HO2S DTCs are set, go to next step.
Check for PCM related DTCs. If other DTCs are set, diagnose affected DTC first. If no other DTCs are set, go to step 5 .
Repair cause of HO2S silicon contamination, leading, incorrect gasket sealer, rich fuel mixture or antifreeze contamination. Replace HO2S. After replacing sensor, go to next step 18 .
Using scan tool, store DTC information from VCM into scan tool. Clear DTC information from VCM. Start and warm engine to normal operating temperature. Operate engine under the conditions for setting this DTC. If this DTC run and failed this ignition, go to step 7 . If this DTC did not run or did not fail this ignition, go to next step.
Check for exhaust system leak between engine and HO2S, poor HO2S terminal contact, improperly torqued HO2S, faulty HO2S, poor VCM connector terminal contact. Check HO2S high or low circuit for intermittent open or short, or excessive resistance. Check for contaminated HO2S. Repair as necessary. After repairs, go to step 18 . If no problems were found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks between engine and HO2S. Check HO2S and VCM connectors for proper terminal contact. Repair as necessary. After repairs, go to step 18 . If no problems were found, go to next step.
Turn ignition off. Disconnect affected HO2S harness connector. Using a jumper wire connected to ground, jumper HO2S low circuit terminal on harness connector. Using scan tool, monitor HO2S voltage. If scan tool voltage reading is 351-551 mV, go to next step. If scan tool voltage reading is not 351-551 mV, go to step 13 .
Jumper HO2S high signal circuit to ground. Monitor HO2S voltage. If scan tool voltage reading is 20 mV, go to next step. If scan tool voltage reading is not 20 mV, go to step 14 .
Remove jumper wire. Using a test light connected to chassis ground, probe HO2S heater ignition feed circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 15 .
Connect test light between HO2S heater ignition feed circuit and heater ground circuit on harness connector terminal. If test light illuminates, go to next step. If test light does not illuminate, go to step 16 .
Repair cause of HO2S contamination. Replace sensor. After replacing sensor, go to step 17 .
Check for short between HO2S high and low circuits or between HO2S high signal and ignition voltage source circuits. Repair as necessary. After repairs, go to step 18 . If circuits are okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check HO2S high and low signal circuits for an open or short in circuit. Repair as necessary. After repairs, go to step 18 .
Repair HO2S heater ignition feed circuit. After repairs, go to step 18 .
Repair HO2S heater ground circuit. After repairs, go to step 18 .
Replace HO2S. 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 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 .

Never solder HO2S wires. An intermittent may be caused by a poor connection, rubbed-through wire insulation or a broken wire inside the insulation.

DTC P1153: HO2S INSUFFICIENT SWITCHING BANK 2, SENSOR 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.

VCM supplies a voltage of about.45 volt between HO2S signal and HO2S ground circuits. HO2S varies voltage from about one volt with rich exhaust to.1 volt with lean exhaust. HO2S produces no voltage and acts as an open circuit when temperature is less than 600°F (316°C). An open sensor circuit or a cold sensor causes open loop operation.

DTC will set when the number of lean-to-rich and rich-to-lean transitions within a 100 second sample period are less than calibrated 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.
Check for HO2S related DTC(s). If any other HO2S DTCs are set, go to step 4 . If no other HO2S DTCs are set, go to next step.
Check for VCM related DTCs. If VCM DTCs are set, diagnose affected DTC(s) first. If no VCM DTCs are set, go to step 5 .
Repair cause of HO2S silicon contamination, leading, incorrect gasket sealer, rich fuel mixture or antifreeze contamination. Replace HO2S. After replacing sensor, go to next step 18 .
Using scan tool, store DTC information from VCM into scan tool. Clear DTC information from VCM. Start and warm engine to normal operating temperature. Operate engine under the conditions for setting this DTC. If this DTC run and failed this ignition, go to step 7 . If this DTC did not run or did not fail this ignition, go to next step.
Check for exhaust system leak between engine and HO2S, poor HO2S terminal contact, improperly torqued HO2S, faulty HO2S, poor VCM connector terminal contact. Check HO2S high or low circuit for intermittent open or short, or excessive resistance. Check for contaminated HO2S. Repair as necessary. After repairs, go to step 18 . If no problems were found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks between engine and HO2S. Check HO2S and VCM connectors for proper terminal contact. Repair as necessary. After repairs, go to step 18 . If no problems were found, go to next step.
Turn ignition off. Disconnect affected HO2S harness connector. Using a jumper wire connected to ground, jumper HO2S low circuit terminal on harness connector. Using scan tool, monitor HO2S voltage. If scan tool voltage reading is 351-551 mV, go to next step. If scan tool voltage reading is not 351-551 mV, go to step 13 .
Jumper HO2S high signal circuit to ground. Monitor HO2S voltage. If scan tool voltage reading is 20 mV, go to next step. If scan tool voltage reading is not 20 mV, go to step 14 .
Remove jumper wire. Using a test light connected to chassis ground, probe HO2S heater ignition feed circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 15 .
Connect test light between HO2S heater ignition feed circuit and heater ground circuit on harness connector terminal. If test light illuminates, go to next step. If test light does not illuminate, go to step 16 .
Repair cause of HO2S contamination. Replace sensor. After replacing sensor, go to step 17 .
Check for short between HO2S high and low circuits or between HO2S high signal and ignition voltage source circuits. Repair as necessary. After repairs, go to step 18 . If circuits are okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check HO2S high and low signal circuits for an open or short in circuit. Repair as necessary. After repairs, go to step 18 .
Repair HO2S heater ignition feed circuit. After repairs, go to step 18 .
Repair HO2S heater ground circuit. After repairs, go to step 18 .
Replace HO2S. 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 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 P1153: HO2S INSUFFICIENT SWITCHING BANK 2, SENSOR 1 (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

A lean-to-rich switch is determined when HO2S voltages changes from less than 300 mV to greater than 600 mV. A rich-to-lean switch is determined when HO2S voltage changes greater than 600 mV to less than 300 mV. DTC will set when PCM determines that within 100 seconds the HO2S lean-to-rich switches are less than 10 and rich-to-lean switches are less than 10.

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. Using scan tool, monitor FAIL THIS IGN under DTC info. If scan tool indicates that DTC P1153 test failed, go to next step. If scan tool does not indicate that this test failed, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1133 test failed, go to step 8 . If scan tool does not indicate that DTC P1133 test failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to next step. If exhaust leak is not present, repeat step 2 .
Ensure that HO2S is securely installed. Check for corrosion on terminals and terminal tension at sensor and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 9 . If circuits are okay, go to next step.
Disconnect HO2S. Connect a fused jumper wire between ground and PCM connector (PCM side), HO2S low signal circuit. Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage. If HO2S voltage is within a range of 350-550 mV, go to next step. If HO2S voltage is not within a range of 350-550 mV, go to step 10 .
Connect a fused jumper wire between ground and HO2S high and low signal circuits. Using scan tool, monitor voltage. If voltage reading is less than 200 mV, go to step 12 . If voltage reading is not less than 200 mV, go to step 11 .
Replace oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After replacing oxygen sensor, go to step 13 .
Repair or replace wiring or terminal as necessary. After repairs, go to step 13 .
Repair open in sensor low signal circuit or grounded high signal circuit. After repairs, go to step 13 .
Repair open in sensor high signal circuit or faulty PCM connectors. After repairs, go to step 13 .
Replace affected HO2S. After replacing sensor, 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 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.

A malfunction in HO2S heater circuit will set DTC. Check circuit for intermittent open or faulty connectors. Oxygen supply inside HO2S is provided through wires.

DTC P1153: HO2S INSUFFICIENT SWITCHING BANK 2, SENSOR 1 (5.7L "F" & "Y" BODIES)

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

A lean-to-rich switch is determined when HO2S voltages changes from less than 300 mV to greater than 600 mV. A rich-to-lean switch is determined when HO2S voltage changes greater than 600 mV to less than 300 mV. DTC will set when PCM determines that within 100 seconds, the HO2S lean-to-rich and rich-to-lean switches are less than 10.

