Engine Control System - Tests W/codes - DTC p0100-p0134

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 P0100: MAF SENSOR CIRCUIT (3.0L "V" BODY)

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

Circuit Description

Mass Airflow (MAF) sensor measures airflow rate into engine. MAF sensor has a switched battery feed, a ground, a signal circuit and a signal return circuit. As airflow increases, a greater amount of current is required to maintain the hot wires at a constant temperature. MAF sensor converts the changes in current draw to a frequency signal read by the ECM. ECM calculates airflow (grams per second) based on this signal.

ECM monitors the MAF sensor frequency and can determine if sensor is stuck low, stuck high, not providing the airflow value expected for a given operating condition, or not providing signal variation expected during normal operation. DTC P0100 will set if MAF signal indicates an airflow of less than 1.11 grams per second (gm/s), or exceeds the maximum value for a given engine RPM. See MAF SPECIFICATIONS table. Conditions must be present for at least 0.1 second.

For duplication of DTC, ensure battery voltage is greater than 11 volts, DTCs P1220 and P1120 are not present, and engine speed is greater than 500 RPM.

Engine RPM	Max. Grams Per Second
1000	23
2000	32
3000	39
4000	50
5000	62
6000	70

MAF SPECIFICATIONS

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, read MAF sensor voltage. If voltage is greater than 4.8 volts, go to step 7 . If voltage is 4.8 volts or less, go to next step.
Start engine and allow it to reach normal operating temperature. With engine idling, monitor MAF sensor voltage on scan tool. If MAF sensor voltage is less than 0.2 volt, go to step 12 . If MAF sensor voltage is 0.2 volt or greater, go to next step.
Check for air leaks between MAF sensor and throttle body. Repair as necessary. After repairs, go to step 27 . If no problem is found, go to next step.
Move/wiggle harness and related connectors while monitoring MAF sensor voltage on scan tool. If movement changes MAF sensor voltage, go to step 16 . If movement does not change MAF sensor voltage, go to next step.
Turn ignition on, with engine off. Review FREEZE FRAME data for DTC P0100 and note parameters. Clear DTCs. Turn ignition off for 15 seconds. Start engine and operate under conditions required to duplicate DTC, and as close to conditions recorded in FREEZE FRAME as possible. See «CIRCUIT DESCRIPTION»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134__circuit-description) . Check for DTCs. If DTC P0100 is set, go to step 23 . If DTC P0100 is not set, go to step 28 .
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. If scan tool displays zero volts, go to next step. If scan tool does not display zero volts, go to step 11 .
Using DVOM, measure voltage between 5-volt reference circuit and ground circuit at MAF sensor harness connector. If voltage is greater than 4.5 volts, go to next step. If voltage is not as specified, go to step 17 .
Using a test light connected to ground, probe signal return circuit at MAF sensor harness connector. If test light illuminates, go to step 24 . If test light does not illuminate, go to next step.
Turn ignition off. Disconnect ECM harness connectors. Using DVOM, check for continuity in MAF sensor signal return circuit between ECM and MAF sensor harness connectors. If continuity is present, go to step 25 . If continuity is not present, go to step 18 .
Turn ignition off. Disconnect ECM harness connectors. Turn ignition on, with engine off. Using DVOM, check for voltage between ground and signal circuit at MAF sensor harness connector. If voltage is present, go to step 19 . If voltage is not present, go to step 26 .
Disconnect MAF sensor. Using test light connected to battery positive, probe signal circuit at MAF sensor harness connector. If scan tool displays 5 volts, go to next step. If scan tool does not display 5 volts, go to step 14 .
Using test light connected to ground, probe battery feed circuit at MAF sensor harness connector. If test light illuminates, go to step 23 . If test light does not illuminate, go to step 20 .
Turn ignition off. Disconnect ECM harness connectors. Using DVOM, check for continuity in MAF sensor signal circuit between ECM and MAF sensor harness connectors. If continuity is present, go to next step. If continuity is not present, go to step 21 .
Using DVOM, check for continuity between MAF sensor signal circuit and ground. If continuity is present, go to step 22 . If continuity is not present, go to step 25 .
Repair harness or connections as necessary. After repairs, go to step 27 .
Repair open or high resistance in ground circuit. After repairs, go to step 27 .
Repair open or high resistance in signal return circuit. After repairs, go to step 27 .
Repair short to voltage in signal circuit. After repairs, go to step 27 .
Repair open or high resistance in switched battery feed circuit. After repairs, go to step 27 .
Repair open or high resistance in signal circuit. After repairs, go to step 27 .
Repair short to ground in signal circuit. After repairs, go to step 27 .
Check for poor connections and terminal tension at MAF sensor harness connector. Repair as necessary. After repairs, go to step 27 . If no problem is found, go to next step.
Replace MAF sensor. After repairs, go to step 27 .
Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 27 . If no problem is found, go to next step.
Replace ECM. New ECM must be programmed with theft deterrent module frequency code currently on vehicle. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate under conditions required to duplicate DTC. See «CIRCUIT DESCRIPTION»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134__circuit-description) . Check for DTCs. If DTC P0100 is set, go to step 2 . If DTC P0100 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 test. If no other DTCs are present, system is okay.

Diagnostic Aids

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 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 (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. If sensor signal is only affected when harness is moved at a component, and there is no problem with wiring harness or connections, component may be faulty.

Check for plugged intake air duct or dirty air filter.

DTC P0101: MAF SYSTEM PERFORMANCE (3.0L "V" BODY)

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

ECM monitors the MAF sensor frequency and can determine if sensor is stuck low, stuck high, not providing the airflow value expected for a given operating condition, or not providing the signal variation expected during normal operation. DTC P0101 will set if the difference between TP sensor No. 1 and TP sensor No. 2 is less than 6 percent and/or relative throttle angle is 0.5.

For duplication of DTC, ensure engine running time is greater than 3 seconds, and DTCs P1120, P1220 and P1221 are not 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 DTC P0120, P1120 or P1220 is also set, diagnose affected DTC first. If specified DTCs are not set, go to next step.
If DTC P0100 is also set, diagnose DTC. If DTC P0100 is not set, go to next step.
Start engine. While observing TP and MAF sensor signals on scan tool, quickly depress accelerator pedal to Wide Open Throttle (WOT) and release. If both parameters increase in value as WOT is performed, go to step 6 . If both parameters do not increase in value as WOT is performed, go to next step.
If MAF sensor signal did not increase in value during WOT, go to step 13 . If TP signal did not increase in value during WOT, diagnose using DTC P1221.
Turn ignition on, with engine off. Review FREEZE FRAME data for DTC P0101 and note parameters. Clear DTCs. Turn ignition off for 15 seconds. Start engine and operate under conditions required to duplicate DTC, and as close to conditions recorded in FREEZE FRAME as possible. See «CIRCUIT DESCRIPTION»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . Check for DTCs. If DTC P0101 is set, go to next step. If DTC P0101 is not set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check for objects blocking MAF sensor inlet screen. Check for intake manifold and throttle body vacuum leaks or air leaks in intake duct system between MAF sensor and throttle body. Check PCV system operation. Check for loose or missing oil fill cap or unseated engine oil dipstick. Repair as necessary. After repairs, go to step 28 . If no problems are found, go to next step.
Turn ignition on, with engine off. Disconnect MAF sensor connector. If scan tool displays less than.5 volt, go to next step. If scan tool displays.5 volt or greater, go to step 12 .
Using DVOM, measure voltage between 5-volt reference circuit and ground circuit at MAF sensor harness connector. If voltage is greater than 4.5 volts, go to next step. If voltage is not as specified, go to step 18 .
Using a test light connected to battery positive, probe signal return circuit at MAF sensor harness connector. If test light illuminates, go to step 25 . If test light does not illuminate, go to next step.
Turn ignition off. Disconnect ECM harness connectors. Using DVOM, check for continuity in MAF sensor signal return circuit between ECM and MAF sensor harness connectors. If continuity is present, go to step 26 . If continuity is not present, go to step 19 .
Turn ignition off. Disconnect ECM harness connectors. Turn ignition on, with engine off. Using DVOM, check for voltage on signal circuit at MAF sensor harness connector. If voltage is present, go to step 20 . If voltage is not present, go to step 27 .
Disconnect MAF harness sensor. Using a test light connected to battery positive, probe MAF sensor signal circuit at MAF sensor harness connector. If scan tool displays 5 volts, go to next step. If scan tool does not display 5 volts, go to step 15 .
Using a test light connected to ground, probe MAF sensor battery feed circuit at MAF sensor harness connector. If test light illuminates, go to step 24 . If test light does not illuminate, go to step 21 .
Turn ignition off. Disconnect ECM harness connectors. Using DVOM, check for continuity in MAF sensor signal circuit between ECM and MAF sensor harness connectors. If continuity is present, go to next step. If continuity is not present, go to step 22 .
Using DVOM, check for continuity between MAF sensor signal circuit and ground. If continuity is present, go to step 23 . If continuity is not present, go to step 26 .
Repair harness connector or terminal connections as necessary. After repairs, go to step 28 .
Repair open or high resistance in ground circuit. After repairs, go to step 28 .
Repair open or high resistance in signal return circuit. After repairs, go to step 28 .
Repair short to voltage in signal circuit. After repairs, go to step 28 .
Repair open or high resistance in switched battery feed circuit. After repairs, go to step 28 .
Repair open or high resistance in signal circuit. After repairs, go to step 28 .
Repair short to ground in signal circuit. After repairs, go to step 28 .
Check for poor connections and terminal tension at MAF sensor harness connector. Repair as necessary. After repairs, go to step 28 . If no problems are found, go to next step.
Replace MAF sensor. After repairs, go to step 28 .
Check for poor connections and terminal tension at ECM harness connectors. Repair as necessary. After repairs, go to step 28 . If no problems are found, go to next step.
Replace ECM. New ECM must be programmed with theft deterrent module frequency code currently on vehicle. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate under conditions required to duplicate DTC. See «CIRCUIT DESCRIPTION»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . Check for DTCs. If DTC P0101 is set, go to step 2 . If DTC P0101 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 test. 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 skewed or stuck TP sensor. A faulty TP sensor or TP sensor circuit can cause ECM to incorrectly calculate predicted mass airflow value.

Check for sticking throttle plate or excessive deposits on throttle plate or throttle bore, TP sensor signal circuit for short to voltage or for poor connection or high resistance in TP sensor ground circuit.

Check for plugged intake air duct or dirty air filter. A wide open throttle acceleration from a stop should cause mass airflow displayed on scan tool to increase from about 4-7 gm/s at idle to 100 gm/s or greater at the time of 1-2 shift. If increase is not as specified, check for a restriction.

Check for water entering air intake system and contaminating MAF sensor. Water rapidly cools hot wires in sensor, causing a false indication of excessive airflow. Check air filter housing for evidence of water.

DTC P0101: MAF SYSTEM PERFORMANCE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

Mass Airflow (MAF) sensor measures amount of air entering engine during a given time. PCM uses MAF sensor information for fuel delivery calculations. MAF sensor readings during acceleration are much higher than those during deceleration or idle.

PCM calculates what MAF sensor reading should be when received from sensor under certain conditions using engine speed (RPM), throttle position, and barometric pressure parameters. When certain test conditions are met, PCM will compare its calculated MAF value to actual value received from sensor. If difference is too great, DTC P0101 will set.

For duplication of DTC, ensure

Engine is running with EGR duty cycle and pintle position at less than 50 percent.
System voltage is 9-18 volts.
Throttle angle is less than 50 percent.
MAP and TP sensor values are steady.

These conditions must be present for a predetermined 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.
Using scan tool, check for DTCs. If DTC P1374 or P1635 is also set, diagnose these DTCs first. If DTC P1374 or P1635 is not set, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Select SPECIFIC DTC function. If scan tool indicates DTC P0101 FAILED THIS IGN, go to next step. If scan tool does not indicate FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
DO NOT clear DTCs. Disconnect MAF sensor connector. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and then stalls, go to step 6 .
Turn ignition off. Reconnect MAF sensor. Start engine. Monitor MAF signal on scan tool. Slowly increase engine speed to 3000 RPM. If MAF sensor signal increases with engine RPM, go to step 7 . If MAF sensor signal does not increase with engine RPM, go to next step.
Diagnose MAP sensor circuit. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article. After repairs, go to step 20 .
Turn ignition on. Ensure throttle is closed. Using scan tool, observe THROTTLE AT IDLE display. If scan tool indicates YES, go to next step. If scan tool does not indicate YES, diagnose using DTC P0121.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, with engine off. Using DVOM, measure voltage between ground and signal circuit at MAF sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 10 .
Connect test light between ignition feed circuit and ground circuit terminals at MAF sensor harness connector. If test light illuminates, go to step 13 . If test light does not illuminate, go to step 12 .
If voltage is less than 4.5 volts, go to step 14 . If voltage is not as specified, go to next step.
Turn ignition off. Disconnect PCM connectors. Turn ignition on, with engine off. Using DVOM, measure voltage between ground and signal circuit terminal at MAF sensor harness connector. If voltage is near zero volts, go to step 20 . If voltage is not as specified, go to step 17 .
Using a test light connected to ground, probe ignition feed circuit terminal at MAF sensor harness connector. If test light illuminates, go to step 15 . If test light does not illuminate, go to step 16 .
Check for poor connection at MAF sensor connector. Repair as necessary. After repairs, go to step 20 . If connection is okay, go to step 18 .
Check MAF sensor signal circuit for excessive resistance between PCM and MAF sensor connectors. Check for excessive resistance in sensor ground circuit. Check for MAF signal circuit shorted to sensor ground circuit. Check for poor connection at PCM. Repair as necessary. After repairs, go to step 20 . If no problems are found, go to step 19 .
Locate and repair open in MAF sensor ground circuit. After repairs, go to step 20 .
Locate and repair open or excessive resistance in MAF sensor ignition feed circuit. After repairs, go to step 20 .
Locate and repair short to voltage in MAF sensor signal circuit. After repairs, go to step 20 .
Replace MAF sensor. After repairs, go to step 20 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, review and record FAILURE RECORDS data. Clear DTCs. Start engine and operate vehicle as close to conditions recorded in FAILURE RECORDS as possible. Monitor SPECIFIC DTC info for DTC P0101. If scan tool indicates DTC P0101 FAILED THIS IGN, go to step 2 . If scan tool does not indicate DTC P0101 FAILED THIS IGN, system is okay.

Check for sticking throttle plate. Check for carbon build-up on throttle plate and throttle bore. Check TP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article. Check for poor connection at PCM. Check for misrouted or damaged MAF sensor wiring harness. Ensure harness is not close to high-voltage components.

DTC P0101: MAF SYSTEM PERFORMANCE (3.5L "W" BODY & 4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

For duplication of DTC, ensure

Other DTCs are not set.
Engine is running with EGR duty cycle and pintle position is at less than 50 percent.
System voltage is 9-18 volts.
Throttle angle is less than 50 percent.
MAP and TP sensor values are steady.

These conditions must be present for a predetermined 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.
If DTC P0102, P0103, P0107, P0108, P0121, P0122, P0123 or P1635 is also set, diagnose these DTCs first. If specified DTCs are not set, go to next step.
Turn ignition off. Remove MAP sensor from intake manifold, leaving harness connected. Connect a hand-held vacuum pump to MAP sensor. Turn ignition on, with engine off. Observe MAP sensor display on scan tool while slowly applying 20 in. Hg of vacuum to MAP sensor. Each one in. Hg of vacuum should result in a smooth 3-4 kPa decrease in MAP sensor value. If MAP sensor value changes as specified, go to next step. If MAP sensor value does not change as specified, go to step 19 .
Apply 20 in. Hg of vacuum to MAP sensor. If MAP sensor reading on scan tool is 34 kPa or less, go to next step. If MAP sensor value is not as specified, go to step 19 .
Disconnect vacuum source from MAP sensor. If MAP sensor reading returns to original value, go to next step. If MAP sensor does not return to original value, go to step 19 .
Turn ignition on, with engine off. Review FREEZE FRAME and/or FAILURE RECORDS data for DTC P0101 and observe parameters. Clear DTCs. Turn ignition off for 15 seconds. Start engine and operate under conditions required to duplicate DTC, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. See «CIRCUIT DESCRIPTION»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . Using scan tool, check for DTCs. If DTC P0101 is set, go to next step. If DTC P0101 is not set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check for restricted MAF sensor inlet. Check for intake manifold and throttle body vacuum leaks. Check PCV system operation. Check for leaks at EGR flange and pipes. Repair as necessary. After repairs, go to step 21 . If no problems are found, go to next step.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, with engine off. Using DVOM, measure voltage between battery ground and signal circuit at MAF sensor harness connector. If voltage is near 5 volts, go to next step. If voltage is not as specified, go to step 10 .
Connect a test light between ignition feed circuit and ground circuit at MAF sensor harness connector. If test light illuminates, go to step 13 . If test light does not illuminate, go to step 12 .
If voltage is less than 4.5 volts, go to step 14 . If voltage is not as specified, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Using DVOM, measure voltage between ground and signal circuit at MAF sensor harness connector. If voltage is near zero volts, go to step 20 . If voltage is not as specified, go to step 17 .
Using a test light connected to battery ground, probe ignition feed circuit at MAF sensor harness connector. If test light illuminates, go to step 15 . If test light does not illuminate, go to step 16 .
Check for poor connections and terminal tension at MAF sensor. Repair as necessary. After repairs, go to step 21 . If no problems are found, go to step 18 .
Check MAF sensor signal circuit for an open, short to ground, or short to MAF sensor ground circuit. Repair as necessary. After repairs, go to step 21 . If no problems are found, go to step 20 .
Locate and repair open in MAF sensor ground circuit. After repairs, go to step 21 .
Locate and repair open in MAF sensor ignition feed circuit. After repairs, go to step 21 .
Locate and repair short to voltage in MAF sensor signal circuit. After repairs, go to step 21 .
Replace MAF sensor. After repairs, go to step 21 .
Replace MAP sensor. After repairs, go to step 21 .
Replace PCM. Perform PCM reprogramming procedures. After repairs, go to step 21 .
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate under conditions required to duplicate DTC. See «CIRCUIT DESCRIPTION»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . Using scan tool, check for DTCs. If DTC P0101 is set, go to step 2 . If DTC P0101 is not set, go to next step.
Using scan tool, review CAPTURED INFO. If any DTCs are present that have not been diagnosed, go to appropriate DTC test. If no DTCs are present, system is okay.

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

Check for skewed or stuck TP sensor. A faulty TP sensor or TP sensor circuit can cause PCM to incorrectly calculate predicted mass airflow value.

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

DTC P0101: MAF SYSTEM PERFORMANCE (3.8L "C", "F", "G", "H" & "W" BODIES)

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

For duplication of DTC, ensure

Engine is running with EGR duty cycle and pintle position at less than 50 percent.
System voltage is 9-18 volts.
Throttle angle is less than 50 percent.
MAP and TP sensor values are steady.

These conditions must be present for a predetermined 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.
If any other DTCs are set, diagnose these DTCs first. See appropriate DTC test. If no other DTCs are set, go to next step.
Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, monitor SPECIFIC DTC info for DTC P0101. If scan tool indicates DTC P0101 FAILED THIS IGN, go to next step. If scan tool does not indicate DTC P0101 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition on. Observe MAP and BARO values on scan tool. If scan tool reads 65-105 kPa, go to next step. If scan tool does not read 65-105 kPa, go to step 8 .
Start engine. Observe MAP sensor display on scan tool with engine idling. If scan tool reads 29-48 kPa, go to next step. If scan tool does not read 29-48 kPa, go to step 7 .
Using scan tool, observe MAP sensor value while slowly increasing engine speed to 3000 RPM. If MAP sensor value increases as engine RPM increases, go to step 9 . If MAP sensor value does not increase with engine RPM, go to step 8 .
Check for throttle body inlet screen blockage. Check for vacuum leaks at intake manifold, throttle body, or EGR valve flange and pipes. Check for PCV valve faulty, missing or incorrectly installed. Check for skewed or unresponsive MAP sensor. Repair as necessary. After repairs, go to step 22 . If no problems are found, go to step 9 .
Replace MAP sensor. After repairs, go to step 22 .
Turn ignition on. Ensure throttle is closed. Using scan tool, read THROTTLE AT IDLE. If scan tool displays YES, go to next step. If scan tool does not display YES, diagnose using DTC P0121.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. Using DVOM, measure voltage between chassis ground and signal circuit at MAF sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 12 .
Connect a test light between ignition feed circuit and ground circuit at MAF sensor harness connector. If test light illuminates, go to step 15 . If test light does not illuminate, go to step 14 .
If voltage is less than 4.5 volts, go to step 16 . If voltage is not as specified, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Using DVOM, measure voltage between chassis ground and signal circuit at MAF sensor harness connector. If voltage is about zero volts, go to step 21 . If voltage is not as specified, go to step 19 .
Connect test light between chassis ground and ignition feed circuit at MAF sensor harness connector. If test light illuminates, go to step 17 . If test light does not illuminate, go to step 18 .
Check for faulty connection at MAF sensor. Repair as necessary. After repairs, go to step 22 . If connection is okay, go to step 20 .
Check for open or short in MAF sensor signal circuit between PCM and MAF sensor. Repair as necessary. After repairs, go to step 22 . If signal circuit is okay, go to step 21 .
Locate and repair open in MAF sensor ground circuit. After repairs, go to step 22 .
Locate and repair open in MAF sensor ignition feed circuit. After repairs, go to step 22 .
Locate and repair short to voltage in MAF sensor signal circuit. After repairs, go to step 22 .
Replace MAF sensor. After repairs, go to step 22 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Clear DTCs. Start engine and operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P0101. If scan tool displays DTC P0101 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0101 FAILED THIS IGN, system is okay.

Check for skewed or stuck Throttle Position (TP) sensor. Using scan tool, read TP ANGLE value with throttle closed. If value is not zero percent, check for and repair the following condition(s)

Throttle plate sticking or excessive deposits on throttle plate or throttle bore.
TP sensor signal circuit shorted to voltage.
Faulty connection or high resistance in TP sensor ground circuit.

If none of the listed conditions exist and TP ANGLE value is not zero percent, replace TP sensor.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

Check for plugged intake air duct or dirty air filter. A wide-open throttle acceleration from a stop should cause MAF reading on scan tool to increase from about 4-7 grams per second at idle to 100 grams per second or greater at time of 1-2 shift. If MAF reading on scan tool does not increase, check for restriction.

Check for a skewed MAP sensor, which can cause Barometric (BARO) pressure reading to be incorrectly calculated. This condition may also cause high Idle Air Control (IAC) counts. If IAC counts are high, replace MAP sensor.

DTC P0101: MAF SYSTEM PERFORMANCE (4.0L "G" BODY & 4.6L DEVILLE & ELDORADO)

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

This test determines if MAF sensor is providing proper readings to the PCM. MAF sensor is a high frequency device that measures the rate of airflow through the throttle body. MAF sensor outputs a series of pulses that varies in frequency with airflow. PCM uses this signal for fuel control.

MAF sensor readings during acceleration will be much higher than those during deceleration or idle. PCM calculates what MAF sensor reading should be from the sensor under certain conditions using engine speed (RPM), throttle position, and altitude parameters. When certain test conditions are met, PCM will compare its calculated MAF value to the actual value received from the sensor. The calculated MAF reading is calculated by comparing MAP, RPM and IAT values. If difference between calculated MAF and actual MAF is too great, DTC P0101 will set.

For duplication of DTC, ensure

Other DTCs are not set.
System voltage is 11-16 volts.
System is in "closed loop" fuel control.
Canister purge duty cycle is less than or equal to 99.6 percent.
EGR rescaled pintle position is less than or equal to 240 counts.
Traction control is not active.
TP sensor angle is 50 percent or less.
100 msec delta MAP is 5 kPa or less.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Using scan tool, check for stored DTCs. If DTC P0106, P0107, P0108, P0112, P0113, P0300, P0401, P0441, P1108, P1404, P1406, P1441, P1508, P1509 or P1645 is also present, diagnose affected DTCs first. If DTCs are not present, or after diagnosing affected DTCs, go to next step.
Check vacuum leaks at MAF sensor seal, throttle body spacer, intake manifold, PCV, EGR valve, plate or tubes and brake booster and hoses. Repair as necessary and retest. If no vacuum leaks are found, go to next step.
Check for stuck or incorrect PCV valve. Check for air (unmetered) leaks at oil dipstick tube or oil filler cap. Repair as necessary and retest. If no problem is found, go to next step.
Using FREEZE FRAME and FAILURE RECORDS data function on scan tool, duplicate conditions under which DTC P0101 was set. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Diagnose using DTC P0106, and then return to this step. If repairs were necessary, verify repairs and retest. If no problem is found, go to next step.
Replace MAF sensor and retest.

For intermittent setting of DTC P0101, use FREEZE FRAME data under which the DTC set, looking for faulty data from other sensors which may set this DTC. An improperly installed air cleaner or distorted intake air duct may cause DTC to set. Check for improper air cleaner or intake air duct installation.

DTC P0101: MAF SYSTEM PERFORMANCE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

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

MAF sensor is a high frequency device that measures the rate of airflow through the throttle body. MAF sensor outputs a series of pulses that varies in frequency with airflow. VCM uses this signal for fuel control.

MAF sensor readings during acceleration will be much higher than those during deceleration or idle. VCM calculates what MAF sensor reading should be from the sensor under certain conditions using engine speed (RPM) and barometric pressure parameters. When certain test conditions are met, PCM will compare its calculated MAF value to the actual value received from the sensor. If difference between calculated MAF and actual MAF is too great, DTC P0101 will set.

For duplication of DTC, ensure

Other DTCs are not set.
System voltage is 11-16 volts.
Canister purge duty cycle is less than or equal to 99.6 percent.
EGR pintle position and duty cycle is less than 90 percent.
TP sensor voltage is steady.
Throttle position is less than 90 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, monitor MAP sensor value. If MAP sensor value is greater than 105 kPa, go to step 20 . If MAP sensor value is not greater than 105 kPa, go to next step.
Turn ignition off. Remove MAP sensor from intake manifold. Leave sensor harness connected. Start engine and slightly raise idle speed to prevent stalling during test. Using a hand-held vacuum pump, slowly apply vacuum up to 20 in. Hg. Each inch of applied vacuum should result in a 3-4 kPa decrease in MAP sensor value on scan tool. If MAP sensor value reading changes smoothly through entire range of test, go to next step. If MAP sensor value reading is erratic, go to step 20 .
With engine running, apply 20 in. Hg of vacuum to MAP sensor. If scan tool reading is 34 kPa or less, go to next step. If scan tool reading is not 34 kPa or less, go to step 20 .
With engine running, disconnect vacuum source from MAP sensor. If MAP sensor value matches BARO value on scan tool, go to next step. If values do not match, go to step 20 .
Check for the following conditions: Objects blocking MAF sensor inlet screen. Vacuum leaks in intake manifold, throttle body, EGR flange and pipes, MAP sensor seal, EVAP purge valve seal or fuel meter body seal. Malfunctioning, missing or incorrectly installed PCV valve. Repair as necessary. After repairs, go to step 23 . If no problems are found, go to next step.
Turn ignition on, with engine off. Using scan tool, observe TP sensor angle. If TP sensor angle is zero percent, go to next step. If TP sensor angle is not zero percent, diagnose using DTC P0121.
Turn ignition on, with engine off. Using scan tool, review and record FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions. Monitor SPECIFIC DTC INFO for DTC P0101. If scan tool indicates that DTC P0101 FAILED THIS IGN, go to next step. If scan tool does not indicate that DTC P0101 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, with engine off. Using DVOM, measure voltage between signal circuit and ground circuit at MAF sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 11 .
Connect a test light between ignition positive feed circuit and ground circuit at MAF sensor harness connector. If test light illuminates, go to step 14 . If test light does not illuminate, go to step 13 .
If voltage is less than 4.5 volts, go to step 15 . If voltage is not as specified, go to next step.
Turn ignition off. Disconnect VCM harness connector. Turn ignition on, with engine off. Using DVOM, measure voltage between ground and MAF sensor signal circuit at VCM harness connector. If voltage is about zero volts, go to step 22 . If voltage is not as specified, go to step 18 .
Using a test light connected to chassis ground, probe ignition positive feed circuit at MAF sensor harness connector. If test light illuminates, go to step 16 . If test light does not illuminate, go to step 17 .
Check for poor connection at MAF sensor. Repair as necessary. After repairs, go to step 23 . If connection is okay, go to step 19 .
Check MAF signal circuit for an open, short to ground or short to MAF sensor ground circuit. Repair as necessary. After repairs, go to step 23 . If circuit is okay, go to step 21 .
Repair open in MAF sensor ground circuit. After repairs, go to step 23 .
Repair open in MAF sensor ignition positive feed circuit. After repairs, go to step 23 .
Repair short to voltage in MAF sensor signal circuit. After repairs, go to step 23 .
Replace MAF sensor. After repairs, go to step 23 .
Replace MAP sensor. After repairs, go to step 23 .
Check for poor connections at VCM. Repair as necessary. After repairs, go to step 23 . If connections are okay, go to next step.
Replace VCM. Perform VCM, CKP and Passlock® reprogramming procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Start engine and allow it to reach normal operating temperature. Select SPECIFIC DTC, and then enter DTC P0101. Operate vehicle within the conditions for setting this DTC. See «CIRCUIT DESCRIPTION»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

A faulty TP sensor or TP sensor circuit can cause VCM to incorrectly calculate predicted mass airflow value. Observe throttle angle with throttle closed. If throttle angle is not zero, check for throttle plate sticking or excessive deposits on throttle plate or throttle bore, TP signal circuit shorted to voltage, or for poor connection or high resistance in TP sensor ground circuit. If a problem is not found and TP sensor angle at closed throttle is not zero, replace TP sensor.

Inspect VCM connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connection. Inspect MAF sensor harness routing to ensure it is not too close to high-voltage wires such as spark plug leads. Inspect wiring harness for damage. If harness is okay, observe scan tool while wiggling MAF sensor related connectors and wiring harness. A change in display will indicate location of fault.

A Wide Open Throttle (WOT) acceleration from a stop should cause mass airflow displayed on scan tool to increase from about 4-7 gm/s at idle to 100 gm/s or greater at 1-2 shift. If mass airflow does not indicate as specified, check for a plugged intake air duct or dirty air filter element. A skewed MAP sensor can cause BARO reading to be incorrectly calculated. To check MAP sensor, compare BARO reading on vehicle being diagnosed to a BARO reading on a normally operating vehicle. If a large difference is noted (over 8 kPa), replace MAP sensor. This may cause abnormally high IAC counts. If a comparison vehicle is not available, check IAC counts with engine running just off idle. If IAC counts are high, replace MAP sensor.

IF DTC P0101 can not be duplicated, FAILURE RECORDS data can be useful in determining vehicle mileage since DTC was last set. This may determine how often DTC sets.

DTC P0101: MAF SYSTEM PERFORMANCE (4.6L SEVILLE)

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

For duplication of DTC, ensure

Other DTCs are not set.
System voltage is 11-16 volts.
System is in "closed loop" fuel control.
Canister purge duty cycle is less than or equal to 99.6 percent.
EGR rescaled pintle position is less than or equal to 240 counts.
Traction control is not active.
TP sensor angle is 50 percent or less.
100 msec delta MAP is 5 kPa or less.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine. Using scan tool, monitor MAF sensor frequency. If value is greater than 1135 Hz, fault is not present. Check for intermittent condition by wiggling wire harnesses. If value is not as specified, go to next step.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. Using DVOM, measure voltage between ground and signal circuit at MAF sensor harness connector. If voltage is 4.7-5.3 volts, go to next step. If voltage is not as specified, go to step 6 .
Using DVOM, measure voltage between ground and ignition positive feed circuit at MAF sensor harness connector. If voltage is 10.5-15 volts, go to next step. If voltage is not as specified, go to step 7 .
Using DVOM, measure voltage between ground circuit and ignition positive feed circuit at MAF sensor harness connector. If voltage measured is within 0.5 volt of voltage measured in step 4) , go to step 9 . If voltage is not as specified, go to step 8 .
Turn ignition off. Using scan tool, record FLUID LIFE INDEXES, and then wait 30 seconds. Disconnect PCM harness connector C2 (Clear). Check MAF sensor signal circuit for an open or short to ground. Repair as necessary and retest. If no problem is found, go to step 11 .
Repair open or high resistance in MAF sensor ignition positive feed circuit and retest.
Repair open or high resistance in MAF sensor ground circuit and retest.
Check MAF sensor harness connector for poor terminal contact. Repair as necessary and retest. If no problem is found, go to next step.
Replace MAF sensor and retest.
Check PCM harness connector C2 (Clear) for poor terminal contact. Repair as necessary and retest. If no problem is found, go to next step.
Replace PCM. Perform PCM reprogramming procedures.

DTC P0101: MAF SYSTEM PERFORMANCE (5.7L "F" & "Y" BODIES)

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

Mass Airflow (MAF) sensor is hot-wire type and is used to measure airflow rate into engine. MAF sensor has a battery feed, ground and signal circuit. As airflow increases, a greater amount of current is required to maintain hot wires at a constant temperature. MAF sensor converts changes in current draw to a frequency signal read by PCM. PCM calculates airflow (grams per second) based on this signal.

This test checks for a stuck MAF sensor signal. If MAF sensor frequency varies less than a predetermined minimum amount, DTC P0101 will set.

For duplication of DTC, ensure

Other DTCs are not set.
Engine is running.
System voltage is 11-18 volts.
TP sensor angle is less than 50 percent when BARO-MAP is greater than 65 kPa.
Change in TP sensor is less than 3 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine. Using scan tool, monitor MAP sensor voltage. If voltage is 0.8-4 volts, go to next step. If voltage is not as specified, diagnose using DTC P0107 or P0108.
Turn ignition off. Remove MAP sensor from intake manifold, leaving wiring harness connected. Install a hand-held vacuum pump to MAP sensor. Turn ignition on, with engine off. Observe MAP sensor reading on scan tool while applying vacuum. Each one in. Hg applied should result in 3-4 kPa decrease. Value should change smoothly with each increase in vacuum. If MAP value changed smoothly without any erratic reading, go to next step. If reading is erratic, go to step 19 .
Apply up to 20 in. Hg of vacuum to MAP sensor. If MAP sensor reading on scan tool is 34 kPa or less, go to next step. If MAP sensor reading is not as specified, go to step 19 .
Remove vacuum source from MAP sensor. If MAP sensor reading returns to original value observed in step 3) , go to next step. If reading does not return to original value, go to step 19 .
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for 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 and enter DTC P0101. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check for blockage in MAF sensor inlet screen, intake manifold leak, vacuum leak at throttle body, leak at EGR valve flange and pipes, or faulty PCV valve. Repair or replace as necessary. After repairs, go to step 21 . If no problem is found, go to next step.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, with engine off. Using DVOM, measure voltage between ground and signal circuit at MAF sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 10 .
Connect a test light between ignition positive feed circuit and ground circuit at MAF sensor harness connector. If test light illuminates, go to step 13 . If test light does not illuminate, go to step 12 .
If voltage is less than 4.5 volts, go to step 14 . If voltage is not as specified, go to next step.
Turn ignition off. Disconnect PCM harness connector C2 (Red). Turn ignition on, with engine off. Using DVOM, measure voltage between ground and MAF sensor signal circuit. If voltage is about zero volts, go to step 20 . If voltage is not as specified, go to step 17 .
Using a test light connected to battery ground, probe ignition positive feed circuit at MAF sensor harness connector. If test light illuminates, go to step 15 . If test light does not illuminate, go to step 16 .
Check for poor connection at MAF sensor connector. Repair as necessary. After repairs, go to step 21 . If connection is okay, go to step 18 .
Check MAF signal circuit between PCM and MAF sensor for an open, short to ground or short to MAF sensor ground circuit. Repair as necessary. After repairs, go to step 21 . If circuit is okay, go to step 20 .
Locate and repair open in MAF sensor ground circuit. After repairs, go to step 21 .
Locate and repair open in MAF sensor ignition positive feed circuit. After repairs, go to step 21 .
Locate and repair short to voltage in MAF sensor signal circuit. After repairs, go to step 21 .
Replace MAF sensor. After repairs, go to step 21 .
Replace MAP sensor. After repairs, go to step 21 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start engine and allow it to reach normal operating temperature. Select SPECIFIC DTC, and then enter DTC P0101. Operate vehicle within conditions for setting DTC P0101. 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.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. Also, check for vacuum or PCV system leaks, incorrect PCV valve, engine oil dipstick not fully seated or engine oil filler cap loose or missing.