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. Using scan tool, monitor FAIL THIS IGN under DTC info. If scan tool indicates that DTC P1153 test failed, go to next step. If scan tool does not indicate that DTC P1153 test failed, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1133 test failed, go to step 8 . If scan tool does not indicate that DTC P1133 test failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 14 . If exhaust leak is not present, go to next step.
Ensure that HO2S is securely installed. Check for corrosion on terminals and terminal tension at sensor and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 14 . If circuits are okay, go to next step.
Disconnect HO2S. Connect a fused jumper wire between ground and HO2S low signal circuit (PCM side). Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage. If HO2S voltage is within 350-550 mV, go to next step. If HO2S voltage is not within 350-550 mV, go to step 10 .
Connect a fused jumper wire between ground and HO2S high and low signal circuits (PCM side). Using scan tool, monitor voltage. If voltage reading is less than 200 mV, go to step 13 . If voltage reading is not less than 200 mV, go to step 9 .
Replace oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After replacing oxygen sensor, go to step 14 .
Remove jumper wire fro HO2S low circuit. Check voltage between HO2S low signal circuit and battery ground. If voltage reading is about 5 volts, go to step 12 . If voltage reading is not about 5 volts, go to step 11 .
Repair short to ground or voltage in sensor high signal circuit. After repairs, go to step 14 .
Repair open in sensor low signal circuit or faulty PCM connectors. After repairs, go to step 14 .
Repair open in sensor high signal circuit or faulty PCM connectors. After repairs, go to step 14 .
Replace HO2S. After replacing oxygen sensor, 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 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.

A malfunction in HO2S heater circuit will set DTC. Check circuit for intermittent open or faulty connectors. Oxygen supply inside HO2S is provided through wires.

DTC P1154: HO2S TRANSITION TIME RATIO BANK 2, SENSOR 1 (3.8L "F" BODY)

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

PCM reads Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this period, PCM counts the number of Lean/Rich (L/R) and Rich/Lean (R/L) switches.

With this information, an average time for all transitions can be determined. PCM then divides R/L average by L/R rich average to obtain a ratio. If HO2S ratio is not within range, DTC will set.

Condition for setting DTC is when PCM detects that bank 2 HO2S 1 transitions time ratio is less than.4 and greater than 4 for 2 minutes after "closed-loop" enable.

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. Operate vehicle within conditions required to set DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays that this DTC FAILED THIS IGN, go to next step. If scan tool does not display that this DTC FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1133 and/or P1134 test also failed, go to step 8 . If scan tool does not indicate that DTC P1133 and/or P1134, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 14 . If no exhaust leak is found, go to next step.
Visually inspect HO2S 2 for secure installation or corrosion on terminals. Check terminal tension at HO2S and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 14 . If terminals and connections are okay, go to next step.
Disconnect HO2S harness connector. Connect a jumper wire between ground and HO2S low circuit. Using scan tool, monitor HO2S voltage. If voltage reading is 350-550 mV, go to next step. If voltage reading is not 350-550 mV, go to step 10 .
Connect a jumper wire between ground and HO2S harness connector signal and low circuits. Using scan tool, monitor HO2S voltage. If voltage reading is 200 mV, go to step 13 . If voltage reading is not 200 mV, go to step 9 .
Repair condition causing fuel, sealant, oil or coolant contamination. Replace affected HO2S. After replacing sensor, go to step 14 .
Using DVOM connected to ground, check voltage on HO2S low circuit. If voltage reading is about 5 volts, go to step 12 . If voltage reading is not about 5 volts, go to step 11 .
Repair short to ground or short to voltage in HO2S signal circuit. After repairs, go to step 14 .
Repair open in HO2S low circuit or faulty PCM connections. After repairs, go to step 14 .
Repair open HO2S signal circuit or faulty PCM connections. After repairs, go to step 14 .
Replace HO2S. After replacing sensor, go to next step.
Using scan tool, clear DTCs. Operate vehicle within conditions required to set DTC. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2 . If scan tool does not display that this DTC FAILED THIS IGN, go to next step.
Using scan tool, select CAPTURE INFO and REVIEW INFO option. Check if any undiagnosed DTCs are displayed. Diagnose affected DTCs. If no additional DTCs are displayed, system is okay.

A malfunction in the HO2S heater ignition feed or ground circuit may cause this DTC to set. Check HO2S heater circuit for intermittent faults or poor connections. If circuits and connections are good, and DTC still resets, replace HO2S.

DTC P1154: HO2S TRANSITION TIME RATIO BANK 2, SENSOR 1 (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

This test is used in conjunction with the front oxygen sensor slow response diagnostic test (DTC P0153). The ratio of the response times that was calculated are compared to calibrated limits. If the number of both lean-to-rich transitions (switches) and rich-to-lean transitions were both zero, then ratio will be set to zero. Otherwise, the ratio is calculated based on which average response time was 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.
Using scan tool, check if other DTCs are present. If other DTCs are present, diagnose affected DTC(s) first. If no other DTCs are present, go to next step.
Start engine. Using scan tool, select ENGINE 1 and observe ECT display. Operate engine until temperature reaches 185°F (85°C). Note ENGINE SPEED and BNK 2 SEN 1 display. Operate engine at 1200-2000 RPM for about 2 minutes. After 2 minutes, check if front oxygen sensor voltage rapidly swings from less than.3 volt to greater than.6 volt. If oxygen sensor voltage is swinging as specified, go to next step. If oxygen sensor voltage is not swinging as specified, go to step 5 .
With engine at 1200-2000 RPM, note scan tool LOOP STATUS display. If scan tool display reads CLOSED, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If scan tool display does not read CLOSED, go to step 8 .
If front oxygen sensor voltage remains between.3-.6 volt longer that it swings out of this range, go to step 8 . If voltage does not remain between.3-.6 volt, go to next step.
Check terminal contact at PCM harness connector C2. Repair as necessary. If terminal contact is okay, go to next step.
Check terminal contact at front oxygen sensor connector. Repair as necessary. If harness connector is okay, go to next step.
Replace front oxygen sensor. Check for possible sensor contamination, i.e. leaded fuel, incorrect gasket seal or over rich operation. If failure is caused by an over rich condition, check fuel injection system. See appropriate BASIC DIAGNOSTIC PROCEDURES article.

If fault is not present, check PCM grounds. Never solder oxygen sensor wires.

DTC P1154: HO2S TRANSITION TIME RATIO BANK 2, SENSOR 1 (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

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

VCM reads Heated Oxygen Sensor (HO2S) activity for 100 seconds. During this period, VCM counts the number of Lean/Rich (L/R) and Rich/Lean (R/L) switches.

With this information, an average time for all transitions can be determined. VCM then divides R/L average by L/R rich average to obtain a ratio. If HO2S ratio is not within range, 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.
Check for HO2S related DTC(s). If any other HO2S DTCs are set, go to step 4 . If no other HO2S DTCs are set, go to next step.
Check for PCM related DTCs. If other DTCs are set, diagnose affected DTC first. If no other DTCs are set, go to step 5 .
Repair cause of HO2S silicon contamination, leading, incorrect gasket sealer, rich fuel mixture or antifreeze contamination. Replace HO2S. After replacing sensor, go to next step 18 .
Using scan tool, store DTC information from VCM into scan tool. Clear DTC information from VCM. Start and warm engine to normal operating temperature. Operate engine under the conditions for setting this DTC. If this DTC run and failed this ignition, go to step 7 . If this DTC did not run or did not fail this ignition, go to next step.
Check for exhaust system leak between engine and HO2S, poor HO2S terminal contact, improperly torqued HO2S, faulty HO2S, poor VCM connector terminal contact. Check HO2S high or low circuit for intermittent open or short, or excessive resistance. Check for contaminated HO2S. Repair as necessary. After repairs, go to step 18 . If no problems were found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks between engine and HO2S. Check HO2S and VCM connectors for proper terminal contact. Repair as necessary. After repairs, go to step 18 . If no problems were found, go to next step.
Turn ignition off. Disconnect affected HO2S harness connector. Using a jumper wire connected to ground, jumper HO2S low circuit terminal on harness connector. Using scan tool, monitor HO2S voltage. If scan tool voltage reading is 351-551 mV, go to next step. If scan tool voltage reading is not 351-551 mV, go to step 13 .
Jumper HO2S high signal circuit to ground. Monitor HO2S voltage. If scan tool voltage reading is 20 mV, go to next step. If scan tool voltage reading is not 20 mV, go to step 14 .
Remove jumper wire. Using a test light connected to chassis ground, probe HO2S heater ignition feed circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 15 .
Connect test light between HO2S heater ignition feed circuit and heater ground circuit on harness connector terminal. If test light illuminates, go to next step. If test light does not illuminate, go to step 16 .
Repair cause of HO2S contamination. Replace sensor. After replacing sensor, go to step 17 .
Check for short between HO2S high and low circuits or between HO2S high signal and ignition voltage source circuits. Repair as necessary. After repairs, go to step 18 . If circuits are okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check HO2S high and low signal circuits for an open or short in circuit. Repair as necessary. After repairs, go to step 18 .
Repair HO2S heater ignition feed circuit. After repairs, go to step 18 .
Repair HO2S heater ground circuit. After repairs, go to step 18 .
Replace HO2S. 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 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 .

Never solder HO2S wires. An intermittent may be caused by a poor connection, rubbed-through wire insulation or a broken wire inside the insulation.

DTC P1154: HO2S TRANSITION TIME RATIO BANK 2, SENSOR 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.

This diagnostic test is used in conjunction with HO2S bank 2, sensor 1 slow response diagnostic test P0153. Ratio of response times that were calculated are compared to calibrated limits. If number of lean-to-rich and rich-to-lean transitions were zero, ratios will be set to zero. Otherwise, ratio is calculated based on which average response time was greater.

DTC will set when the number of lean-to-rich and rich-to-lean transitions within a 100 second sample period were less than a calibrated 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.
Check for HO2S related DTC(s). If any other HO2S DTCs are set, go to step 4 . If no other HO2S DTCs are set, go to next step.
Check for VCM related DTCs. If VCM DTCs are set, diagnose affected DTC(s) first. If no VCM DTCs are set, go to step 5 .
Repair cause of HO2S silicon contamination, leading, incorrect gasket sealer, rich fuel mixture or antifreeze contamination. Replace HO2S. After replacing sensor, go to next step 18 .
Using scan tool, store DTC information from VCM into scan tool. Clear DTC information from VCM. Start and warm engine to normal operating temperature. Operate engine under the conditions for setting this DTC. If this DTC run and failed this ignition, go to step 7 . If this DTC did not run or did not fail this ignition, go to next step.
Check for exhaust system leak between engine and HO2S, poor HO2S terminal contact, improperly torqued HO2S, faulty HO2S, poor VCM connector terminal contact. Check HO2S high or low circuit for intermittent open or short, or excessive resistance. Check for contaminated HO2S. Repair as necessary. After repairs, go to step 18 . If no problems were found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check exhaust system for leaks between engine and HO2S. Check HO2S and VCM connectors for proper terminal contact. Repair as necessary. After repairs, go to step 18 . If no problems were found, go to next step.
Turn ignition off. Disconnect affected HO2S harness connector. Using a jumper wire connected to ground, jumper HO2S low circuit terminal on harness connector. Using scan tool, monitor HO2S voltage. If scan tool voltage reading is 351-551 mV, go to next step. If scan tool voltage reading is not 351-551 mV, go to step 13 .
Jumper HO2S high signal circuit to ground. Monitor HO2S voltage. If scan tool voltage reading is 20 mV, go to next step. If scan tool voltage reading is not 20 mV, go to step 14 .
Remove jumper wire. Using a test light connected to chassis ground, probe HO2S heater ignition feed circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 15 .
Connect test light between HO2S heater ignition feed circuit and heater ground circuit on harness connector terminal. If test light illuminates, go to next step. If test light does not illuminate, go to step 16 .
Repair cause of HO2S contamination. Replace sensor. After replacing sensor, go to step 17 .
Check for short between HO2S high and low circuits or between HO2S high signal and ignition voltage source circuits. Repair as necessary. After repairs, go to step 18 . If circuits are okay, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Check HO2S high and low signal circuits for an open or short in circuit. Repair as necessary. After repairs, go to step 18 .
Repair HO2S heater ignition feed circuit. After repairs, go to step 18 .
Repair HO2S heater ground circuit. After repairs, go to step 18 .
Replace HO2S. 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 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 P1154: HO2S TRANSITION TIME RATIO BANK 2, SENSOR 1 (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

A lean-to-rich switch is determined when HO2S voltages changes from less than 300 mV to greater than 600 mV. A rich-to-lean switch is determined when HO2S voltage changes greater than 600 mV to less than 300 mV. DTC will set when PCM determines that HO2S transition time ratio is not at expected 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 warm engine to normal operating temperature. Using scan tool, monitor FAIL THIS IGN under DTC info. If scan tool indicates that DTC P1154 test failed, go to next step. If scan tool does not indicate that this test failed, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1134 test failed, go to step 8 . If scan tool does not indicate that DTC P1134 test failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 14 . If exhaust leak is not present, repeat next step.
Ensure that HO2S is securely installed. Check for corrosion on terminals and terminal tension at sensor and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 14 . If circuits are okay, go to next step.
Disconnect HO2S. Connect a fused jumper wire between ground and PCM connector (PCM side), HO2S low signal circuit. Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage. If HO2S voltage is within a range of 350-550 mV, go to next step. If HO2S voltage is not within a range of 350-550 mV, go to step 10 .
Connect a fused jumper wire between ground and HO2S high and low signal circuits. Using scan tool, monitor voltage. If voltage reading is less than 200 mV, go to step 13 . If voltage reading is not less than 200 mV, go to step 9 .
Replace oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After replacing oxygen sensor, go to step 14 .
Remove jumper wire from HO2S low circuit. Check voltage from HO2S low signal circuit to battery ground. If voltage reading is about 5 volts, go to step 12 . If voltage reading is not about 5 volts, go to step 11 .
Repair high signal circuit for a short to ground or short to voltage. After repairs, go to step 14 .
Repair open in sensor low signal circuit or faulty PCM connections. After repairs, go to step 14 .
Repair open in sensor high signal circuit or faulty PCM connectors. After repairs, go to step 14 .
Replace affected HO2S. After replacing sensor, 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 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.

A malfunction in HO2S heater circuit will set DTC. Check circuit for intermittent open or faulty connectors. Oxygen supply inside HO2S is provided through wires.

DTC P1154: HO2S TRANSITION TIME RATIO BANK 2, SENSOR 1 (5.7L "F" & "Y" BODIES)

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 warm engine to normal operating temperature. Using scan tool, monitor FAIL THIS IGN under DTC info. If scan tool indicates that DTC P1154 test failed, go to next step. If scan tool does not indicate that DTC P1154 test failed, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
If scan tool indicates that DTC P1134 test failed, go to step 8 . If scan tool does not indicate that DTC P1134 test failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 14 . If exhaust leak is not present, go to next step.
Ensure that HO2S is securely installed. Check for corrosion on terminals and terminal tension at sensor and PCM. Check for damaged wiring. Repair as necessary. After repairs, go to step 14 . If circuits are okay, go to next step.
Disconnect HO2S. Connect a fused jumper wire between ground and HO2S low signal circuit (PCM side). Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage. If HO2S voltage is within 350-550 mV, go to next step. If HO2S voltage is not within 350-550 mV, go to step 10 .
Connect a fused jumper wire between battery ground and HO2S high and low signal circuits (PCM side). Using scan tool, monitor voltage. If voltage reading is less than 200 mV, go to step 13 . If voltage reading is not less than 200 mV, go to step 9 .
Replace oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After replacing oxygen sensor, go to step 14 .
Remove jumper from HO2S low circuit. Check voltage between battery ground and HO2S low signal circuit. If voltage reading is about 5 volts, go to step 12 . If voltage reading is not about 5 volts, go to step 11 .
Repair short to ground or voltage in sensor high signal circuit. After repairs, go to step 14 .
Repair open in sensor low signal circuit or faulty PCM connectors. After repairs, go to step 14 .
Repair open in sensor high signal circuit or faulty PCM connectors. After repairs, go to step 14 .
Replace HO2S. After replacing oxygen sensor, 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 conditions for setting this DTC. If scan tool indicates that this DTC test ran and passed, go to next step. If scan tool does not indicate that this DTC 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.

A malfunction in HO2S heater circuit will set DTC. Check circuit for intermittent open or faulty connectors. Oxygen supply inside HO2S is provided through wires.

DTC P1161: HO2S HEATER CIRCUIT BANK 2, SENSOR 2 (3.0L "V" BODY)

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.
Check fuse No. 43 (30-amp) located in ECM housing. If fuse is open, go to step 5 . If fuse is okay, go to next step.
Check bank 2 HO2S 2 heater control and ignition circuit for open or short to ground. If circuit is faulty, go to step 6 . If circuit is okay, go to next step.
Replace ECM. Program replacement ECM using required equipment and with frequency code of theft deterrent module that is currently on vehicle. After replacing ECM, go to step 7 .
Check circuit for short to ground. If circuit is shorted, go to next step.
Repair as necessary. After repairs, go to next step.
Using scan tool, clear DTCs. Operate vehicle within conditions required to set DTC. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC failed this ignition, return to step 2 . If scan tool does not display that this DTC failed this ignition, go to next step.
Using scan tool, select CAPTURE INFO and REVIEW INFO option. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

Powertrain Control Module (PCM) internal circuitry can identify if vehicle fuel system is capable of supplying adequate amounts of fuel during heavy acceleration (power enrichment). When a power enrichment mode of operation is requested, PCM will allow additional fuel to be provided to the engine. If PCM does not detect a rich exhaust, a DTC P1171 will set.