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

For duplication of DTC, ensure

Engine is running.
System voltage is greater than 8 volts.
Throttle angle is less than 75 percent.
MAF signal frequency is less than 1200 Hertz (Hz).

These conditions must be present for a predetermined 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.
Start engine and allow it to idle. Using scan tool, select ENG 1 data list. Monitor MAF FREQUENCY. If frequency is less than 1200 Hz, go to step 4 . If frequency is not less than 1200 Hz, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Select SPECIFIC DTC function, and then enter DTC P0102. If scan tool indicates FAILED THIS IGN, go to next step. If scan tool does not indicate FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check for air leaks at MAF sensor, throttle body spacer, intake manifold, PCV system, EGR system, oil dipstick tube and oil filler cap. Check for restriction in MAF sensor inlet screen. Check operation of PCV system. Repair as necessary. After repairs, go to step 14 . If no problems are found, go to next step.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, with engine off. Using DVOM, measure voltage between battery ground and signal circuit terminal at MAF sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 9 .
Connect a test light between ignition feed circuit and ground circuit terminals at MAF sensor harness connector. If test light illuminates, go to step 8 . If test light does not illuminate, go to next step.
Connect a test light between ground and ignition feed circuit terminal at MAF sensor harness connector. If test light illuminates, go to step 10 . If test light does not illuminate, go to step 11 .
Check for poor connection at MAF sensor connector. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 12 .
Check MAF sensor signal circuit between PCM and MAF sensor for an open, short to voltage, short to ground, or short to MAF ground circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 13 .
Locate and repair open in MAF sensor ground circuit. After repairs, go to step 14 .
Locate and repair open in MAF sensor ignition feed circuit. After repairs, go to step 14 .
Replace MAF sensor. After repairs, go to step 14 .
Replace PCM. Perform PCM reprogramming procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0102. If scan tool indicates FAILED THIS IGN, go to step 2 . If scan tool does not indicate FAILED THIS IGN, system is okay.

Check for poor connection at PCM. Check for misrouted MAF sensor wiring harness. Ensure harness is not close to high voltage components. Check for damaged wiring harness. Check for plugged intake air duct or filter element.

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (3.5L "W" BODY)

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

For duplication of DTC, ensure engine is running, system voltage is greater than 8 volts, TP sensor angle is less than 50 percent, and IAC counts are greater than 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.
Start engine and allow it to idle. Using scan tool, monitor MAF frequency. If MAF frequency is less than 1200 Hz, go to step 4 . If MAF frequency is not as specified, go to next step.
Turn ignition off. Wait for 15 seconds. Turn ignition on. Using scan tool, review and record FAILURE RECORDS data. Clear DTCs. Operate vehicle within FAILURE RECORDS conditions. Monitor SPECIFIC DTC INFO and select DTC P0102. If scan tool indicates FAILED THIS IGN, go to next step. If scan tool does not indicate FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check for air leaks at MAF sensor, throttle body spacer, intake manifold, PCV system and EGR system. Check for restriction in MAF sensor inlet and duct work. Check operation of PCV system. Repair as necessary. After repairs, go to step 14 . If no problems are found, go to next step.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, with engine off. Using DVOM, measure voltage between battery ground and signal circuit terminal at MAF sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 9 .
Connect a test light between ignition feed circuit and ground circuit terminals at MAF sensor harness connector. If test light illuminates, go to step 8 . If test light does not illuminate, go to next step.
Connect a test light between ground and ignition feed circuit terminal at MAF sensor harness connector. If test light illuminates, go to step 10 . If test light does not illuminate, go to step 11 .
Check for poor connection at MAF sensor connector. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 12 .
Check MAF sensor signal circuit between PCM and MAF sensor for an open, short to voltage, short to ground, or short to MAF ground circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 13 .
Locate and repair open in MAF sensor ground circuit. After repairs, go to step 14 .
Locate and repair open in MAF sensor ignition feed circuit. After repairs, go to step 14 .
Replace MAF sensor. After repairs, go to step 14 .
Replace PCM. Perform PCM reprogramming procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0102. If scan tool indicates FAILED THIS IGN, go to step 2 . If scan tool does not indicate FAILED THIS IGN, go to next step.
Review CAPTURED INFO on scan tool. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

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

Check for skewed or stuck TP sensor. A faulty TP sensor or TP sensor circuit can cause PCM to incorrectly calculate predicted mass airflow value.

DTC P0102: MAF SENSOR CIRCUIT-LOW-FREQUENCY (3.8L "C", "F", "G", "H" & "W" BODIES)

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

PCM calculates what MAF sensor reading should be received from sensor under certain conditions using engine speed (RPM), throttle position, and altitude parameters. When certain test conditions are met, PCM will compare its calculated MAF value to actual value received from sensor. If MAF sensor signal frequency is less than 1200 Hertz (Hz), DTC P0102 will set.

For duplication of DTC, ensure engine is running, system voltage is greater than 8 volts, and TP sensor angle is less than 50 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, monitor MAF FREQUENCY. If frequency is less than 1200 Hz, go to step 4 . If frequency is not less than 1200 Hz, go to next step.
Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0102 FAILED THIS IGN, go to next step. If DTC P0102 FAILED THIS IGN is not displayed, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check for MAF sensor inlet screen blockage. Check for vacuum leaks at intake manifold, throttle body or EGR valve flange and pipes. Check for PCV valve faulty, missing or incorrectly installed. Repair as necessary. After repairs, go to step 14 . If no problems are found, go to next step.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, with engine off. Using DVOM, measure voltage between MAF sensor harness connector signal circuit and chassis ground. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 9 .
Connect a test light between MAF sensor harness connector ignition feed and ground circuits. If test light illuminates, go to step 8 . If test light does not illuminate, go to next step.
Connect test light between MAF sensor harness connector ignition feed circuit and battery ground. If test light illuminates, go to step 10 . If test light does not illuminate, go to step 11 .
Check for faulty connection at MAF sensor. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 12 .
Check MAF sensor signal circuit between PCM and MAF sensor for open or short. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 13 .
Locate and repair open in the MAF sensor ground circuit. After repairs, go to step 14 .
Locate and repair open MAF sensor ignition feed circuit. After repairs, go to step 14 .
Replace MAF sensor. After repairs, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data, and then clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P0102. If scan tool displays DTC P0102 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0102 FAILED THIS IGN, system is okay.

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

This test determines if MAF sensor circuit failed, by monitoring the MAF signal. MAF sensor is a high-frequency device that measures the rate of airflow through the throttle body. MAF sensor outputs a series of pulses that varies in frequency with airflow. PCM uses this signal for fuel control.

MAF sensor readings during acceleration will be much higher than those during deceleration or idle. PCM reads the MAF sensor input each 4X ignition reference pulse. If MAF sensor output drops to less than 1135 Hz, DTC P0102 will set.

For duplication of DTC, ensure engine is running and system voltage is 10.5 volts or greater.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine. Using scan tool, check MAF sensor reading. If reading is not greater than 1.3 gm/s, go to next step. If reading is greater than 1.3 gm/s, fault is not present at this time.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. Using DVOM, measure voltage (backprobe) between ground and MAF sensor input circuit at PCM harness connector. If voltage is 4-6 volts, go to next step. If voltage is not as specified, go to step 6 .
Measure voltage between ground and MAF sensor power circuit at MAF sensor harness connector. If voltage is 10 volts or greater, go to next step. If voltage is not as specified, go to step 7 .
Measure voltage between MAF sensor harness connector ground circuit and power circuit. If voltage is within 0.5 volt of voltage measured previously in step 4) , go to step 9 . If voltage is not as specified, go to step 8 .
Record FLUID LIFE INDEX as indicated on scan tool. Turn ignition off. Wait 30 seconds, and then disconnect PCM harness connector C2. Using DVOM, check MAF sensor input circuit for an open or short to ground. Repair as necessary and verify repair. If circuit is okay, go to step 11 .
Repair open or short to ground in MAF sensor power feed circuit and retest.
Repair open or high resistance in MAF sensor ground circuit and retest.
Check terminal contact at MAF sensor. Repair as necessary. If terminal contact is okay, go to next step.
Replace MAF sensor and retest.
Check terminal contact of MAF sensor input circuit at PCM harness connector. Repair as necessary. If terminal contact is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

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

MAF sensor readings during acceleration will be much higher than those during deceleration or idle. VCM calculates what MAF sensor reading should be from the sensor under certain conditions using engine speed (RPM) and barometric pressure parameters. When certain test conditions are met, PCM will compare its calculated MAF value to the actual value received from the sensor. If detected MAF sensor frequency is 10 Hertz (Hz) or less, DTC P0102 will set.

For duplication of DTC, ensure engine is running, engine speed is greater than 300 RPM, and system voltage is greater than 8 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.
Install scan tool. Start engine. With engine at idle, monitor MAF sensor display on scan tool. If MAF display is less than 2 gm/s, go to step 4 . If MAF display is not less than 2 gm/s, go to next step.
Turn ignition on, engine off. Using scan tool, review and record FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, monitor SPECIFIC DTC for DTC P0102. 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-p0100-p0134) .
Check MAF fuse. If fuse is open, go to step 11 . If fuse is okay, go to next step.
Check for the following conditions: Objects blocking MAF sensor inlet screen. Intake manifold vacuum leaks. Vacuum leaks at throttle body. Vacuum leaks at EGR valve flange and pipes. Crankcase ventilation valve faulty, missing or incorrectly installed. Repair as necessary. After repairs, go to step 17 . If no problem is found, go to next step.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, engine off. Using DVOM, measure voltage between ground and signal circuit at MAF sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 10 .
Connect test light between MAF ignition feed and ground circuits at MAF sensor harness connector. If test light illuminates, go to step 9 . If test light does not illuminate, go to next step.
Connect a test light between ignition feed circuit at MAF sensor harness connector and battery ground. If test light illuminates, go to step 12 . If test light does not illuminate, go to step 13 .
Check for poor connection at MAF sensor. Repair as necessary. After repairs, go to step 17 . If connection is okay, go to step 14 .
Check for open, short to ground, short to MAF ground circuit or short to voltage in MAF signal circuit between MAF sensor and VCM. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 15 .
Locate and repair short to ground in MAF sensor ignition voltage circuit. After repairs, go to step 17 .
Locate and repair open in MAF sensor ground circuit to MAF sensor. After repairs, go to step 17 .
Locate and repair open in ignition feed circuit to MAF sensor. After repairs, go to step 17 .
Replace MAF sensor. After repairs, go to step 17 .
Check for poor connections at VCM. Repair as necessary. After repairs, go to step 17 . If connections are okay, go to next step.
Replace VCM. Perform VCM, CKP and Passlock® reprogramming procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0102. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Inspect VCM connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal to wire connection. Inspect MAF sensor harness routing to ensure it is not too close to high-voltage wires such as spark plug leads. Inspect wiring harness for damage. If harness is okay, observe scan tool while wiggling MAF sensor related connectors and wiring harness. A change in display will indicate location of fault.

A Wide Open Throttle (WOT) acceleration from a stop should cause mass airflow displayed on scan tool to increase from about 4-7 gm/s at idle to 100 gm/s or greater at the time of the 1-2 shift. If mass airflow does not respond as specified, check for restrictions.

IF DTC P0102 cannot be duplicated, FAILURE RECORDS data can be useful in determining vehicle mileage since DTC was last set. This may determine how often DTC sets.

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

For duplication of DTC, ensure engine is running, engine speed is greater than 300 RPM, and system voltage is at least 8 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.
Connect scan tool. Start engine and let idle. Using scan tool, monitor MAF sensor frequency. If MAF sensor frequency is less than 10 Hz, go to step 4 . If MAF frequency is not as specified, go to next step.
Turn ignition on, engine off. Using scan tool, review and record FAILURE RECORDS data. Turn ignition off for 15 seconds. Start engine. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, monitor SPECIFIC DTC for DTC P0102. 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-p0100-p0134) .
Inspect ENG 1 fuse (10-amp), located in underhood electrical center. If fuse is open, go to step 19 . If fuse is okay, go to next step.
Turn ignition off. Disconnect MAF sensor connector. Turn ignition on, with engine off. Using DVOM, measure voltage between, battery ground and signal circuit at MAF sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 7 .
Turn ignition off. Using a fused jumper wire, jumper MAF sensor signal circuit to ground. Start engine. If additional DTCs set, go to step 20 . If no additional DTCs set, go to step 11 .
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Using DVOM, check for voltage between ground and MAF sensor signal circuit at PCM harness connector. If voltage is present, go to step 14 . If voltage is not present, go to next step.
Turn ignition off. Check MAF sensor signal circuit for continuity between MAF sensor and PCM harness connectors. If continuity is present, go to next step. If continuity is not present, go to step 15 .
Check MAF sensor signal circuit for continuity to ground. If continuity is present, go to step 16 . If continuity is not present, go to next step.
Check MAF sensor signal circuit for continuity to any other circuit at both PCM harness connectors. If continuity is present, go to step 17 . If continuity is not present, go to step 22 .
Connect a test light between ignition feed circuit and ground circuit at MAF sensor harness connector. If test light illuminates, go to step 13 . If test light does not illuminate, go to next step.
Using a test light connected to battery ground, probe ignition feed circuit at MAF sensor harness connector. If test light illuminates, go to step 18 . If test light does not illuminate, go to step 19 .
Check for poor connections at MAF sensor. Repair as necessary. After repairs, go to step 24 . If connections are okay, go to step 21 .
Locate and repair short to voltage in MAF sensor signal circuit. After repairs, go to step 24 .
Locate and repair open in MAF sensor signal circuit. After repairs, go to step 24 .
Locate and repair short to ground in MAF sensor signal circuit. After repairs, go to step 24 .
Repair circuits that are shorted together. After repairs, go to step 24 .
Repair open in MAF sensor ground circuit. After repairs, go to step 24 .
Repair open or grounded MAF sensor ignition feed circuit. After repairs, go to step 24 .
Repair circuits that are shorted together between MAF sensor signal circuit and circuit for which DTC set. After repairs, go to step 24 .
Replace MAF sensor. After repairs, go to step 24 .
Check for poor PCM harness connections. Repair as necessary. After repairs, go to step 24 . If connections are okay, go to next step.
Replace PCM. Perform PCM relearn procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0102. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Check for engine vacuum leaks at PCV system and engine oil dipstick. Check for incorrect PCV valve application.

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (5.7L "F" & "Y" BODIES)

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

This test checks for a stuck MAF sensor signal. If MAF sensor frequency varies less than a predetermined minimum amount, DTC P0102 will set.

For duplication of DTC, ensure engine is running, engine speed is greater than 300 RPM, and system voltage is at least 8 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.
Start and operate engine at idle. Using scan tool, select ENGINE 2 DATA LIST and monitor MAF sensor grams per second (gm/s) display. If MAF sensor value is less than 10 Hz, go to step 4 . If MAF sensor value is not less than 10 Hz, 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, and then enter DTC P0102. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect MAF sensor harness connector. Turn ignition on, with engine off. Using DVOM, measure voltage between MAF signal circuit and battery ground. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 8 .
Connect a test light between MAF sensor ignition feed circuit and ground circuit at harness connector. If test light illuminates, go to step 7 . If test light does not illuminate, go to next step.
Connect a test light between MAF sensor ignition feed circuit and ground. If test light illuminates, go to step 9 . If test light does not illuminate, go to step 10 .
Check for poor connection at MAF sensor harness terminals. Repair or replace terminal(s). After repairs, go to step 13 . If terminals are okay, go to step 11 .
Check MAF signal circuit between PCM and MAF sensor for an open, short to ground, or short to MAF sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Locate and repair open in ground circuit to MAF sensor. After repairs, go to step 13 .
Locate and repair open in ignition feed circuit to MAF sensor. After repairs, go to step 13 .
Replace MAF sensor. After repairs, go to step 13 .
Replace PCM. Reprogram replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0102. Operate vehicle in 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 P0103: MAF SENSOR CIRCUIT-HIGH FREQUENCY (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

PCM calculates what MAF sensor reading should be received from sensor under certain conditions using engine speed (RPM), throttle position, and altitude parameters. When these test conditions are met, PCM will compare its calculated MAF value to actual value received from sensor. If detected MAF sensor frequency is greater than 11,500 Hertz (Hz), DTC P0103 will set.

For duplication of DTC, ensure engine is running, system voltage is greater than 8 volts, and throttle angle is less than 50 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine and allow it to idle. Using scan tool, monitor MAF frequency. If frequency is less than 11,500 Hz, go to step 4 . If frequency is not less than 11,500 Hz, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Select SPECIFIC DTC function then enter DTC P0103. If scan tool indicates FAILED THIS IGN, go to next step. If scan tool does not indicate FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect MAF sensor harness connector. Start engine. Using scan tool, monitor MAF frequency. If frequency is zero Hz, go to next step. If frequency is not zero Hz, go to step 7 .
Check for poor connection at MAF sensor connector. Repair as necessary. After repairs, go to step 10 . If connector is okay, go to next step.
Replace MAF sensor. After repairs, go to step 10 .
Check for incorrect routing of MAF sensor wiring harness. Ensure harness is not near ignition coils or other high-voltage components. Reroute wiring harness as necessary. After repairs, go to step 10 . If wiring harness is routed correctly, go to next step.
Check MAF signal circuit terminal connections at PCM. Repair as necessary. After repairs, go to step 10 . If terminal connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0103. If scan tool indicates FAILED THIS IGN, go to step 2 . If scan tool does not indicate FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P0103: MAF SENSOR CIRCUIT-HIGH FREQUENCY (3.5L "W" BODY)

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

For duplication of DTC, ensure engine is running, system voltage is greater than 8 volts, TP sensor angle is less than 50 percent, and IAC counts are greater than 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.
Start engine and let idle. Using scan tool, monitor MAF frequency. If MAF frequency is greater than 11,500 Hz, go to step 4 . If MAF frequency is not as specified, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Select SPECIFIC DTC function then enter DTC P0103. If scan tool indicates FAILED THIS IGN, go to next step. If scan tool does not indicate FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect MAF sensor harness connector. Start engine. Using scan tool, monitor MAF frequency. If frequency is zero Hz, go to next step. If frequency is not zero Hz, go to step 7 .
Check for poor connection at MAF sensor connector. Repair as necessary. After repairs, go to step 10 . If connector is okay, go to next step.
Replace MAF sensor. After repairs, go to step 10 .
Check for incorrect routing of MAF sensor wiring harness. Ensure harness is not near ignition coils or other high-voltage components. Reroute wiring harness as necessary. After repairs, go to step 10 . If wiring harness is routed correctly, go to next step.
Check MAF signal circuit terminal connections at PCM. Repair as necessary. After repairs, go to step 10 . If terminal connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0103. If scan tool indicates FAILED THIS IGN, go to step 2 . If scan tool does not indicate FAILED THIS IGN, go to next step.
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.

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

Check for skewed or stuck TP sensor. A faulty TP sensor or TP sensor circuit can cause PCM to incorrectly calculate predicted mass airflow value.

DTC P0103: MAF SENSOR CIRCUIT-HIGH FREQUENCY (3.8L "C", "F", "G", "H" & "W" BODIES)

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

PCM calculates what MAF sensor reading should be received from sensor under certain conditions using engine speed (RPM), throttle position, and altitude parameters. When these test conditions are met, PCM will compare its calculated MAF value to actual value received from sensor. If MAF signal frequency is greater than 11,500 Hertz (Hz), DTC P0103 will set.

For duplication of DTC, ensure engine is running, system voltage is greater than 8 volts, and TP sensor angle is less than 50 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine. With engine at idle, use scan tool to read MAF FREQUENCY. If frequency is greater than 10,500 Hz on VIN K, or greater than 11,500 Hz on VIN 1, go to step 4 . If frequency is less than specified, go to next step.
Turn engine off. Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0103 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0103 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect MAF sensor harness connector. Start engine and allow it to idle. Using scan tool, read MAF sensor frequency. If frequency is zero Hz, go to next step. If frequency is not as specified, go to step 7 .
Check for faulty connection at MAF sensor. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Replace MAF sensor. After repairs, go to step 10 .
Ensure MAF sensor harness is not routed too close to high-voltage wires, such as spark plug cables, ignition coils or other high voltage components. Reroute harness if necessary. After repairs, go to step 10 . If harness routing is okay, go to next step.
Check MAF sensor signal circuit connection at PCM. Repair connection as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0103. If scan tool displays DTC P0103 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0103 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P0103: MAF SENSOR CIRCUIT-HIGH FREQUENCY (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

MAF sensor readings during acceleration will be much higher than those during deceleration or idle. If detected MAF sensor frequency is greater than 11,000 Hertz (Hz), DTC P0103 will set.

For duplication of DTC, ensure other DTCs are not set, Engine speed is between zero and 6375 RPM, system voltage is at least 10.5 volts, and throttle angle is 50 degrees or less.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Using scan tool, select FREEZE FRAME function under SPECIFIC DTC. Duplicate conditions under which DTC was set. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check terminal contact at MAF sensor connector. Repair as necessary. If terminal contact is okay, go to next step.
Replace MAF sensor.

Check for Electromagnetic Interference (EMI) on MAF sensor wires, caused by wiring being too close to spark plug wires or high-power transmitters (mobile radio) operating in the vicinity. A battery charger may also set this DTC.

DTC P0103: MAF SENSOR CIRCUIT-HIGH-FREQUENCY (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P","S" & "T" SERIES)

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

Mass Airflow (MAF) sensor measures amount of air entering engine at a given time to determine fuel delivery. MAF sensor information is used for fuel delivery calculations. MAF sensor produces a frequency signal which can be monitored with a scan tool. If detected MAF frequency is 1100 Hertz (Hz) or greater for more than one second, DTC P0103 will set.

For duplication of DTC, ensure engine is running, engine speed is greater than 300 RPM, and system voltage is greater than 8 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.
Install scan tool. Start engine. With engine at idle, monitor MAF display on scan tool. If MAF display is greater than 20 gm/s, go to step 4 . If MAF is not greater than 20 gm/s, go to next step.
Turn ignition on, with engine off. Using scan tool, review and record FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, monitor SPECIFIC DTC for this 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-p0100-p0134) .
Turn ignition off. Disconnect MAF sensor connector. Start and operate engine at idle. Using scan tool, monitor MAF display. If scan tool display is zero gm/s, go to next step. If scan tool display is not zero gm/s, go to step 7 .
Check for poor connection at MAF sensor. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Replace MAF sensor. After repairs, go to step 10 .
Check MAF sensor harness for incorrect routing near secondary ignition wires or coils, or other high voltage components such as solenoids, relays or motors. Repair/reroute wiring as necessary. After repairs, go to step 10 . If routing is okay, go to next step.
Check for poor connection at MAF signal circuit terminal of VCM. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Replace VCM. Perform VCM, CKP and Passlock® system reprogramming procedures 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, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Inspect VCM connectors for backed-out terminals, improper mating, broken locks, improperly-formed or damaged terminals and poor terminal-to-wire connection. Inspect MAF sensor harness routing to ensure it is not too close to high-voltage wires such as spark plug leads. Inspect wiring harness for damage. If harness is okay, observe scan tool while wiggling MAF sensor related connectors and wiring harness. A change in display will indicate location of fault.

DTC P0103: MAF SENSOR CIRCUIT-HIGH-FREQUENCY (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

For duplication of DTC, ensure engine is running, engine speed is greater than 300 RPM, and system voltage is greater than 8 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.
Install scan tool. Start engine. With engine at idle, monitor MAF sensor frequency on scan tool. If MAF sensor frequency is greater than 13,500 Hz, go to step 4 . If MAF sensor frequency is not as specified, go to next step.
Turn ignition on, with engine off. Using scan tool, review and record FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions and as close to conditions required to duplicate DTC. See «CIRCUIT DESCRIPTION»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . Using scan tool, monitor SPECIFIC DTC for this 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-p0100-p0134) .
Turn ignition off. Disconnect MAF sensor connector. Start and operate engine at idle. Using scan tool, monitor MAF sensor frequency. If scan tool displays a MAF sensor frequency, go to step 7 . If scan tool does not display a MAF sensor frequency, go to next step.
Check for poor connection at MAF sensor. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Replace MAF sensor. After repairs, go to step 10 .
Check MAF sensor harness for incorrect routing near secondary ignition wires or coils, or other high voltage components such as solenoids, relays or motors. Repair/reroute wiring as necessary. After repairs, go to step 10 . If routing is okay, go to next step.
Check for poor connection at MAF signal circuit terminal of PCM. Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
Replace PCM. Perform PCM reprogramming procedures 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, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

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

DTC P0103: MAF SENSOR CIRCUIT-HIGH FREQUENCY (5.7L "F" & "Y" BODIES)

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

Mass Airflow (MAF) sensor is hot-wire type and is used to measure airflow rate into engine. MAF sensor has a battery feed, ground and signal circuit. As airflow increases, a greater amount of current is required to maintain hot wire at a constant temperature. MAF sensor converts changes in current draw to a frequency signal read by PCM. PCM calculates airflow (grams per second) based on this signal.

PCM monitors MAF sensor frequency and can determine if sensor is stuck low, stuck high, not providing airflow value expected for a given operating condition, or that signal variation expected during normal operation is not present. This test checks for a stuck MAF sensor signal. If MAF sensor frequency is greater than 14,000 Hertz (Hz), DTC P0103 will set.

For duplication of DTC, ensure engine is running, engine speed is at least 300 RPM, and system voltage is at least 8 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.
Start and operate engine at idle. Using scan tool, monitor MAF sensor frequency. If MAF sensor frequency is greater than 14,000 Hz, go to step 4 . If MAF sensor value is not as specified, 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, and then enter DTC P0103. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect MAF sensor harness connector. Start engine. Using scan tool, monitor MAF sensor frequency. If a MAF sensor frequency is displayed, go to step 7 . If a MAF sensor frequency is not displayed, go to next step.
Check for poor connection at MAF sensor harness connector terminal. Repair or replace as necessary. After repairs, go to step 10 . If harness connector terminals are okay, go to next step.
Replace MAF sensor. After repairs, go to step 10 .
Check MAF sensor harness for incorrect routing near secondary ignition wires or components, or solenoids, relays or motors. Correct problem as necessary. After repairs, go to step 10 . If routing is okay, go to next step.
Check MAF sensor signal circuit terminal connections at PCM. Repair as necessary. After repairs, go to step 10 . If connections are okay, go to next step.
Replace PCM. Program replacement PCM using necessary equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0103. 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.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. Also, check for water entering air intake system to MAF sensor. Water rapidly cools hot wire in sensor, causing a false indication of excessive airflow.

DTC P0105: MAP SENSOR CIRCUIT RANGE/PERFORMANCE (1.9L SATURN)

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

PCM has internal tables that compare MAP sensor values with TP sensor values. MAP sensor is a variable resistor that responds to changes in intake manifold pressure. The voltage ranges from 1.0-1.5 volts at idle (high manifold vacuum) to 4.0-4.5 volts at wide open throttle (low manifold vacuum).

TP sensor is a potentiometer which responds to changes in throttle plate angle. At closed throttle position, output of the sensor is low (about.5 volt). As the throttle plate opens, the output signal increases so that at wide open throttle, the output will be high (about 5 volts).

DTC will set if MAP or TP sensor value is out of range for greater than 2 seconds when DTC P0107, P0108, P0122, P0123, P0506 or P0507 is set, engine speed is 1600-4000 RPM, engine speed change is less than 100 RPM, EGR commanded steady, A/C command is unchanged, and IAC change is less than 10 counts.

DTC will set if either MAP or TP sensor is out of range. To distinguish which one failed, review malfunction history information on scan tool and attempt to duplicate conditions.

Check sensor and PCM connection for corrosion. Check for proper terminal connections. With ignition on, engine off, MAP reading should be the same as BARO reading because manifold pressure is equal to atmospheric pressure (no vacuum-high voltage). Comparing this reading to a known-good vehicle with the same sensor is a good way to check accuracy of suspect sensor. Reading should be within 0.4 volt. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0105: MAP/TP SENSOR PERFORMANCE/RANGE (2.2L & 2.4L "J" BODY & 2.4L ALERO & GRAND AM "N" BODY)

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

PCM supplies a 5-volt reference signal and a ground circuit to both the MAP sensor and TP sensor. MAP sensor returns a signal to PCM relative to intake manifold pressure, and TP sensor returns a signal to PCM relative to throttle plate opening.

PCM can determine if sensors are out of range by comparing sensor values to expected limits predetermined by PCM during all modes of operation. DTC P0105 will set if MAP sensor is out of an expected range as determined by engine calibration.

For duplication of DTC, ensure

DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0131, P0132, P0171, P0172, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0341, P0342, P0440, P0442, P0502, P0506, P0507 or P1441 is not set.
Ensure engine speed is greater than 600 RPM.
TCC is stable within one percent.
Engine speed is stable within 50 RPM.
IAC valve is stable within 5 counts.
TP sensor is stable within 2 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other MAP, TP, A/C or fuel tank pressure sensor DTCs are set, go to applicable DTC test. If specified DTCs are not set, go to next step.
Inspect condition of MAP and TP sensors and harnesses. Repair as necessary. After repairs, go to step 28 . If no problems are found, go to next step.
Using scan tool, monitor TP sensor voltage with throttle fully closed. If voltage is less than 0.9 volt, go to next step. If voltage is not as specified, go to step 6 .
Using scan tool, select TP ANGLE parameter. Monitor scan tool display while slowly depressing accelerator pedal to the floor and releasing (repeat several times). If value displayed on scan tool smoothly increases to greater than 98 percent and decreases to less than one percent according to accelerator pedal movement, go to step 7 . If value on scan tool does not change as specified, go to step 19 .
Check throttle body incorrect air rate adjustment, and binding or damaged linkage. Repair as necessary. After repairs, go to step 28 . If no problem is found, go to step 19 .
Using scan tool, compare BARO reading with a known-good vehicle. BARO reading should be within 3 kPa of other vehicle. Ensure readings are within specification for the present altitude. If readings are as specified, go to next step. If readings are not as specified, go to step 11 .
Using scan tool, monitor MAP sensor value while starting engine. If MAP sensor value changes, go to next step. If MAP sensor value does not change, go to step 10 .
With engine running, snap throttle while monitoring MAP sensor display on scan tool. If MAP sensor value changes rapidly, go to step 28 . If MAP sensor value does not change rapidly, go to next step.
Turn engine off. Turn ignition on. Remove MAP sensor or vacuum hose (if applicable) from manifold port. Check for leaks or restrictions. Repair as necessary. After repairs, go to step 28 . If no problem is found, go to next step.
Turn ignition off. Disconnect MAP sensor harness connector. Turn ignition on. If MAP sensor value on scan tool is zero volts, go to next step. If MAP sensor value on scan tool is not zero volts, go to step 13 .
Using a fused jumper wire, jumper 5-volt reference circuit to signal circuit at MAP sensor harness connector. If MAP sensor value on scan tool is 5.0 volts, go to step 14 . If MAP sensor value on scan tool is not 5.0 volts, go to step 15 .
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Check MAP sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 28 . If circuit is okay, go to step 27 .
Using a test light connected to battery positive, probe ground circuit at MAP sensor harness connector. If test light illuminates, go to step 16 . If test light does not illuminate, go to step 18 .
Check MAP sensor 5-volt reference circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 28 . If connection is okay, go to step 27 .
Check for poor connections at MAP sensor. Repair as necessary. After repairs, go to step 28 . If connections are okay, go to next step.
Replace MAP sensor. After repairs, go to step 28 .
Check MAP sensor ground circuit for poor connections. Repair as necessary. After repairs, go to step 28 . If circuit is okay, go to step 27 .
Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. If TP sensor value on scan tool is zero volts, go to next step. If TP sensor value on scan tool is not zero volts, go to step 21 .
Using a fused jumper wire, jumper 5-volt reference circuit to signal circuit at TP sensor harness connector. If TP sensor value on scan tool is 5 volts, go to step 22 . If TP sensor value on scan tool is not 5 volts, go to step 23 .
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Check TP sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 28 . If circuit is okay, go to step 27 .
Using a test light connected to battery positive, probe ground circuit at TP sensor harness connector. If test light illuminates, go to step 24 . If test light does not illuminate, go to step 25 .
Check TP sensor 5-volt reference or signal circuit for poor connections. Repair as necessary. After repairs, go to step 28 . If circuits are okay, go to step 27 .
Check for poor connections at TP sensor. Repair as necessary. After repairs, go to step 28 . If connections are okay, go to next step.
Replace TP sensor. After repairs, go to step 28 .
Check TP sensor ground circuit for poor connection or high resistance at TP sensor harness connector. Repair as necessary. After repairs, go to step 28 . If circuit is okay, go to next step.
Replace PCM. Program replacement PCM using necessary equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start engine and allow it to reach normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0105. 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.

Ensure TP sensor is not stuck and MAP sensor has a dedicated vacuum source free of restriction or leaks. Check connections at all related components. Slight resistance in circuits or connections can set DTC P0105.

Other engine conditions such as incorrect cam timing, restricted exhaust, worn piston rings, and low fuel pressure may result in excessively high or low MAP values, causing DTC P0105 to set.