Conditions for setting DTC are: DTCs P0131, P0132, P0133, P0134 and P1133 not set, ECT is greater than 70°F (20°C), engine running longer than 20 seconds in "closed-loop", O2S 1 voltage is less than 300 mV for 5 seconds and engine is in power enrichment mode.

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 present, diagnose affected DTC(s). If no other DTCs are present, go to next step.
Check fuel level in tank. Add fuel as necessary. If fuel level was low (almost empty), go to step 5 . If fuel level was okay, go to next step.
Start engine. Ensure coolant temperature is 167-203°F (75-95°C). Raise engine speed to 1200 RPM. Using scan tool, observe O2S 1 voltage. Voltage should vary within a range of 100-900 mV. Occasionally voltage should increase by greater than 447 mV (during power enrichment mode). If voltage is as specified, go to BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article. If voltage is not as specified, go to DTC P0134 diagnosis.
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 this DTC. 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, system is okay. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .

A restricted fuel filter can supply adequate amounts of fuel at idle, but may not be able to supply enough fuel during heavy acceleration. Water or alcohol in fuel may cause low O2S 1 voltage during acceleration. Check for defective or plugged fuel injectors.

DTC P1189: ENGINE OIL PRESSURE SWITCH CIRCUIT (4.6L "E" & "K" BODIES)

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

Engine oil pressure switch is a normally closed switch. When oil pressure increases to greater than 1 or 4.5 psi, switch contact opens. PCM supplies 12 volts to oil pressure input circuit. When oil pressure is low, the 12 volts is pulled low to ground. This test checks for a short to ground in the low oil pressure switch circuit. If engine has been off long enough for engine temperature to drop by 10°C, then an open (low oil pressure) condition of the circuit should be observed prior to engine start. If engine has not been cranked and low oil pressure has not been detected, DTC P1189 will set. DTC will also set if circuit is shorted 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.
Warm engine to normal operating temperature. After warming up engine, turn engine off for at least 30 seconds. Turn ignition on, engine off. Ensure engine was not cranked. Using scan tool, check engine oil pressure. If scan tool indicates that oil pressure is low, fault is not present. If scan tool does not indicate that oil pressure is low, go to next step.
Disconnect oil pressure sensor connector. If scan tool indicates that oil pressure is low, go to step 6 . If scan tool does not indicate that oil pressure is low, go to next step.
Using scan tool, record fluid life index. Turn ignition off. Wait 30 seconds then disconnect PCM harness connector C2. Check resistance between ground and PCM harness connector C2 terminal No. 57. If resistance reading is 10,000 ohms or less, go to next step. If resistance reading is not 10,000 ohms or less, go to step 7 .
Repair short to ground in oil pressure switch circuit.
Replace oil pressure switch.
Replace PCM. Program replacement PCM using required equipment.

A generic Field Effects Transistor (FET) driver is used to operate all actuators. This DTC will set if the PCM/TCM has determined that this device has failed.

Record all DTCs and diagnose affected DTCs. If DTC P1215 resets, replace PCM.

DTC P1220: TP SENSOR NO. 2 CIRCUIT (3.8L "F" BODY)

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

The Throttle Position (TP) sensor is a potentiometer, mounted on throttle body/TAC assembly. TP sensor is actually 2 sensors within one housing. Two separate signal, ground and reference circuits are used in order to connect the TP assembly and Throttle Actuator Control (TAC) module.

TP sensor No. 1 signal voltage increases as throttle opens. The signal circuit for TP sensor is pulled up to reference voltage. DTC will set when TP sensor No. 2 voltage is less than 0.25 volt or greater than 4.5 volts 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.
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. NOTE: If scan tool indicates NO and DTC P1515 or P1516 is not present, go to step 4 .
Turn ignition on. Using scan tool, observe TP SENSORS DISAGREE parameter. If scan tool indicates YES, go to next step. If scan tool does not indicate YES, go to DTC P1515 test.
Depress throttle to Wide Open Throttle (WOT), the release slowly while observing TP sensor No. 1 voltage on scan tool. If scan tool voltage reading remains at or close to one volt, go to next step. If scan tool voltage reading does not remain at or close to one volt, go to step 6 .
Check ELEC THROT CONT and TCS BATT fuses. If either fuse is open, go to step 16 . If either fuse is not open, go to step 20 .
Turn ignition off for 15 seconds. Turn ignition on, with engine off. Using scan tool, select DTC option and FAILED IGNITION option. Move/wiggle harnesses and related connections while monitoring DTC information. If harness movement causes this DTC to set, go to step 11 . If harness movement does not cause this DTC to set, go to next step.
Turn ignition off. Disconnect TAC harness connector. Using DVOM, check resistance between reference and return circuits at TAC harness connector. If resistance is 4500-5500 ohms, go to next step. If resistance is not 4500-5500 ohms, go to step 30 .
Turn ignition on. Check voltage between ground and signal circuit in TAC harness connector. If voltage reading is 3.9-4.6 volts, go to next step. If voltage reading is not 3.9-4.6 volts, go to step 11 .
Check voltage between ground and reference circuit in TAC harness connector. If voltage reading is 3.9-4.6 volts, go to next step. If voltage reading is not 3.9-4.6 volts, go to step 13 .
Check resistance between TP sensors No. 1 and 2 sensor ground circuits in the TAC harness connector. If resistance is 0-5 ohms, go to step 29 . If resistance is not 0-5 ohms, go to step 15 .
Turn ignition off. Leave TP sensor disconnected. Disconnect TAC module harness connector. Turn ignition on, with engine off. Check voltage between battery ground and signal circuit in TAC harness connector. If any voltage is present, go to step 22 . If no voltage is present, go to next step.
Check signal circuit for short to ground. If circuit is grounded, go to step 23 . If circuit is okay, go to step 17 .
Turn ignition on, with engine off. Check voltage between ground and reference circuit in TAC harness connector. If any voltage is present, go to step 25 . If no voltage is present, go to next step.
Check reference circuit for short to ground. If circuit is shorted, go to step 26 . If circuit is okay, go to step 18 .
Turn ignition off. Check for open in ground circuit. If circuit is open, go to step 19 . If circuit is okay, go to step 27 .
Repair short to ground in TAC module battery feed or ignition feed circuit. After repairs, go to step 33 .
Check harness for continuity between signal circuit and all other circuits at TAC module connector. If continuity is exists on all circuits, go to step 21 . If continuity does not exist on all circuits, go to step 24 .
Check harness for continuity between reference circuit and all other circuits at the TAC module connector. If continuity exists on all circuits, go to step 21 . If continuity does not exist on all circuits, go to step 28 .
Check harness for continuity between ground circuit and all other circuits at TAC module connector. If continuity exists on all circuits, go to step 21 . If continuity does not exist on all circuits, go to step 31 .
Repair open/high resistance in TAC module battery feed or ignition feed circuits. After repairs, go to step 33 .
Repair harness or connections as necessary. After repairs, go to step 33 .
Repair short to voltage in signal circuit. After repairs, go to step 33 .
Repair short to ground in signal circuit. After repairs, go to step 33 .
Check open/high resistance in signal circuit. Repair as necessary. After repairs, go to step 33 . If circuit is okay, go to step 31 .
Repair short to voltage in reference circuit. After repairs, go to step 33 .
Repair short to ground in reference circuit. After repairs, go to step 33 .
Check open/high resistance in ground circuit. Repair as necessary. After repairs, go to step 33 . If circuit is okay, go to step 31 .
Check open/high resistance in reference circuit. Repair as necessary. After repairs, go to step 33 . If circuit is okay, go to step 31 .
Check for poor connection at TAC connector. Repair as necessary. After repairs, go to step 33 . If connections are okay, go to next step.
Replace throttle body/TAC assembly. After replacing throttle body, go to step 33 .
Check for poor connections at TAC module harness connector. Repair as necessary. After repairs, go to step 33 . If terminal contacts or tension are okay, go to next step.
Replace TAC module. After replacing module, 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 that 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, repeat step 3 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

DTC P1220: TP SENSOR NO. 2 CIRCUIT (3.0L "V" BODY)

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

This DTC will run when battery voltage is greater than 7 volts. DTC will set when TP sensor No. 1 voltage is less than 0.16 volt or greater than 4.8 volts, or difference between TP sensor No. 1 and TP sensor No. 2 is greater than 13 percent and both conditions met for 140 milliseconds.