DTC P0105: MAP/TP SENSOR PERFORMANCE/RANGE (2.2L "S" SERIES & CUTLASS & MALIBU 2.4L "N" BODY)

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

For duplication of DTC, ensure

DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0131, P0132, P0171, P0172, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0341, P0342, P0440, P0442, P0502, P0506, P0507 or P1441 is not set.
Ensure engine speed is greater than 900 RPM.
TCC is stable within one percent.
Engine speed is stable within 50 RPM.
IAC valve is stable within 5 counts.
TP sensor is stable within 2 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check vacuum hoses, intake manifold and throttle body for vacuum leaks. Repair as necessary. After repairs, go to step 40 . If no problem is found, go to next step.
Using scan tool, select TP ANGLE parameter. Monitor scan tool display while slowly depressing accelerator pedal to the floor and releasing (repeat several times). If value displayed on scan tool smoothly increases to greater than 98 percent and decreases to zero percent according to accelerator pedal movement, go to next step. If value on scan tool does not change as specified, go to step 26 .
Using scan tool, monitor TP sensor voltage with throttle fully closed. If voltage is less than 0.9 volt, go to next step. If voltage is not as specified, go to step 26 .
Using scan tool, compare BARO reading with a known-good vehicle. Ensure readings are within specification for the present altitude. If readings are as specified, go to next step. If readings are not as specified, go to step 24 .
Using scan tool, monitor MAP sensor value while starting engine. If MAP sensor value changes, go to next step. If MAP sensor value does not change, go to step 14 .
With engine running, snap throttle while monitoring MAP sensor display on scan tool. If MAP sensor value changes rapidly, go to next step. If MAP sensor value does not change rapidly, go to step 10 .
Turn engine off. Turn ignition on. Using scan tool, review and record FREEZE FRAME data. Start engine. Operate vehicle within FREEZE FRAME conditions and under conditions for setting DTC. See «CIRCUIT DESCRIPTION»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . Monitor TP and MAP sensor values on scan tool while depressing accelerator pedal. Sensor values should change rapidly. Ensure MAP sensor performs correctly through entire range. If operation is as specified, go to next step. If operation is not as specified, go to step 10 .
If TP sensor performs correctly through entire range, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If TP sensor does not perform correctly through entire range, go to step 26 .
Turn ignition off. Disconnect MAP sensor connector. Turn ignition on. Using scan tool, monitor MAP sensor value. If MAP sensor value is zero volts, go to next step. If MAP sensor value is not zero volts, go to step 12 .
Using DVOM, measure voltage between ground and 5-volt reference circuit at MAP sensor harness connector. If voltage is 5 volts, go to next step. If voltage is not 5 volts, go to step 17 .
Using a fused jumper wire, jumper 5-volt reference circuit to signal circuit at MAP sensor harness connector. If scan tool reads 5 volts, go to next step. If scan tool does not read 5 volts, go to step 19 .
Using a test light connected to battery positive, probe ground circuit at MAP sensor harness connector. Using DVOM, measure voltage between ground and test light probe. If voltage is greater than 0.5 volt, go to step 21 . If voltage is not as specified, go to step 16 .
Disconnect vacuum source from MAP sensor. Connect hand-held vacuum pump to MAP sensor. Turn ignition on, with engine off. Apply 15 inches Hg to MAP sensor. Observe scan tool. If MAP sensor value changes, go to next step. If MAP sensor value does not change, go to step 16 .
Remove MAP sensor. Inspect port for restrictions. Repair as necessary. After repairs, go to step 40 . If no problem is found, go to step 25 .
Check for poor connections at MAP sensor harness connector. Repair as necessary. After repairs, go to step 40 . If connections are okay, go to step 24 .
If MAP sensor voltage is near 12 volts, go to next step. If MAP sensor voltage is not as specified, go to step 22 .
Check MAP sensor 5-volt reference circuit for a short to battery positive. Repair as necessary. After repairs, go to step 40 . If circuit is okay, go to step 39 .
Check MAP sensor signal circuit for high resistance or poor connection. Repair as necessary. After repairs, go to step 40 . If circuit is okay, go to next step.
Check MAP sensor 5-volt reference circuit for high resistance or poor connection. Repair as necessary. After repairs, go to step 40 . If circuit is okay, go to step 39 .
Check MAP sensor ground circuit for high resistance or poor connection. Repair as necessary. After repairs, go to step 40 . If circuit is okay, go to step 39 .
Check MAP sensor 5-volt reference circuit for a short to ground or poor connection. Repair as necessary. After repairs, go to step 40 . If circuit is okay, go to step 39 .
Check MAP sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 40 . If circuit is okay, go to step 39 .
Check MAP sensor circuits for chaffing and rubbed-through insulation. Repair as necessary. After repairs, go to step 40 . If circuits are okay, go to next step.
Check for high resistance or poor connection at MAP sensor. Repair as necessary. If connection is okay, replace MAP sensor. After repairs, go to step 40 .
Turn ignition off. Disconnect TP sensor connector. Turn ignition on. Monitor TP sensor value on scan tool. If voltage is zero volts, go to next step. If voltage is not zero volts, go to step 30 .
Using DVOM, measure voltage between ground and 5-volt reference circuit at TP sensor harness connector. If voltage is 5 volts, go to next step. If voltage is not as specified, go to step 32 .
Using a fused jumper wire, jumper 5-volt reference circuit to signal circuit at TP sensor harness connector. If scan tool displays 5 volts, go to next step. If scan tool does not display 5 volts, go to step 36 .
Using a test light connected to battery positive, probe ground circuit at TP sensor harness connector. Using DVOM, measure voltage between ground and test light probe. If voltage is greater than 0.5 volt, go to step 31 . If voltage is not as specified, go to step 32 .
Check TP sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 40 . If circuit is okay, go to step 39 .
Check TP sensor ground circuit for high resistance or poor connection at TP sensor harness connector. Repair as necessary. After repairs, go to step 40 . If circuit is okay, go to step 39 .
Using DVOM, measure voltage between ground and 5-volt reference circuit at MAP sensor harness connector. If voltage is near 5 volts, go to step 36 . If voltage is not as specified, go to next step.
Disconnect A/C pressure and fuel tank pressure sensors. Using DVOM, measure voltage between ground and 5-volt reference circuit at TP sensor harness connector. If voltage is near 5 volts, leave DVOM connected and go to next step. If voltage is not as specified, go to step 35 .
Reconnect each disconnected component until voltage reading changes. Replace component that caused voltage to change. After repairs, go to step 40 .
Check TP sensor 5-volt reference circuit for a short to voltage. Repair as necessary. After repairs, go to step 40 . If circuit is okay, go to step 39 .
Check TP sensor circuit for high resistance or poor connection. Repair as necessary. After repairs, go to step 40 . If circuit is okay, go to step 39 .
Check for high resistance or poor connections at TP sensor harness connector. Repair as necessary. If connections are okay, replace TP sensor. After repairs, go to step 40 .
Check for high resistance or poor connections at PCM harness connectors. Repair as necessary. After repairs, go to step 40 . If connections are okay, go to next step.
Replace PCM. Program replacement PCM using necessary equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start engine and allow it to reach normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0105. 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.

Other engine conditions such as incorrect cam timing, restricted exhaust, worn piston rings, and low fuel pressure may result in excessively high or low MAP values, causing DTC P0105 to set.

DTC P0105: MAP SENSOR CIRCUIT-INSUFFICIENT ACTIVITY (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

This test determines when the MAP sensor is sticking. The PCM does this by checking for throttle position changes that are not immediately followed by MAP signal changes. When a throttle position change of 3.2 degrees within.5 second occurs, the PCM watches the MAP signal for one second following the throttle position change. If MAP signal does not change by at least 4 kPa in this period and MAP sensor reading is greater than 17.3 kPa than the expected MAP reading (based on engine speed and throttle position), DTC P0105 will set.

For duplication of DTC, MAP signal must change less than 4 kPa in one second following a 3.2 degree change in throttle position, and the MAP signal is not within 17.3 kPa of expected MAP reading. Condition must occur 5 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.
Using scan tool, view FREEZE FRAME data. Note MAP data value. If MAP value is.08 volt or less, diagnose using DTC P0107. If MAP value is not.08 volt or less, go to next step.
If MAP value is 5.06 volts or greater than the value specified in step 2) , diagnose using DTC P0108. If MAP value is not 5.06 volts or greater, go to next step.
Check for poor terminal contact at MAP sensor connector and PCM. Repair as necessary and verify repair. If terminal contact is okay, go to next step.
Replace MAP sensor.

DTC P0106: MAP SYSTEM PERFORMANCE (2.2L "J" BODY)

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

Powertrain Control Module (PCM) and Alternative Fuel Engine Control Unit (AFECU) both supply a 5-volt reference, signal and ground circuit to Manifold Absolute Pressure (MAP) sensor. As manifold pressure changes, monitored MAP sensor signal voltage changes. PCM and AFECU compare detected sensor voltage changes to a predetermined value which coincides with a change in TP sensor value. If expected MAP value is not detected and does not coincide with change in TP sensor value, DTC P0106 will set.

For duplication of DTC, ensure engine is running on alternative fuel, no AFECU DTCs are set (with the exception of DTCs P1215, P1432 and P1433), and TP sensor angle is less than 70 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, establish communication with AFECU. Record MAP value. If MAP value is 75 kPa at altitude or 95 kPa at sea level, go to next step. If MAP value is not as specified, go to step 7 .
Disconnect vacuum source from MAP sensor, leaving electrical harness connected. Connect a hand-held vacuum pump to MAP sensor. Slowly apply 20 inches Hg, one inch Hg at a time to MAP sensor while observing scan tool display. MAP sensor value should decrease steadily 3-4 kPa for each inch Hg. If MAP sensor value decrease was erratic, go to step 7 . If MAP sensor value decrease was steady, go to next step.
With 20 inches Hg applied to MAP sensor, observe MAP value on scan tool. If MAP value is less than 34 kPa, go to next step. If MAP value is 34 kPa or greater, go to step 7 .
Disconnect vacuum source from MAP sensor. If MAP value returns to value recorded in step 2) , go to next step. If MAP value is not as specified, go to step 7 .
Fault is not present at this time. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . Also check for undiagnosed DTCs. If DTCs are present, go to applicable DTC test. If no DTCs are present, go to step 10 .
Inspect MAP sensor harness connections. If a problem is found, go to next step. If connections are okay, go to step 9 .
Repair connections as necessary. After repairs, go to step 10 .
Replace MAP sensor. After repairs, go to next step.
Using scan tool, clear DTCs. Start engine and allow it to reach normal operating temperature. Select SPECIFIC DTC function, and then enter this DTC. Operate vehicle within conditions required to duplicate DTC. If scan tool indicates that this DTC test ran and passed, system is okay. If scan tool does not indicate that this DTC test ran and passed, go to step 2 .

"Fault is not present at this time" indicates an intermittent condition. See appropriate TROUBLE SHOOTING - NO CODES article for further diagnosis.

DTC P0106: MAP SYSTEM PERFORMANCE (2.4L "N" BODY)

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

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Manifold Absolute Pressure (MAP) sensor. As manifold pressure changes, monitored MAP sensor signal voltage changes. PCM compares detected sensor voltage changes to a predetermined value set by PCM. If PCM does not see expected value, DTC P0106 will set.

For duplication of DTC, ensure

DTCs P0107, P0108, P0117, P0118, P0121, P0122, P0123, P0131, P0132, P0171, P0172, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0341, P0342, P0404, P0405, P0440, P0442, P0446, P0452, P0453, P0502, P0506, P0507, P0601, P0602 or P1442 are not set.
Engine speed is greater than 900 RPM.
Initial idle MAP value is greater than 60 kPa.
Throttle position is less than 50 percent and changes are greater than 12 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, compare BARO reading with a known-good vehicle. If BARO reading is normal for the altitude, go to next step. If BARO reading is not normal for the altitude, go to step 6 .
Start engine while watching MAP sensor value. If MAP sensor value changes, go to step 8 . If MAP value does not change, go to next step.
Turn ignition off. Disconnect vacuum source and connect a hand-held vacuum pump to MAP sensor. Turn ignition on, with engine off. Apply 15 inches Hg to MAP sensor while monitoring MAP sensor value on scan tool. If MAP sensor value changes, go to next step. If MAP sensor value does not change, go to step 6 .
Turn ignition off. Remove MAP sensor vacuum hose from manifold port. Inspect manifold port and hose for restriction. Repair as necessary. After repairs, go to step 7 . If no problems were found, go to next step.
Replace MAP sensor. After repairs, go to next step.
Using scan tool, clear DTCs. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions required to duplicate DTC. Select SPECIFIC DTC function then enter 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, go to step 2 .
Check for additional undiagnosed DTCs. Diagnose affected DTCs as necessary. If no other undiagnosed DTCs are set, system is okay.

DTC P0106: MAP SYSTEM PERFORMANCE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

This test monitors TP sensor, engine speed, MAP, EGR flow and A/C clutch status. Engine operation denotes that a large change in manifold pressure must be preceded by a change in engine load due to changes in throttle angle, engine speed, EGR flow or A/C clutch status. If these parameters remain constant and there is a rapid change in MAP value, DTC P0106 will set.

For duplication of DTC, ensure DTCs P0122 and P0123 are not set, and engine speed is 500 RPM or greater.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P0300 is also present, diagnose this DTC first. If DTC P0300 is not present, go to next step.
Turn ignition on, with engine off. Using scan tool, monitor MAP value. If MAP value is greater than 75 kPa at altitude, or 95 kPa at sea level, go to next step. If MAP value is not as specified, go to step 7 .
Disconnect vacuum source from MAP sensor. Remove MAP sensor from manifold if necessary. Connect a hand-held vacuum pump to MAP sensor. Slowly apply 20 in. Hg to sensor and note MAP value. Each one in. Hg applied to MAP sensor should result in a 3-4 kPa drop in MAP sensor value. Watch for erratic reading. If reading is erratic, go to step 7 . If reading changes smoothly, go to next step.
If MAP sensor reading is 34 kPa or less with 20 in. Hg applied to sensor, go to next step. If MAP sensor reading is greater than 34 kPa with 20 in. Hg applied, go to step 7 .
Disconnect vacuum source from MAP sensor. If MAP sensor reading returns to original value as specified in step 3) , fault is not present at this time. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If MAP sensor reading does not return to original value, go to next step.
Replace MAP sensor.

"Fault is not present at this time" indicates an intermittent condition. See appropriate TROUBLE SHOOTING - NO CODES article for further diagnosis.

DTC P0106: MAP SYSTEM PERFORMANCE (4.3L, 5.0L & 5.7L "C", "G", "K", "L", "M", "P", "S" & "T" 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 (high vacuum) to 4.0-4.5 volts at wide open throttle (low vacuum). A change in throttle position and engine speed should precede change in MAP. If change does not occur, MAP malfunction is present. DTC P0106 will set if MAP voltage is outside acceptable limits for more than 24 seconds. VCM utilizes MAP signal and throttle position to determine fuel delivery.

For duplication of DTC, ensure

Engine is running.
No IAC, EGR or TP sensor DTCs are set.
Change in engine speed is less than 75 RPM.
Change in throttle position is less than 1.5 percent.
Change in EGR flow is less than 2 percent.
Change in IAC is less than 4 counts.
No change in brake switch status.
No change in clutch status (M/T).
No change in power steering switch status.
No change in A/C clutch status.
Engine speed is between 400-5000 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.
Disconnect and plug MAP sensor vacuum source. Using scan tool, view and record MAP value. If MAP value is greater than 75 kPa at altitude, or 95 kPa at sea level, go to next step. If MAP value is not as specified, go to step 6 .
Turn ignition off. Connect a hand-held vacuum pump to MAP sensor. Slowly apply 20 in. Hg, one in. Hg at a time to MAP sensor while observing scan tool display. MAP sensor value should decrease steadily 3-4 kPa for each in. Hg. If MAP sensor value decrease was erratic, go to step 6 . If MAP sensor value decrease was steady, go to next step.
With 20 in. Hg applied to MAP sensor, observe MAP value on scan tool. If MAP value is less than 34 kPa, go to next step. If MAP value is not as specified, go to step 6 .
Slightly raise idle to prevent stalling. Disconnect vacuum source from MAP sensor. If MAP value returns to value recorded in step 2 , see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If MAP value is not as specified, go to next step.
Check MAP sensor harness connections. If a problem is found, go to next step. If connections are okay, go to step 8 .
Repair connections as necessary. After repairs, go to step 9 .
Replace MAP sensor. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Check MAP sensor vacuum source for leaks, restrictions or faulty connections. Ensure vacuum source only supplies MAP sensor and not other systems such as cruise control, auxiliary vacuum gauges, etc.

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (1.9L SATURN)

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

MAP sensor responds to manifold pressure (vacuum). PCM measures the voltage drop across MAP sensor. Voltage ranges from 1.0-1.5 volts at idle (high vacuum) to greater than 4.0-4.5 volts at wide open throttle (low vacuum).

DTC will set if MAP reading is less than.3 volt when either the engine speed is less than 1000 RPM and no TP sensor related DTC have been set, or engine speed is greater than 1000 RPM and TP sensor is greater than 10 percent and no TP sensor related DTCs have been set. MAP sensor signal is continuously checked when engine is running.

Connect scan tool. Start engine. Check MAP sensor reading. If MAP sensor reading is less than.3 volt, go to next step. If MAP sensor reading is.3 volt or greater, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect MAP sensor harness connector. Using a fused jumper wire, jumper MAP sensor terminals "B" and "C". If MAP sensor reading is less than.3 volt, go to next step. If MAP sensor reading is.3 volt or greater, check for terminal tightness at PCM harness connector or for faulty MAP sensor.
Remove jumper wire. Measure voltage ground and MAP sensor terminal "C". If voltage is 4-6 volts, go to next step. If voltage is not as specified, check for open in 5-volt reference signal circuit to MAP sensor or PCM.
Check MAP sensor terminal "B" circuit for an open, short to ground or short to MAP sensor terminal "A" (5-volt return circuit). Repair as necessary. If circuit is okay, check for terminal tightness at PCM harness connector or for faulty PCM.

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

With ignition on, engine off, the MAP sensor reading should be the same as barometric pressure (no vacuum-high voltage). Comparing this reading with a known-good sensor is a good way to verify accuracy of suspect sensor. Readings should be within 0.4 volt. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (2.2L "J" BODY & "S" SERIES & 2.4L "J" & "N" BODIES)

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

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Manifold Absolute Pressure (MAP) sensor. As manifold pressure changes, monitored MAP sensor signal voltage changes. MAP sensor signal voltage should be 1.0-1.5 volts at idle and 4.5-4.8 volts at Wide Open Throttle (WOT). If MAP value is less than 11.8 kPa for at least 6.25 seconds, DTC P0107 will set.

For duplication of DTC, ensure DTCs P0122 or P0123 are not set, engine speed is less than 1000 RPM, or greater than 1000 RPM with Throttle Position (TP) sensor angle greater than 15 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and run engine at idle. Using scan tool, observe MAP sensor voltage. If voltage is less than.25 volt, go to next step. If voltage is not less than.25 volt, go to step 4 .
Turn ignition off. Disconnect MAP sensor connector. Connect a fused jumper wire between MAP sensor signal circuit and 5-volt reference circuit terminals at MAP sensor harness connector. Turn ignition on. Observe scan tool. If voltage is greater than 4.7 volts, go to step 5 . If voltage is not greater than 4.7 volts, go to step 6 .
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MAP sensor voltage is less than.25 volt, go to step 3 . If MAP sensor voltage is not less than.25 volt, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect and inspect MAP sensor connector. If connections are faulty, go to step 8 . If connections are okay, go to step 11 .
Turn ignition off. Disconnect jumper wire from MAP sensor connector. Using a test light connected to battery positive, probe MAP sensor signal circuit terminal at MAP sensor harness connector. Turn ignition on, engine off. Observe scan tool. If MAP sensor voltage is greater than 4 volts, go to next step. If MAP sensor voltage is not greater than 4 volts, go to step 13 .
Check MAP sensor 5-volt reference circuit for an open or short to ground. If 5-volt reference circuit is faulty, go to step 10 . If 5-volt reference circuit is okay, go to step 12 .
Repair connector pins and/or wiring as necessary. After repairs, go to step 15 .
Replace MAP sensor. After repairs, go to step 15 .
Repair 5-volt reference circuit to MAP sensor. After repairs, go to step 15 .
Remove MAP sensor vacuum hose from intake manifold. Check manifold port and hose for restriction. Repair as necessary. After repairs, go to step 15 . If manifold port and hose are okay, go to step 9 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 15 .
Turn ignition off. Check MAP sensor signal circuit for an open or short to chassis or sensor ground. If circuit is open or shorted to ground, go to next step. If circuit is okay, go to step 12 .
Repair MAP sensor signal circuit. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to 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 DTC test ran and passed, go to next step. If scan tool does not indicate that this DTC test ran and passed, go to step 2 .
Check if additional DTCs are set. Diagnose affected DTCs as necessary. If no other DTCs are set, system is okay.

Turn ignition on, with engine off. MAP sensor voltage signal should be 4.5-4.8 volts. Compare this reading with a known-good vehicle with same style MAP sensor. Voltage readings should be within.4 volt of each other. After repairs are completed, use scan tool and access FUEL TRIM RESET function. Reset long term fuel trim to 128.

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

Manifold Absolute Pressure (MAP) sensor measures 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, is sent at wide open throttle (low vacuum). If MAP sensor signal is less than 12.1 kPa for more than 2 seconds, DTC P0107 will set.

For duplication of DTC, ensure no TP sensor related DTCs are present, engine is running, system voltage is greater than 9 volts, and TP angle is greater than 10 percent with engine speed greater than 1000 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.
Turn ignition on, with engine off. Using scan tool, read MAP sensor voltage. If voltage is about zero volts, go to step 4 . If voltage is not about zero volts, go to next step.
With ignition on, engine off, use scan tool to read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0107 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0107 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect MAP sensor harness connector. Connect a fused jumper wire between MAP sensor harness connector 5-volt reference circuit and signal circuit. If scan tool MAP voltage is about 4.95 volts, go to step 10 . If voltage is not about 4.95 volts, go to next step.
Turn ignition off. Remove jumper wire. Connect a test light between MAP sensor harness connector signal circuit and battery voltage. Turn ignition on. If voltage is about 4.95 volts, go to next step. If voltage is not 4.95 volts, go to step 8 .
Turn ignition off. Disconnect PCM connectors. Check PCM harness connector 5-volt reference circuit for an open or short to ground. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for faulty connection of 5-volt reference circuit at PCM. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 11 .
Turn ignition off. Disconnect PCM connectors. Check PCM harness connector MAP signal circuit for an open, short to ground or short to sensor ground. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for faulty connection of MAP signal circuit at PCM. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 11 .
Replace MAP sensor. After repairs, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0107. If scan tool displays DTC P0107 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0107 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe MAP display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (3.5L "W" BODY)

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

For duplication of DTC, ensure

No TP sensor related DTCs are present.
Engine is running.
Idle speed is steady.
TP angle is greater than zero percent if engine speed is less than 1000 RPM, or TP angle is greater than 10 percent if engine speed is greater than 1000 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.
Observe MAP value displayed on scan tool. If MAP value is near zero volts, go to step 4 . If MAP value is not as specified, go to next step.
Turn ignition off. Wait 15 seconds. Turn ignition on. Review and record FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, monitor SPECIFIC DTC info. for DTC P0107. If scan tool indicates DTC P0107 failed this ignition, go to next step. If scan tool does not indicate DTC P0107 failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition on, with engine off. Disconnect MAP sensor connector. Using a fused jumper wire, jumper 5-volt reference circuit to signal circuit at MAP sensor harness connector. Observe scan tool display. If MAP value is greater than 4.6 volts, go to step 10 . If MAP value is not as specified, go to next step.
Remove jumper wire. Using a test light connected to battery positive, probe signal circuit at MAP sensor harness connector. Observe scan tool display. If MAP value is near 4.6 volts, go to next step. If MAP value is not as specified, go to step 8 .
Turn ignition off. Disconnect PCM harness connectors. Check 5-volt reference circuit for an open or short to ground. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 11 .
Turn ignition off. Disconnect PCM harness connectors. Check MAP signal circuit for an open, short to chassis ground, or short to MAP sensor ground circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check MAP sensor signal circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 11 .
Replace MAP sensor. After repairs, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off. Wait 15 seconds. Operate vehicle within conditions required to set DTC. Using scan tool, select SPECIFIC DTC INFO for DTC P0107. If scan tool indicates DTC P0107 test ran and passed, go to next step. If scan tool does not indicate DTC P0107 ran and passed, go to step 2 .
Check if additional DTCs are set. Diagnose affected DTCs as necessary. If no other DTCs are set, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe MAP display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P0107: MAP SENSOR CIRCUIT-LOW 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). If MAP sensor signal voltage is less than 0.1 volt for more than 67 crankshaft revolutions, DTC P0107 will set.

For duplication of DTC, ensure

No TP sensor related DTCs are present.
Engine is running and idle speed is steady.
TP sensor angle is greater than zero percent if engine speed is less than 1000 RPM, or TP sensor angle is greater than 6 percent if engine speed is greater than 1000 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.
Turn ignition on. Using scan tool, read MAP sensor voltage. If voltage is about zero volts, go to step 4 . If voltage is not as specified, go to next step.
Turn ignition on. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0107 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0107 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect MAP sensor harness connector. Connect a fused jumper wire between MAP sensor harness connector 5-volt reference circuit and signal circuit. If scan tool voltage is greater than 4.6 volts, go to step 10 . If voltage is not greater than 4.6 volts, go to next step.
Using a test light connected to battery positive, probe signal circuit at MAP sensor harness connector. Observe scan tool display. If voltage reading is about 4.6 volts, go to next step. If voltage is not as specified, go to step 8 .
Turn ignition off. Disconnect PCM harness connectors. Check PCM harness connector 5-volt reference circuit for an open or short to ground. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 11 .
Turn ignition off. Disconnect PCM harness connectors. Check PCM harness connector MAP signal circuit for an open, short to chassis ground, or short to MAP sensor ground circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check MAP sensor signal circuit for poor connection at PCM harness connector. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 11 .
Replace MAP sensor. After repairs, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on. 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 P0107. If scan tool displays DTC P0107 FAILED THIS IGN, return to step 4 . If scan tool does not display DTC P0107 FAILED THIS IGN, system is okay.

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

MAP sensor is a sensor that changes resistance based upon manifold vacuum. PCM provides a 5-volt reference voltage and ground. Monitored MAP sensor signal varies 1-5 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 values as an indicator of engine load. If detected MAP sensor signal voltage is.08 volt or less, DTC P0107 will set.

For duplication of DTC, ensure

DTCs P0122 and P0123 are not set.
Engine speed is 700 RPM or less.
TP sensor value is 18 degrees or less.

DTCs P0122 and P0123 are not set.
Engine speed is 1800 RPM or less.
TP sensor value is 13 degrees or greater.
Transaxle is not in Park or Neutral.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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, note MAP display. If MAP value displayed is 17 kPa or less, go to next step. If MAP value displayed is not 17 kPa or less, go to DTC P0106 for diagnosis.
Turn ignition off. Disconnect MAP sensor harness connector. Jumper MAP sensor harness connector 5-volt reference terminal to signal circuit terminal. Turn ignition on. If scan data displays a value greater than 102 kPa, go to step 13 . If scan data displays a value of 102 kPa or less, go to next step.
Remove jumper wire. Using DVOM, measure voltage between MAP sensor harness connector 5-volt reference terminal and ground. If voltage reading is 4.5 volts or greater, go to next step. If voltage reading is less than 4.5 volts, go to step 7 .
Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, and then disconnect PCM harness connector C1. Using DVOM, measure resistance between ground and MAP sensor signal circuit in PCM harness connector C1. If resistance is 10,000 ohms or greater, go to next step. If resistance is not 10,000 ohms or greater, go to step 9 .
Measure resistance of MAP sensor signal circuit between PCM and MAP sensor harness connectors. If resistance is 5 ohms or greater, go to step 10 . If resistance is not 5 ohms or greater, go to step 19 .
Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, and then disconnect PCM harness connector C1. Using DVOM, measure resistance between MAP sensor 5-volt reference circuit and MAP sensor ground circuit. If resistance is 10,000 ohms or greater, go to next step. If resistance is not 10,000 ohms or greater, go to step 12 .
Measure resistance of 5-volt reference circuit between MAP sensor and PCM harness connectors. If resistance is less than 5 ohms, go to step 15 . If resistance is not less than 5 ohms, go to step 11 .
Repair MAP sensor signal circuit for a short to ground or short to MAP sensor ground circuit and retest.
Repair open in MAP sensor signal circuit and retest.
Repair open in MAP sensor 5-volt reference circuit and retest.
Repair MAP sensor 5-volt reference circuit for a short to ground or short to MAP sensor ground circuit and retest.
Check terminal contact at MAP sensor. Repair as necessary and retest. If terminal contact is okay, go to next step.
Replace MAP sensor and retest.
Disconnect PCM harness connector C1. Check for short to ground between PCM and each of the other 5-volt reference circuits (i.e. TP sensor, EGR sensor, fuel tank pressure sensor). If resistance on any of the other circuits is less than 10,000 ohms, go to step 17 . If resistance on any of the other circuits is not less than 10,000 ohms, go to next step.
Measure resistance between a known-good engine ground and each of the other 5-volt reference circuits. If resistance is less than 10,000 ohms, go to step 18 . If resistance is not less than 10,000 ohms, go to step 19 .
Repair short to ground or replace shorted sensor on affected circuit that measured low and retest.
Repair 5-volt reference circuit that is shorted to engine or body ground on affected circuit and retest.
Check terminal contacts at PCM harness connector C1. Repair as necessary. If terminal contacts are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment and retest.

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" 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. If MAP signal voltage is less than.04 volt for more than one second, DTC P0107 will set.

For duplication of DTC, ensure

No TP sensor related DTCs are set.
Engine is running.
Throttle position is at least zero percent when engine speed is less than 800 RPM, or throttle position is at least 12.5 percent when engine speed is greater than 800 RPM.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Install scan tool. Start and operate engine at idle. Monitor MAP sensor voltage on scan tool. If MAP sensor voltage is less than.25 volt, go to next step. If MAP sensor voltage reading is not as specified, go to step 5 .
Turn ignition off. Disconnect MAP sensor connector. Turn ignition on, with engine off. Measure voltage between ground and 5-volt reference circuit at MAP sensor harness connector. If voltage is greater than 4.7 volts, go to next step. If voltage is not as specified, go to step 9 .
Turn ignition off. Connect a jumper wire between 5-volt reference circuit and signal circuit at MAP sensor harness connector. Turn ignition on, with engine off. 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 as specified, go to step 7 .
This DTC is intermittent. If any additional DTCs are present, go to applicable DTC test. If no other DTCs are present, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check for poor connection at MAP sensor. If a problem is found, go to step 17 . If connection is okay, go to step 16 .
Check for an open in MAP sensor signal circuit. If a problem is found, go to step 17 . If circuit is okay, go to next step.
Check for short to ground in MAP sensor signal circuit. If a problem is found, go to step 17 . If circuit is okay, go to step 15 .
Turn ignition off. Disconnect VCM harness connector C3. Check for an open in MAP sensor 5-volt reference circuit. If a problem is found, go to step 17 . If circuit is okay, go to next step.
Reconnect VCM harness connector. Turn ignition on, with engine off. Measure voltage between ground and 5-volt reference circuit at MAP sensor harness connector. Disconnect TP, EGR and FTP sensor harness connectors, one at a time. If voltage reads greater than 4.7 volts after disconnecting one of the sensors, go to next step. If voltage is not greater than 4.7 volts with all sensors disconnected, go to step 14 .
If suspect sensor is EGR sensor, go to next step. If EGR sensor is not suspect, go to step 13 .
Check for a short between 5-volt reference circuit and EGR feed control circuit. If a problem is found, go to step 17 . If circuit is okay, go to next step.
Replace sensor that caused voltage to increase to greater than 4.7 volts when disconnected. After repairs, go to step 19 .
Ensure all sensors are still disconnected. Turn ignition off. Using a test light connected to battery positive, probe 5-volt reference circuit MAP sensor harness connector. If test light illuminates, go to step 17 . If test light does not illuminate, go to next step.
Check for poor connection at VCM. If a problem is found, go to step 17 . If connections are okay, go to step 18 .
Replace MAP sensor. After repairs, go to step 19 .
Repair circuit as necessary. After repairs, go to step 19 .
Replace VCM. Program replacement VCM 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, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

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

To test accuracy of a suspect sensor, compare reading with a known-good vehicle. 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 0.1 volt indicate 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 P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

Manifold Absolute Pressure (MAP) sensor measures pressure changes within intake manifold to indicate engine load. MAP sensor is mounted on top of intake manifold. MAP sensor has a 5-volt reference circuit, ground and a signal circuit.

MAP sensor voltage (depending on altitude) can range from 1.0-1.5 volts at idle (high vacuum) to 4.0-4.9 volts at wide open throttle (low vacuum). When PCM senses a signal voltage less than.10 volt for greater than 2 seconds, DTC P0107 will set.

For duplication of DTC, ensure engine is running, no TP sensor DTCs are set, and TP angle is zero percent when engine speed is less than 1200 RPM, or TP angle is less than 20 percent when engine speed is greater than 1200 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.
Start and operate engine at idle. Using scan tool, monitor Failed This Ignition option under DTC information option. If DTC P1635 fails in this ignition cycle, go to DTC P1635 diagnostic test. If DTC P1635 did not fail in this ignition cycle, go to next step.
Monitor MAP sensor voltage on ENGINE 1 DATA LIST. If MAP sensor voltage is less than.20 volt, go to step 5 . If sensor voltage is not less than.20 volt, 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, and then enter DTC P0107. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect MAP sensor harness connector. Using a fused jumper wire, jumper 5-volt reference circuit and MAP signal circuit at MAP sensor harness connector. Observe MAP voltage display on scan tool. If MAP sensor voltage is about 5 volts, go to step 11 . If MAP voltage is not about 5 volts, go to next step.
Using a test light connected to battery positive, probe MAP sensor signal circuit at MAP sensor harness connector. Observe MAP voltage display on scan tool. If MAP voltage is about 5 volts, go to next step. If MAP voltage is not about 5 volts, go to step 9 .
Turn ignition off. Disconnect PCM harness connector C1. Check for an open or short to ground in 5-volt reference circuit. Repair as necessary. After repairs, go to step 13 . If circuits are okay, go to next step.
Check 5-volt reference circuit at PCM connector for poor terminal connection. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Turn ignition off. Disconnect PCM harness connector C2. Check MAP sensor signal circuit for an open, short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Check for poor connection on MAP sensor signal circuit at PCM. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Check MAP sensor signal circuit for poor connection at PCM. Repair as necessary. If terminals are okay, replace MAP sensor. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0107. 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, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

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. All 5-volt reference circuits are internally connected within PCM. If all MAP sensor circuits are okay, check related 5-volt reference circuits. Also, check EGR valve and related circuits for malfunctions.

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (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 operate engine at idle. Using scan tool, monitor Failed This Ignition option under DTC information option. If DTC P1635 fails in this ignition cycle, go to DTC P1635 diagnostic test. If DTC P1635 did not fail in this ignition cycle, go to next step.
Monitor MAP sensor voltage on ENGINE 1 DATA LIST. If MAP sensor voltage is less than.10 volt, go to step 5 . If sensor voltage is not less than.10 volt, 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, and then enter DTC P0107. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect MAP sensor harness connector. Using a fused jumper wire, jumper 5-volt reference circuit and MAP signal circuit at MAP sensor harness connector. Observe MAP voltage display on scan tool. If MAP sensor voltage is about 5 volts, go to step 11 . If MAP voltage is not about 5 volts, go to next step.
Using a test light connected to battery positive, probe MAP sensor signal circuit at MAP sensor harness connector. Observe MAP voltage display on scan tool. If MAP voltage is about 5 volts, go to next step. If MAP voltage is not about 5 volts, go to step 9 .
Turn ignition off. Disconnect PCM harness connector C1. Check for an open or short to ground in 5-volt reference circuit. Repair as necessary. After repairs, go to step 13 . If circuits are okay, go to next step.
Check 5-volt reference circuit at PCM connector for poor terminal connection. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Turn ignition off. Disconnect PCM harness connector C2. Check MAP sensor signal circuit for an open, short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Check for poor connection on MAP sensor signal circuit at PCM. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Check MAP sensor signal circuit for poor connection at PCM. Repair as necessary. If terminals are okay, replace MAP sensor. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0107. 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, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation.

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (1.9L SATURN)

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

MAP sensor responds to manifold pressure (vacuum). PCM measures the voltage drop across MAP sensor. Voltage ranges from 1.0-1.5 volts at idle (high vacuum) to 4.0-4.5 volts at wide open throttle (low vacuum).

DTC will set if MAP reading is greater than 4.9 volts (90 kPa) when either the engine speed is greater than 1600 RPM, TP sensor less than 70 percent and no TP sensor DTC have been set, or engine speed is less than 1600 RPM and TP sensor is less than 50 percent and no TP sensor DTC have been set. MAP sensor signal is continuously checked when engine is running.

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

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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 vacuum to MAP sensor. If vacuum reading is greater than 16 in. Hg, go to next step. If vacuum reading is not as specified, repair vacuum leak.
Disconnect MAP sensor. If MAP sensor reading indicates that voltage is present, go to next step. If MAP sensor reading indicates that voltage is not present, probe terminal "A" (5-volt return circuit) at MAP sensor harness connector using a test light connected to battery positive. If test light illuminates, check for faulty MAP sensor or MAP sensor connections. If test light does not illuminate, check for an open in 5-volt return circuit.
Turn ignition off. Disconnect PCM harness connector and remove MAP sensor signal circuit terminal from harness connector. Reconnect PCM harness connector. Turn ignition on. If scan tool indicates MAP voltage, replace PCM. If scan tool does not indicate MAP voltage, check signal circuit for short to voltage or short to 5-volt reference circuit.

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

With ignition on, engine off, the MAP sensor reading should be the same as barometric pressure (no vacuum/high voltage). Comparing this reading with a known-good sensor is a good way of verify accuracy of suspect sensor. Readings should be within.4 volt of each other. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (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) supplies a 5-volt reference signal and a ground circuit to Manifold Absolute Pressure (MAP) sensor. PCM monitors a signal circuit from MAP sensor. As manifold pressure changes, MAP sensor signal voltage changes. MAP sensor signal voltage should be 1.0-1.5 volts at idle and 4.5-4.8 volts at Wide Open Throttle (WOT). If MAP value is greater than 82 kPa for at least 1.25 seconds.

For duplication of DTC, ensure DTCs P0122 or P0123 are not set, engine is running, Throttle Position (TP) sensor angle is less than 12 percent, and Vehicle Speed Sensor (VSS) signal is less than one 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.
Start and operate engine at idle. Using scan tool, observe MAP sensor voltage. If voltage is 4 volts or greater, go to next step. If voltage is not as specified, go to step 4 .
Turn ignition off. Disconnect MAP sensor connector. Turn ignition on. Using scan tool, observe MAP sensor voltage. If voltage is one volt or less, go to step 5 . If voltage is not as specified, go to step 6 .
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MAP sensor voltage is 4 volts or greater, go to step 3 . If MAP sensor voltage is not as specified, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Using test light connected to battery positive, probe ground circuit at MAP sensor harness connector. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 11 .
Turn ignition off. Check MAP sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 12 .
Using DVOM, measure voltage between ground and 5-volt reference circuit at MAP sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 9 .
Check for plugged or leaking MAP sensor vacuum hose. Repair as necessary. After repairs, go to step 10 . If vacuum hose is okay, go to step 13 .
Turn ignition off. Check 5-volt reference circuit for short to voltage. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 12 .
Repair vacuum source. After repairs, go to step 14 .
Check for an open in MAP sensor ground circuit or poor connection at PCM. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 14 .
Check for poor ground circuit connection at MAP sensor. Repair as necessary. If connection is okay, replace MAP sensor. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to 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 DTC test ran and passed, go to next step. If scan tool does not indicate that this DTC test ran and passed, go to step 2 .
Check if additional DTCs are set. Diagnose affected DTCs as necessary. If no other DTCs are set, system is okay.

Turn ignition on, with engine off. MAP sensor voltage signal should be 4.5-4.8 volts. Compare this reading with a known-good vehicle with same style MAP sensor. Voltage readings should be within.4 volt of each other. Check 5-volt reference for short to battery voltage. After repairs are completed, use scan tool and access FUEL TRIM RESET function. Reset long term fuel trim to 128.

DTC P0108: MAP SENSOR CIRCUIT-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 signal circuit at closed throttle (high vacuum). A high voltage signal, 4 volts, is sent at wide open throttle (low vacuum). If PCM detects a MAP signal voltage that is excessively high, DTC P0108 will set.

For duplication of DTC, ensure no TP sensor related DTCs are present, engine is running, throttle position is less than 2 percent, engine speed is less than 3000 RPM, and MAP sensor signal voltage is greater than 4.3 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.
Correct any engine idle or vacuum problems before proceeding. Start engine and allow it to idle. Using scan tool, read MAP sensor voltage. If voltage is greater than 3.5 volts, go to step 4 . If voltage is not as specified, go to next step.
With ignition on, engine off, use scan tool to read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0108 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0108 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect MAP sensor harness connector. Turn ignition on. If voltage is zero volts, go to next step. If voltage is not as specified, go to step 6 .
Using a test light connected to battery positive, probe ground circuit at MAP sensor harness connector. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 9 .
Check MAP sensor signal circuit for short to voltage. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 11 .
Check ground circuit for faulty connection at MAP sensor. Repair as necessary. After repairs, go to step 16 . If connection is okay, go to next step.
Check for plugged or leaking vacuum supply to MAP sensor. If a problem is found, go to step 15 . If vacuum supply is okay, go to step 12 .
Check for faulty MAP sensor ground circuit connection at PCM. If MAP sensor connection is faulty, repair as necessary. After repairs, go to step 16 . If connection is okay, go to next step.
Check continuity of MAP sensor ground circuit. If resistance is greater than 5 ohms, repair circuit as necessary. After repairs, go to step 16 . If resistance is 5 ohms or less, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 16 .
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Check 5-volt reference circuit for short to voltage. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to next step.
Check for faulty connection at MAP sensor. Repair as necessary. After repairs, go to step 16 . If connection is okay, go to next step.
Replace MAP sensor. After repairs, go to step 16 .
Repair faulty vacuum source. After repairs, go to next step.
Turn ignition on, with engine off. 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 P0108. If scan tool displays DTC P0108 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0108 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe MAP display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (3.5L "W" BODY)

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, about 2 volts, is sent to PCM on signal circuit at closed throttle (high vacuum) idle. A high voltage signal, about 4 volts, is sent at wide open throttle (low vacuum). If MAP sensor signal is greater than 4.2 volts for 10 seconds, DTC P0108 will set.

For duplication of DTC, ensure no TP sensor related DTCs are present, engine is running with steady idle under 3000 RPM, and TP angle is less than 2 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Correct any engine idle or vacuum problems before proceeding. Start engine and allow it to idle. Using scan tool, read MAP sensor voltage. If voltage is greater than 3.5 volts, go to step 4 . If voltage is not as specified, go to next step.
Turn ignition off. Wait 15 seconds. Turn ignition on. Review and record FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, monitor SPECIFIC DTC info. for DTC P0108. If scan tool indicates DTC P0108 failed this ignition, go to next step. If scan tool does not indicate DTC P0108 failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect MAP sensor connector. Observe MAP sensor voltage on scan tool. If voltage is zero volts, go to next step. If voltage is not as specified, go to step 6 .
Using a test light connected to battery positive, probe ground circuit at MAP sensor harness connector. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 9 .
Check MAP sensor signal circuit for a short to voltage or short to 5-volt reference circuit. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 11 .
Check ground circuit for poor connection at MAP sensor harness connector. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to next step.
Check for plugged or leaking vacuum supply to MAP sensor. Repair as necessary. After repairs, go to step 15 . If vacuum supply is okay, go to step 12 .
Check for poor MAP sensor ground circuit connection at PCM. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to next step.
Measure resistance of MAP sensor ground circuit between MAP sensor and PCM. If resistance is greater than 5 ohms, repair open or poor connection as necessary. After repairs, go to step 16 . If resistance is 5 ohms or less, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 16 .
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Check 5-volt reference circuit for a short to battery voltage. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to next step.
Check for poor connections at MAP sensor. Repair as necessary. After repairs, go to step 16 . If connections are okay, go to next step.
Replace MAP sensor. After repairs, go to step 16 .
Repair vacuum source. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off. Wait 15 seconds. Operate vehicle within conditions required to set DTC. Using scan tool, select SPECIFIC DTC INFO for DTC P0108. If scan tool indicates DTC P0108 test ran and passed, go to next step. If scan tool does not indicate DTC P0108 ran and passed, go to step 2 .
Check if additional DTCs are set. Diagnose affected DTCs as necessary. If no other DTCs are set, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe MAP display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

DTC P0108: MAP SENSOR CIRCUIT-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). If PCM detects a MAP sensor signal voltage greater than 4.2 volts for more than 67 crankshaft revolutions, DTC P0108 will set.

For duplication of DTC, ensure

No TP sensor related DTCs are present.
System voltage is greater than 9 volts.
Idle speed is steady and less than 900 RPM.
Throttle position is less than 2 percent.
Engine has been running for a predetermined time depending on ECT at start-up.

Predetermined time ranges from 0.5 second with ECT greater than 86°F (30°C) to 2 minutes with ECT -22°F (-30°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.
Correct any engine idle or vacuum problems before proceeding. Start engine and allow it to idle. Using scan tool, read MAP sensor voltage. If voltage is greater than 3.5 volts, go to step 4 . If voltage is not greater than 3.5 volts, go to next step.
Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0108 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0108 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect MAP sensor harness connector. Turn ignition on. If scan tool reading is zero volts, go to next step. If scan tool reading is not zero volts, go to step 6 .
Connect a test light between MAP sensor harness connector ground circuit and battery voltage. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 9 .
Check MAP sensor signal circuit for short to voltage or 5-volt reference circuit. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 11 .
Check ground circuit for poor connection at MAP sensor. Repair as necessary. After repairs, go to step 16 . If connection is okay, go to next step.
Check for plugged or leaking vacuum supply to MAP sensor. If vacuum supply is not okay, go to step 15 . If vacuum supply is okay, go to step 12 .
Check MAP sensor ground circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 16 . If connection is okay, go to next step.
Measure resistance of MAP sensor ground circuit between MAP sensor and PCM. If resistance is greater than 5 ohms, repair open or poor connection as necessary. After repairs, go to step 16 . If resistance is 5 ohms or less, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 16 .
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Check 5-volt reference circuit for short to battery voltage. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to next step.
Check for poor connections at MAP sensor. Repair as necessary. After repairs, go to step 16 . If connections are okay, go to next step.
Replace MAP sensor. After repairs, go to step 16 .
Repair faulty vacuum source. After repairs, go to next step.
Turn ignition on, with engine off. 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 P0108. If scan tool displays DTC P0108 FAILED THIS IGN, go to step 4 . If scan tool does not display DTC P0108 FAILED THIS IGN, system is okay.

DTC P0108: MAP SENSOR CIRCUIT-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 is a sensor that changes resistance based upon manifold vacuum. PCM provides a 5-volt reference voltage and ground circuit. A PCM-monitored 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 values as an indicator of engine load. If PCM detects a MAP sensor voltage of 5.06 volts or greater, DTC P0108 will set.

For duplication of DTC, ensure DTCs P0122 and P0123 are not set, engine is running, and throttle angle is 20.5 degrees or less.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on, with engine off. Using scan tool, check and note MAP sensor display. If MAP value displayed is greater than 102 kPa, go to next step. If MAP value displayed is not as specified, go to DTC P0106 for diagnosis.
Turn ignition off. Disconnect MAP sensor harness connector. Turn ignition on. If MAP sensor value is less than 16 kPa, go to next step. If MAP sensor value is not as specified, go to step 5 .
Measure voltage between ground and 5-volt reference circuit at MAP sensor harness connector. If voltage is greater than 5.5 volts, go to step 7 . If voltage is not as specified, go to step 8 .
Measure voltage between MAP sensor signal circuit and ground. If voltage reading is greater than.5 volt, go to next step. If voltage reading is not as specified, go to step 10 .
Repair short to voltage in MAP sensor signal circuit.
Repair short to battery voltage in MAP sensor 5-volt reference circuit.
Check terminal contact at MAP sensor. Repair as necessary. If terminal contact is okay, go to next step.
Replace MAP sensor.
Check MAP sensor signal circuit terminal contact at PCM harness connector C1. Repair as necessary. If terminal contacts are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" 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. If VCM detects MAP sensor voltage greater than 4.4 volts for more than one second, DTC P0108 will set.

For duplication of DTC, ensure no TP sensor DTCs are set, engine is running, and throttle position is less then 0.4 percent when engine speed is less than 1200 RPM, or throttle position is less than 20 percent when engine speed is greater than 1200 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.
If idle is unstable, incorrect, or if manifold vacuum at idle is less than 15 in. Hg, repair as necessary. After repairs, install scan tool. With engine idling, monitor MAP sensor voltage using scan tool. If MAP sensor voltage is greater than 4.4 volts, go to next step. If MAP sensor voltage is not greater than 4.4 volts, go to step 4 .
Turn ignition off. Disconnect MAP sensor connector. Turn ignition on. Monitor MAP sensor voltage using scan tool. If MAP sensor voltage is less than one volt, go to step 7 . If MAP sensor voltage is not less than one volt, go to step 10 .
Turn ignition on, with engine off. Monitor Throttle Position (TP) angle on scan tool. If TP angle is less than 2 percent, go to next step. If TP angle is not less than 2 percent, go to DTC P0121 for diagnosis.
Depress accelerator pedal to Wide Open Throttle (WOT). Monitor TP angle on scan tool. If TP angle is 100 percent, go to next step. If TP angle is not 100 percent, go to DTC P0121 for diagnosis.
DTC is intermittent. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If any additional DTCs are set, go to applicable DTC test.
Measure voltage between ground and 5-volt reference circuit at MAP sensor harness connector. If voltage is greater than 5.2 volts, go to step 11 . If voltage is not greater than 5.2 volts, go to next step.
Using a test light connected to battery positive, probe ground circuit at MAP sensor harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 13 .
Replace MAP sensor. After repairs, go to step 18 .
Check MAP sensor signal circuit for a short to voltage. If circuit is shorted, go to step 15 . If circuit is okay, go to step 14 .
Turn ignition off. Disconnect VCM harness connectors. Turn ignition on. Measure voltage between ground and MAP sensor 5-volt reference circuit at VCM harness connector. If voltage is greater than zero volts, go to step 16 . If voltage is not greater than zero volts, go to next step.
Measure voltage between ground and TP sensor 5-volt reference circuit at VCM harness connector. If voltage is greater than zero volts, go to step 16 . If voltage is not greater than zero volts, go to step 17 .
Check for an open in MAP sensor ground circuit. If circuit is open, go to step 15 . If circuit is okay, go to next step.
Check for poor connection at VCM. If connections are faulty, go to next step. If connections are okay, go to step 17 .
Repair circuit or connections as necessary. After repairs, go to step 18 .
Repair short to battery voltage in 5-volt reference circuit. After repairs, go to step 18 .
Replace VCM. Program replacement VCM 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, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

An intermittent ground in MAP signal circuit or 5-volt reference circuit will result in other DTCs. 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 that of a known-good vehicle. Reading should be 3.6-4.9 volts and the 2 readings should be within 0.4 volt of each other. 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 0.1 volt indicate a poor connection or connector. If okay, replace sensor. Ensure electrical connection remains securely connected. If sensor is removed from intake manifold, replace sensor-to-manifold seal.

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES TRUCKS)

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

MAP sensor voltage (depending on altitude) can range from 1.0-1.5 volts at idle (high vacuum) to 4.0-4.9 volts at wide open throttle (low vacuum). When PCM senses a signal voltage greater than 4.3 volts for greater than 4 seconds, DTC P0108 will set.

For duplication of DTC, ensure engine is running, no TP sensor DTCs are set, and TP angle is less than 5 percent when engine speed is no greater than 1000 RPM, or TP angle is less than 18 percent when engine speed is greater than 1000 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.
Start and operate engine at idle. Using scan tool, monitor Failed This Ignition option under DTC information option. If DTC P1635 fails in this ignition cycle, go to step 7 . If DTC P1635 did not fail in this ignition cycle, go to next step.
If idle is unstable or incorrect, repair as necessary. After repairs, install scan tool. With engine idling, monitor MAP sensor voltage using scan tool. If MAP sensor voltage is greater than 4.3 volts, go to step 5 . If MAP sensor voltage is not greater than 4.3 volts, 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, and then enter DTC P0108. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect MAP sensor harness connector. Observe MAP sensor voltage displayed on scan tool. If MAP sensor voltage is less than one volt, go to next step. If MAP sensor voltage is not as specified, go to step 7 .
Using a test light connected to battery positive, probe ground circuit at MAP sensor harness connector. If test light illuminates, go to step 8 . If test light does not illuminate, go to step 10 .
Check MAP sensor signal circuit for a short to voltage 5-volt reference circuit. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 12 .
Measure voltage between ground and 5-volt reference circuit at MAP sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 15 .
Check for plugged or leaking vacuum supply to MAP sensor. If vacuum supply is not okay, go to step 13 . If vacuum supply is not okay, go to step 14 .
Disconnect PCM harness connector C1 (Blue). Measure resistance of MAP sensor ground circuit between MAP sensor and PCM. If resistance is greater than 5 ohms, repair circuit for an open or poor connection as necessary. After repairs, go to step 16 . If resistance is not as specified, go to next step.
Check MAP sensor ground circuit for poor 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 repairs, go to step 16 .
Check for poor connections at MAP sensor harness connector. Repair as necessary. If connections are okay, replace MAP sensor. After repairs, go to step 16 .
Repair faulty vacuum supply. After repairs, go to step 16 .
Repair 5-volt reference circuit for short to battery voltage. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0108. 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, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation.

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (5.7L "F" & "Y" BODIES)

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

MAP sensor voltage (depending on altitude) can range from 1.0-1.5 volts at idle (high vacuum) to 4.0-4.9 volts at wide open throttle (low vacuum). When PCM senses a MAP sensor signal voltage greater than 4.3 volts, DTC P0108 will set.

For duplication of DTC, ensure engine is running, no TP sensor related DTCs are set, TP sensor angle is less than 5 percent when engine speed is less than 1000 RPM, or TP sensor angle is less than 18 percent when engine speed is greater than 1000 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.
Start and operate engine at idle. Using scan tool, monitor FAILED THIS IGNITION option under DTC information option. If scan tool indicates that DTC P1635 failed this ignition, diagnose DTC P1635 first. If scan tool does not indicate that DTC P1635 failed this ignition, go to next step.
If engine is running rough or unstable, repair idle problem first. See appropriate TROUBLE SHOOTING - NO CODES article. After repairs, start engine. Using scan tool, monitor MAP sensor voltage. If MAP sensor voltage is greater than 4.3 volts, go to step 5 . If MAP sensor voltage is not greater than 4.3 volts, 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, and then enter DTC P0108. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect MAP sensor harness connector. Note MAP sensor voltage displayed on scan tool. If MAP sensor voltage is less than one volt, go to next step. If MAP sensor voltage is not less than one volt, go to step 7 .
Using a test light connected to battery positive, probe MAP sensor harness ground circuit. If test light illuminates, go to step 8 . If test light does not illuminate, go to step 10 .
Check MAP sensor signal circuit for short to voltage or to 5-volt reference circuit. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 12 .
Using DVOM, measure voltage between 5-volt reference circuit and battery ground. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 15 .
Check for plugged or leaking vacuum supply to MAP sensor. Repair as necessary. After repairs, go to step 13 . If vacuum supply is okay, go to step 14 .
Check for poor sensor ground terminal connection at PCM. Repair as necessary. After repairs, go to step 16 . If terminal is okay, go to next step.
Measure resistance in MAP sensor ground circuit. If resistance is greater than 2 ohms, repair open or poor terminal connection. After repairs, go to step 16 . If resistance is not greater than 2 ohms, go to next step.
Replace PCM. Program replacement PCM using necessary equipment. After repairs, go to step 16 .
Replace MAP sensor. After repairs, go to step 16 .
Repair vacuum supply to MAP sensor. After repairs, go to step 16 .
Repair 5-volt reference circuit for short to battery voltage. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0108. 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, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

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. If all MAP sensor circuits are okay, check related 5-volt reference circuits.

DTC P0110: IAT SENSOR CIRCUIT (3.0L "V" BODY)

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

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

When intake air is cold, sensor resistance is high. ECM will sense a high signal voltage (low temperature). When intake air is warm, sensor resistance is low. ECM will sense a low signal voltage (high temperature). When IAT signal voltage indicates an intake air temperature greater than 282°F (139°C) or less than -45°F (-43°C), DTC P0110 will set.

For duplication of DTC, ensure engine has been running for at least 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.
Turn ignition on, with engine off. Using scan tool, monitor IAT sensor temperature. If IAT sensor temperature is greater than 282°F (139°C), go to step 6 . If IAT sensor temperature is not greater than 282°F (139°C), go to next step.
If IAT sensor temperature is less than -45°F (-43°C), go to step 8 . If IAT sensor temperature is not less than -45°F (-43°C), go to next step.
Turn ignition on, with engine off. Move IAT sensor and ECM wiring harness and connectors while observing scan tool display. If IAT sensor value on scan tool display changes when moving wiring harness or connectors, go to step 12 . If IAT sensor value on scan tool display does not change when moving wiring harness or connectors, go to next step.
Turn ignition on, with engine off. Review FREEZE FRAME data for this DTC and note parameters. Clear DTCs. Turn ignition off for 15 seconds. Start engine and operate as close to conditions recorded in FREEZE FRAME as possible. Check for DTCs. If DTC P0110 is set, go to next step. If DTC P0110 is not set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Observe scan tool display. If IAT sensor temperature is less than -45°F (-43°C), go to step 17 . If IAT sensor temperature is not less than -45°F (-43°C), go to next step.
Turn ignition off. Disconnect ECM harness connector, located in engine compartment relay center. Using DVOM, check for continuity between IAT sensor signal circuit and ground. If continuity is present, go to step 13 . If continuity is not present, go to step 19 .
Disconnect IAT sensor connector. Jumper IAT sensor harness connector terminals together. Observe scan tool display. If IAT sensor temperature is greater than 282°F (139°C), go to step 16 . If IAT sensor temperature is not greater than 282°F (139°C), go to next step.
Jumper IAT sensor signal circuit to a known-good ground. Observe scan tool display. If IAT sensor temperature is greater than 282°F (139°C), go to step 11 . If IAT sensor temperature is not greater than 282°F (139°C), go to next step.
Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Using DVOM, check continuity of sensor signal circuit between ECM and IAT sensor harness connectors. If continuity is present, go to step 18 . If continuity is not present, go to step 14 .
Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Using DVOM, check continuity of sensor ground circuit between ECM and IAT sensor harness connectors. If continuity is present, go to step 18 . If continuity is not present, go to step 15 .
Repair harness or connections as necessary. After repairs, go to step 20 .
Repair short to ground in signal circuit. After repairs, go to step 20 .
Repair open or high resistance in signal circuit. After repairs, go to step 20 .
Repair open or high resistance in ground circuit. After repairs, go to step 20 .
Check for poor connections and terminal tension at IAT sensor harness connector. Repair as necessary. After repairs, go to step 20 . If connections and terminals are okay, go to next step.
Replace IAT sensor. After repairs, go to step 20 .
Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 20 . 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 repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate as close to conditions recorded in FREEZE FRAME as possible. Check for DTCs. If DTC P0110 is set, go to step 2 . If DTC P0110 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

If other DTCs are set that share the same ground circuit, check point where circuits ground to chassis or engine block. If engine has been allowed to sit over night, engine coolant temperature and engine intake air temperature values should display within a few degrees of each other.

When checking IAT sensor, test sensor at various temperature levels to check for shifted sensor. See appropriate SENSOR OPERATING RANGE CHARTS article. A shifted sensor could result in poor driveability complaints.

DTC P0111: IAT SENSOR CIRCUIT PERFORMANCE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

The IAT sensor is a thermistor that varies resistance based on temperature. Low temperature will result in a high signal voltage. This test monitors IAT sensor voltage. If PCM detects a 0.3 volt change in IAT sensor signal in a.25 second period, DTC P0111 will set.

For duplication of DTC, ensure 2 seconds have passed since key ON.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If DTC P0112 or P0113 is also present, diagnose affected DTCs first. If other DTCs are not present, go to next step.
Turn ignition on, with engine off. Using scan tool, select FAILURE RECORD in DTC mode and note IAT snapshot display. If snapshot reading is less than -29°F (-34°C), go to next step. If snapshot reading is not less than -29°F (-34°C), go to step 5 .
An intermittent high resistance reading occurred on IAT sensor circuit. Check for open in IAT ground circuit and IAT signal circuit. Repair as necessary. If circuits are okay, go to step 7 .
If snapshot IAT sensor reading is greater than 291°F (144°C), go to next step. If reading is not greater than 291°F (144°C), go to step 7 .
An intermittent low resistance reading occurred in the IAT sensor circuit. Check for possible short to ground in IAT sensor signal circuit. Repair as necessary. If circuit is okay, go to next step.
Artificially raise IAT temperature, from cool to warm. As IAT sensor warms, watch IAT sensor reading on scan tool. Look for a skip or jump in the value. If a skip or jump is noted, go to next step. If value did not skip or jump, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Replace IAT sensor.

Artificially changing the IAT temperature can be done by careful warming using heat gun or by cooling IAT in refrigerator, and then allowing it to warm. Ensure sensor temperature-to-resistance is as specified. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0112: IAT SENSOR CIRCUIT-HIGH TEMPERATURE (1.9L SATURN)

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

Intake Air Temperature (IAT) sensor is a thermistor located in the air intake passage of the air induction system. When sensor is cold, resistance is high. Resistance decreases as sensor temperature increases. PCM supplies and monitors a 5-volt signal circuit to the sensor which is also connected to ground. PCM reads voltage drop on the sensor signal line to determine air temperature.

DTC will set if IAT reading is less than -22°F (-30°C) when engine run time is greater than 10 seconds, vehicle speed less than 15 MPH, airflow is less than 16 gm/s and no VSS DTC is present and if conditions are met for about 6 seconds.

Note. A short to battery voltage on IAT sensor signal circuit will damage IAT sensor. If circuit is found to be shorted, test sensor for proper resistance. See appropriate SENSOR OPERATING RANGE CHARTS article.

Turn ignition on. Using scan tool, monitor IAT sensor reading. If IAT sensor reading is greater than 257°F (125°C), go to next step. If IAT sensor reading is not greater than 257°F (125°C), problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Using scan tool, monitor IAT sensor reading. If IAT sensor reading is less than -22°F (-30°C), replace IAT sensor. If IAT sensor reading is not less than -22°F (-30°C), go to next step.
Turn ignition off. Disconnect PCM harness connector J2. Turn ignition on. Using scan tool, monitor IAT sensor reading. If IAT sensor reading is less than -22°F (-30°C), go to next step. If IAT sensor reading is not less than -22°F (-30°C), replace PCM.
Repair short to ground or short to IAT sensor ground circuit in IAT sensor signal circuit between IAT sensor and PCM.

Use scan tool to review malfunction history diagnostic information. This data can be used to duplicate intermittent problems. Check tightness of harness connector terminals.

Using scan tool, compare ECT and IAT temperature after engine has cooled overnight at ambient temperature. ECT and IAT temperatures should be within 4 degrees of each other with ignition on, engine off. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (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) supplies and monitors a 5-volt reference signal and a ground circuit to Intake Air Temperature (IAT) sensor. When intake air is cold, sensor resistance is high and when intake air is warm, sensor resistance low. When PCM senses a signal voltage lower (temperature higher) than the normal operating range of the sensor, DTC P0112 will set.

For duplication of DTC, ensure engine has been running for more than 6 minutes, vehicle speed is greater than 15 MPH, and IAT sensor signal voltage indicates IAT temperature is greater than 262°F (128°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 on, with engine off. Using scan tool, observe IAT sensor value. If IAT sensor value is greater than 262°F (128°C), go to step 4 . If IAT sensor value is not greater than 262°F (128°C), go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Note IAT sensor value displayed on scan tool. If IAT sensor value is greater than 262°F (128°C), go to next step. If IAT value is not greater than 262°F (128°C), no problem is indicated at this time. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor connector. Note IAT sensor value displayed on scan tool. If IAT sensor value is less than -22°F (-30°C), go to next step. If IAT sensor value is not less than -22°F (-30°C), go to step 6 .
Replace IAT sensor. After repairs, go to step 10 .
Turn ignition off. Connect a test light between positive battery terminal and signal circuit terminal at IAT sensor harness connector. If test light illuminates, go to next. If test light does not illuminate, go to step 9 .
Turn ignition off. Disconnect PCM harness connector. Connect test light between battery positive terminal and signal circuit at IAT sensor harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 9 .
Repair short to ground in IAT sensor signal circuit. After repairs, go to step 10 .
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. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter 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 , go to step 2 .
Check if additional DTCs are set. Diagnose affected DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation.

If other DTCs are set for components that share the same ground and/or 5-volt reference circuit, check for faulty connections or wiring. PCM 5-volt reference circuits are internally connected within PCM.

If engine is allowed to sit overnight, ECT and IAT sensor values should be within a few degrees of each other. If sensor temperatures are not within a few degrees of each other, test IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

Intake Air Temperature (IAT) 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 IAT signal voltage indicates an intake air temperature greater than 275°F (135°C).

For duplication of DTC, ensure engine has been running greater than 10 seconds, no active ECT or VSS sensor related DTCs are present, and vehicle speed is greater than 25 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. Using scan tool, read INTAKE AIR TEMP. If temperature is greater than 266°F (130°C), go to step 4 . If temperature is not as specified, go to next step.
Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0112 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0112 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If sensor temperature is less than -30°F (-22°C), go to step 6 . If temperature is -30°F (-22°C) or greater, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Check IAT sensor signal circuit for short to ground. If short is found, go to step 7 . If circuit is okay, go to step 8 .
Replace IAT sensor. After repairs, go to step 9 .
Repair IAT sensor signal circuit. After repairs, go to step 9 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, with engine off. 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 P0112. If scan tool displays DTC P0112 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0112 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe IAT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (3.5L "W" BODY)

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. As temperature of sensor increases, resistance decreases. High temperature will result in a low signal voltage. DTC P0112 will set when IAT signal voltage indicates an intake air temperature greater than 275°F (135°C).

For duplication of DTC, ensure engine has been running greater than 10 seconds, no active ECT or VSS sensor related DTCs are present, and vehicle speed is greater than 25 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. Using scan tool, read INTAKE AIR TEMP. If temperature is greater than 266°F (130°C), go to step 4 . If temperature is not as specified, go to next step.
Turn ignition off and wait 15 seconds. Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0112 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0112 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If sensor temperature is less than -36°F (-38°C), go to step 6 . If temperature is -36°F (-38°C) or greater, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Check IAT sensor signal circuit for short to ground or short to IAT sensor ground circuit. If short is found, go to step 7 . If circuit is okay, go to step 8 .
Replace IAT sensor. After repairs, go to step 9 .
Repair IAT sensor signal circuit. After repairs, go to step 9 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, with engine off. 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 P0112. If scan tool displays DTC P0112 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0112 FAILED THIS IGN, go to next step.
Check if additional DTCs are set. Diagnose affected DTCs as necessary. If no other DTCs are set, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe IAT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (3.8L "C", "F", "G", "H" & "W" 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. As temperature of sensor increases, resistance decreases. High temperature will result in a low signal voltage. DTC P0112 will set when IAT signal voltage indicates an intake air temperature greater than 275°F (135°C) for 20 seconds or more.

For duplication of DTC, ensure engine has been running for longer than 10 seconds, no VSS, ECT or MAF sensor DTCs are set, and vehicle speed is greater than 25 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 INTAKE AIR TEMP. If temperature is greater than 266°F (130°C), go to step 4 . If temperature is not greater than 266°F (130°C), go to next step.
Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0112 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0112 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If IAT sensor temperature is less than -36°F (-38°C), go to step 6 . If temperature is not less than -36°F (-38°C), go to next step.
Turn ignition off. Disconnect PCM harness connectors. Check IAT sensor signal circuit for short to ground. If short is found, go to step 7 . If circuit is okay, go to step 8 .
Replace IAT sensor. After repairs, go to step 9 .
Repair IAT sensor signal circuit. After repairs, go to step 9 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, with engine off. 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 P0112. If scan tool displays DTC P0112 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0112 FAILED THIS IGN, system is okay.

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

The IAT 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 P0112 will set when PCM sees an IAT sensor reading of 282°F (139°C) when coolant temperature is less than 230°F (110°C).

For duplication of DTC, ensure DTCs P0117 and P0118 are not set, engine coolant temperature is 230°F (110°C) or less, and vehicle speed is 15 MPH or greater.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, monitor IAT sensor display. If IAT temperature reading is 282°F (139°C) or greater, go to next step. If IAT temperature reading is not greater than 282°F (139°C), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. If IAT temperature reading is 282°F (139°C) or greater, go to next step. If IAT temperature reading is not greater than 282°F (139°C), go to step 6 .
Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, and then disconnect PCM harness connector C2. Using DVOM, measure resistance of IAT signal circuit between PCM harness connector and ground. If resistance is greater than 10,000 ohms, go to step 8 . If resistance is not greater than 10,000 ohms, go to next step.
Repair IAT sensor signal circuit for short to ground or short to IAT ground circuit.
Check terminal contact at IAT sensor. Repair as necessary. If terminal contact is okay, go to next step.
Replace IAT sensor.
Check terminal contact at PCM. Repair as necessary. If terminal contact is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

IAT sensor can be damaged by backfire in intake manifold. If more than one IAT sensor has been replaced, check for signs of engine backfire.

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

Note. For circuit reference, see appropriate wiring diagrams 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 and monitors 5-volt reference circuit 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 P0112 will set if IAT voltage is less than a calibrated value for more than 5 seconds.

For duplication of DTC, ensure engine has been running for more than 100 seconds, no VSS DTCs are set, and vehicle speed is greater than 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.
Install scan tool. Start engine. Using scan tool, monitor IAT sensor voltage. If voltage is less than.82 volt, go to next step. If voltage is not less than.82 volt, go to step 5 .
Turn engine off. Disconnect IAT sensor connector. Turn ignition on. Monitor IAT sensor voltage on scan tool. If voltage is greater than 4 volts, go to step 7 . If voltage is not greater than 4 volts, go to next step.
Turn ignition off. Disconnect VCM harness connector C2. Using DVOM, check IAT sensor signal circuit for short to ground. If circuit is shorted, go to step 6 . If circuit is okay, go to step 8 .
DTC is intermittent. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If any additional DTCs are set, go to applicable DTC test.
Repair short to ground in IAT signal circuit. After repairs, go to step 9 .
Replace IAT sensor. After repairs, go to step 9 .
Replace VCM. Program replacement VCM and perform Passlock® reprogramming and CKP system variation learn procedures 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, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

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 P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES & 5.7L "F" & "Y" BODIES)

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 sensor is located in air intake passage of engine air induction system. IAT sensor has a signal circuit and a ground circuit. PCM applies 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 air temperature.

When intake air is cold, sensor resistance is high and when intake air is warm, sensor resistance low. When PCM detects an intake air temperature greater than 282°F (139°C) for 5 seconds, DTC P0112 will set.

For duplication of DTC, ensure DTCs P0101, P0102, P0103, P0117, P0118, P0125, P0500, P0502, and P0503 are not set, engine has been running for more than 30 seconds and vehicle speed is greater than 25 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, monitor IAT display. If IAT reading is greater than 282°F (139°C), go to step 4 . If IAT reading is not greater than 282°F (139°C), 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, and then enter DTC P0112. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Note IAT sensor value displayed on scan tool. IAT sensor value should be -38°F (-39°C). If IAT value is as specified, go to step 6 . If IAT value is not as specified, go to next step.
Turn ignition off. Disconnect PCM harness connector C2 and check IAT signal circuit for short to ground. Repair as necessary. After repairs, go to step 8 . If circuit is okay, go to step 7 .
Replace IAT sensor. After repairs, go to step 8 .
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, and then enter DTC P0112. 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, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

If engine is allowed to sit overnight, ECT and IAT sensor values should be within a few degrees of each other. If temperatures are not within 5°F (3°C), see appropriate SENSOR OPERATING RANGE CHARTS article. If it is determined that DTC is intermittent, performing DTC P1112 diagnostics may isolate cause of fault.

DTC P0113: IAT SENSOR CIRCUIT-LOW TEMPERATURE (1.9L SATURN)

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

Intake Air Temperature (IAT) sensor is a thermistor located in the air intake passage of the air induction system. When sensor is cold, resistance is high and decreases as sensor temperature increases. PCM supplies a 5-volt signal to the sensor which is also connected to ground. PCM reads voltage drop on the sensor signal line to determine air temperature.

DTC P0113 will set if IAT reading is less than -22°F (-30°C) when engine run time is greater than 10 seconds, no VSS DTCs are present, air flow is less than 16 gm/second, and vehicle speed is less than 15 MPH. All conditions must be met for about 6 seconds.