ECM will illuminate MIL on the second consecutive drive trip that the diagnostic runs and fails. DTC will clear when ECM turns off MIL after 3 consecutive drive trips that the diagnostic runs and passes. A history DTC will clear after 40 consecutive warm-up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic. DTC will also clear when battery is disconnected or cleared by scan tool.

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 other DTCs. If DTC P1120 is also set, go to step 8 . If DTC P1120 is not set, go to next step.
Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. Using a test light connected to ground, probe TP sensor 5-volt reference circuit. If test light illuminates, go to step 7 . If test light does not illuminate, go to next step.
Probe test light to TP sensor signal circuit. If test light illuminates, go to step 9 . If test light does not illuminate, go to next step.
Turn ignition off. Disconnect ECM harness connector. Using DVOM, check resistance of TP sensor signal circuit. If resistance is less than 2 ohms, go to next step. If resistance is not less than 2 ohms, go to step 10 .
Replace TP sensor/throttle body assembly. After replacing assembly, go to step 11 .
Repair open in ground circuit. After repairs, go to next step 11 .
Repair open or short in 5-volt reference circuit. After repairs, go to step 11 .
Repair short to ground in TP sensor signal circuit. After repairs, go to step 11 .
Repair open on TP sensor signal circuit. After repairs, 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 that 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, repeat step 2 .
Using scan tool, check for additional undiagnosed DTCs. Diagnose affected DTCs. If no additional DTCs are set, system is okay.

With ignition on, monitor TP sensor voltage on scan tool while slowly depressing accelerator pedal from 0-100 percent. The voltage should increase as pedal is depressed and decrease as pedal is released.

DTC P1220: TP SENSOR NO. 2 CIRCUIT (5.7L "Y" BODY)

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

The Throttle Position (TP) sensor is a potentiometer, mounted on side of air control valve assembly (throttle body). TP sensor is actually 2 sensors within one housing.

TP sensor No. 1 signal voltage increases as throttle opens from less than 1.1 volt at zero percent throttle to greater than 3.7 volts at 100 percent throttle. TP sensor No. 2 signal voltage decreases from greater than 3.9 volts at zero percent throttle to less than 1.2 volt at 100 percent throttle.

Signal circuit for TP sensor No. 1 is pulled up to 5 volts and signal circuit for TP sensor No. 2 is pulled to ground through Throttle Actuator Control (TAC) module. DTC will set when TP sensor voltage is less than 0.13 volt or greater than 4.87 volts and 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.
If DTC P1515, P1516 or P1518 is also present, diagnose affected DTC first. If DTC P1515, P1516 or P1518 is not present, go to next step.
Remove duct from throttle body assembly. Disconnect throttle actuator motor connector. Manually close throttle blade while monitoring scan tool TP SENSOR NO. 2 voltage display. If voltage reading is 4.3-4.8 volts, go to next step. If voltage reading is not 4.3-4.8 volts, go to step 7 .
Manually rotate throttle blade to wide open throttle. If voltage reading is.13-1.0 volt, go to next step. If voltage reading is not.13-1.0 volt, go to step 7 .
Reconnect throttle actuator motor connector. Turn ignition off for 15 seconds. Turn ignition on, with engine off. Using scan tool, select DTC function, then enter this DTC. Monitor scan tool while moving wiring harness and related connectors. If scan tool indicates this test failed this ignition, go to step 25 . If scan tool does not indicate that this test failed this ignition, go to next step.
While monitoring scan tool, fully open and close throttle. If scan tool indicates this test failed this ignition, go to step 35 . 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-p0704-p1272) .
Using scan tool, monitor TP sensor No. 2 voltage. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 11 .
Disconnect TP sensor No. 2 harness connector. If scan tool indicates zero volts, go to next step. If scan tool does not indicate zero volts, go to step 12 .
Turn ignition off. Using DVOM, check resistance between battery ground and TP sensor No. 2 ground circuit in TP sensor harness connector. If resistance is 0-5 ohms, go to next step. If resistance is not 0-5 ohms, go to step 33 .
Turn ignition off. Disconnect Accelerator Pedal Position (APP) sensor harness connector. Turn ignition on, with engine off. Using DVOM, check voltage between TP sensor No. 2 5-volt reference circuit and battery ground. If voltage reading is about 5 volts, go to step 13 . If voltage reading is not about 5 volts, go to step 17 .
Disconnect TP sensor harness connector. Using DVOM, check voltage between TP sensor No. 2 signal circuit and battery voltage. If voltage reading is 5 volts, go to step 19 . If voltage reading is not 5 volts, go to step 14 .
Turn ignition off. Leave TP sensor disconnected. Disconnect Throttle Actuator Control (TAC) module connector containing TP sensor circuits. Turn ignition on, with engine off. Check voltage between battery ground TP sensor No. 2 signal circuit at sensor harness connector. If any voltage is present, go to step 30 . If no voltage is present, go to step 16 .
Turn ignition off. Disconnect TAC module harness connector. Turn ignition on, with engine off. Check voltage between battery ground and APP sensor No. 2 signal circuit at TAC module harness connector. If any voltage is present, go to step 24 . If no voltage is present, go to step 22 .
Turn ignition off. Leave TP sensor disconnected. Disconnect TAC module connector containing TP sensor circuits. Check continuity of TP sensor No. 2 signal circuit. If continuity exists, go to next step. If continuity does not exist, go to step 31 .
Check continuity between battery ground and TP sensor No. 2 signal circuit. If continuity exists, go to step 32 . If continuity does not exist, go to next step.
Check continuity of TP sensor No. 2 signal circuit and all other circuits in both TAC module connectors. If continuity exists, go to step 34 . If continuity does not exist, go to step 37 .
Turn ignition off. Leave TP and APP sensors disconnected. Disconnect TAC module connector containing the TP sensor circuits. Turn ignition on, with engine off. Check voltage from TP sensor No. 2 5-volt reference circuit in TP sensor harness connector to battery ground. If any voltage is present, go to step 26 . If no voltage is present, go to next step.
Turn ignition on. Disconnect the other TAC module connector. Turn ignition on, with engine off. Check voltage from APP sensor No. 2 5-volt reference circuit at TAC module harness connector to battery ground. If any voltage is present, go to step 27 . If no voltage is present, go to step 22 .
Turn ignition off. Disconnect Throttle Actuator Control (TAC) module connector containing TP sensor circuits. Check resistance of TP sensor No. 2 5-volt reference circuit. If resistance is 0-20 ohms, go to next step. If resistance is not 0-20 ohms, go to step 28 .
Check continuity between TP sensor No. 2 5-volt reference circuit and battery ground. If continuity exists, go to step 29 . If continuity does not exists, go to next step.
Turn ignition off. Disconnect the other TAC module connector. Check resistance between APP sensor No. 2 5-volt reference circuit and battery ground. If resistance is 0-2 ohms, go to step 29 . If resistance is not 0-2 ohms, go to next step.
Check continuity between TP sensor No. 2 5-volt reference circuit and all other circuits in both TAC module connectors. If continuity exists, go to step 34 . If continuity does not exist, go to next step.
Check continuity between APP sensor No. 2 5-volt reference circuit and all other circuits in both TAC module connectors. If continuity exists, go to step 34 . If continuity does not exist, go to step 35 .
Repair short to voltage in APP signal circuit. After repairs, go to step 39 .
Repair harness/connections as necessary. After repairs, go to step 39 .
Repair short to voltage in TP sensor No. 2 5-volt reference circuit. After repairs, go to step 39 .
Repair short to voltage in APP sensor 5-volt reference circuit. After repairs, go to step 39 .
Repair open or high resistance in 5-volt reference circuit. After repairs, go to step 39 .
Repair short to ground in 5-volt reference circuit. After repairs, go to step 39 .
Repair signal circuit shorted to voltage. After repairs, go to step 39 .
Replace open or high resistance in signal circuit. After repairs, go to step 39 .
Repair short to ground in signal circuit. After repairs, go to step 39 .
Repair open or high resistance in ground circuit. After repairs, go to step 39 .
Repair circuits that are shorted together. After repairs, go to step 39 .
Check for poor terminal contact or terminal tension at TP sensor harness connector. Repair as necessary. After repairs, go to step 39 . If terminal contacts or tension are okay, go to next step.
Replace throttle body assembly. After replacing throttle body, go to step 39 .
Check for poor terminal contact or terminal tension at TAC module harness connector. Repair as necessary. After repairs, go to step 39 . If terminal contacts or tension are okay, go to next step.
Replace TAC module. After replacing module, 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 that 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, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

DTC P1221: TP SENSOR CIRCUIT (3.0L "V" BODY)

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

The Throttle Position (TP) sensor is a potentiometer, mounted on side of throttle body assembly. TP sensor provides a voltage signal that changes relative to throttle blade angle. TP sensor has a 5-volt reference, ground and signal circuit. Signal circuit is pulled up to 5 volts within the ECM. DTC will set when ECM senses a signal voltage outside of the normal operating range of the sensor, in which TP sensor No. 1 and No. 2 difference is greater than 7 percent for at least 140 milliseconds.