Turn ignition on. Connect scan tool and monitor IAT sensor reading. If IAT reading is less than 22°F (30°C), go to next step. If IAT sensor reading is not less than 22°F (30°C), problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Using a fused jumper wire, jumper terminals together at IAT sensor harness connector. If IAT reading is greater than 266°F (130°C), replace IAT sensor. If IAT reading is not greater than 266°F (130°C), go to next step.
Remove jumper wire, and then jumper IAT signal circuit to ground. If IAT reading is greater than 266°F (130°C), go to next step. If IAT reading is not greater than 266°F (130°C), go to step 5 .
Using DVOM, check for continuity in IAT sensor ground circuit between IAT sensor and PCM. If continuity is present, connections or PCM is faulty. If continuity is not present, repair open ground circuit.
Turn ignition off. Disconnect PCM harness connectors. Using DVOM, check for continuity in IAT sensor signal circuit between IAT sensor and PCM. If continuity is present, connections or PCM is faulty. If continuity is not present, repair open signal circuit.

Use scan tool to review malfunction history diagnostic information. This data can be used to duplicate intermittent problems. Check tightness of harness connector terminals. DTC can also set if vehicle has been in extremely cold ambient temperature of -35°F (-37°C).

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (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) supplies and monitors a 5-volt reference signal and a ground circuit to Intake Air Temperature (IAT) sensor. When intake air is cold, sensor resistance is high and when intake air is warm, sensor resistance low. When IAT sensor signal voltage indicates an intake air temperature less than -40°F (-40°C) for more than 3 seconds, DTC P0113 will set.

For duplication of DTC, ensure engine has been running for more than 6 minutes, engine coolant temperature is greater than -40°F (-40°C), and vehicle speed is greater than 24 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, observe IAT sensor value. If IAT sensor value is less than -22°F (-30°C), go to step 4 . If IAT sensor value is not less than -22°F (-30°C), go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Note IAT sensor value displayed on scan tool. If IAT sensor value is less than -22°F (-30°C), go to next step. If IAT value is not less than -22°F (-30°C), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect IAT sensor connector. Connect a jumper wire between signal circuit and sensor ground circuit terminals at IAT sensor harness connector. Turn ignition on. Note IAT sensor value displayed on scan tool. If IAT sensor value is greater than 266°F (130°C), go to step 6 . If IAT sensor value is not greater than 266°F (130°C), go to next step.
Connect a jumper wire between ground and signal circuit terminal at IAT sensor harness connector. Note IAT sensor value displayed on scan tool. If IAT sensor value is greater than 266°F (130°C), go to step 7 . If IAT sensor value is not greater than 266°F (130°C), go to step 8 .
Turn ignition off. Check for poor connection at IAT sensor. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 10 .
Turn ignition off. Check for an open IAT sensor ground circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 9 .
Turn ignition off. Check for an open or short to voltage in IAT sensor signal circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for poor IAT sensor ground or a poor IAT sensor signal circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuits are okay, go to step 11 .
Replace IAT sensor. After repairs, go to step 12 .
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. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0113. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed through wire insulation or broken wire inside insulation.

If engine is allowed to sit overnight, ECT and IAT sensor values should be within a few degrees of each other. If temperatures are not within a few degrees of each other, test IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0113: IAT SENSOR CIRCUIT-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 that varies resistance based on temperature. As temperature of sensor increases, resistance decreases. Low temperature will result in a high signal voltage. DTC P0113 will set when PCM sees an IAT sensor voltage of greater than 5 volts.

For duplication of DTC, ensure

No ECT or VSS sensor DTCs are set.
Vehicle speed is less than 35 MPH.
MAF value is less than 12 grams per second.
Engine coolant temperature is greater than 140°F (60°C).
IAT signal voltage indicates an intake air temperature less than -35°F (-37°C).

All conditions must be present for at least 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, read INTAKE AIR TEMP. If temperature is less than -22°F (-30°C), go to step 4 . If temperature is not as specified, go to next step.
Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0113 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0113 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Connect a jumper wire between signal and ground circuits at IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If temperature is greater than 266°F (130°C), go to step 6 . If temperature is not as specified, go to next step.
Connect jumper wire between chassis ground and signal circuit at IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If temperature is greater than 266°F (130°C), go to step 7 . If temperature is not as specified, go to step 8 .
Check for faulty connection at IAT sensor. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 10 .
Turn ignition off. Disconnect PCM harness connectors. Check IAT sensor ground circuit for an open. Repair as necessary. After repairs, go to step 12 . If no open is found, go to step 9 .
Turn ignition off. Disconnect PCM harness connectors. Check IAT signal circuit for an open. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for faulty IAT signal or ground circuit connection at PCM. Repair as necessary. After repairs, go to step 12 . If connections are okay, go to step 11 .
Replace IAT sensor. After repairs, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0113. If scan tool displays DTC P0113 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0113 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe IAT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (3.5L "W" BODY)

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. As temperature of sensor increases, resistance decreases. High temperature will result in a low signal voltage. DTC P0113 will set when IAT signal voltage indicates an intake air temperature less than -29°F (-34°C).

For duplication of DTC, ensure

Engine has been running for more than 3 minutes.
No active ECT, MAF or VSS sensor related DTCs are present.
Vehicle speed is greater than 25 MPH.
Mass air flow is greater than 12 grams per second.
Engine coolant temperature is less than 140°F (60°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, read INTAKE AIR TEMP. If temperature is less than -24°F (-31°C), go to step 4 . If temperature is not as specified, go to next step.
Turn ignition off and wait 15 seconds. Turn ignition on. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0113 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0113 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Connect a jumper wire between signal and ground circuits at IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If temperature is greater than 266°F (130°C), go to step 6 . If temperature is not as specified, go to next step.
Connect jumper wire between chassis ground and signal circuit at IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If temperature is greater than 266°F (130°C), go to step 7 . If temperature is not as specified, go to step 8 .
Check for faulty connection at IAT sensor. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 10 .
Turn ignition off. Disconnect PCM harness connectors. Check IAT sensor ground circuit for an open. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 9 .
Turn ignition off. Disconnect PCM harness connectors. Check IAT signal circuit for an open. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for faulty IAT signal or ground circuit connection at PCM. Repair as necessary. After repairs, go to step 12 . If connections are okay, go to step 11 .
Replace IAT sensor. After repairs, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off and wait 15 seconds. Turn ignition on. Read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Select SPECIFIC DTC INFO for DTC P0113. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe IAT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (3.8L "C", "F", "G" & "H" 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. As temperature of sensor increases, resistance decreases. Low temperature will result in a high signal voltage. DTC P0113 will set when IAT signal voltage indicates an intake air temperature less than -36°F (-38°C).

For duplication of DTC, ensure no ECT, MAF or VSS DTCs are set, engine has been running for more than 3 minutes, vehicle speed is less than 5 MPH, MAF value is less than 8 grams per second, and ECT is greater than 140°F (60°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 on, engine off. Using scan tool, read INTAKE AIR TEMP. If temperature is less than -36°F (-38°C), go to step 4 . If temperature is not less than -36°F (-38°C), go to next step.
Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0113 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0113 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Connect a jumper wire between signal and ground circuits at IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If IAT is greater than 275°F (135°C), go to step 6 . If IAT is not greater than 275°F (135°C), go to next step.
Connect jumper wire between chassis ground and signal circuit at IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If IAT is greater than 275°F (135°C), go to step 7 . If IAT is not greater than 275°F (135°C), go to step 8 .
Check for short to voltage or faulty connection at IAT sensor. Repair as necessary. After repairs, go to step 12 . If no problem is found, go to step 10 .
Turn ignition off. Disconnect PCM harness connectors. Check IAT sensor ground circuit for an open. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 9 .
Turn ignition off. Disconnect PCM harness connectors. Check IAT signal circuit for an open. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for faulty IAT signal or ground circuit connection at PCM. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 11 .
Replace IAT sensor. After repairs, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0113. If scan tool displays DTC P0113 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0113 FAILED THIS IGN, system is okay.

If DTC cannot be duplicated, the information included in the Failure Records data can be used in determining vehicle mileage since DTC was last set.

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (3.8L "W" BODY)

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. As temperature of sensor increases, resistance decreases. Low temperature will result in a high signal voltage. DTC P0113 will set when IAT signal voltage indicates an intake air temperature less than -29°F (-34°C).

For duplication of DTC, ensure no ECT, MAF or VSS DTCs are set, engine has been running for more than 3 minutes, vehicle speed is less than 35 MPH, MAF value is less than 12 grams per second, and ECT is greater than 140°F (60°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 on, engine off. Using scan tool, read INTAKE AIR TEMP. If temperature is less than -24°F (-31°C), go to step 4 . If temperature is not less than -24°F (-31°C), go to next step.
Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0113 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0113 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Connect a jumper wire between signal and ground circuits at IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If IAT is 284°F (140°C), go to step 6 . If IAT is not 284°F (140°C), go to next step.
Connect jumper wire between chassis ground and signal circuit at IAT sensor harness connector. Using scan tool, read INTAKE AIR TEMP. If scan tool temperature is 284°F (140°C), go to step 7 . If scan tool temperature is not 284°F (140°C), go to step 8 .
Check for faulty connection at IAT sensor. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 10 .
Turn ignition off. Disconnect PCM harness connectors. Check IAT sensor ground circuit for an open. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 9 .
Turn ignition off. Disconnect PCM harness connectors. Check IAT signal circuit for an open. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for faulty IAT signal or ground circuit connection at PCM. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 11 .
Replace IAT sensor. After repairs, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0113. If scan tool displays DTC P0113 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0113 FAILED THIS IGN, system is okay.

If DTC cannot be duplicated, the information included in the Failure Records data can be used in determining vehicle mileage since DTC was last set.

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

The IAT sensor is a thermistor that varies resistance based on temperature. As temperature of sensor increases, resistance decreases. Low temperature will result in a high signal voltage. DTC P0113 will set when PCM sees an IAT sensor reading of -35°F (-37°C) or less with engine operating conditions that should have raised IAT temperature.

For duplication of DTC, ensure

DTCs P0101, P0102, P0117 and P0118 are not set.
Engine speed is 500 RPM or greater for 20 seconds.
Vehicle speed has been greater than 7 MPH for 5 seconds in this engine run cycle.
MAF input is 60 grams per second or less.
Vehicle speed is 50 MPH or less.
ECT is 32°F (0°C) or greater, or ECT is less than 32°F (0°C) and IAT is at least 81°F (27°C) less than ECT.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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, note IAT display. If IAT reading is -35°F (-37°C) or less, go to next step. If IAT reading is greater than -35°F (-37°C), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Using jumper wire, jumper IAT sensor harness connector terminals "A" and "B". If IAT reading is 247°F (147°C) or greater, go to next step. If IAT reading is less than 247°F (147°C), go to step 5 .
Check terminal contact at IAT sensor. Repair as necessary. If terminal contact is okay, go to step 10 .
Using jumper wire, jumper IAT sensor connector terminal "A" to ground. If IAT temperature reading is 247°F (147°C) or greater, go to next step. If IAT temperature reading is less than 247°F (147°C), go to step 7 .
Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, and then disconnect PCM harness connector C1. Using DVOM, measure resistance of IAT sensor ground circuit between IAT sensor and PCM harness connectors. If resistance is 5 ohms or less, go to step 11 . If resistance is not 5 ohms or less, go to step 8 .
Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, and then disconnect PCM harness connector C2. Using DVOM, measure resistance between IAT harness connector terminal "A" and IAT sensor signal circuit at PCM harness connector C2. If resistance is 5 ohms or less, go to step 11 . If resistance is not 5 ohms or less, go to step 9 .
Repair open in IAT sensor ground circuit.
Repair open in IAT sensor signal circuit.
Replace IAT sensor.
Check terminal contact at PCM harness connectors. Repair as necessary. If terminal contact is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

IAT sensor can be damaged by backfire in intake manifold. If IAT sensor has been replaced more than once, check for signs of backfire.

Under severe cold weather conditions, this DTC could set if the actual outside temperature (IAT) is less than -35°F (-37°C) and ECT is at least 81°F (27°C) warmer than IAT.

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" 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 and monitors the 5-volt reference circuit 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 P0113 will set when IAT voltage is greater than 4.9 volts for more than 5 seconds.

For duplication of DTC, ensure no ECT, MAF and VSS sensor DTCs are set, vehicle speed is less than 2 MPH, MAF is less than 250 grams per second, engine coolant temperature is greater than 185°F (85°C), and engine run time is greater than 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.
Install scan tool. Start engine. Using scan tool, monitor IAT sensor voltage. If voltage is greater than 4.9 volts, go to next step. If voltage is not greater than 4.9 volts, go to step 6 .
Turn engine off. Disconnect IAT sensor connector. Turn ignition on. Connect a jumper wire between IAT sensor terminals. Monitor IAT sensor voltage on scan tool. If voltage is less than.82 volt, go to step 5 . If voltage is not less than.82 volt, go to next step.
Connect a jumper wire between IAT signal circuit of IAT sensor connector and ground. Monitor IAT sensor voltage on scan tool. If voltage is less than.82 volt, go to step 8 . If voltage is not less than.82 volt, go to step 9 .
Measure voltage between IAT sensor signal circuit and a known-good ground. If voltage is greater than 5.2 volts, go to step 10 . If voltage is not greater than 5.2 volts, go to step 7 .
DTC is intermittent. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If any additional DTCs are set, go to applicable DTC test.
Check for poor connections at IAT sensor and VCM. If a problem is found, go to step 11 . If no problem is found, go to step 12 .
Check for open in IAT ground circuit between IAT sensor and VCM. If IAT ground circuit is open, go to step 11 . If IAT ground circuit is okay, go to step 13 .
Check for open in IAT signal circuit between IAT sensor and VCM. If IAT signal circuit is open, go to step 11 . If IAT signal circuit is okay, go to step 13 .
Repair short to voltage in IAT sensor signal circuit. After repairs, go to step 14 .
Repair circuit as necessary. After repairs, go to step 14 .
Replace IAT sensor. After repairs, go to step 14 .
Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP system variation learn procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

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 at various locations 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 P0113: IAT SENSOR CIRCUIT-HIGH 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 when intake air is warm, sensor resistance low. When PCM detects an intake air temperature less than -31°F (-35°C) for 5 seconds, DTC P0113 will set.

For duplication of DTC, ensure DTCs P0101, P0102, P0103, P0117, P0118, P0125, P0500, P0502, and P0503 are not set, engine coolant temperature is greater than 32°F (0°C), vehicle speed is less than 7 MPH, and MAF is less than 15 grams per 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.
Connect scan tool. Turn ignition on. Monitor IAT sensor display on scan tool. If scan tool displays -38°F (39°C), go to next step. If scan tool does not display -38°F (39°C), go to step 4 .
If DTCs P1635 and P1639 are also set, go to step 14 . If DTCs P1635 and P1639 are not set, go to step 5 .
Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Turn ignition off for 15 seconds. Start engine. Operate vehicle within conditions required to set DTC and as close to conditions noted in FAILURE RECORDS data as possible. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0113 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0113 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect MAF/IAT sensor connector. Using a fused jumper wire, jumper IAT sensor terminals together at harness connector. Observe IAT parameter on scan tool. If scan tool displays 284°F (140°C), go to step 8 . If scan tool does not display 284°F (140°C), go to next step.
Using a fused jumper wire, jumper IAT sensor signal circuit to a known-good ground. If scan tool displays 284°F (140°C), go to step 10 . If scan tool does not display 284°F (140°C), go to next step.
Turn ignition off. Disconnect PCM harness connector C2. Check IAT sensor signal circuit for an open. If circuit is open, go to step 11 . If circuit is okay, go to step 16 .
Turn ignition off. Remove jumper wire from IAT sensor harness connector. Disconnect PCM harness connectors. Turn ignition on. Using DVOM, check for voltage between ground and IAT sensor signal circuit at PCM harness connector. If voltage is present, go to step 14 . If voltage is not present, go to next step.
Using DVOM, check for continuity between IAT sensor signal circuit and all other circuits at PCM harness connectors. If DVOM displays 0-2 ohms resistance at any circuit, go to step 15 . If continuity is not present in any circuit, go to step 12 .
Turn ignition off. Disconnect PCM harness connector C2. Check IAT sensor ground circuit for an open. If circuit is open, go to step 13 . If circuit is okay, go to step 16 .
Repair IAT sensor signal circuit. After repairs, go to step 18 .
Replace IAT sensor. After repairs, go to step 18 .
Repair IAT sensor ground circuit. After repairs, go to step 18 .
Repair IAT sensor signal circuit for a short to voltage. After repairs, go to step 18 .
Repair short between IAT sensor signal circuit and PCM circuit that indicated continuity. After repairs, go to step 18 .
Inspect PCM harness connector for poor connections. Repair as necessary. After repairs, go to step 18 . If connections are okay, go to next step.
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, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

DTC P0113: IAT SENSOR CIRCUIT-HIGH 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 when intake air is warm, sensor resistance low. When IAT sensor indicates a temperature less than -31°F (-35°C), DTC P0113 will set.

For duplication of DTC, ensure DTCs P0101, P0102, P0103, P0117, P0118, P0125, P0500, P0502, P0503 or P1258 are not set, engine coolant temperature is greater than 32°F (0°C), vehicle speed is less than 7 MPH, and MAF is less than 15 grams per 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 display. If IAT value is -38°F (-39°C), go to next step. If IAT value is not as specified, go to step 4 .
If DTCs P1635 and P1639 are also set, go to step 14 . If DTCs P1635 and P1639 are not set, go to step 5 .
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, and then enter DTC P0113. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect IAT sensor harness connector. Connect a fused jumper wire across IAT sensor harness connector terminals. Note IAT sensor value displayed on scan tool. If IAT value is 284°F (140°C), go to step 8 . If IAT value is not as specified, go to next step.
Connect jumper wire between IAT sensor signal circuit and known-good ground. Note IAT sensor value displayed on scan tool. If IAT value is 284°F (140°C), go to step 10 . If IAT value is not as specified, go to next step.
Turn ignition off. Disconnect PCM harness connector C2. Check IAT signal circuit for open. If circuit is open, go to step 11 . If circuit is okay, go to step 16 .
Turn ignition off. Remove jumper wire from IAT sensor harness connector. Disconnect PCM harness connectors. Turn ignition on. Using a DVOM, check for voltage between ground and IAT sensor signal circuit at PCM harness connector. If voltage is present, go to step 14 . If voltage is not present, go to next step.
Using DVOM, check for continuity between IAT sensor signal circuit and all other circuits at PCM harness connectors. If DVOM displays 0-2 ohms resistance at any circuit, go to step 15 . If continuity is not present in any circuit, go to step 12 .
Turn ignition off. Disconnect PCM harness connector C2. Check IAT sensor ground circuit for an open. If circuit is open, go to step 13 . If circuit is okay, go to step 16 .
Repair IAT sensor signal circuit. After repairs, go to step 18 .
Replace IAT sensor. After repairs, go to step 18 .
Repair IAT sensor ground circuit. After repairs, go to step 18 .
Repair IAT sensor signal circuit for a short to voltage. After repairs, go to step 18 .
Repair short between IAT sensor signal circuit and PCM circuit that indicated continuity. After repairs, go to step 18 .
Check PCM for poor harness connections. Repair as necessary. After repairs, go to step 18 . If connections are okay, go to next step.
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, and then enter DTC P0113. 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. If no undiagnosed DTCs are displayed, system is okay.

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 P0115: ECT SENSOR CIRCUIT (3.0L "V" BODY)

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

Engine Coolant Temperature (ECT) sensor contains a thermistor which changes resistance based on temperature. ECT sensor is located in coolant crossover pipe at center rear of engine. Sensor has a signal and ground circuit. ECM applies about 5 volts on signal circuit of sensor. ECM monitors changes in voltage caused by changes in resistance of sensor to determine engine coolant temperature.

When engine coolant is cold, sensor resistance is high. ECM will sense a high signal voltage (low temperature). When engine coolant is warm, sensor resistance is low. ECM will sense a low signal voltage (high temperature). When ECT signal voltage indicates an engine coolant temperature greater than 282°F (139°C) or less than -45°F (-43°C), DTC P0115 will set. For duplication of DTC, ensure 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, monitor ECT sensor temperature. If ECT sensor temperature is greater than 282°F (139°C), go to step 6 . If ECT sensor temperature is not greater than 282°F (139°C), go to next step.
If ECT sensor temperature is less than -45°F (-43°C), go to step 8 . If ECT sensor temperature is -45°F (-43°C) or greater, go to next step.
Turn ignition on, with engine off. Move/wiggle ECT sensor and ECM wiring harness and connectors while observing scan tool display. If ECT sensor value on scan tool display changes when moving wiring harness or connectors, go to step 12 . If ECT sensor value on scan tool display does not change when moving wiring harness or connectors, go to next step.
Turn ignition on, with engine off. Review FREEZE FRAME data for this DTC and note parameters. Clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Check for DTCs. If DTC P0115 is set, go to next step. If DTC P0115 is not set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect ECT sensor connector. Observe scan tool display. If ECT sensor temperature is less than -45°F (-43°C), go to step 17 . If ECT sensor temperature is -45°F (-43°C) or greater, go to next step.
Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Using DVOM, check for continuity between ECT sensor signal circuit and ground. If continuity is present, go to step 13 . If continuity is not present, go to step 19 .
Disconnect ECT sensor connector. Jumper ECT sensor harness connector terminals together. Observe scan tool display. If ECT sensor temperature is greater than 282°F (139°C), go to step 16 . If ECT sensor temperature is not greater than 282°F (139°C), go to next step.
Jumper ECT sensor signal circuit to a known-good ground. Observe scan tool display. If ECT sensor temperature is greater than 282°F (139°C), go to step 11 . If ECT sensor temperature is not greater than 282°F (139°C), go to next step.
Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Using DVOM, check continuity of sensor signal circuit between ECM and ECT sensor harness connectors. If continuity is present, go to step 18 . If continuity is not present, go to step 14 .
Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Using DVOM, check continuity of sensor ground circuit between ECM and ECT sensor harness connectors. If continuity is present, go to step 18 . If continuity is not present, go to step 15 .
Repair harness or connections as necessary. After repairs, go to step 20 .
Repair short to ground in signal circuit. After repairs, go to step 20 .
Repair open or high resistance in signal circuit. After repairs, go to step 20 .
Repair open or high resistance in ground circuit. After repairs, go to step 20 .
Check for poor connections and terminal tension at ECT sensor harness connector. Repair as necessary. After repairs, go to step 20 . If connections and terminals are okay, go to next step.
Replace ECT sensor. After replacing sensor, go to step 20 .
Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 20 . 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 repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Check for DTCs. If DTC P0115 is set, go to step 2 . If DTC P0115 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.

When checking ECT sensor, test sensor at various temperature levels to check for shifted sensor. See appropriate SENSOR OPERATING RANGE CHARTS article. A shifted sensor could result in poor driveability complaints.

DTC P0116: ECT SENSOR CIRCUIT PERFORMANCE (3.0L "V" BODY)

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

When engine coolant is cold, sensor resistance is high. ECM will sense a high signal voltage (low temperature). When engine coolant is warm, sensor resistance is low. ECM will sense a low signal voltage (high temperature). When the difference between calculated engine coolant temperature and actual engine coolant temperature is greater than 7°F (12°C), DTC P0116 will set. For duplication of DTC, ensure 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.
Disconnect ECT sensor connector. Observe scan tool display. If ECT sensor temperature is less than -45°F (-43°C), go to next step. If ECT sensor temperature is -45°F (-43°C) or greater, diagnose using DTC P0115.
Jumper ECT sensor harness connector terminals. Observe scan tool display. If ECT sensor temperature is greater than 282°F (139°C), go to next step. If ECT sensor temperature is not greater than 282°F (139°C), diagnose using DTC P0115.
Replace ECT sensor. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and let idle. Check for DTCs. If DTC P0116 is set, go to step 2 . If DTC P0116 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.

If other DTCs are set that share the same ground circuit, check point where circuits ground to chassis or engine block. If engine has been allowed to sit overnight, ECT and IAT values should be within a few degrees of each other.

When checking ECT sensor, test sensor at various temperature levels and to check for shifted sensor. See appropriate SENSOR OPERATING RANGE CHARTS article. A shifted sensor could result in poor driveability complaints.

Check for stuck open thermostat. A stuck thermostat during very cold temperatures will cause engine temperature to increase too slowly and could result in this DTC being set.

DTC P0116: ECT SENSOR CIRCUIT PERFORMANCE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

ECT sensor circuit uses 2 pull-up resistors for temperature sensing. When sensor resistance is high, indicating low temperature, the PCM uses a 3650 ohms resistor and a 348 ohms resistor in series. As temperature increases to 122°F (50°C), the sensor resistance will decrease to 973 ohms. This resistance corresponds to.97 volt at the PCM. At this point the PCM shifts to the single 348 ohms pull-up resistor to measure temperature at greater than 122°F (50°C).

The PCM monitors the voltage signal of the circuit and assumes that engine operation causes coolant temperatures to change at slow rates. This test monitors the ECT sensor voltage. If PCM detects a 0.3 volt or greater change in ECT voltage in one second, DTC P0116 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 DTCs P0117 or P0118 are present, diagnose affected DTCs first. If DTCs are not present, go to next step.
Turn ignition on. Using scan tool, select FAILURE REC under DTC mode and note ECT display. If the snapshot for ECT sensor reading is less than -35°F (-37°C), go to next step. If snapshot ECT sensor reading is not less than -35°F (-37°C), go to step 5 .
An intermittent high resistance reading occurred on the ECT sensor circuit. Check for open in ECT sensor ground and signal circuits. Repair as necessary. If circuits are okay, go to step 7 .
If ECT snapshot reading is greater than 247°F (147°C), go to next step. If ECT snapshot reading is not greater than 247°F (147°C), go to step 7 .
An intermittent low resistance reading occurred on the ECT sensor circuit. Check for short to ground in ECT sensor signal circuit. Repair as necessary. If circuits are okay, go to next step.
Allow engine to cool to less than 95°F (35°C). Start engine and raise ECT sensor temperature from cool to warm. As ECT sensor warms, watch ECT sensor reading on scan tool. Look for a skip or jump in the value. If a skip or jump is noted, go to next step. If value did not skip or jump, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Replace ECT sensor.

If fault is not present, perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM.

DTC P0117: ECT SENSOR CIRCUIT-HIGH TEMPERATURE (1.9L SATURN)

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

Engine Coolant Temperature (ECT) sensor is a thermistor located in lower coolant passage in cylinder head. ECT sensor resistance is high when coolant temperature is low and resistance drops when coolant temperature increases. PCM provides a 5-volt reference and a ground to ECT sensor. PCM monitors voltage drop on the signal line to determine coolant temperature. ECT sensor is used for fuel/ignition control, hot/cold coolant light, temperature gauge and cooling fan.

DTC P0117 will set if ECT reads greater than 284°F (140°C) when engine has been running for more than 10 seconds. DTC will set if these conditions are met after 5 seconds. ECT signal is continuously monitored when ignition is on.

Turn ignition on. Connect scan tool and monitor ECT sensor temperature reading. If scan tool reading is greater than 284°F (140°C), go to next step. If ECT reading is not greater than 284°F (140°C), problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect ECT sensor harness connector. If ECT reading is less than -32°F (-35°C), check tightness of harness connector terminals or replace ECT sensor. If ECT reading is not less than -32°F (-35°C), go to next step.
Turn ignition off. Disconnect PCM harness connector J2. Remove ECT signal circuit terminal from PCM harness connector. Reconnect PCM. Turn ignition on. If ECT reading is less than -32°F (-35°C), go to next step. If ECT reading is not less than -32°F (-35°C), go to step 5 .
Repair ECT sensor signal circuit for a short to ground or short to ECT sensor ground circuit.
Replace PCM. Program replacement PCM using required equipment.

Use scan tool to review malfunction history diagnostic information. This data can be used to duplicate intermittent problems. Check tightness of harness connector terminals.

Start engine and observe ECT reading on scan tool. ECT reading should increase smoothly to about 190°F (88°C) as thermostat opens, and then stabilizes. PCM will turn on cooling fan if an ECT DTC is set.

DTC P0117: ECT SENSOR CIRCUIT-LOW VOLTAGE (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) supplies and monitors a 5-volt reference signal and a ground circuit to Engine Coolant Temperature (ECT) sensor. With engine cold, sensor resistance is high and when engine is warm, sensor resistance is low. When ECT sensor indicates engine coolant temperature is greater than 280°F (138°C) for more than 6 seconds, DTC P0117 will set. For duplication of DTC, ensure engine has been running for more than 2 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, observe ECT sensor value. If ECT sensor value is greater than 266°F (130°C), go to step 4 . If ECT sensor value is not greater than 266°F (130°C), go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Using scan tool, observe ECT sensor value. If ECT sensor value is greater than 266°F (130°C), go to next step. If ECT sensor value is not greater than 266°F (130°C), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect ECT sensor connector. Turn ignition on, with engine off. Observe ECT sensor value. If ECT sensor value is less than -22°F (-30°C), go to step 6 . If ECT sensor value is not less than -22°F (-30°C), go to next step.
Check for short to ground in ECT sensor signal circuit. Repair as necessary. After repairs, go to step 8 . If circuit is okay, go to step 7 .
Replace ECT sensor. After repairs, go to step 8 .
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. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0117. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation.

If engine is allowed to sit overnight, ECT and IAT sensor values should be within a few degrees of each other. If temperatures are not within a few degrees of each other, test ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0117: ECT SENSOR CIRCUIT-LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

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 P0117 will set when ECT sensor signal indicates an engine coolant temperature greater than 284°F (140°C) for more 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.
Turn ignition on. Using scan tool, read ENG COOL TEMP. If temperature is greater than 266°F (130°C), go to step 4 . If temperature is not as specified, go to next step.
Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0117 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0117 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect ECT sensor harness connector. Using scan tool, read ENG COOL TEMP. If temperature is less than -22°F (-30°C), go to step 6 . If temperature is not as specified, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Check ECT sensor signal circuit for short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 8 . If circuit is okay, go to step 7 .
Replace ECT sensor. After repairs, go to step 8 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0117. If scan tool displays DTC P0117 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0117 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe ECT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

If DTC P0117 cannot be duplicated, the information included in the FAILURE RECORDS data can be useful in determining vehicle mileage since the DTC was last set. If it is determined that the DTC occurs intermittently, performing DTC P1114 diagnosis may isolate cause of fault.

DTC P0117: ECT SENSOR CIRCUIT-LOW VOLTAGE (3.5L "W" 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. Using scan tool, read ENG COOL TEMP. If temperature is greater than 266°F (130°C), go to step 4 . If temperature is not as specified, go to next step.
Turn ignition off and wait 15 seconds. Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0117 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0117 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect ECT sensor harness connector. Using scan tool, read ENG COOL TEMP. If temperature is less than -24°F (-31°C), go to step 6 . If temperature is not as specified, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Check ECT sensor signal circuit for short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 8 . If circuit is okay, go to step 7 .
Replace ECT sensor. After repairs, go to step 8 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0117. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe ECT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for a skewed or mis-scaled ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0117: ECT SENSOR CIRCUIT-LOW VOLTAGE (3.8L "C", "F", "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.
Turn ignition on. Using scan tool, read ENG COOL TEMP. If temperature is greater than 282°F (139°C), go to step 4 . If temperature is not greater than 282°F (139°C), go to next step.
Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0117 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0117 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect ECT sensor harness connector. Using scan tool, read ENG COOL TEMP. If temperature is -38°F (-39°C), go to step 6 . If temperature is not -38°F (-39°C), go to next step.
Turn ignition off. Disconnect PCM harness connectors. Check ECT sensor signal circuit for short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 8 . If circuit is okay, go to step 7 .
Replace ECT sensor. After repairs, go to step 8 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0117. If scan tool displays DTC P0117 FAILED THIS IGN, return to step 2 . If scan tool does not display DTC P0117 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe ECT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for a skewed or mis-scaled ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0117: ECT SENSOR CIRCUIT-LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

ECT sensor is a thermistor whose resistance varies with temperature. As temperature of sensor increases, resistance decreases. A high coolant temperature will result in low signal voltage. DTC P0117 sets because coolant temperature cannot be greater than 247°F (147°C) when the IAT is less than 212°F (100°C) or the engine has been running long enough to cool the coolant to less than 247°F (147°C).

For duplication of DTC, ensure DTCs P0112, P0113, P0122 and P0123 are not set, IAT temperature is 212°F (100°C) or less, and engine is running with throttle angle at 5-35 degrees for at least 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. Using scan tool, note ECT display. If temperature reading is 247°F (147°C) or greater, go to next step. If temperature reading is not 247°F (147°C) or greater, fault is not present at this time.
Disconnect ECT sensor harness connector. If temperature reading is 18°F (-28°C) or less, go to step 6 . If temperature reading is not 18°F (-28°C) or less, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition on and wait 30 seconds, and then disconnect PCM harness connector C2. Using DVOM, measure resistance between ground and ECT sensor signal terminal and resistance between sensor signal and sensor ground circuits. If resistance on both circuits is less than 10,000 ohms, go to step 8 . If resistance on both circuits is not less than 10,000 ohms, go to next step.
Repair short to ground or sensor ground circuit in ECT sensor signal circuit.
Check terminal contact at ECT sensor connector. Repair as necessary. If terminal contact is okay, go to next step.
Replace ECT sensor.
Check terminal contact of ECT sensor signal circuit at PCM connector C2, terminal No. 74. Repair as necessary. If terminal contact is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

DTC P0117: ECT SENSOR CIRCUIT-LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" 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 cold, 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 P0117 will set if ECT sensor voltage is less than 0.25 volt for more than 20 seconds. For duplication of DTC, ensure engine has been running for more than 5 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, monitor ECT sensor voltage. If voltage is less than.25 volt, go to next step. If voltage is not less than.25 volt, go to step 5 .
Disconnect ECT sensor connector. Monitor ECT sensor voltage on scan tool. If voltage is greater than 4 volts, go to step 7 . If voltage is not greater than 4 volts, go to next step.
Turn ignition off. Disconnect VCM harness connector C2. Check ECT sensor signal circuit for a short to ground. If circuit is shorted, go to step 6 . If circuit is okay, go to step 8 .
DTC is intermittent. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If any additional DTCs are set, go to applicable DTC test.
Repair short to ground in ECT signal circuit. After repairs, go to step 9 .
Replace ECT sensor. After repairs, go to step 9 .
Replace VCM. Program replacement VCM 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, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Scan tool displays engine temperature in degrees centigrade. After engine is started, temperature should steadily rise, and 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. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0117: ECT SENSOR CIRCUIT-LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES & 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 located on left-side cylinder head near front of engine used to monitor engine coolant temperature. PCM supplies 5 volts to sensor. When engine coolant is cold, sensor resistance will be high and PCM will sense a high voltage signal. When engine coolant is warm, sensor resistance will be low and PCM will sense a low voltage signal. DTC P0117 will set if ECT sensor indicates a temperature greater than 282°F (139°C) for 20 seconds or more. For duplication of DTC, ensure engine has been running for more 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.
Turn ignition on. Using scan tool, monitor ECT sensor display. If scan tool displays greater than 282°F (139°C), go to step 4 . If scan tool does not display greater than 282°F (139°C), go to next step.
Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data. Turn ignition off for 15 seconds. Start engine and operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0117 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0117 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect ECT sensor connector. If scan tool displays less than -22°F (-30°C), go to step 6 . If scan tool does not display less than -22°F (-30°C), go to next step.
Turn ignition off. Disconnect PCM harness connector C1. Check ECT sensor signal circuit for a short to ground. Repair as necessary. After repairs, go to step 8 . If circuit is okay, go to step 7 .
Replace ECT sensor. After repairs, go to step 8 .
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, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe ECT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for a skewed or mis-scaled ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0118: ECT SENSOR CIRCUIT-LOW TEMPERATURE (1.9L SATURN)

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

Engine Coolant Temperature (ECT) sensor is a thermistor located in lower coolant passage in cylinder head. ECT sensor resistance is high when coolant temperature is cold and resistance drops when coolant temperature increases. PCM provides a 5-volt reference and a ground signal to ECT sensor. PCM reads voltage drop on the signal line to determine coolant temperature. ECT sensor is used for fuel/ignition control, hot/cold coolant light, temperature gauge and cooling fan.