ECM will illuminate MIL and records the operating conditions in the Freeze Frame on the second consecutive drive trip that the diagnostic runs and fails. ECM informs the Transmission Control Module (TCM) of this condition and TCM enters the default mode. TCM will also request ECM to illuminate MIL and set DTC P1700.

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, monitor TP sensor voltage. If scan tool voltage reading is 0.3-0.9 volt, go to next step. If scan tool voltage reading is not 0.3-0.9 volt, go to step 6 .
Fully depress accelerator pedal. If scan tool voltage reading is 4-5 volts, go to next step. If scan tool voltage reading is not 4-5 volts, go to step 6 .
Wiggle/move TP sensor and ECM harness connectors while observing scan tool display. If TP sensor value is affected by moving harness or connectors, go to step 17 . If TP sensor value is not affected by moving harness or connectors, go to next step.
Turn ignition off. Disconnect TP sensor harness connector. Using 2 jumper wires, jumper TP sensor 5-volt reference and ground circuit between harness connector and sensor. Connect DVOM to 5-volt reference circuit between sensor and harness connector. Turn ignition on, with engine off. Slowly move throttle to Wide Open Throttle (WOT), then slowly return to closed position while observing voltage on DVOM. Voltage should increase and decrease smoothly as throttle is moved to WOT and closed throttle position. If voltage changes smoothly, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) . If voltage does not change smoothly (spikes or drops out), go to step 26 .
Disconnect TP sensor harness connector. Using DVOM, check voltage between battery ground and TP sensor signal circuit at harness connector. If voltage reading is 4.7-5.3 volts, go to step 10 . If voltage is not 4.7-5.3 volts, go to next step.
Turn ignition off. Leave TP sensor harness connector disconnected. Disconnect ECM harness connector. Turn ignition on. Using DVOM, check voltage between battery ground and TP sensor signal circuit at harness connector. If any voltage is present, go to step 21 . If no voltage is present, go to next step.
Check for continuity in TP sensor signal circuit. If continuity exists, go to next step. If continuity does not exist, go to step 22 .
Check for continuity between TP sensor signal circuit and battery ground. If continuity exists, go to step 23 . If continuity does not exist, go to step 27 .
If voltage is 4.7-5.3 volts, go to step 14 . If voltage is not 4.7-5.3 volts, go to next step.
Turn ignition off. Leave TP sensor harness connector disconnected. Disconnect ECM harness connector. Turn ignition on, with engine off. If any voltage is present, go to step 18 . If voltage is not present, go to next step.
Check continuity on TP sensor 5-volt reference circuit. If continuity exists, go to next step. If continuity does not exist, go to step 19 .
Check continuity between TP sensor 5-volt reference circuit and battery ground. If continuity exists, go to step 20 . If continuity does not exist, go to step 27 .
Turn ignition off. Using test light connected to battery voltage, probe TP sensor ground circuit at harness connector. If test light illuminates, go to step 16 . If test light does not illuminate, go to next step.
Leave TP sensor harness connector. Disconnect ECM harness connector. Check continuity of TP sensor ground circuit at harness connector. If continuity exists, go to step 27 . If continuity does not exist, go to step 24 .
Turn ignition on, with engine off. Using a fused jumper wire, jumper TP sensor signal circuit to TP sensor ground circuit. Using scan tool, monitor TP sensor voltage. If scan tool voltage reading is 0.5 volt, go to step 25 . If scan tool voltage reading is not 0.5 volt, go to step 28 .
Repair harness or connections as necessary. After repairs, go to step 29 .
Repair short to voltage in 5-volt reference. After repairs, go to step 29 .
Repair open/high resistance in 5-volt reference. 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/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/high resistance in ground circuit. After repairs, go to step 29 .
Check for poor connection or poor terminal tension. If problem is found, go to step 29 . If no problem is found, go to next step.
Replace TP sensor. After replacing sensor, go to step 29 .
Check for poor connection or poor terminal tension at ECM harness connection. If problem is found, go to step 29 . If no problem is found, go to next step.
Replace ECM. Program replacement ECM using required equipment and program ECM with frequency code of theft deterrent module that is currently on vehicle. After replacing ECM, 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 that 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, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

Check for poor connections at ECM or at component. Check for damaged harness. If harness appears to be okay, observe scan tool while moving/wiggling related connectors and wiring harnesses. A change in scan tool display will help in locating fault. If other DTCs are set, DTCs sharing the same 5-volt reference circuit, check entire circuit up to any other components. If DTCs are set that share the same ground circuit, check the point where circuits ground to chassis or engine block.

DTC P1221: TP SENSOR NO. 1 & 2 PERFORMANCE (3.8L "F" BODY)

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

TP sensor No. 1 signal voltage increases as throttle opens. The signal circuit for TP sensor is pulled up to reference voltage. DTC will set when TP sensors No. 1 and 2 disagree by greater than.17 volts 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.
Turn ignition on, with engine off. Using scan tool, monitor TP DISAGREE parameter. If scan tool indicates NO, go to next step. If scan tool does not indicate NO, go to step 4 .
Turn ignition on, with engine off. Using scan tool, select DTC options and FAILED THIS IGNITION option while moving/wiggling harness and related connections. If harness movement causes this DTC to set, go to step 10 . If harness movement does not cause this DTC to set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Turn ignition off. Disconnect TAC module harness connector. Turn ignition on. Using DVOM, check voltage between ground and TP sensors No. 1 and 2 reference circuits. If voltage reading is 3.9-4.6 volts, go to next step. If voltage reading is not 3.9-4.6 volts, go to step 11 .
Check voltage between ground and TP sensors No. 1 and 2 signal circuits. If voltage reading is 3.9-4.6 volts, go to next step. If voltage reading is not 3.9-4.6 volts, go to step 12 .
Check continuity between TP sensors No. 1 and 2 reference circuits at TAC harness connector. If continuity exists, go to step 13 . If continuity does not exist, go to next step.
Check continuity between TP sensors No. 1 and 2 signal circuits at TAC harness connector. If continuity exists, go to step 13 . If continuity does not exist, go to next step.
Check continuity between TP sensors No. 1 and 2 reference circuits at TAC harness connector. If continuity exists, go to step 15 . If continuity does not exist, go to next step.
Check continuity between TP sensors No. 1 and 2 signal circuits at TAC harness connector. If continuity exists, go to step 16 16. If continuity does not exist, go to step 14 .
Repair harness/connections as necessary. After repairs, go to step 17 .
Check for short to voltage in reference circuit. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 14 .
Check for short to voltage in signal circuit. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 14 .
Replace throttle body/TAC assembly. After replacing throttle body assembly, go to step 17 .
Replace TAC module. After replacing module, go to step 17 .
Repair shorted TP sensors No. 1 and 2 reference circuits. After repairs, go to step 17 .
Repair shorted TP sensors No. 1 and 2 signal circuits. After repairs, go to step 17 .
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 that 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, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

DTC P1221: TP SENSOR NO. 1 & 2 PERFORMANCE (5.7L "Y" BODY)

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

The Throttle Position (TP) sensor is a potentiometer, mounted on side of throttle body assembly. TP sensor is actually 2 sensors within one housing.

TP sensor No. 1 signal voltage increases as throttle opens from less than one volt at zero percent throttle to greater than 3.8 volts at 100 percent throttle. TP sensor No. 2 signal voltage decreases from greater than 3.8 volts at zero percent throttle to less than one volt at 100 percent throttle.

Signal circuit for TP sensor No. 1 is pulled up to 5 volts and signal circuit for TP sensor No. 2 is pulled to ground through the Throttle Actuator Control (TAC) module. DTC will set when TP sensor No. 2 disagrees with TP sensor No. 1 by greater than 7.5 percent and 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.
Turn ignition on, with engine off. Using scan tool, monitor TP SENSORS DISAGREE parameters. If scan tool displays NO, go to next step. If scan tool does not display NO, go to step 5 .
Remove duct from throttle body assembly. Disconnect throttle actuator motor connector. Manually open throttle blade to wide open throttle and then slowly return it to closed throttle while stopping briefly at 25, 50, 75 and 100 percent in each direction. If scan tool display changes from NO to YES, go to step 25 . If scan tool display does not change from NO to YES, go to next step.
Reconnect throttle actuator motor connector. Turn ignition off for 15 seconds. Turn ignition on, with engine off. Using scan tool, select DTC function, then enter this DTC. Monitor scan tool while moving wiring harness and related connectors. If scan tool indicates this test failed this ignition, go to step 14 . If scan tool does not indicate that this test failed this ignition, go to «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0704-p1272) .
Disconnect throttle actuator harness connector. Turn ignition on, with engine off. Close throttle blade completely by hand while observing TP sensor No. 1 voltage on scan tool. If voltage reading is 0.13-0.67 volt, go to step 9 . If voltage reading is not 0.13-0.67 volt, go to next step.
Disconnect TP sensor harness connector. Using a jumper wire, jumper TP sensor No. 1 5-volt reference circuit to TP sensor No. 2 signal circuit. Observe TP sensor No. 2 voltage on scan tool. If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 12 .
Jumper TP sensor No. 1 signal circuit to TP sensor No. 1 ground circuit. Monitor TP sensor No. 1 voltage on scan tool. If voltage reading is zero volts, go to step 24 . If voltage reading is not zero volts, go to next step.
Jumper TP sensor No. 1 signal circuit to battery ground circuit. Monitor TP sensor No. 1 voltage on scan tool. If voltage reading is zero volts, go to step 16 . If voltage reading is not zero volts, go to step 14 .
Disconnect TP sensor harness connector. Jumper TP sensor No. 2 5-volt reference circuit to TP sensor No. 2 signal circuit. Monitor TP sensor No. 2 voltage on scan tool. If voltage reading is 5 volts, go to step 11 . If voltage reading is not 5 volts, go to next step.
Jumper TP sensor No. 2 signal circuit to TP sensor No. 1 5-volt reference circuit. Monitor TP sensor No. 2 voltage on scan tool. If voltage reading is 5 volts, go to step 18 . If voltage reading is not 5 volts, go to step 20 .
Jumper TP sensor No. 1 signal circuit to TP sensor No. 2 ground circuit. Monitor TP sensor No. 1 voltage on scan tool. If voltage reading is zero volts, go to step 24 . If voltage reading is not zero volts, go to step 22 .
Disconnect TAC module harness connector. Check resistance between TP sensor 5-volt reference circuit and TAC module. If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 27 .
Check continuity between TP sensor No. 1 5-volt reference circuit and all other circuits in both TAC module connectors. If continuity exists, go to step 26 . If continuity does not exist, go to step 28 .
Disconnect TAC module harness connectors. Check resistance between TP sensor No. 1 signal circuit and TAC module connector. If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 27 .
Check continuity between TP sensor No. 1 signal circuit and all other circuit in both TAC connectors. If continuity exists, go to step 26 . If continuity does not exist, go to step 28 .
Disconnect TAC module harness connectors. Check resistance between TP sensor No. 1 ground circuit and TAC module connector. If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 27 .
Check continuity between TP sensor No. 1 ground circuit and all other circuits in both TAC module connectors. If continuity exists, go to step 26 . If continuity does not exist, go to step 28 .
Disconnect TAC module harness connectors. Check resistance between TP sensor 5-volt reference circuit and TAC module connector. If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 27 .
Check continuity between TP sensor No. 2 5-volt reference circuit and all other circuits in both TAC module connectors. If continuity exists, go to step 26 . If continuity does not exist, go to step 28 .
Disconnect TAC module harness connectors. Check resistance between TP sensor No. 2 signal circuit and TAC module connector. If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 27 .
Check continuity between TP sensor No. 1 signal circuit and all other circuit in both TAC module connectors. If continuity exists, go to step 26 . If continuity does not exist, go to step 28 .
Disconnect TAC module harness connectors. Check resistance between TP sensor No. 2 ground circuit and TAC module connector. If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 27 .
Check continuity between TP sensor No. 2 ground circuit and all other circuits in both TAC module connectors. If continuity exists, go to step 26 . If continuity does not exist, go to step 28 .
Check for poor connections or terminal tension at TP sensor connector. Repair as necessary. After repairs, go to step 30 . If connections or terminal tension is okay, go to next step.
Replace throttle body assembly. After replacing throttle body, go to step 30 .
Repair circuits that are shorted together. After repairs, go to step 30 .
Repair circuit with high resistance. After repairs, go to step 30 .
Check for poor connections or terminal tension at TAC module connector. Repair as necessary. After repairs, go to step 30 . If connections or terminal tension is okay, go to next step.
Replace TAC module. After replacing module, 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 that 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, repeat step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs.

DTC P1257: SUPERCHARGER SYSTEM OVERBOOST (3.8L "C", "G" & "H" BODIES)

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

Normally PCM commands Boost Control (BC) solenoid to operate at 100 percent (ON) Pulse Width Modulation (PWM) to allow for full intake boost upon demand. If Reverse is selected, PCM detects rapid deceleration, or engine is load is extremely high, PCM commands BC solenoid to operate at zero percent (OFF) PWM. DTC will set when IAT is greater than 14°F (-10°C), engine torque exceeds maximum predetermined torque threshold value and conditions are present for at least 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.
Using scan tool, select LAST TST FAIL. Record any other failed DTCs. If any other DTCs set, diagnose affected DTCs before proceeding. If no other DTCs set, go to next step.
Disconnect BC solenoid harness connector. Turn ignition on. Connect a test light across BC solenoid harness connector terminals. If test light illuminates, go to step 9 . If test light does not illuminate, go to next step.
Disconnect inlet vacuum signal hose from by-pass valve actuator. Connect a vacuum gauge to by-pass valve actuator. Start and allow engine to idle in Park. If vacuum is greater than 12 in. Hg, go to next step. If vacuum is not greater than 12 in. Hg, go to step 12 .
Reconnect BC solenoid harness connector and inlet vacuum signal hose. Disconnect boost signal hose between BC solenoid and by-pass valve actuator. Connect vacuum gauge to by-pass valve actuator. Using scan tool, turn BC solenoid off. If vacuum is greater than 12 in. Hg, go to next step. If vacuum is not greater than 12 in. Hg, go to step 12 .
Check for restriction in boost signal hose between BC solenoid and supercharger by-pass valve actuator. Repair as necessary. After repairs, go to step 15 . If no restriction is found, go to next step.
Check for binding by-pass valve, sticking or misadjusted by-pass valve actuator linkage. Repair as necessary. After repairs are complete, go to step 15 . If no problem is found, go to next step.
Replace by-pass valve actuator. After replacing by-pass valve actuator, go to step 15 .
Turn ignition off. Disconnect PCM. Turn ignition on. If test light illuminates, go to next step. If test light does not illuminate, go to step 13 .
Locate and repair short to ground in BC solenoid driver circuit. After repairs, go to step 15 .
Repair restriction in inlet vacuum signal hose, or blocked inlet vacuum source. After repairs, go to step 15 .
Check for restriction in boost source hose to BC solenoid. Repair as necessary. After repairs, go to step 15 . If no restriction is found, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 15 .
Replace BC solenoid. After replacing solenoid, go to next step.
Read and record FAILURE RECORDS data for this DTC. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P1257 FAILED THIS IGN, return to step 2 . If scan tool does not display DTC P1257 FAILED THIS IGN, repair is complete.

Check for faulty connections or damaged harness. Connect a DVOM between BC solenoid driver circuit at PCM harness connector and engine ground. With ignition on, observe DVOM while moving all related harness and connectors. A change in voltage display indicates fault location.

Check BC solenoid driver circuit for short to ground. Check for binding by-pass valve. Check for sticking or misadjusted by-pass valve actuator.

DTC P1258: ENGINE COOLANT OVER-TEMPERATURE PROTECTION (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

PCM has the ability to disable 4 injectors during an engine over-temperature (overheating) condition. Engine is considered over-temperature whenever ECT reaches 268°F (131°C). This protection mode allows the PCM to alternate between groups of cylinders, thereby reducing coolant temperature. This is accomplished by disabling the fuel injectors. This DTC is set to show that an overheating condition was or is observed by the PCM and that the protection mode has been engaged.

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 P0108 or P1114 is set. If any of these DTC(s) are present, diagnose affected DTC(s). If DTC(s) are not present, diagnose cooling system.