DTC P0118 will set if ECT reads less than -31°F (-35°C) when engine has been running for more than 4 minutes. ECT signal is continuously monitored when ignition is on.

Turn ignition on. Connect scan tool and monitor ECT sensor reading. If ECT reading is less than -32°F (-35°C), go to next step. If ECT reading is not less than -32°F (-35°C), problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect ECT sensor harness connector. Using a fused jumper wire, jumper ECT harness connector terminals together. If ECT reading is greater than 266°F (130°C), replace ECT sensor. If ECT reading is not greater than 266°F (130°C), go to next step.
Remove jumper wire. Jumper ECT signal circuit to ground. If ECT reading is greater than 266°F (130°C), go to step 5 . If ECT reading is not greater than 266°F (130°C), go to next step.
Remove jumper wire. Turn ignition off. Disconnect PCM harness connectors. Using DVOM, check for continuity in ECT signal circuit between ECT sensor and PCM. If continuity is present, PCM or terminal connections are faulty. Repair as necessary. If continuity is not present, repair open circuit.
Using DVOM, check for continuity in ECT ground circuit between ECT sensor and PCM. If continuity is present, PCM or terminal connections are faulty. Repair as necessary. If continuity is not present, repair open circuit.

Use scan tool to review malfunction history diagnostic information. This data can be used to duplicate intermittent problems. Check tightness of harness connector terminals.

Start engine and observe ECT reading on scan tool. ECT reading should rise smoothly to about 190°F (88°C) as thermostat opens and then stabilizes. PCM will turn on cooling fan if an ECT DTC is set.

ECT temperature can be compared to IAT temperature with scan tool, if engine has cooled overnight at ambient temperature. ECT and IAT temperatures should be within 4 degrees of each other with ignition on, engine off. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0118: ECT SENSOR CIRCUIT-HIGH VOLTAGE (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) supplies and monitors a 5-volt reference signal and a ground circuit to Engine Coolant Temperature (ECT) sensor. With engine cold, sensor resistance is high and when engine is warm, sensor resistance is low. When ECT sensor indicates engine coolant temperature less than -40°F (-40°C) for more than 6 seconds, DTC P0118 will set. For duplication of DTC, ensure engine has been running for more than one minute.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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 ECT sensor value. If ECT sensor value is less than -22°F (-30°C), go to step 4 . If ECT sensor value is not less than -22°F (-30°C), go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Using scan tool, observe ECT sensor value. If ECT sensor value is less than -22°F (-30°C), go to next step. If ECT sensor value is not less than -22°F (-30°C), see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect ECT sensor harness connector. Connect a jumper wire between ECT sensor signal circuit and sensor ground circuit terminals at ECT sensor harness connector. Turn ignition on, with engine off. If ECT sensor value is greater than 266°F (130°C), go to step 6 . If ECT value is not greater than 266°F (130°C), go to next step.
Connect a jumper wire between ground and signal circuit terminal at ECT sensor harness connector. If ECT sensor value is greater than 266°F (130°C), go to step 7 . If ECT sensor value is not greater than 266°F (130°C), go to step 8 .
Turn ignition off. Disconnect and inspect ECT sensor connector. Repair as necessary. After repairs, go to step 12 . If connector is okay, go to step 10 .
Turn ignition off. Check for open ECT sensor ground circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 9 .
Turn ignition off. Check ECT sensor signal circuit for an open or short to voltage. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for poor ECT sensor ground or a poor ECT sensor signal circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuits are okay, go to step 11 .
Replace ECT sensor. After repairs, go to step 12 .
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. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0118. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. If other DTCs are set for components that share the 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 P0118: ECT SENSOR CIRCUIT-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 that varies resistance based on temperature. As temperature of sensor increases, resistance decreases. Low temperature will result in a high signal voltage. DTC P0118 will set when ECT sensor indicates engine coolant temperature less than -40°F (-40°C) for more 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.
Turn ignition on. Using scan tool, read ENG COOL TEMP. If temperature is less than -22°F (-30°C), go to step 4 . If temperature is not as specified, go to next step.
Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0118 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0118 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect ECT sensor harness connector. Connect a jumper wire between ECT sensor harness connector signal and ground circuits. Using scan tool, read ENG COOL TEMP. If temperature is greater than 266°F (130°C), go to step 6 . If temperature is not as specified, go to next step.
Connect jumper wire between chassis ground and ECT sensor harness connector signal circuit. Using scan tool, read ENG COOL TEMP. If temperature is greater than 266°F (130°C), go to step 7 . If temperature is not as specified, go to step 8 .
Check for faulty connection at ECT sensor. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 10 .
Turn ignition off. Disconnect PCM harness connectors. Check ECT sensor ground circuit for an open. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 9 .
Turn ignition off. Disconnect PCM harness connectors. Check ECT signal circuit for an open. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for faulty ECT signal or ground circuit connection at PCM. Repair as necessary. After repairs, go to step 12 . If connections are okay, go to step 11 .
Replace ECT sensor. After repairs, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, with engine off. 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 P0118. If scan tool displays DTC P0118 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0118 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe ECT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

If DTC P0118 cannot be duplicated, the information included in the FAILURE RECORDS data can be useful in determining vehicle mileage since the DTC was last set. If it is determined that the DTC occurs intermittently, performing DTC P1115 diagnosis may isolate cause of fault.

DTC P0118: ECT SENSOR CIRCUIT-HIGH VOLTAGE (3.5L "W" BODY)

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 P0118 will set when ECT sensor signal indicates an engine coolant temperature less than 9°F (-13°C) for at least 10 seconds. For duplication of DTC, ensure engine has been running for more 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.
Turn ignition on. Using scan tool, read ENG COOL TEMP. If temperature is less than -24°F (-31°C), go to step 4 . If temperature is not as specified, go to next step.
Turn ignition off and wait 15 seconds. Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0118 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0118 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect ECT sensor harness connector. Connect a jumper wire between ECT sensor harness connector signal and ground circuits. Turn ignition on. Using scan tool, read ENG COOL TEMP. If temperature is greater than 266°F (130°C), go to step 7 . If temperature is not as specified, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Check ECT sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Connect jumper wire between chassis ground and ECT sensor harness connector signal circuit. Using scan tool, read ENG COOL TEMP. If temperature is greater than 266°F (130°C), go to step 8 . If temperature is not as specified, go to step 9 .
Check for faulty connection at ECT sensor. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 11 .
Turn ignition off. Disconnect PCM harness connectors. Check ECT sensor ground circuit for an open. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 10 .
Turn ignition off. Disconnect PCM harness connectors. Check ECT signal circuit for an open. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Check for faulty ECT signal or ground circuit connection at PCM. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
Replace ECT sensor. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0118. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe ECT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for a skewed or mis-scaled ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0118: ECT SENSOR CIRCUIT-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. Low temperature will result in a high signal voltage. DTC P0118 will set when ECT sensor signal indicates engine coolant temperature less than -38°F (-39°C) for at least 10 seconds. For duplication of DTC, ensure engine has been running for 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.
Turn ignition on. Using scan tool, read ENG COOL TEMP. If temperature is less than -36°F (-38°C), go to step 4 . If temperature is not less than -36°F (-38°C), go to next step.
Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0118 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0118 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect PCM and ECT harness connectors. Turn ignition on. Check ECT sensor signal circuit for short to ground. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Turn ignition off. Reconnect PCM harness connector. Jumper ECT signal circuit and sensor ground circuit at ECT sensor harness connector. Turn ignition on. Observe ECT value displayed on scan tool. If ECT value is 284°F (140°C), go to step 7 . If ECT value is not 284°F (140°C), go to next step.
Connect a jumper wire between ECT sensor harness connector signal and ground circuits. Using scan tool, read ECT value display. If ECT value is 284°F (140°C), go to step 8 . If ECT value is not 284°F (140°C), go to step 9 .
Check for faulty connection at ECT sensor. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 11 .
Turn ignition off. Disconnect PCM harness connectors. Check ECT sensor ground circuit for an open. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 10 .
Turn ignition off. Disconnect PCM harness connectors. Check ECT signal circuit for an open. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Check for faulty ECT signal or ground circuit connection at PCM. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Replace ECT sensor. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs PCM, go to next step.
Turn ignition on, engine off. 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 P0118. If scan tool displays DTC P0118 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0118 FAILED THIS IGN, system is okay.

If DTC cannot be duplicated, the information included in the Failure Records data can be used in determining vehicle mileage since DTC was last set. If it is determined that the DTC occurs intermittently, performing DTC P1115 diagnosis may isolate cause of fault.

DTC P0118: ECT SENSOR CIRCUIT-HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

ECT sensor is a thermistor that varies resistance with temperature. As sensor temperature increases, resistance decreases. A low coolant temperature will result in high signal voltage. DTC P0118 will set if ECT sensor reading is -36°F (-38°C) or less when IAT is greater than 23°F (-5°C) or when the engine is running with throttle angle at 7 degrees or greater for at least 3.5 minutes. For duplication of DTC, ensure DTCs P0112, P0113, P0122 and P0123 are not 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, note ECT display. If temperature reading is -31°F (-35°C) or less, go to next step. If temperature reading is not -31°F (-35°C) or less, fault is not present. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect ECT sensor harness connector. Using jumper wire, jumper ECT sensor connector terminals together. If temperature reading is greater than 275°F (135°C), go to step 9 . If temperature reading is not greater than 275°F (135°C), go to next step.
Connect jumper from ECT sensor signal circuit to ground. If temperature reading is greater than 275°F (135°C), go to step 6 . If temperature reading is not greater than 275°F (135°C), go to next step.
Remove jumper wire. Store fluid life reading indicated in scan tool. Turn ignition off for 30 seconds, and then disconnect PCM harness connector C2. Using DVOM, measure resistance in ECT sensor signal circuit between PCM and ECT sensor connectors. If resistance is 5 ohms or less, go to step 11 . If resistance is not 5 ohms or less, go to step 7 .
Remove jumper wire. Store fluid life index indicated on scan tool. Turn ignition off for 30 seconds, and then disconnect PCM harness connector C1. Using DVOM, measure resistance in sensor ground circuit between PCM and ECT sensor connectors. If resistance is 5 ohms or less, go to step 11 . If resistance is not 5 ohms or less, go to step 8 .
Repair open in ECT sensor signal circuit.
Repair open in ECT sensor ground circuit.
Check terminal contact at ECT sensor. Repair as necessary. If terminal contact is okay, go to next step.
Replace ECT sensor.
Check ECT sensor ground and signal circuit terminal contact at PCM harness connector. Repair as necessary. If terminal contacts are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

If fault is not present, check all powertrain ground circuits. If DTC cannot be duplicated, the information included in the Failure Records data can be used in determining vehicle mileage since DTC was last set.

DTC P0118: ECT SENSOR CIRCUIT-HIGH VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" 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 applies and monitors the 5-volt reference voltage to sensor. When engine coolant is cold, 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 P0118 will set if ECT sensor voltage is greater than 4.9 volts for more than 20 seconds. For duplication of DTC, ensure 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.
Install scan tool. Start engine. Monitor ECT sensor voltage on scan tool. If voltage is greater than 4.9 volts, go to next step. If voltage is not greater than 4.9 volts, go to step 6 .
Turn engine off. Disconnect ECT sensor connector. Turn ignition on. Connect a jumper wire between ECT sensor terminals. Monitor ECT sensor voltage on scan tool. If voltage is less than.82 volt, go to step 5 . If voltage is not less than.82 volt, go to next step.
Connect a jumper wire between ECT signal circuit of ECT sensor connector and ground. Monitor ECT sensor voltage on scan tool. If voltage is less than.82 volt, go to step 8 . If voltage is not less than.82 volt, go to step 9 .
Remove jumper wire. Measure voltage between ECT sensor signal circuit and a known-good ground. If voltage is greater than 5.2 volts, go to step 10 . If voltage is not greater than 5.2 volts, go to step 7 .
DTC is intermittent. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If any additional DTCs are set, go to applicable DTC test.
Check for poor connections at ECT sensor and VCM. If connections are faulty, go to step 11 . If connections are okay, go to step 13 .
Check for open or poor connection in ECT ground circuit between ECT sensor and VCM. If ECT ground circuit is open, go to step 11 . If ECT ground circuit is okay, go to step 14 .
Check ECT sensor signal circuit for open or poor connection between ECT sensor and VCM. If ECT signal circuit is open, go to step 11 . If ECT signal circuit is okay, go to step 14 .
Repair short to voltage in ECT signal circuit. After repairs, go to step 12 .
Repair as necessary. After repairs, go to step 15 .
Reconnect ECT sensor connector. Start engine. Using scan tool, monitor ECT sensor voltage. If sensor voltage is less than 4.9 volts, go to step 15 . If sensor voltage is not less than 4.9 volts, go to next step.
Replace ECT sensor. After repairs, go to step 15 .
Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP system variation learn procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

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 194°F (90°C), and then stabilize when thermostat opens. A skewed or mis-scaled sensor could cause poor driveability conditions. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0118: ECT SENSOR CIRCUIT-HIGH VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES & 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 left-side cylinder head near front of engine. ECT sensor uses a signal circuit and a ground circuit. PCM applies voltage (about 5 volts) on signal circuit to sensor and monitors changes in this voltage caused by changes in resistance of sensor to determine coolant temperature.

When coolant is cold, sensor resistance is high and when coolant is warm, sensor resistance is low. When PCM senses engine coolant temperature less than -38°F (-39°C) for 20 seconds, DTC P0118 will set. For duplication of DTC, ensure engine has been running for more than 60 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, monitor ECT display. If ECT value is -38°F (-39°C), go to next step. If ECT value is not as specified, go to step 4 .
If DTCs P1635 and P1639 are also set, go to step 14 . If DTCs P1635 and P1639 are not set, go to step 5 .
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, and then enter DTC P0118. If scan tool indicates this test failed this ignition, go to next step. If scan tool does not indicate this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect ECT sensor harness connector. Using a fused jumper wire, jumper terminals together at ECT harness connector. Observe ECT display on scan tool. If ECT value is 284°F (140°C), go to step 8 . If ECT value is not as specified, go to next step.
Connect a fused jumper wire between ECT signal circuit and ground. If ECT value is 284°F (140°C), go to step 10 . If ECT value is not as specified, go to next step.
Turn ignition off. Disconnect PCM harness connector C1 and check ECT sensor signal circuit for an open. If circuit is open, go to step 11 . If circuit is okay, go to step 16 .
Turn ignition off. Remove jumper wire from ECT sensor harness connector. Disconnect PCM harness connectors. Turn ignition on. Check for voltage between ground and ECT sensor signal circuit at PCM harness connector. If voltage is present, go to step 14 . If voltage is not present, go to next step.
Measure resistance between ECT sensor signal circuit and all other circuits in PCM harness connectors. If resistance is 0-2 ohms, go to step 15 . If resistance is not as specified, go to step 12 .
Turn ignition off. Disconnect PCM harness connector C1. Check ECT sensor ground circuit for an open. If circuit is open, go to step 13 . If circuit is okay, go to step 16 .
Repair ECT sensor signal circuit. After repairs, go to step 18 .
Replace ECT sensor. After repairs, go to step 18 .
Repair ECT sensor ground circuit. After repairs, go to step 18 .
Repair ECT sensor signal circuit for a short to voltage. After repairs, go to step 18 .
Repair short between ECT sensor signal circuit and circuit at PCM harness connector that indicated continuity. After repairs, go to step 18 .
Check for poor connections at PCM. Repair as necessary. After repairs, go to step 18 . If connections are okay, go to next step.
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, and then enter DTC P0118. 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, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

If engine is allowed to sit overnight, ECT and IAT sensor values should be within a few degrees of each other. If temperatures are not within 5°F (3°C), test ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

If it is determined that DTC is intermittent, performing DTC P1115 diagnostics may isolate cause of fault.

DTC P0120: TP SYSTEM PERFORMANCE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

TP sensor is a potentiometer. At low throttle angle, TP sensor voltage is low. PCM uses TP sensor signal voltage to determine idle, Wide Open Throttle (WOT), deceleration enleanment and acceleration enrichment. This test monitors both the MAP and TP sensors. Engine operation requires that any large change in throttle position must be followed by a change in manifold pressure. If MAP remains constant following a large change in throttle angle, DTC P0120 will set.

For duplication of DTC, ensure DTCs P0107 and P0108 are not set, MAP is greater than 21.8 kPa, MAP is not within 12 kPa of BARO pressure, engine speed is less than 500 RPM, engine metal overtemp is not active, and traction control is not active.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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 P0300 is also present. If DTC P0300 is present, diagnose DTC P0300 first. If DTC P0300 is not present, go to next step.
If DTC P0121 or P0122 is present, diagnose affected DTC first. If DTCs are not present, go to next step.
Using scan tool, select FAILURE RECORDS. Note TP sensor display. If snapshot TP sensor reading is less than zero degrees, go to next step. If snapshot TP sensor reading is not less than zero degrees, go to step 8 .
An intermittent low voltage reading occurred on the TP sensor circuit. Check for possible open or short to ground in TP sensor signal circuit or open in 5-volt reference circuit. Repair as necessary. If circuits are okay, go to next step.
Slowly depress accelerator from closed throttle to wide open throttle. Note TP sensor reading. Watch for a sudden skip or jump in TP sensor reading. If reading skips or jumps, go to next step. If reading does not skip or jump, fault is not present at this time.
Check for binding or sticky throttle. Check for chaffed TP sensor wires. Repair as necessary. If no problem is found, go to step 11 .
If snapshot TP sensor reading is greater than 85 degrees, go to next step. If the snapshot of TP sensor reading is not greater than 85 degrees, go to step 6 .
An intermittent high voltage reading occurred on the TP sensor circuit. Check for open in TP sensor ground circuit or short in TP sensor signal circuit. Repair as necessary. If circuits are okay, go to next step.
Slowly depress accelerator from closed throttle to wide open throttle. Note TP sensor reading. Watch for a sudden skip or jump in TP sensor reading. If reading skips or jumps, go to next step. If reading does not skip or jump, fault is not present.
Replace TP sensor.

DTC P0121: TP SENSOR PERFORMANCE (2.2L "J" BODY)

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

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Throttle Position (TP) sensor, and monitors the TP signal circuit for changes in throttle angle. TP sensor signal voltage should be about.6 volt at idle and 4.5 volts or greater at wide open throttle. DTC P0121 will set if TP sensor angle is greater than a specified percentage at a given engine speed.

For duplication of DTC, ensure

Engine is operating on alternative fuel.
No Alternative Fuel Electronic Control Unit (AFECU) DTCs are set (with the exception of DTCs P1215, P1432 and P1433).
Engine MAP is less than 45 kPa.
TP sensor angle has changed less than 2 percent in 2 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, establish communication with AFECU. Monitor TP sensor angle data. If TP angle is less than 2 percent, go to next step. If TP angle is not less than 2 percent, go to step 6 .
Slowly depress throttle to Wide Open Throttle (WOT). If TP angle is greater than 98 percent, go to next step. If TP angle is not greater than 98 percent, go to step 6 .
Release throttle. If TP angle is less than 2 percent, go to next step. If TP angle is not less than 2 percent, go to step 6 .
Fault is not present at this time. If any undiagnosed DTCs are present, diagnose affected DTCs. If no undiagnosed DTCs are present, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor. If TP sensor voltage is greater than 4.9 volts, go to next step. If TP sensor voltage is not greater than 4.9 volts, go to step 10 .
Measure voltage between ground and 5-volt reference circuit at TP sensor harness connector. If voltage is 4.8-5.2 volts, go to next step. If voltage is not as specified, go to step 12 .
Using a fused jumper wire, jumper TP sensor signal circuit to engine ground. If TP sensor voltage is less than.08 volt, go to next step. If TP sensor voltage is not less than.08 volt, go to step 14 .
Using a fused jumper wire, jumper 5-volt reference circuit and signal circuit together at TP sensor harness connector. Connect an additional fused jumper wire sensor ground circuit and 5-volt reference circuit at TP sensor harness connector. If TP sensor voltage is less than.08 volt, go to step 11 . If TP sensor voltage is not less than.08 volt, go to step 15 .
Check TP sensor signal circuit for short to ground or sensor ground circuit. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 18 .
Check TP sensor signal circuit for short to voltage or 5-volt reference circuit. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 16 .
Turn ignition off. Disconnect AFECU harness connectors. Turn ignition on. Measure voltage between ground and 5-volt reference circuit at TP sensor harness connector. If voltage is 4.8-5.2 volts, go to step 18 . If voltage is not as specified, go to next step.
Check 5-volt reference circuit for a short to voltage, ground or high circuit resistance. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 17 .
Check TP sensor signal circuit for an open or high resistance. Check all circuit related connectors and splices for poor terminal contact. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 18 .
Check TP sensor ground circuit for high resistance or poor terminal contact at PCM. Repair as necessary. After repairs, go to step 19 . If circuit is okay, go to step 17 .
Replace TP sensor. After repairs, go to step 19 .
Replace PCM. Program replacement PCM using required equipment. Perform CKP system variation learn procedure. After repairs, go to step 19 .
Replace AFECU. After repairs, go to next step.
Using scan tool, clear DTCs from both control modules. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0118. Operate vehicle within conditions that set 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, go to step 2 .

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. If other DTCs are set for components that share the same ground and/or 5-volt reference circuit, check for faulty connections or wiring. The PCM 5-volt reference circuits are internally connected within PCM. Also, using FREEZE FRAME data may aid in determining conditions present when DTC was set.

DTC P0121: TP SENSOR PERFORMANCE (2.4L "N" BODY)

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

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Throttle Position (TP) sensor, and monitors the TP signal circuit for changes in throttle angle. TP sensor signal voltage should be about.5 volt at idle and 4.5 volts or greater at wide open throttle. DTC P0121 will set if TP sensor angle is greater than 7 percent at idle after attempting to auto-zero, or TP angle is greater than the following specified percentages at the given RPM for at least 6 seconds

2 percent at 0 RPM
10 percent at 800 RPM
20 percent at 1600 RPM
25 percent at 2400 RPM
30 percent at 3200 RPM
35 percent at 4000-4800 RPM
40 percent at 5600 RPM
40 percent at 6400 RPM

For duplication of DTC, ensure

DTCs P0106, P0107, P0108, P0171, P0172, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0335, P0341, P0342, P0404, P0405, P0440, P0442, P0452, P0453, P0502, P0506, P0507, P0601, P0602 or P1441 are not set.
Engine is running.
ECT is greater than 68°F (20°C).
TP stable at plus or minus 2 percent.
MAP is less than 37 kPa.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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, check for DTCs. If any EGR, A/C or fuel tank pressure sensor DTCs are present, diagnose affected DTC. If specified DTCs are not present, go to next step.
If scan tool displays a TP voltage at less than.9 volt when throttle is fully closed, go to next step. If TP voltage is not less than.9 volt when throttle is fully closed, go to step 6 .
Observing scan tool, depress accelerator to floor, and then slowly release pedal. TP sensor angle value should increase steadily to about 98 percent when pedal is depressed and decrease steadily to about one percent when pedal is released. If TP sensor angle value is as specified, go to next step. If TP sensor angle value is not as specified, go to step 6 .
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If TP sensor angle value-versus-RPM value is greater than specified value in conditions for setting DTC, go to next step. If TP sensor angle value-versus-RPM value is not greater than the specified value in conditions for setting DTC, go to step 16 .
Turn ignition off. Disconnect TP sensor connector. Turn ignition on. Observe TP sensor display on scan tool. If TP sensor voltage is near zero volts, go to next step. If TP sensor voltage is not as specified, go to step 8 .
Using a fused jumper wire, jumper 5-volt reference circuit and signal circuit together at TP sensor harness connector. If TP sensor voltage is about 5 volts, go to step 9 . If TP sensor voltage is not as specified, go to step 10 .
Check TP sensor signal circuit for short to voltage. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 15 .
Using a test light connected to battery positive, probe TP sensor ground circuit at TP sensor harness connector. If test light illuminates, go to step 11 . If test light does not illuminate, go to step 12 .
Check TP sensor 5-volt reference circuit and signal circuit for poor connections or terminal tension. Repair as necessary. After repairs, go to step 16 . If no problem is found, go to step 13 .
Check TP sensor harness connector for poor connections or terminal tension. Repair as necessary. After repairs, go to step 16 . If no problem is found, go to step 14 .
Check TP sensor ground circuit for poor connections or terminal tension at PCM. Repair as necessary. After repairs, go to step 16 . If no problem is found, go to step 15 .
Check PCM harness connectors for poor connections or terminal tension. Repair as necessary. After repairs, go to step 16 . If no problem is found, go to step 15 .
Turn ignition off. Replace TP sensor. After repairs, go to step 16 .
Replace PCM. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0121. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. If other DTCs are set for components that share the same ground and/or 5-volt reference circuit, check for faulty connections or wiring. The PCM 5-volt reference circuits are internally connected within PCM. Also, using FREEZE FRAME data may aid in determining conditions present when DTC was set.

DTC P0121: TP SENSOR PERFORMANCE (3.1L "N" & "W" BODIES & 3.4L "U" SERIES)

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

The Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Throttle Position (TP) sensor, and a signal circuit to monitor changes in throttle angle. TP sensor signal voltage should be about.5 volt at idle and 4.0 volts or greater at wide open throttle. DTC P0121 will set if PCM detects an out-of-range condition.

For duplication of DTC, ensure no active TP sensor or MAP sensor DTCs are present, engine is running, MAP sensor reading is less than 50 kPa or greater than 70 kPa, and predicted throttle angle is not close to actual throttle angle.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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 MAP sensor reading. If MAP sensor value is less than 65 kPa, go to next step. If MAP sensor scan tool value is not as specified, go to step 6 .
Disconnect MAP sensor harness connector. Connect a test light between the 5-volt reference circuit and signal circuit terminals at MAP sensor harness connector. If MAP sensor value is less than 65 kPa, go to step 5 . If MAP sensor value is not less than 65 kPa, go to next step.
Check for an open, short to ground or short to MAP ground circuit in MAP sensor signal circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Replace MAP sensor. After repairs, go to step 13 .
Observing scan tool, depress accelerator to floor, and then slowly release pedal. TP sensor angle value should increase steadily to 100 percent when pedal is depressed and decrease steadily to zero percent when pedal is released. If TP sensor angle value is as specified, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If TP sensor angle value is not as specified, go to next step.
Disconnect TP sensor connector. Observe TP sensor display on scan tool. If TP sensor voltage is near zero volts, go to next step. If TP sensor voltage is not near zero volts, go to step 9 .
Connect at test light between 5-volt reference circuit and signal circuit terminals at TP sensor harness connector. If scan tool voltage is about 5 volts, go to step 11 . If voltage is not about 5 volts, go to step 10 .
Check TP signal circuit for short to voltage. Check TP sensor ground circuit for high resistance between PCM and TP sensor. Check TP sensor ground circuit for poor connection. Repair as necessary. After repairs, go to step 13 . If circuits are okay, go to step 12 .
Check TP sensor signal circuit or 5-volt reference circuit for high resistance between PCM and TP sensor. Check TP sensor signal circuit or 5-volt reference circuit for a poor connection. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Replace TP sensor. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0121. If scan tool indicates DTC P0121 FAILED THIS IGN, go to step 2 . If scan tool does not indicate DTC P0121 FAILED THIS IGN, system is okay.

Check for damaged or sticking throttle plate or IAC valve. A throttle valve place or IAC valve that allows too much airflow while throttle should be closed may cause a high idle and DTC P0121 to set.

A skewed MAP signal or faulty MAP sensor or an incorrect MAP signal may cause PCM to incorrectly calculate the predicted TP sensor value during high engine load situations. Check for an unusually low MAP reading. This condition can cause DTC to set.

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

If DTC cannot be duplicated, the information included in the FAILURE RECORDS data can be useful in determining vehicle mileage since DTC was last set. If it is determined that DTC is intermittent, performing DTC P1121 or P1122 diagnosis may isolate cause of fault.

DTC P0121: TP SENSOR PERFORMANCE (3.4L "N" 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.
Observing scan tool, depress accelerator to floor, and then slowly release pedal. TP sensor angle value should increase steadily to 100 percent when pedal is depressed and decrease steadily to zero percent when pedal is released. If TP sensor angle value is as specified, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If TP sensor angle value is not as specified, go to next step.
Disconnect TP sensor. Monitor TP sensor reading on scan tool. If TP sensor reading is near zero volts, go to next step. If TP sensor reading is not near zero volts, go to step 5 .
Connect a test light between 5-volt reference circuit and signal circuit at TP sensor harness connector. Monitor TP sensor reading on scan tool. If TP sensor reading is 5 volts, go to step 7 . If TP sensor reading is not 5 volts, go to step 6 .
Check TP signal circuit for short to voltage. Check TP sensor ground circuit for high resistance between PCM and TP sensor. Check TP sensor ground circuit for poor connection. Repair as necessary. After repairs, go to step 9 . If circuits are okay, go to step 8 .
Check TP sensor signal circuit or 5-volt reference circuit for high resistance between PCM and TP sensor. Check TP sensor signal circuit or 5-volt reference circuit for a poor connection. Repair as necessary. After repairs, go to step 9 . If circuit is okay, go to step 8 .
Replace TP sensor. After repairs, go to step 9 .
Replace PCM. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition on, with engine off. Using scan tool, review FAILURE RECORDS data and note parameters. Start engine and operate vehicle as close to conditions recorded in FAILURE RECORDS data as possible. Monitor SPECIFIC DTC info for DTC P0121. If scan tool indicates DTC P0121 FAILED THIS IGN, go to step 2 . If scan tool does not indicate DTC P0121 FAILED THIS IGN, system is okay.

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

DTC P0121: TP SENSOR PERFORMANCE (3.5L "W" BODY)

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

The Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Throttle Position (TP) sensor, and a signal circuit to monitor changes in throttle angle. TP sensor signal voltage should be less than one volt at idle and 4.0 volts or greater at wide open throttle. DTC P0121 will set if PCM detects an out-of-range condition.

For duplication of DTC, ensure no active TP sensor or MAP sensor DTCs are present, engine is running, MAP sensor reading is less than 50 kPa or greater than 70 kPa, MAP is steady within 5 kPa, IAC position is 0-130 counts, and throttle angle is steady.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, monitor MAP sensor reading. If MAP sensor reading is less than 65 kPa, go to next step. If MAP sensor reading is not less than 65 kPa, go to step 6 .
Turn ignition off. Remove MAP sensor from intake manifold, leaving harness connected. Turn ignition on. Using a hand-held vacuum pump, apply 20 in. of vacuum, one inch at a time to MAP sensor. Each one inch of vacuum applied should result in a 3-4 kPa drop in MAP sensor value. If MAP sensor value changes smoothly through entire range, go to next step. If operation is not as specified, go to step 5 .
Apply 20 in. of vacuum to MAP sensor, and then release vacuum. If MAP sensor value is about 34 kPa with vacuum applied, and then returns to barometric pressure when vacuum is released, go to step 12 . If operation is not as specified, go to next step.
Replace MAP sensor. After repairs, go to step 13 .
Monitor TP angle reading on scan tool while slowly opening throttle. If TP angle reading increased steadily throughout entire range, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If operation is not as specified, go to next step.
Disconnect TP sensor. If TP sensor reading is near zero volts, go to next step. If TP sensor reading is not near zero volts, go to step 9 .
Using a fused jumper wire, jumper 5-volt reference circuit and signal circuit together at TP sensor harness connector. If TP sensor reading is 5 volts, go to step 11 . If TP sensor reading is not 5 volts, go to step 10 .
Check TP sensor signal circuit for a short to voltage and TP sensor ground circuit for poor connection or high resistance between TP sensor and PCM. Repair as necessary. After repairs, go to step 13 . If circuits are okay, go to step 12 .
Check TP sensor signal circuit or 5-volt reference circuit for a poor connection or high resistance between TP sensor and PCM. Repair as necessary. After repairs, go to step 13 . If circuits are okay, go to step 12 .
Replace TP sensor. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0121. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

Check for damaged or sticking throttle plate or IAC valve. A throttle valve place or IAC valve that allows too much airflow while throttle should be closed may cause a high idle and DTC P0121 to set.

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

DTC P0121: TP SENSOR PERFORMANCE (3.8L "C", "F", "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 P0121 will set if PCM detects an out of range condition.

For duplication of DTC, ensure no MAP or TP sensor DTCs are set, engine is running, ECT sensor temperature is greater than 158°F (70°C), MAP sensor reading is less than 50 kPa or greater than 70 kPa, and MAP is steady for 5 seconds or more.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, monitor TP angle reading while slowly opening throttle. If TP angle reading increases steadily from zero percent to 100 percent, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If operation is not as specified, go to next step.
Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. Using scan tool, monitor TP sensor voltage. If voltage is near zero volts, go to next step. If voltage is not near zero volts, go to step 5 .
Turn ignition off. Using a fused jumper wire, jumper 5-volt reference circuit and signal circuit together at TP sensor harness connector. Turn ignition on. Using scan tool, monitor TP sensor voltage. If voltage is 5 volts, go to step 8 . If voltage is not 5 volts, go to step 6 .
Check TP sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 11 .
Check TP sensor 5-volt reference circuit for high resistance or poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check TP sensor signal circuit for high resistance or poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 11 .
Check TP sensor ground circuit for high resistance or poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for poor connections at PCM. Repair as necessary. After repairs, go to step 12 . If connections are okay, go to next step.
Replace TP sensor. After repairs, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0121. If scan tool displays DTC P0121 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0121 FAILED THIS IGN, system is okay.

Check for and repair the following condition(s)

Throttle plate sticking or excessive deposits on throttle plate or throttle bore.
Check TP sensor harness connector terminals for damage.
A steady throttle movement from a stop should cause TP ANGLE value reading on scan tool to increase smoothly as throttle is opened.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high voltage wires, such as spark plug cables. If connections and harness appear okay, observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for skewed MAP signal or faulty MAP sensor.

DTC P0121: TP SENSOR CIRCUIT INSUFFICIENT ACTIVITY (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

TP sensor is a potentiometer. At low throttle angle, TP sensor voltage is low. PCM uses TP sensor signal voltage to determine idle, Wide Open Throttle (WOT), deceleration enleanment and acceleration enrichment. This test determines when the TP sensor reading is too high and out of its estimated range for the current engine speed. PCM monitors changes in TP sensor. If change is.6 degree or less within 0.1 second, PCM compares the current throttle position with a stored value. If current throttle position is greater than the stored value, TP sensor is considered stuck and DTC P0121 will set.

For duplication of DTC, ensure

DTCs P0106, P0107, P0108, P0122 and P0123 are not set.
Engine speed is 400 RPM or greater.
Throttle position changes less than 0.6 degrees in 0.1 second.
MAP pressure is less than or equal to 60.3 kPa.
Traction control is not active.
All 8 cylinders are enabled.
Engine overheat condition is not present.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, view TP sensor display. If TP sensor reading is greater than.01 volt, go to next step. If TP sensor reading is not greater than.01 volt, diagnose using DTC P0122.
Check TP sensor display while slowly depressing accelerator from closed to WOT. Check TP sensor display for a stuck condition. If a stuck condition is observed, go to next step. If a stuck condition is not observed, diagnose using DTC P0106.
Replace TP sensor and verify repairs.

DTC P0121: TP SENSOR PERFORMANCE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" 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 0.6 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 P0121 will set if TP sensor value does not closely match what VCM predicts TP sensor value should be.