DTC P1258: ENGINE COOLANT OVER-TEMPERATURE FUEL DISABLED (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

PCM has the ability to disable a number of injectors during an engine over temperature (overheating) condition. Engine is considered over temperature whenever ECT is greater than 250°F (121°C). This protection mode allows the PCM to alternate between groups of cylinders, thereby reducing coolant temperature. This is accomplished by disabling the fuel injectors. This DTC is set to show that an overheating condition was or is observed by the PCM and that the protection mode has been engaged.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, diagnose cause of engine overheating.

DTC P1258: ENGINE COOLANT OVER-TEMPERATURE FUEL DISABLED (5.7L "F" & Y" BODIES)

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

In order to reduce engine temperature, PCM has ability to disable a number or fuel injectors during and engine over-temperature condition. Engine is considered over-temperature when Engine Coolant Temperature (ECT) sensor reaches a predetermined temperature. DTC sets when PCM senses ECT sensor is in over-temperature condition, and PCM enters protection mode.

DTC will set when following conditions are present: DTC P0117, P0118 or P0125 not set, engine is running, ECT greater than 270°F (132°C) and these conditions present for greater than 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.
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If other ECT related DTC(s) are present, diagnose affected DTC(s). If no other DTC(s) are present, repair cooling system or mechanical problem as necessary.

If an overheating condition is present, overheat condition must be repaired and engine oil and filter must be changed. Using FREEZE FRAME and/or FAILURE RECORDS data may aid in locating intermittent condition. If DTC cannot be duplicated, information included in FREEZE FRAME and/or FAILURE RECORDS can be useful in determining how many miles since DTC set. It can also be used to determine how many ignition cycles diagnostic reported a pass and/or fail condition. Operate vehicle within same freeze frame conditions (RPM, load, vehicle speed, temperature, etc.) that are noted. This will isolate when DTC failed. If other DTC(s) are set that share same ground and/or 5-volt reference circuit, check for faulty connections or wiring.

DTC P1271: APP SENSOR NO. 1 & 2 (3.0L "V" BODY)

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

This DTC will run when battery voltage is greater than 7 volts. DTC will set when voltage for Accelerator Pedal Position (APP) sensor No. 1 or No. 2 is less than.68 volt or greater than.88 volt. ECM will illuminate MIL and records the operating conditions in the Freeze Frame on the second consecutive drive trip that the diagnostic runs and fails.

DTC will clear when ECM turns off MIL after 3 consecutive drive trips that the diagnostic runs and does not fail. A history DTC clears after 40 consecutive warm-up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic. DTC will also clear when battery is disconnected or cleared by scan tool.

DTC P1271: APP SENSORS NO. 1 & 2 CORRELATION ERROR (3.8L "F" BODY)

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

The Accelerator Pedal Position (APP) sensors are mounted on accelerator pedal/TAC module assembly. The are 3 individual APP sensors within one housing and 3 separate signal, ground and reference circuits are used which are contained with the Throttle Actuator Control (TAC) module. The APP sensor signal voltage increases as accelerator pedal is depressed. The signal circuits pull to ground within the TAC module.

DTC will set when APP sensor No. 1 disagrees with APP sensor No. 2 by greater than 10.5 percent or the APP No. 1 signal is shorted to the APP No. 2 signal and all these conditions are present 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.
Check if other DTCs are also set. If other DTCs are also set, diagnose affected DTCs first. If no other DTCs are set, go to next step.
Replace TAC module. After replacing module, 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 DTC(s) are displayed, go to applicable DTC test.

Check for poor connections, corrosion, misrouted harness, rubbed-through wire insulation or broken wire inside insulation. When TAC module detects a problem within the ETC system and PCM receives a message across the serial data and greater than one ETC system related DTC may set due to the many redundant tests run continuously on this system. Locating and repairing one individual problem may correct more than one DTC.

DTC P1272: APP SENSORS NO. 2 & 3 CORRELATION ERROR (3.8L "F" BODY)

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

DTC will set when APP sensor No. 1 disagrees with APP sensor No. 3 by greater than 10.5 percent or the APP No. 1 signal is shorted to the APP No. 3 signal and all these conditions are present 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.
Check if other DTCs are also set. If other DTCs are also set, diagnose affected DTCs first. If no other DTCs are set, go to next step.
Replace TAC module. After replacing module, 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 DTC(s) are displayed, go to applicable DTC test.

Check for poor connections, corrosion, misrouted harness, rubbed-through wire insulation or broken wire inside insulation. When TAC module detects a problem within the ETC system and PCM receives a message across the serial data and more than one ETC system related DTC may set due to the many redundant tests run continuously on this system. Locating and repairing one individual problem may correct more than one DTC.

See also:
• DIAGNOSTIC AIDS
• DIAGNOSTIC AIDS
• DIAGNOSTIC AIDS

Engine Control System - Tests W/codes - DTC p0704-p1272 GMC Savana I

MODEL IDENTIFICATION

DTC P0704: CLUTCH SWITCH CIRCUIT (3.8L "F" BODY)

Circuit Description

Diagnostic Procedures

Diagnostic Aids

DTC P0704: CLUTCH SWITCH CIRCUIT (4.3L "S" & "T" SERIES)

DTC P0704: CLUTCH SWITCH CIRCUIT (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0704: CLUTCH SWITCH CIRCUIT (5.0L, 5.7L & 7.4L "C", "K" & "P" SERIES)

DTC P0704: CLUTCH SWITCH CIRCUIT (5.7L "F" BODY)

DTC P0704: CLUTCH SWITCH CIRCUIT (5.7L "Y" BODY)

DTC P0705: TRANSMISSION RANGE SWITCH CIRCUIT (2.2L "J" BODY, 2.2L "S" SERIES & 2.4L "J" & "N" BODIES)

Scheme 26

DTC P0705: TRANSAXLE RANGE SWITCH CIRCUIT (3.1L "N" & "W" BODIES)

Scheme 27

DTC P0705: TRANSAXLE RANGE SWITCH CIRCUIT (3.4L "N" BODY)

DTC P0705: TRANSAXLE RANGE SWITCH CIRCUIT (3.8L "C", "G", "H" & "W" BODIES)

DTC P0705: TRANSMISSION RANGE SWITCH CIRCUIT (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0706: TRANSAXLE RANGE SWITCH PERFORMANCE (3.1L "N" & "W" BODIES & 3.4L "N" BODY)

DTC P0706: TRANSAXLE RANGE SYSTEM PERFORMANCE (3.8L "C", "G", "H" & "W" BODIES)

DTC P0706: TRANSMISSION RANGE SWITCH PERFORMANCE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0706: TRANSMISSION RANGE SWITCH PERFORMANCE (5.7L "Y" BODY)

DTC P0801: REVERSE INHIBIT SOLENOID CONTROL CIRCUIT (5.7L "F" & "Y" BODIES)

DTC P0803: SKIP SHIFT SOLENOID CONTROL CIRCUIT (5.7L "F" BODY) OR 1-4 UPSHIFT SOLENOID CONTROL CIRCUIT (5.7L "Y" BODY)

DTC P0804: 1-4 UPSHIFT LIGHT CONTROL CIRCUIT (5.7L "Y" BODY)

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.5L "W" BODY)

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L "C" & "K" SERIES)

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L "L", "M", "S" & "T" SERIES)

DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.5L "W" BODY)

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

DTC P1108: BARO-TO-MAP SENSOR CIRCUIT COMPARISON TOO HIGH (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.5L "W" BODY)

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P1111: IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (5.7L "F" & "Y" BODIES)

DTC P1112: INTAKE PLENUM SWITCHOVER VALVE CIRCUIT (3.0L "V" BODY)

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "U" SERIES)

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.5L "W" BODY)

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P1112: IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (5.7L "F" & "Y" BODIES)

DTC P1113: INTAKE RESONANCE SWITCHOVER VALVE CIRCUIT (3.0L "V" BODY)

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.5L "W" BODY)

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P1114: ECT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE (5.7L "F" & "Y" BODIES)

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.5L "W" BODY)

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "P" SERIES)

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P1115: ECT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (5.7L "F" & "Y" BODIES)

DTC P1120: TP SENSOR NO. 1 CIRCUIT (3.8L "F" BODY)

DTC P1120: TP SENSOR NO. 1 CIRCUIT (5.7L "Y" BODY)

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.5L "W" BODY)

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (3.8L "C", "G", "H" & "W" BODIES)

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE (4.3L "C", "K", "L", "M", "S" & "T" SERIES)