For duplication of DTC, ensure DTC P0122 is not set, no IAC or MAP sensor DTCs are set, engine is running, BARO is not in default, and throttle position is steady.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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. Using scan tool, observe TP sensor value. If TP sensor value is greater than 2 percent, go to step 6 . If TP sensor value is not greater than 2 percent, go to next step.
Slowly depress throttle to WOT while observing scan tool. TP sensor value should increase from zero percent to 100 percent. If operation is as specified, go to next step. If operation is not as specified, go to step 10 .
Release throttle. If TP sensor value is greater than 2 percent, go to step 6 . If TP sensor value is not greater than 2 percent, go to next step.
DTC is intermittent. If any 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-p0100-p0134) .
Disconnect TP sensor harness connector. If TP sensor value is zero volts, go to next step. If TP sensor value is not zero volts, go to step 9 .
Turn ignition off. Using a test light connected to battery voltage, probe ground circuit at TP sensor harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 14 .
Turn ignition on. Using a test light connected to ground, probe 5-volt reference circuit at TP sensor harness connector. If test light illuminates, go to step 15 . If test light does not illuminate, go to step 19 .
Turn ignition off. Disconnect VCM harness connector C2. Turn ignition on. Measure voltage between ground and signal circuit at TP sensor harness connector. If voltage is greater than zero volts, go to step 13 . If voltage is not greater than zero volts, go to step 22 .
Turn ignition off. Disconnect TP sensor harness connector. Using a fused jumper wire, jumper 5-volt reference circuit to signal circuit at TP sensor harness connector. Turn ignition on. If TP sensor value is 100 percent, go to step 17 . If TP sensor value is not 100 percent, go to next step.
Turn ignition on. Measure voltage between ground and 5-volt reference circuit at TP sensor harness connector. If voltage is about 5.2 volts, go to next step. If voltage is not as specified, go to step 16 .
Turn ignition off. Disconnect VCM harness connector C2. Measure resistance in TP sensor signal circuit between TP sensor and VCM. If resistance is about zero ohms, go to step 22 . If resistance is not as specified, go to step 18 .
Repair short to voltage in TP sensor signal circuit. After repairs, go to step 24 .
Repair open in TP sensor ground circuit. After repairs, go to step 24 .
Repair short to voltage in 5-volt reference circuit. After repairs, go to step 24 .
Repair low voltage condition in 5-volt reference circuit. After repairs, go to step 24 .
Check for poor connection at TP sensor. If connection is faulty, go to next step. If connection is okay, go to step 19 .
Repair circuit as necessary. After repairs, go to step 24 .
Check for binding or sticking throttle linkage and/or cables. If a problem is found, go to next step. If no problem is found, go to step 21 .
Repair throttle linkage as necessary. After repairs, go to step 24 .
Replace TP sensor. After repairs, go to step 24 .
Check for poor connection as VCM. Repair as necessary. After repairs, go to step 24 . If connection is okay, go to next step.
Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP system variation learn procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0121. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

Scan tool displays throttle position in volts. Voltage should be about.45-.85 volt with throttle closed and ignition on. Voltage should steadily increase as throttle is moved toward wide open throttle. Scan tool throttle angle percentage will display as zero percent with closed throttle and 100 percent with wide open throttle. Check connector and sensor terminals for moisture or corrosion. Clean and replace as necessary. If corrosion is found, check connector seal and repair or replace as necessary. If DTC is intermittent, see appropriate TROUBLE SHOOTING - NO CODES article.

DTC P0121: TP SENSOR CIRCUIT-INSUFFICIENT ACTIVITY (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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. TP sensor voltage signal changes relative to throttle blade angle. TP sensor uses a 5-volt reference, a ground and a signal circuit. 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. The predicted value is calculated from engine speed and other inputs. If PCM detects predicted throttle position is less than actual TP sensor value, DTC P0121 will set.

For duplication of DTC, ensure engine is running, IAC is 0-255 counts, engine coolant temperature is greater than 32°F (0°C), MAP delta is less than 1.5 kPa during test, MAP is less than 55 kPa or greater than 65 kPa, and MAP is steady.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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, check for DTCs. If DTC P1404 or P1639 fails this ignition cycle, diagnose affected DTC. If DTC P1404 or P1639 are not present, go to next step.
Start engine. Monitor MAP sensor voltage. Increase engine speed to 2000 RPM. If MAP sensor voltage changed when engine speed changed, go to step 8 . If MAP sensor voltage did not change when engine speed changed, go to next step.
Turn ignition on, engine off. Move/wiggle MAP sensor and PCM harness connectors. If MAP value changes when harness or connectors are moved, go to step 17 . If MAP value does not change, go to next step.
Remove MAP sensor from intake manifold. Leave harness connector connected. Install a hand-held vacuum pump to MAP sensor. Slowly apply vacuum (up to 20 in. Hg) to MAP sensor. Each inch of vacuum applied should result in a 3-4 kPa drop in MAP sensor value on scan tool. Observe if value changes smoothly with each increase in vacuum. If MAP value changes smoothly, go to next step. If MAP value does not change or is erratic, go to step 18 .
Apply about 20 in. Hg to MAP sensor. If MAP reading is 34 kPa or less, go to next step. If MAP reading is not 34 kPa or less, go to step 18 .
Disconnect vacuum source from MAP sensor. If MAP reading returns to original value measured in step 5) , go to next step. If MAP reading does not return to original value, go to step 18 .
Turn ignition on, engine off. Monitor TP sensor voltage while moving accelerator from closed to wide open throttle. TP sensor reading should change from less than one volt to greater than 4 volts. If TP sensor reading is as specified, go to next step. If TP sensor reading is not as specified, go to step 10 .
Review and record FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 15 seconds. Start engine. Operate vehicle within conditions required for diagnostic run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Using scan tool, select DTC option, SPECIFIC DTC option, and then enter DTC which was set. If scan tool indicates that this diagnostic failed this ignition cycle, go to next step. If scan tool does not indicate that this diagnostic failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor harness connector. Observe TP sensor display on scan tool. If TP sensor voltage is zero volts, go to next step. If TP sensor voltage is not zero volts, go to step 14 .
Using a fused jumper wire, jumper TP sensor 5-volt reference circuit to TP sensor signal circuit. If TP sensor voltage is about 5 volts, go to next step. If TP sensor voltage is not about 5 volts, go to step 15 .
Check for poor connection at TP sensor. Repair as necessary. After repairs, go to step 19 . If connection is okay, go to next step.
Replace TP sensor. After repairs, go to step 19 .
Check TP sensor signal circuit for short to voltage, TP sensor ground for high resistance between PCM and TP sensor, or TP sensor ground circuit for poor connection. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to step 16 .
Check TP sensor signal circuit or 5-volt reference circuit for poor connection. Check TP sensor signal circuit or 5-volt reference circuit for high resistance between PCM and TP sensor. Repair as necessary. After repairs, go to step 19 . If circuits are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 19 .
Locate and repair affected circuit. After repairs, go to step 19 .
Replace MAP sensor. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC option and SPECIFIC DTC option. Operate vehicle within conditions for running the DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool indicates that this test did not pass, go to step 2 .
Select CAPTURE INFO option and REVIEW INFO on scan tool. If scan tool displays any DTCs that have not been diagnosed, diagnose affected DTCs. If no undiagnosed DTCs are present, system is okay.

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. If it is determined DTC is intermittent, performing DTC P1121 diagnostics may isolate cause of fault.

DTC P0121: TP SENSOR CIRCUIT-INSUFFICIENT ACTIVITY (5.7L "F" BODY)

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

For duplication of DTC, ensure no MAP or TP sensor DTCs are set, engine is running, engine coolant temperature is greater than 32°F (0°C), IAC is between 0-255 counts, MAP is less than 55 kPa or greater than 65 kPa, and MAP is steady.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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, monitor FAILED THIS IGNITION option under DTC information option. If DTC P1639 fails this ignition cycle, diagnose DTC 1639. If DTC P1639 did not fail this ignition cycle, go to next step.
Start engine. Monitor MAP sensor voltage. Increase engine speed to 2000 RPM. If MAP sensor voltage changed when engine speed changed, go to step 8 . If MAP sensor voltage did not change when engine speed changed, go to next step.
Turn ignition on, engine off. Move/wiggle MAP sensor and PCM harness connectors. If MAP value changes when harness or connectors are moved, go to step 16 . If MAP value does not change, go to next step.
Remove MAP sensor from intake manifold. Leave harness connector connected. Install a hand-held vacuum pump to MAP sensor. Slowly apply vacuum (up to 20 in. Hg) to MAP sensor. Each inch of vacuum applied should result in a 3-4 kPa drop in MAP sensor value on scan tool. Observe if value changes smoothly with each increase in vacuum. If MAP value changes smoothly, go to next step. If MAP value does not change or is erratic, go to step 17 .
Apply about 20 in. Hg to MAP sensor. If MAP reading is 34 kPa or less, go to next step. If MAP reading is not 34 kPa or less, go to step 17 .
Disconnect vacuum source from MAP sensor. If MAP reading returns to original value measured in step 5) , go to next step. If MAP reading does not return to original value, go to step 17 .
Turn ignition on, engine off. Monitor TP sensor voltage while moving accelerator from closed to wide open throttle. TP sensor reading should change from less than one volt to greater than 4 volts. If TP sensor reading is as specified, go to next step. If TP sensor reading is not as specified, go to step 10 .
Review and record FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 15 seconds. Start engine. Operate vehicle within conditions required for diagnostic run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Using scan tool, select DTC option, SPECIFIC DTC option, and then enter DTC which was set. If scan tool indicates that this diagnostic failed this ignition cycle, go to next step. If scan tool does not indicate that this diagnostic failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor harness connector. Observe TP sensor display on scan tool. If TP voltage is zero volts, go to next step. If TP sensor is not zero volts, go to step 13 .
Using a fused jumper wire, jumper TP sensor 5-volt reference circuit to TP sensor signal circuit. If TP sensor voltage is about 5 volts, go to next step. If TP sensor voltage is not about 5 volts, go to step 14 .
Replace TP sensor. After repairs, go to step 18 .
Check TP sensor signal circuit for short to voltage, TP sensor ground for high resistance between PCM and TP sensor, or TP sensor ground circuit for poor connection. Repair as necessary. After repairs, go to step 18 . If circuits are okay, go to step 15 .
Check TP sensor signal circuit or 5-volt reference circuit for poor connection. Check TP sensor signal circuit or 5-volt reference circuit for high resistance between PCM and TP sensor. Repair as necessary. After repairs, go to step 18 . If circuits are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 18 .
Locate and repair affected circuit. After repairs, go to step 18 .
Replace MAP sensor. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC option and SPECIFIC DTC option. Operate vehicle within conditions for running the DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool indicates that this test did not pass, go to step 2 .
Select CAPTURE INFO option and REVIEW INFO on scan tool. If scan tool displays any DTCs that have not been diagnosed, diagnose affected DTCs. If no undiagnosed DTCs are present, system is okay.

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. If it is determined DTC is intermittent, performing DTC P1121 diagnostics may isolate cause of fault.

DTC P0122: TP SENSOR CIRCUIT-LOW VOLTAGE (1.9L SATURN)

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

Throttle Position (TP) sensor is a variable resistor. TP sensor input voltage will be low when throttle blade is closed and increase when throttle is opened.

DTC P0122 will set if TP sensor voltage is less than.2 volt with engine running and no other TP sensor DTCs have been set. TP sensor signal is continuously monitored.

Connect scan tool. Check if DTC P1635 is also present. If DTC P1635 is present, diagnose that DTC first. If DTC P1635 is not present, go to next step.
Using scan tool, monitor TP sensor voltage reading. If TP sensor reading is less than.2 volt, go to next step. If TP sensor reading is.2 volt or greater, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor harness connector. Using a jumper wire, jumper TP sensor harness connector terminals "A" and "C" together. If TP sensor reading is still less than.2 volt, go to next step. If TP sensor reading is.2 volt or greater, TP sensor or harness connections are at fault.
Remove jumper wire. Using a test light connected to battery positive, probe TP sensor harness connector terminal "C". If TP sensor voltage still reads less than.2 volt, go to next step. If TP sensor voltage reads.2 volt or greater, check for open in 5-volt reference signal circuit to TP sensor (terminal "A").
Turn ignition off. Disconnect PCM harness connectors J2 and J3. Measure resistance between TP sensor harness connector terminals "B" and "C". If resistance is greater than 2 ohms, go to next step. If resistance is 2 ohms or greater, check for shorted circuit between terminals "B" and "C" or circuit shorted to ground.
Check continuity of TP sensor signal circuit between PCM and sensor harness connector terminals. Repair as necessary. If circuit is okay, PCM or harness connections are faulty.

Use scan tool to review malfunction history diagnostic information. This data can be used to duplicate a problem. Normal voltage readings should vary smoothly from.4 volt to 4.7 volts as throttle is moved from closed to wide open position.

DTC P0122: TP SENSOR CIRCUIT-LOW VOLTAGE (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) supplies a 5-volt reference signal and a ground circuit to Throttle Position (TP) sensor, and a signal circuit to monitor throttle angle. TP sensor signal voltage should be less than one volt at idle and greater than 4.5 volts at wide open throttle. DTC P0122 will set if TP sensor voltage is less than 0.1 volt for more than 6 seconds. For duplication of DTC, ensure 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, observe TP sensor voltage. If voltage is less than.2 volt, go to step 4 . If voltage is not less than.2 volt, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If TP sensor voltage is less than.2 volt, go to next step. If TP sensor voltage is not less than.2 volt, go to step 12 .
Turn ignition off. Disconnect TP sensor connector. Connect a jumper wire between signal circuit and 5-volt reference circuit terminals at TP sensor harness connector. Turn ignition on. Observe TP sensor voltage. If voltage is greater than 4 volts, go to step 10 . If voltage is not greater than 4 volts, go to next step.
Remove jumper wire. Connect a test light between battery positive and signal circuit terminal at TP sensor harness connector. If voltage is greater than 4 volts, go to next step. If voltage is not greater than 4 volts, go to step 8 .
Check 5-volt reference circuit for an open or short to ground. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check 5-volt reference circuit terminal for poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuit terminal is okay, go to step 11 .
Check TP sensor signal circuit for an open or short to ground. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for poor TP sensor signal circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 11 .
Replace TP sensor. After repairs, go to step 12 .
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. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0122. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation.

DTC P0122: TP SENSOR CIRCUIT-LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

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 P0122 will set if TP sensor signal is less than 2.0 percent. For duplication of DTC, ensure 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, engine off. With throttle closed, use scan tool to read TP sensor voltage. If voltage is less than 0.16 volt, go to step 4 . If voltage is not less than 0.16 volt, go to next step.
With ignition still on, engine off, use scan tool to read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0122 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0122 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor harness connector. Connect a jumper wire between TP sensor harness connector 5-volt reference and signal circuits. If voltage is 5 volts, go to step 10 . If voltage is not 5 volts, go to next step.
Connect a test light between TP sensor harness connector signal circuit and battery positive. Observe TP sensor display on scan tool. If voltage is 5 volts, go to next step. If voltage is not 5 volts, go to step 8 .
Turn ignition off. Disconnect PCM harness connectors. Check PCM harness connector 5-volt reference circuit for open or short to ground. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Turn ignition off. Check for faulty connection of 5-volt reference circuit at PCM. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Turn ignition off. Disconnect PCM harness connectors. Check PCM harness connector TP signal circuit for open, short to ground or short to ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Check for faulty connection of TP signal circuit at PCM. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Check for faulty connection of TP signal circuit at TP sensor. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
Replace TP sensor. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0122. If scan tool displays DTC P0122 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0122 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe TP sensor display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

DTC P0122: TP SENSOR CIRCUIT-LOW VOLTAGE (3.5L "W" BODY)

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

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Throttle Position (TP) sensor, and a signal circuit to monitor throttle angle. TP sensor signal voltage should be less than one volt at idle and greater than 4 volts at wide open throttle. DTC P0122 will set if TP sensor voltage is less than 0.1 volt for more than one second. For duplication of DTC, ensure 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.
Monitor TP sensor voltage on scan tool. If TP sensor voltage is less than.16 volt, go to step 4 . If TP sensor voltage is not less than.16 volt, go to next step.
Turn ignition off and wait 15 seconds. Turn ignition on. Using scan tool, review and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0122 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0122 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor. Using a fused jumper wire, jumper 5-volt reference circuit to signal circuit at TP sensor harness connector. Monitor TP sensor voltage on scan tool. If TP sensor voltage is about 5 volts, go to step 11 . If TP sensor voltage is not about 5 volts, go to next step.
Using a test light connected to battery positive, probe signal circuit at TP sensor harness connector. Monitor TP sensor voltage on scan tool. If TP sensor voltage is about 5 volts, go to next step. If TP sensor voltage is not about 5 volts, go to step 8 .
Turn ignition off. Disconnect PCM harness connectors. Check 5-volt reference circuit for an open or short to ground. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 13 .
Turn ignition off. Disconnect PCM harness connectors. Check 5-volt reference circuit for short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Check TP sensor signal circuit for an open, short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Check TP sensor signal circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 13 .
Check signal circuit for poor connection at TP sensor harness connector. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to next step.
Replace TP sensor. After repairs, go to step 14 .
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 option and SPECIFIC DTC option. Operate vehicle within conditions for running the DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool indicates that this test did not pass, go to step 2 .
Select CAPTURE INFO option and REVIEW INFO on scan tool. If scan tool displays any DTCs that have not been diagnosed, diagnose affected DTCs. If no undiagnosed DTCs are present, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe TP sensor display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

If DTC cannot be duplicated, the information included in the FAILURE RECORDS data can be useful in determining vehicle mileage since DTC was last set.

DTC P0122: TP SENSOR CIRCUIT-LOW VOLTAGE (3.8L "C", "F", "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 P0122 will set if TP sensor signal voltage is less than 0.1 volt for more than 10 seconds. For duplication of DTC, ensure 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, engine off. With throttle closed, use scan tool to read TP sensor voltage. If voltage is less than 0.16 volt, go to step 4 . If voltage is not less than 0.16 volt, go to next step.
With ignition still on, engine off, use scan tool to read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0122 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0122 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor harness connector. Connect a jumper wire between TP sensor harness connector 5-volt reference and signal circuits. If scan tool voltage reading is 5 volts, go to step 11 . If scan tool voltage reading is not 5 volts, go to next step.
Connect a test light between TP sensor harness connector signal circuit and battery positive. If scan tool voltage reading is 5 volts, go to next step. If scan tool reading is not 5 volts, go to step 8 .
Turn ignition off. Disconnect PCM harness connectors. Check PCM harness connector 5-volt reference circuit for open or short to ground. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Check for faulty connection of 5-volt reference circuit at PCM. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 13 .
Turn ignition off. Disconnect PCM harness connectors. Check 5-volt reference circuit for short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Check TP signal circuit for an open, short to ground or short to sensor ground. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Check for faulty TP signal circuit connection at PCM. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 13 .
Check for faulty connection of TP signal circuit at TP sensor. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to next step.
Replace TP sensor. After repairs, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0122. If scan tool displays DTC P0122 FAILED THIS IGN, go to step 4 . If scan tool does not display DTC P0122 FAILED THIS IGN, system is okay.

DTC P0122: TP SENSOR CIRCUIT-VOLTAGE LOW (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

TP sensor is a potentiometer. At low throttle angle, TP sensor voltage is low. PCM uses TP sensor signal voltage to determine idle, Wide Open Throttle (WOT), deceleration enleanment and acceleration enrichment. This test determines when the TP sensor reading is too high and out of its estimated range for the current engine speed. PCM monitors changes in TP sensor within a certain period of time. If change is.6 degrees or less within.1 second, PCM compares the current throttle position with a stored value. If TP sensor reading is 0.1 volts or less, DTC P0122 will set.

For duplication of DTC, ensure engine speed is 600 RPM or greater.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, monitor TP display. If TP sensor reads 0.1 volt or less, go to next step. If TP sensor does not read 0.1 volt or less, fault is not present at this time. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect TP sensor harness connector. Jumper TP sensor 5-volt reference circuit and TP sensor signal circuit together at sensor harness connector. Turn ignition on. If TP sensor reads greater than 4.5 volts, go to step 13 . If TP sensor does not read greater than 4.5 volts, go to next step.
Remove jumper wire. Using DVOM, measure voltage between ground and 5-volt reference circuit terminal. If voltage reading is 4.5 volts or greater, go to next step. If voltage reading is not 4.5 volts or greater, go to step 7 .
Store fluid life index as indicated on scan tool. Turn ignition off for 30 seconds, and then disconnect PCM harness connector C1. Using DVOM, measure resistance between sensor ground and sensor signal circuits. Measure resistance between sensor signal circuit and a known-good engine ground. If resistance on both circuits is 10,000 ohms or greater, go to next step. If resistance on both circuits is not 10,000 ohms or greater, go to step 9 .
Measure resistance on TP sensor signal circuit between PCM harness connector C1 terminal and TP sensor connector terminal. If resistance is greater than 5 ohms, go to step 10 . If resistance is not greater than 5 ohms, go to step 19 .
Store fluid life information as indicated on scan tool. Turn ignition off for 30 seconds and then disconnect PCM harness connector C1. Using DVOM, measure resistance between TP sensor 5-volt reference circuit and sensor ground circuit. Measure resistance between 5-volt reference circuit and a known-good engine ground. If resistance on both tests is 10,000 ohms or greater, go to next step. If resistance on both tests is not 10,000 ohms or greater, go to step 12 .
Measure resistance of 5-volt reference circuit between TP sensor connector terminal and PCM harness connector terminal. If resistance is less than 5 ohms, go to step 15 . If resistance is not less than 5 ohms, go to step 11 .
Repair short to ground in TP sensor signal circuit or short between TP sensor signal circuit and TP sensor ground circuit.
Repair open in TP sensor signal circuit.
Repair open in TP sensor 5-volt reference circuit.
Repair short to ground in TP sensor 5-volt reference circuit or short between TP sensor 5-volt reference circuit and sensor ground circuit.
Check terminal contact at TP sensor connector. Repair as necessary. If terminal contact is okay, go to next step.
Replace TP sensor.
Reconnect TP sensor harness connector. Disconnect PCM harness connector C1. Measure resistance between the 5-volt reference circuit and sensor ground circuit of MAP sensor, EGR position sensor and fuel tank pressure sensor. If resistance measurement for any circuit is less than 10,000 ohms, go to step 17 . If no resistance measurements are less than 10,000 ohms, go to next step.
Measure resistance between 5-volt reference circuit and a known-good engine ground of MAP sensor, EGR position sensor and fuel tank pressure sensor. If resistance measurement for any circuit is less than 10,000 ohms, go to step 18 . If no resistance measurements are less than 10,000 ohms, go to step 19 .
Repair 5-volt reference circuit for a short to sensor ground, or replace shorted sensor.
Repair 5-volt reference circuit for a short to engine/body ground on affected sensor circuit.
Check terminal contact at PCM harness connector C1. Repair as necessary. If terminal contacts are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

If no faults are found, check all PCM related ground connections. If DTC cannot be duplicated, the information included in the FAILURE RECORDS data can be useful in determining vehicle mileage since DTC was last set.

DTC P0122: TP SENSOR CIRCUIT-LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" 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 0.5 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 P0122 will set if TP sensor signal voltage is less than.25 volt for one second or more. For duplication of DTC, ensure 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.
Install scan tool. With throttle closed, monitor TP signal voltage using scan tool. If TP signal voltage is less than.25 volt, go to step 5 . If TP signal voltage is not less than.25 volt, go to next step.
Depress accelerator pedal to WOT while monitoring TP sensor angle on scan tool. If TP angle increases smoothly from zero percent to 100 percent, go to next step. If operation is not as specified, diagnose using DTC P0121.
DTC is intermittent. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If any additional DTCs are set, go to applicable DTC test.
Disconnect TP sensor connector. Connect a jumper wire between TP signal circuit and 5-volt reference circuit at TP sensor connector. Monitor TP signal voltage using scan tool. If TP signal voltage is greater than 4 volts, go to step 13 . If TP signal voltage is not greater than 4 volts, go to next step.
Remove jumper wire. Turn ignition on. Measure voltage between ground and 5-volt reference circuit at TP sensor harness connector. If voltage is greater than 4.7 volts, go to step 14 . If voltage is not greater than 4.7 volts, go to next step.
Turn ignition off. Disconnect VCM harness connector C3. Check for an open in 5-volt reference circuit. If circuit is open, go to step 19 . If circuit is okay, go to next step.
Reconnect VCM harness connector C3. Turn ignition on. Measure voltage between ground and 5-volt reference circuit at TP sensor harness connector. Disconnect EGR position sensor, MAP sensor and fuel tank pressure sensors individually while monitoring voltage. If voltage is greater than 4.7 volts with one of the sensors disconnected, go to next step. If voltage is not greater than 4.7 volts with any of the sensors disconnected, go to step 12 .
If EGR position sensor is suspect, go to next step. If EGR position sensor is not suspect, go to step 11 .
Check for short between 5-volt reference circuit and EGR feed control circuit. If circuits are shorted, go to step 19 . If circuits are okay, go to next step.
Replace sensor causing voltage to increase to greater than 4.7 volts. After repairs, go to step 21 .
Ensure all sensors are still disconnected. Turn ignition off. Using a test light connected to battery positive, probe 5-volt reference circuit at TP sensor harness connector. If test light illuminates, go to step 16 . If test light does not illuminate, go to step 17 .
Check for poor connection at TP sensor. If connection is faulty, go to step 19 . If connection is okay, go to step 18 .
Check TP sensor signal circuit for a short to ground. If circuit is shorted, go to step 19 . If circuit is okay, go to next step.
Check for an open in TP sensor circuit. If circuit is open, go to step 19 . If circuit is okay, go to step 20 .
Repair short to ground in 5-volt reference circuit. After repairs, go to step 21 .
Disconnect VCM harness connector C3. Check for poor connection. If connection is faulty, go to step 19 . If connection is okay, go to step 20 .
Replace TP sensor. After repairs, go to step 21 .
Repair circuit as necessary. After repairs, go to step 21 .
Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP variation learn procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Scan tool displays throttle position in volts. Voltage should be.45-.85 volt with throttle closed and ignition on. An open or short to ground in 5-volt reference circuit or TP signal circuit will cause DTC P0122 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 P0122: TP SENSOR CIRCUIT-LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

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

Throttle Position (TP) sensor provides a voltage signal that changes relative to throttle opening. Signal voltage varies from less than one volt at idle to greater than 4 volts at Wide Open Throttle (WOT). TP sensor signal is one of the most important inputs used by PCM for fuel control and most PCM control outputs. DTC P0122 will set if TP sensor signal voltage is less than 0.2 volt for 10 seconds or more. For duplication of DTC, ensure ignition is on or 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.
Connect scan tool. Start engine and let idle. Check for DTCs. If DTC P1639 failed this ignition, diagnose using DTC P1639. If DTC P1639 did not fail this ignition, go to next step.
Turn ignition on, with engine off. With throttle closed, monitor TP sensor with scan tool. If TP sensor voltage is less than 0.2 volt, go to step 5 . If TP sensor voltage is not less than 0.2 volt, go to next step.
Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data. Turn ignition off for 15 seconds. Start engine and operate vehicle within conditions noted in FAILURE RECORDS data and as close to conditions required to set this DTC as possible. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0122 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0122 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor. Using a fused jumper wire, jumper 5-volt reference circuit and signal circuit together at TP sensor harness connector. Monitor TP sensor on scan tool. If TP sensor voltage is greater than 4.7 volts, go to step 11 . If TP sensor voltage is not greater than 4.7 volts, go to next step.
Using a test light connected to battery positive, probe signal circuit at TP sensor harness connector. If TP sensor voltage is greater than 4.7 volts, go to next step. If TP sensor voltage is not greater than 4.7 volts, go to step 9 .
Turn ignition off. Disconnect PCM harness connector C1. Check 5-volt reference circuit for an open or a short to ground. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Turn ignition off. Disconnect PCM harness connector C2. Check TP sensor signal circuit for an open, short to ground or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Check TP sensor circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
Replace TP sensor. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation.

If it is determined that DTC is intermittent, performing DTC P1122 diagnosis may isolate cause of fault.

DTC P0122: TP SENSOR CIRCUIT-LOW VOLTAGE (5.7L "F" 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. 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 more at wide open throttle. PCM compares actual throttle position from TP sensor to a predicted throttle position value. The predicted value is calculated from engine speed and other inputs. If PCM detects TP sensor voltage less than 0.2 volt for 10 seconds, DTC P0122 will set. For duplication of DTC, ensure ignition is on or engine is running.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Start and operate engine at idle. Using scan tool, monitor FAILED THIS IGNITION option under DTC INFORMATION option. If DTC P1639 failed this ignition, diagnose this DTC. If DTC P1639 did not fail in this ignition cycle, go to next step.
Turn ignition on, with engine off. Using scan tool, monitor TP sensor voltage with throttle closed. If TP sensor voltage is less than 0.2 volt, go to step 5 . If TP sensor voltage is not as specified, 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, and then enter DTC P0122. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect Accelerator and Servo Control Module (ASM). Turn ignition on. If TP sensor voltage is less than 0.2 volt, go to next step. If TP sensor voltage is not less than 0.2 volt, diagnose ASM. See appropriate ANTI-LOCK article in BRAKES.
Disconnect TP sensor connector. Connect a fused jumper wire between 5-volt reference circuit and TP signal circuit at TP sensor harness connector. Observe TP sensor voltage display on scan tool. If TP voltage is greater than 4.7 volts, go to step 12 . If TP sensor voltage is not greater than 4.7 volts, go to next step.
Connect a test light between battery positive and TP sensor signal circuit at TP sensor harness connector. Observe TP sensor voltage on scan tool. If TP sensor voltage is greater than 4.7 volts, go to next step. If TP sensor is not greater than 4.7 volts, go to step 10 .
Turn ignition off. Disconnect PCM harness connector C1. Check 5-volt reference circuit for an open or short to ground. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Check 5-volt reference circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 14 . If terminals are okay, go to step 13 .
Turn ignition off. Disconnect PCM harness connector C2. Check TP signal circuit for an open, short to ground, or short to sensor ground circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Check TP sensor signal circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 14 . If terminals are okay, go to step 13 .
Replace TP sensor. After repairs, go to step 14 .
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, and then enter DTC P0122. 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, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

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. The PCM 5-volt reference circuits are internally connected within PCM. If it is determined that DTC is intermittent, performing DTC P1122 diagnostics may isolate cause of fault.

DTC P0123: TP SENSOR CIRCUIT-HIGH VOLTAGE (1.9L SATURN)

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

Throttle Position (TP) sensor is a variable resistor. TP sensor input voltage will be low when throttle blade is closed and increase when throttle is opened.

DTC P0123 will set if TP sensor voltage is greater than 4.9 volts with engine running and no other TP sensor related DTCs have been set. TP sensor signal is continuously monitored.

Turn ignition on, with engine off. Connect scan tool and monitor TP sensor voltage reading. If TP sensor reading is greater than 4.7 volts, go to next step. If TP sensor reading is not greater than 4.7 volts, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor harness connector. If TP sensor reading is greater than 4.9 volts, go to next step. If TP sensor reading is not greater than 4.9 volts, go to step 4 .
Turn ignition off. Disconnect PCM harness connector J2. Remove TP sensor signal circuit terminal from PCM harness connector. Reconnect PCM harness connector. Turn ignition on. If TP sensor reads greater than 4.9 volts, replace PCM. If TP sensor does not read greater than 4.9 volts, check signal circuit for short to voltage or shorted to 5-volt reference circuit.
Measure voltage between TP sensor harness connector terminals "A" and "B". If voltage reading is greater than 4.9 volts, replace TP sensor. If voltage reading is not greater than 4.9 volts, go to next step.
Check for continuity in TP sensor ground circuit between sensor and PCM. Repair as necessary. If circuit is okay, terminal connections or PCM are faulty.

DTC P0123: TP SENSOR CIRCUIT-HIGH VOLTAGE (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.

DTC P0123 will set if TP sensor voltage is greater than 3.9 volts for 14 seconds with engine speed less than 1500 RPM, or if TP sensor voltage is greater than 4.8 volts with engine speed greater than 1500 RPM.

For duplication of DTC, ensure DTC P0107 or P0108 is not set, engine is running, MAP is less than 60 kPa, and engine speed is less than 1500 RPM, or MAP is greater than 60 kPa and engine speed is greater than 1500 RPM.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Turn ignition on, with engine off (throttle closed). Using scan tool, observe TP sensor voltage. If TP sensor voltage is greater than 0.8 volt, go to step 4 . If voltage is not greater than 0.8 volt, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If TP sensor voltage is greater than 3.9 volts, go to next step. If TP sensor voltage is not greater than 3.9 volts, go to step 12 .
Disconnect TP sensor connector. Observe TP sensor voltage. If voltage is less than 0.3 volt, go to next step. If voltage is not less than 0.3 volt, go to step 6 .
Connect a test light between battery positive and sensor ground circuit terminal at TP sensor harness connector. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 9 .
Check for short to voltage in TP sensor signal circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 11 .
Check for short to battery voltage in 5-volt reference circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Disconnect and inspect TP sensor connector. Repair as necessary. After repairs, go to step 12 . If connector is okay, go to step 10 .
Check for open in ground circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 11 .
Replace TP sensor. After repairs, go to step 12 .
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. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0123. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. If other DTCs are set for components that share the same ground and/or 5-volt reference circuit, check for faulty connections or wiring. The PCM 5-volt reference circuits are internally connected within PCM. Also, using FREEZE FRAME data may aid in determining conditions when DTC was set.

DTC P0123: TP SENSOR CIRCUIT-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 P0123 will set if TP sensor signal is greater than 98 percent with engine running.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Turn ignition on, engine off. Using scan tool, read TP sensor voltage. If voltage is greater than 4.71 volts, go to step 4 . If voltage is not greater than 4.71 volts, go to next step.
With ignition still on, engine off, using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0123 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0123 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor harness connector. If voltage is about zero volts, go to next step. If voltage is not as specified, go to step 6 .
Connect a test light between TP sensor harness connector ground circuit and battery positive. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 8 .
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Check TP sensor harness connector signal circuit for short to voltage. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 11 .
Turn ignition on. While monitoring TP sensor with scan tool, disconnect each component (one at a time) that shares common 5-volt reference circuit. If display changes, replace component that causes change. After repairs, go to step 12 . If display does not change, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, engine off. Check PCM harness connector 5-volt reference circuit for short to voltage. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
Check for faulty connection at TP sensor. Repair as necessary. After repairs, go to step 12 . If TP sensor connection is okay, go to next step.
Replace TP sensor. After repairs, go to step 12 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0123. If scan tool displays DTC P0123 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0123 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe TP sensor display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

Turn ignition on, engine off. Using scan tool TP sensor display, slowly depress accelerator to wide open throttle. If voltage is greater than 4.71 volts at any time, replace TP sensor.

DTC P0123: TP SENSOR CIRCUIT-HIGH VOLTAGE (3.5L "W" BODY)

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

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Throttle Position (TP) sensor, and a signal circuit to monitor throttle angle. TP sensor signal voltage should be less than one volt at idle and greater than 4 volts at wide open throttle. DTC P0123 will set if TP sensor voltage is greater than 4.9 volts for more than one second. For duplication of DTC, ensure engine is running.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Turn ignition on, engine off. Using scan tool, read TP sensor voltage. If voltage is greater than 4.7 volts, go to step 4 . If voltage is not greater than 4.7 volts, go to next step.
Turn ignition off and wait 15 seconds. Turn ignition on. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0123 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0123 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor harness connector. If voltage is about zero volts, go to next step. If voltage is not as specified, go to step 6 .
Connect a test light between TP sensor harness connector ground circuit and battery positive. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 8 .
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Check TP sensor harness connector signal circuit for short to voltage. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
Reconnect TP sensor. Turn ignition on. While monitoring TP sensor with scan tool, disconnect each component (one at a time) that shares common 5-volt reference circuit. If display changes, replace component that causes change. After repairs, go to step 13 . If display does not change, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, engine off. Check PCM harness connector 5-volt reference circuit for short to voltage. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
Check for faulty connection at TP sensor. Repair as necessary. After repairs, go to step 13 . If TP sensor connection is okay, go to step 11 .
Turn ignition off. Disconnect PCM harness connectors. Check TP sensor ground circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Replace TP sensor. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off and wait 15 seconds. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0123. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe TP sensor display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

Turn ignition on, engine off. Using scan tool TP sensor display, slowly depress accelerator to wide open throttle. If voltage is greater than 4.71 volts at any time, replace TP sensor.

If DTC cannot be duplicated, the information included in the FAILURE RECORDS data can be useful in determining vehicle mileage since DTC was last set.

DTC P0123: TP SENSOR CIRCUIT-HIGH VOLTAGE (3.8L "C", "F", "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 P0123 will set if TP sensor voltage is greater than 4.9 volts for more than 10 seconds. For duplication of DTC, ensure ignition is on.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Turn ignition on, engine off. Using scan tool, read TP sensor voltage. If voltage is greater than 4.7 volts, go to step 4 . If voltage is not greater than 4.7 volts, go to next step.
Turn ignition on, with engine off. Use scan tool to read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0123 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0123 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor harness connector. If voltage is zero volts, go to next step. If voltage is not zero volts, go to step 8 .
Measure voltage between ground and 5-volt reference circuit at TP sensor harness connector. If voltage is 5 volts, go to next step. If voltage is not 5 volts, go to step 9 .
Using a test light connected to battery positive, probe ground circuit at TP sensor harness connector. If test light illuminates, go to step 10 . If test light does not illuminate, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, engine off. Check TP sensor ground circuit for an open or high resistance. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 11 .
Check TP sensor signal circuit for short to voltage. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 13 .
Check all 5-volt reference circuits and connected components for short to voltage. Repair as necessary. After repairs, go to step 14 . If circuits are okay, go to step 13 .
Check for poor connections at TP sensor. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 12 .
Check for poor connections at PCM. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
Replace TP sensor. After repairs, go to step 14 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0123. If scan tool displays DTC P0123 FAILED THIS IGN, go to step 4 . If scan tool does not display DTC P0123 FAILED THIS IGN, system is okay.

Turn ignition on, engine off. Observe scan tool TP sensor display while slowly depressing accelerator to wide open throttle. If voltage is greater than 4.71 volts at any time, replace TP sensor.

DTC P0123: TP SENSOR CIRCUIT-HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

TP sensor is a potentiometer. At low throttle angle, TP sensor voltage is low. PCM uses TP sensor signal voltage to determine idle, Wide Open Throttle (WOT), deceleration enleanment and acceleration enrichment. DTC P0123 will set if TP sensor voltage is 4.96 volts or greater. For duplication of DTC, ensure engine speed is between 25 and 3000 RPM.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Turn ignition on. Using scan tool, monitor TP sensor. If TP sensor reads 4.85 volts or greater, go to next step. If TP sensor does not read 4.85 volts or greater, fault is not present at this time. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor harness connector. If TP sensor reads 0.1 volt or greater, go to next step. If TP sensor does not read 0.1 volt or greater, go to step 5 .
Store fluid life index as indicated on scan tool. Turn ignition off for 30 seconds, and then disconnect PCM harness connector C1. Using DVOM, measure voltage between ground and sensor signal terminal. If voltage is greater than 0.5 volt, go to step 9 . If voltage is not greater than 0.5 volt, go to step 12 .
Measure voltage between ground and TP sensor 5-volt reference terminal. If voltage is greater than 5.4 volts, go to step 7 . If voltage is not greater than 5.4 volts, go to next step.
Measure voltage between TP sensor 5-volt reference terminal and sensor ground terminal. If voltage is less than 4.5 volts, go to step 8 . If voltage is not less than 4.5 volts, go to step 10 .
Repair short to battery voltage on 5-volt reference circuit.
Repair open in TP sensor ground circuit.
Repair short to voltage in TP sensor signal circuit.
Check terminal contact at TP sensor. Repair as necessary. If terminal contact is okay, go to next step.
Replace TP sensor.
Check terminal contact at PCM harness connector C1. Repair as necessary. If terminal contacts are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

DTC P0123: TP SENSOR CIRCUIT-HIGH VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

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

Throttle Position (TP) sensor signal circuit provides a voltage signal that changes relative to throttle opening. Signal voltage varies from about 0.5 volt at idle to about 4.0 volts at Wide Open Throttle (WOT). Input is used by VCM for fuel control and most VCM control outputs. DTC P0123 will set if TP sensor signal voltage is greater than 4.7 volts for one second or more. For duplication of DTC, ensure engine is running.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Install scan tool. Turn ignition on. With throttle closed, monitor TP signal voltage using scan tool. If TP signal voltage is greater than 4.7 volts, go to next step. If TP signal voltage is not greater than 4.7 volts, go to step 4 .
Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on, engine off. Using scan tool, monitor TP signal voltage. If TP signal voltage is less than 0.25 volt, go to step 5 . If TP signal voltage is not less than 0.25 volt, go to step 8 .
DTC is intermittent. If no additional DTCs are set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If any additional DTCs are set, go to applicable DTC test.
Using DVOM, measure voltage between ground and 5-volt reference circuit at TP sensor harness connector. If voltage reading is greater than 5.2 volts, go to step 9 . If voltage is not greater than 5.2 volts, go to next step.
Using test light connected to battery voltage, probe TP sensor connector ground circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
Replace TP sensor. After repairs, go to step 15 .
Check for short to voltage in TP sensor signal circuit. If circuit is shorted, go to step 12 . If circuit is okay, go to step 14 .
Turn ignition off. Disconnect VCM harness connectors. Turn ignition on. Measure voltage between ground and TP sensor 5-volt reference circuit at VCM harness connector C3. If voltage is greater than zero volts, go to step 13 . If voltage is not greater than zero volts, go to next step.
Measure voltage between ground and MAP sensor 5-volt reference circuit at VCM harness connector C3. If voltage is greater than zero volts, go to step 13 . If voltage is not greater than zero volts, go to step 14 .
Repair open in TP sensor ground circuit. After repairs, go to step 15 .
Repair circuit as necessary. After repairs, go to step 15 .
Repair short to voltage in 5-volt reference circuit. After repairs, go to step 15 .
Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP system variation learn procedures. After repairs, go to step 15 .
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

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 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. An open in TP ground circuit or short to voltage in TP signal circuit will cause DTC P0123 to set. If DTC is intermittent, see appropriate TROUBLE SHOOTING - NO CODES article.

DTC P0123: TP SENSOR CIRCUIT-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 provides a voltage signal that changes relative to throttle opening. Signal voltage varies from less than one volt at idle to greater than 4 volts at Wide Open Throttle (WOT). TP sensor signal is one of the most important inputs used by PCM for fuel control and most PCM control outputs. DTC P0123 will set if TP sensor signal voltage is greater than 4.75 volts for 10 seconds or more. For duplication of DTC, ensure ignition is on or engine is running.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Connect scan tool. Start engine and let idle. Check for DTCs. If DTCs P1635 and P1639 failed this ignition, diagnose DTCs. If DTCs P1635 and P1639 did not fail this ignition, go to next step.
Turn ignition on, with engine off. With throttle closed, monitor TP sensor with scan tool. If TP sensor voltage is greater than 4.7 volts, go to step 5 . If TP sensor voltage is not greater than 4.7 volts, go to next step.
Turn ignition on, with engine off. Using scan tool, read and record FAILURE RECORDS data. Turn ignition off for 15 seconds. Start engine and operate vehicle within conditions noted in FAILURE RECORDS data and as close to conditions required to set this DTC as possible. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0123 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0123 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect TP sensor. Monitor TP sensor with scan tool. If TP sensor voltage is less than 0.2 volt, go to next step. If TP sensor voltage is not less than 0.2 volt, go to step 9 .
Using a test light connected to battery positive, probe ground circuit at TP sensor harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Measure voltage between ground and 5-volt reference circuit at TP sensor harness connector. If voltage is greater than 5 volts, go to step 13 . If voltage is not greater than 5 volts, go to next step.
Replace TP sensor. After repairs, go to step 14 .
Turn ignition off. Disconnect PCM harness connector C2. Turn ignition on. Check TP sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 12 .
Check for an open in TP sensor ground circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
Turn ignition off. Disconnect PCM harness connector C1. Check TP sensor ground circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 14 . If connection is okay, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 14 .
Repair 5-volt reference circuit for a short to voltage. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

DTC P0123: TP SENSOR CIRCUIT 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. The predicted value is calculated from engine speed and other inputs. If PCM detects TP sensor signal voltage greater than 4.75 volts for 10 seconds, DTC P0123 will set. For duplication of DTC, ensure ignition is on or 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.
Start and operate engine at idle. Using scan tool, monitor FAILED THIS IGNITION option under DTC INFORMATION option. If scan tool indicates that DTC P1639 failed in this ignition, diagnose DTC P1639 first. If scan tool does not indicate that DTC P1639 failed in this ignition, go to next step.
Turn ignition on, with engine off. Using scan tool, monitor TP sensor voltage with throttle closed. If TP sensor voltage is greater than 4.7 volts, go to step 5 . If TP sensor voltage is not greater than 4.7 volts, 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, and then enter DTC P0123. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect Accelerator and Servo Control Module (ASM). Turn ignition on. Monitor TP sensor voltage with scan tool. If TP sensor voltage is greater than 4.7 volts, go to next step. If TP sensor voltage is not greater than 4.7 volts, diagnose traction control module. See appropriate ANTI-LOCK BRAKES article in BRAKES.
Disconnect TP sensor connector. Observe TP sensor voltage display on scan tool. If TP sensor voltage is less than 0.2 volt, go to next step. If TP sensor voltage is not less than 0.2 volt, go to step 10 .
Connect test light between battery positive and TP sensor ground circuit at TP sensor harness connector. If test light illuminates, go to next step. If test light does not illuminate, got step 11 .
Measure voltage between ground and 5-volt reference circuit. If voltage is greater than 5 volts, go to step 14 . If voltage is not greater than 5 volts, go to next step.
Replace TP sensor. After repairs, go to step 15 .
Turn ignition off. Disconnect PCM harness connector C2. Check TP sensor signal circuit for short to voltage or short between TP sensor signal circuit and Accelerator and Servo Control Module (ASM). Repair as necessary. After repairs, go to step 15 . If circuit are okay, go to step 13 .
Check for open in TP sensor ground circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
Turn ignition off. Disconnect PCM harness connector C1. Check TP sensor ground circuit connection at PCM. Repair as necessary. After repairs, go to step 15 . If terminal is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 15 .
Repair 5-volt reference circuit for short to voltage. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0123. 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, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no undiagnosed DTCs are displayed, system is okay.

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.

If it is determined that DTC is intermittent, performing DTC P1121 diagnostics may isolate cause of fault.

DTC P0125: ECT EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL (1.9L SATURN)

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

DTC P0125 will set if coolant temperature is less than 32°F (0°C) after engine has been running for more than 5 minutes when no ECT and IAT DTCs have been set. ECT signal is continuously monitored when engine is running.

DTC P0125 indicates lower than normal coolant temperature and probably does not indicate a faulty ECT sub-system. Low coolant temperature can be caused by a stuck open thermostat or cooling fan is always on.

DTC P0125: ECT EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL (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.

Fuel delivery system will operate in open loop when engine coolant temperature is less than 68°F (20°C). During open loop, PCM ignores oxygen sensor signal and calculates air/fuel ratio based on inputs from Engine Coolant Temperature (ECT) sensor, Throttle Position (TP) sensor and Manifold Absolute Pressure (MAP) sensor. DTC P0125 will set if engine coolant temperature is less than 113°F (40°C) and system is in "open-loop".

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Allow engine to cool to ambient temperature. Turn ignition on, with engine off. Using scan tool, compare ECT sensor temperature reading to IAT sensor temperature reading. If readings are close to each other, go to step 5 . If readings are not close to each other, go to next step.
Disconnect ECT sensor connector. Using DVOM, measure ECT sensor resistance. See appropriate SENSOR OPERATING RANGE CHARTS article. If ECT resistance value is close as indicated, go to next step. If ECT resistance value is not as specified, go to step 15 .
If ECT sensor value is close to IAT sensor reading on scan tool, go to next step. If ECT sensor value is not close to IAT sensor reading on scan tool, go to step 2 .
Disconnect ECT sensor. Turn ignition on. If ECT sensor value is less than -22°F (-30°C), go to next step. If ECT sensor value is not less than -22°F (-30°C), go to step 14 .
Connect a jumper wire between signal circuit and ground circuit terminals at ECT sensor harness connector. If scan tool value is greater than 266°F (130°C), go to next step. If scan tool value is not greater than 266°F (130°C), go to step 8 .
Check for poor connection at ECT sensor. Repair as necessary. After repairs, go to step 16 . If connection is okay, go to step 9 .
Disconnect jumper wire from ECT sensor ground circuit and connect jumper wire to known-good ground. If scan tool value is greater than 266°F (130°C), go to step 11 . If scan tool value is not greater than 266°F (130°C), go to step 12 .
Turn ignition off. Reconnect ECT sensor. Start engine and operate for at least 5 minutes. Monitor ECT on scan tool. If temperature increases to greater than 9°F (5°C), go to next step. If temperature does not increases to greater than 9°F (5°C), go to step 15 .
Turn ignition off. Disconnect ECT sensor. Disconnect PCM harness connectors. Turn ignition on. Measure voltage between ground and ECT sensor ground circuit. If voltage is greater than.5 volt, go to step 13 . If voltage is not greater than.5 volt, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check ECT sensor ground circuit for an open or poor connection at PCM. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 14 .
Check ECT sensor signal circuit for an open or poor connection at PCM. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 14 .
Repair ECT sensor ground circuit for a short to voltage. After repairs, go to step 16 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 16 .
Turn ignition off. Replace ECT sensor. After repairs, go to step 16 .
Using scan tool, 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, and then enter DTC P0125. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. Check and repair wiring as necessary. If wiring is okay, connect a DVOM between signal circuit terminal at ECT sensor harness connector and ground circuit terminal at PCM harness connector. Observe DVOM and bend, wiggle and twist related connectors and wiring harness. If a fault is induced, resistance reading will change.

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

DTC P0125: ECT EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

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

While engine is warming, PCM reads Engine Coolant Temperature (ECT) sensor to determine how long it takes coolant to reach temperature required for closed loop operation. PCM compares actual time required to a predetermined time. DTC P0125 will set if time for engine coolant temperature to reach 70°F (21°C) exceeds a predetermined amount of time.

For duplication of DTC, ensure no IAT or ECT sensor DTCs are present, minimum air temperature is greater than 19°F (-7°C), coolant temperature is greater than -40°F (-40°C), and start-up engine coolant temperature is less than 122°F (50°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.
Allow engine to cool completely. Start engine and allow it to idle. Using scan tool, monitor ENG COOL TEMP. If temperature increases to greater than 70°F (21°C) within 9 minutes, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If specified temperature is not reached within 9 minutes, go to next step.
If any ECT related DTCs are set, diagnose affected DTC before proceeding. If no ECT related DTCs are set, go to next step.
Allow engine to cool. Turn ignition on and observe cooling fans. If cooling fans are off, go to next step. If cooling fans are on, diagnose and repair cooling fan problem.
Check coolant level. If coolant level is low, go to step 9 . If coolant level is okay, go to next step.
Check thermostat operation. If thermostat is operating correctly, go to next step. If thermostat is not operating correctly, go to step 9 .
Compare actual coolant temperature with scan tool ECT value. If temperatures are within 5°F (3°C) of each other, go to step 9 . If temperatures are not within 5°F (3°C) of each other, go to next step.
Check for high resistance in wiring related to ECT sensor and for poor connections at ECT sensor and PCM. If a problem is found with connections, go to step 10 . If no problem is found, go to step 11 .
Repair cooling system as necessary. After repairs, go to step 12 .
Repair as necessary. After repairs, go to step 12 .
Replace ECT sensor. After repairs, go to next step.
Allow engine to cool completely. Using scan tool, clear DTCs. Turn engine on and allow it to idle. Using scan tool, monitor ENG COOL TEMP. If temperature increases to greater than 70°F (21°C) within 9 minutes, repair is complete. If specified temperature is not reached within 9 minutes, go to step 2 .

Check coolant level. Ensure thermostat and cooling fans are operating properly. Check for high resistance in wiring related to ECT sensor. Check for skewed ECT sensor by comparing actual coolant temperature with scan tool display, and replace ECT sensor if temperatures are not close.

Check for faulty connections or damaged harness. If connections and harness appear okay, observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

If DTC cannot be duplicated, the information included in the FAILURE RECORDS data can be useful in determining vehicle mileage since DTC was last set.

DTC P0125: ECT EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL (3.8L "C", "F", "G", "H" & "W" BODIES)

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

While engine is warming, PCM reads Engine Coolant Temperature (ECT) sensor to determine how long it takes coolant to reach temperature required for closed loop operation. PCM compares actual time required to a predetermined time. DTC P0125 will set if closed loop operation temperature of 68°F (20°C) is not reached within 2-5 minutes of engine start-up.

For duplication of DTC, ensure no ECT or IAT DTCs are set, IAT is greater than 19°F (-7°C), and ECT is greater than -40°F (-40°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.
Allow engine to cool completely. Turn engine on and allow it to idle. Using scan tool, monitor ENG COOL TEMP. If temperature increases to greater than 70°F (21°C) within 2 minutes, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If specified temperature is not reached within 2 minutes, go to next step.
If any ECT related DTCs are set, diagnose affected DTC before proceeding. If no ECT related DTCs are set, go to next step.
Allow engine to cool. Turn ignition on and observe cooling fans. If cooling fans are off, go to next step. If cooling fans are on, diagnose and repair cooling fan problem.
Check coolant level. If coolant level is low, go to step 9 . If coolant level is okay, go to next step.
Check thermostat operation. If thermostat is operating correctly, go to next step. If thermostat is not operating correctly, go to step 9 .
Compare actual coolant temperature with scan tool ECT value. If temperatures are within 5°F (3°C) of each other, go to step 9 . If temperatures are not within 5°F (3°C) of each other, go to next step.
Check for high resistance in wiring related to ECT sensor and for poor connections at ECT sensor and PCM. Repair as necessary. After repairs, go to step 11 . If no problem is found, go to step 10 .
Repair cooling system as necessary. After repairs, go to step 11 .
Replace ECT sensor. After repairs, go to next step.
Allow engine to cool completely. Using scan tool, clear DTCs. Turn engine on and allow it to idle. Using scan tool, monitor ENG COOL TEMP. If temperature increases to greater than 70°F (21°C) within 2 minutes, system is okay. If specified temperature is not reached within 2 minutes, go to step 2 .

If DTC cannot be duplicated, the information included in the FAILURE RECORDS data can be useful in determining vehicle mileage since DTC was last set.

DTC P0125: ECT EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

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

This test monitors ECT sensor after timer reaches 4.25 minutes. The PCM looks at the test condition every second and increments the timer each time test conditions are met. After 4.25 minutes, and if ECT drops to less than 41°F (5°C) for 3 seconds, DTC P0125 will set. If ECT is greater than 41°F (5°C), test will be considered passed regardless of timer. The timer will decrement if PCM is disabling fuel to any cylinder during traction control maneuvers, acceleration reduction, torque management, etc. The timer will reset only when engine stops running.

For duplication of DTC, ensure DTCs P0112, P0113, P0117 or P0118 are not set, engine is running, IAT is at 32°F (0°C) or greater, and vehicle speed is at least 10 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. Using scan tool, select FAILURE RECORDS and note ECT display. If ECT sensor reads less than -35°F (-37°C), diagnose using test for DTC P0117. If ECT sensor does not read less than -35°F (-37°C), go to next step.
Start and warm engine to normal operating temperature. Using scan tool, select DATA LIST, ENGINE 1 and note ECT display while engine is warming up. If ECT reading is erratic or skipping (rapid changing), go to step 6 . If ECT reading is normal, go to next step.
After engine is fully warmed up (about 20 minutes), note ECT display. If ECT reading is less than 185°F (85°C), go to next step. If ECT reading is not less than 185°F (85°C), fault is not present at this time. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check ECT sensor ground and signal circuits for high resistance. Repair as necessary. If circuits are okay, repair cooling system.
Check terminal contact at ECT sensor. Repair as necessary. If terminal contact is okay, go to next step.
Replace ECT sensor.

If fault is not present, check for an intermittent cooling system problem.

DTC P0125: ECT EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

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

While engine is warming, VCM monitors ECT sensor to determine the amount of time it takes engine to reach coolant temperature required for closed loop operation. DTC P0125 will set if VCM determines that ECT does not reach minimum coolant temperature required for closed loop operation in a specified amount of time.

For duplication of DTC, ensure engine is running, no ECT or IAT related DTCs are set, ECT and IAT is greater than -40°F (-40°C), and start-up ECT is 104°F (40°C) or less.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check cooling system coolant level. Repair as necessary. If cooling system is okay, go to next step.
Allow vehicle to cool completely. Operate vehicle within the conditions for setting this DTC. If ECT value increases steadily to greater than 68°F (20°C) in 2-5 minutes, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If ECT value does not increases steadily to greater than 68°F (20°C) in 2-5 minutes, go to next step.
Using a thermometer, compare actual coolant temperature with ECT displayed on scan tool. If temperatures are close to same value, check for faulty thermostat. If temperatures are not close to same value, go to next step.
Replace ECT sensor. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

When DTC P0125 is set, ECT sensor is skewed or engine thermostat does not operate properly. An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect VCM harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If connections and harness are okay, observe scan tool while wiggling related connectors and wiring harnesses. A change in display will indicate location of fault.

DTC P0125: ECT EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL (4.8L, 5.3L & 6.0L "C" & "K" SERIES & 5.7L "F" & "Y" BODIES)

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

While engine is warming, PCM monitors ECT sensor to determine the amount of time it takes engine to reach coolant temperature required for closed loop operation. DTC P0125 will set if PCM determines that ECT does not reach minimum coolant temperature required for closed loop operation in a specified amount of time.

For duplication of DTC, ensure

DTCs P0112, P0113, P0117 and P0118 are not set.
Engine is running.
Engine coolant temperature is between -33°F (-36°C) and 104°F (40°C) at engine start-up.
Intake air temperature is greater than 19°F (-7°C).
Vehicle speed is greater than one 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.
If any ECT DTCs are set, go to applicable DTC test. If no ECT DTCs are set, go to next step.
Turn ignition on. Disconnect ECT sensor. If scan tool indicates ECT value is less than -31°F (-35°C), go to next step. If scan tool does not indicate ECT value less than -31°F (-35°C), diagnose using test for DTC P0117.
Using a fused jumper wire, jumper terminals of ECT sensor harness connector together. If scan tool indicates ECT value is greater than 282°F (139°C), go to next step. If scan tool does not indicate ECT value greater than 282°F (139°C), diagnose using test for DTC P0118.
Reconnect ECT sensor. Start engine and let idle for 5 minutes. If scan tool indicates ECT value is at least 93°F (34°C), check cooling system operation. If scan tool does not indicate ECT value is at least 93°F (34°C), go to next step.
Measure resistance of ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article. If ECT sensor resistance is within specifications, go to next step. If ECT sensor is not within specifications, go to step 8 .
Check coolant condition, coolant level, thermostat operation and cooling fan operation. Repair as necessary. After repairs, go to step 9 .
Replace ECT sensor. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

When DTC P0125 is set, ECT sensor is skewed or engine thermostat does not operate properly. An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect PCM harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If connections and harness are okay, observe scan tool while wiggling related connectors and wiring harnesses. A change in display will indicate location of fault.

If DTC cannot be duplicated, the information included in the FAILURE RECORDS data can be useful in determining vehicle mileage since DTC was last set.

If it is determined that DTC is intermittent, performing diagnostics for DTC P1114 or P1115 may isolate cause of fault.

DTC P0130: CLOSED LOOP RATIONALITY (1.9L SATURN)

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

Under certain operating conditions, front oxygen sensor (O2S) voltage should consistently fluctuate over 600 mV and under 300 mV. DTC P0130 will set if voltage does not fluctuate as specified for 50 seconds with TP sensor angle greater than 6 percent, engine running at normal operating temperature, and with system in closed loop fuel control.

Check for faulty or contaminated front O2S. Replace as necessary.

DTC P0130: HO2S CIRCUIT-BANK 1, SENSOR 1 (3.0L "V" BODY)

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

Heated Oxygen Sensor (HO2S) is a wide range-type sensor that calculates amount of oxygen in exhaust stream more accurately than a toggling-type sensor. This HO2S operates more like an air fuel sensor. ECM supplies.28 volt to sensor and uses this voltage as a reference to amount of oxygen in exhaust system. When system is lean, oxygen level will be high and reference voltage will also be high. When oxygen level is low, reference voltage will also be low. ECM monitors variation in voltage and attempts to maintain voltage constant by increasing or decreasing amount of current flow to HO2S. Using this information allows ECM to maintain proper air/fuel ratio.

If ECM detects low HO2S voltage for an extended period of time, DTC P0130 will set. For duplication of DTC, ensure DTCs P1036, P1038, P0140, P0141 and P0135 are not 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 engine and operate to normal operating temperature. Using scan tool, monitor HO2S voltage. If HO2S voltage on scan tool remains less than 399 mV, go to step 4 . If HO2S voltage on scan tool does not remain less than 399 mV, go to next step.
Turn ignition on, with engine off. Review FREEZE FRAME data for this DTC and note parameters. Clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Check for DTCs. If DTC P0130 is set, go to next step. If DTC P0130 is not set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition on, with engine off. Disconnect HO2S connector. Check for signs of water or corrosion. Repair as necessary. If HO2S voltage on scan tool is 375-525 mV, go to step 14 . If HO2S voltage on scan tool is not 375-525 mV, go to next step.
Using DVOM, measure voltage between ground and signal circuit at HO2S harness connector. If voltage is 900-1100 mV, go to next step. If voltage is not 900-1100 mV, go to step 11 .
Using DVOM, measure voltage between ground and low circuit at HO2S harness connector. If voltage is 700-800 mV, go to step 22 . If voltage is not 700-800 mV, go to next step.
Continue to monitor voltage from HO2S low circuit between harness connector and ground. Disconnect all other HO2S harness connectors. As each sensor is disconnected, recheck voltage on DVOM. If disconnecting one of the other sensors restores voltage to 700-800 mV, go to step 14 . If disconnecting the other sensors does not restore voltage to 700-800 mV, go to next step.
Leave all HO2S disconnected. Turn ignition off. Disconnect ECM harness connector. Turn ignition on. Using DVOM, measure voltage between ground and HO2S low circuit at ECM harness connector. If any voltage is present, go to step 15 . If no voltage is present, go to next step.
Using DVOM, check harness continuity of HO2S low circuit. If continuity is present, go to next step. If continuity is not present, go to step 16 .
Using DVOM, check harness continuity between HO2S low circuit and ground. If continuity is present, go to step 17 . If continuity is not present, go to step 21 .
Leave all HO2S disconnected. Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Turn ignition on. Using DVOM, measure voltage between ground and HO2S signal circuit at ECM harness connector. If any voltage is present, go to step 18 . If no voltage is present, go to next step.
Using DVOM, check harness continuity of HO2S signal circuit. If continuity is present, go to next step. If continuity is not present, go to step 19 .
Using DVOM, check harness continuity between HO2S signal circuit and ground. If continuity is present, go to step 20 . If continuity is not present, go to step 21 .
Replace shorted HO2S. After repairs, go to step 23 .
Repair short to voltage in HO2S low circuit. After repairs, go to step 23 .
Repair open or high resistance in HO2S low circuit. After repairs, go to step 23 .
Repair short to ground in HO2S low circuit. After repairs, go to step 23 .
Repair short to voltage in signal circuit. After repairs, go to step 23 .
Repair open or high resistance in signal circuit. After repairs, go to step 23 .
Repair short to ground in signal circuit. After repairs, go to step 23 .
Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 23 . 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 repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Check for DTCs. If DTC P0130 is set, go to step 2 . If DTC P0130 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.

HO2S pigtail or harness may be mispositioned and contacting exhaust system. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, corrosion or water intrusion.

An oxygen supply inside HO2S is necessary for proper operation. This supply of oxygen is provided through HO2S wiring harness. All HO2S wires and connections should be inspected for breaks or contamination. Repair as necessary.

Inspect for poor ECM-to-engine grounds. If fuel pressure is too low, this DTC may set. Check for lean injectors. Inspect for disconnected or damaged vacuum hoses and for vacuum leaks at intake manifold, throttle body and crankcase ventilation system.

An exhaust leak may cause outside air to be pulled into exhaust gas stream past HO2S, causing this DTC to set. Check for exhaust leaks near HO2S.

Check for fuel contamination. Water, even in small amounts can be delivered to fuel injectors. Water can cause a lean condition to be indicated. Excessive alcohol in fuel can also cause this condition.

DTC P0131: O2S CIRCUIT-LOW VOLTAGE-SENSOR 1 (1.9L SATURN)

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

When Oxygen Sensor (O2S) temperature reaches about 600°F (318°C), it becomes an electrical source that responds to the oxygen content in the exhaust. PCM produces a bias voltage of about 450 mV on the oxygen sensor circuit. When sensor is cold, its internal resistance is extremely high, therefore the PCM recognizes the bias as an open circuit. As the sensor warms up, the internal resistance decreases. When sensor reaches about 600°F (318°C), it starts producing a voltage based on the oxygen content in the exhaust stream. This voltage is used by the PCM to determine a rich or lean oxygen sensor signal and adjusts the fuel mixture accordingly.

DTC P0131 will set if O2S voltage is less than 87 mV for 90 seconds, or when O2S voltage is less than 300 mV in power enrichment mode for 90 seconds when the system is in "closed loop", no other engine sensor or misfire DTCs have been set or when commanded air/fuel ratio is about 14.7:1. O2S signal is continuously monitored once these conditions are met.

Connect scan tool. Operate engine at 1500 RPM for one minute. Check ECT reading. Ensure ECT reads greater than 140°F (60°C). Monitor O2S reading. If O2S is reading constantly at less than 300 mV, go to next step. If O2S reading is not constantly at less than 300 mV, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect O2S harness connector. Check O2S reading. If O2S reading is 391-491 mV, replace O2S. If O2S reading is not 391-491 mV, go to next step.
Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe O2S signal circuit at harness connector terminal. If test light illuminates, check signal circuit for short to ground or O2S ground signal circuit. If test light does not illuminate, replace PCM.

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

If system is commanding rich (engine running lean), with O2S signal about 100 mV and short term fuel trim is in the 160s, the system is at or nearing maximum correction. Review scan tool malfunction WOT lean fault. A total of 30 seconds under power enrichment mode per ignition cycle will set a WOT lean fault to YES, if lean condition occurs. Check for low fuel pressure, malfunctioning O2S, external water on sensor or shorted sensor wire to ground, causing possible low O2S voltage.

DTC P0131: O2S CIRCUIT-LOW VOLTAGE-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) supplies about.45 volt to Oxygen Sensor 1 (O2S 1). The O2S 1 varies voltage from about one volt when exhaust is rich to about.10 volt when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects O2S 1 voltage is less than predetermined voltage, DTC P0131 will set.

For duplication of DTC, ensure

DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
Airflow is greater than 3 gm/s.
ECT is greater than 158°F (70°C).
System is in closed-loop operation.
TP sensor angle is 5-50 percent.
Engine has met above conditions for 20 seconds.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine and allow it to reach normal operating temperature. Using scan tool, observe O2S 1 voltage. If voltage remains less than 44 mV, go to step 4 . If voltage does not remain less than 44 mV, go to next step.
Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Using scan tool, observe O2S 1 voltage. If voltage remains less than 44 mV, go to next step. If voltage does not remain less than 44 mV, go to step 7 .
Turn ignition off. Disconnect O2S 1 connector. Turn ignition on, engine off. Observe O2S 1 voltage. If voltage is 407-509 mV, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If voltage is not 407-509 mV, go to next step.
Check for short to ground in O2S 1 signal circuit. Repair as necessary. After repairs, go to step 7 . If circuit is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Reconnect O2S 1 connector. Using scan tool, 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, and then enter DTC P0131. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check oxygen sensor pigtail wire for breaks, contamination or grounding on exhaust manifold. Check for intermittent ground in signal wire between sensor connector and sensor. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor. Check for fuel contamination, improper fuel pressure or exhaust leak, especially near oxygen sensor. Check for vacuum or crankcase leak, causing a lean condition.

DTC P0131: HO2S CIRCUIT-LOW VOLTAGE-BANK 1, SENSOR 1 (3.0L "V" BODY)

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

For duplication of DTC, ensure

Engine load is between 20 and 40 percent.
Engine speed is 1400-2400 RPM.
Air/fuel ratio is between.94 and 1.06.
DTCs P0300-P0306, P0171, P0172, P0174, P0175, P0443, P0446 and P0460 are not set.
Secondary air diagnosis is not running.
There is no maximum or minimum closed loop fuel control.
There is no EVAP high loading indicated.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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 exhaust leaks between HO2S 1 and HO2S 2. If leaks are found, go to step 10 . If no leaks are found, go to next step.
Turn ignition off. Disconnect right-side HO2S 1. Inspect connectors for contamination. If connection is faulty, go to step 11 . If connection is okay, go to next step.
Disconnect ECM harness connectors. Measure resistance of circuit between terminal No. 6 of HO2S 1 and terminal No. 43 of ECM. Also measure resistance of circuit between terminal No. 1 of HO2S 1 and terminal No. 11 of ECM. If resistance of either circuit is less than 2 ohms, go to step 13 . If resistance of neither circuit is less than 2 ohms, go to next step.
If either circuit had no continuity, go to step 12 . If both circuits had continuity, go to next step.
Turn ignition on. Measure voltage between ground and terminal No. 5 (B+ circuit) at ECM harness connector. If battery voltage is present, go to next step. If battery voltage is not present, go to step 13 .
Measure resistance of HO2S heater control circuit between HO2S and ECM. If resistance is 0-2 ohms, go to step 9 . If resistance is not as specified, go to next step.
Repair open or short in circuit. After repairs, go to step 14 .
Replace right-side HO2S 1. After repairs, go to step 14 .
Repair leaks as necessary. After repairs, go to step 14 .
Repair terminals as necessary. After repairs, go to step 14 .
Repair open in affected circuit. After repairs, go to step 14 .
Repair short to ground in affected circuit. After repairs, go to next step.
Using scan tool, clear DTCs. Start engine and allow it to reach normal operating temperature. Select DTC and SPECIFIC DTC function, and then enter this DTC. Operate vehicle within conditions required to set this DTC until scan tool indicates this diagnostic ran. If scan tool indicates this diagnostic passed, go to next step. If scan tool indicates this diagnostic failed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

HO2S pigtail or harness may be mispositioned and contacting exhaust system. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, corrosion or water intrusion.

DTC P0131: HO2S CIRCUIT-LOW VOLTAGE-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.

Powertrain Control Module (PCM) supplies about.45 volt to Heated Oxygen Sensor 1 (HO2S 1). The HO2S 1 varies voltage from about one volt when exhaust is rich to about.10 volt when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects HO2S 1 voltage is less than predetermined voltage, DTC P0131 will set.

For duplication of DTC, ensure

No active misfire, fuel injector circuit, TP sensor, EVAP, IAT sensor, MAP sensor, fuel trim, EGR, ECT sensor, MAF sensor or CKP sensor DTCs are set.
Closed loop commanded air/fuel ratio is 14.4:1-14.9:1.
TP sensor angle is 3-40 percent.
HO2S 1 signal voltage remains less than 175 mV during normal closed loop operation or less than 600 mV during power enrichment mode fuel control 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.
Start engine and operate vehicle within conditions required for setting this DTC. Using scan tool, observe HO2S 1 voltage. If voltage remains less than 300 mV, go to step 4 . If voltage does not remain less than 300 mV, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within the conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0131 until DTC P0131 test runs. If scan tool indicates FAILED THIS IGN, go to next step. If scan tool does not indicate FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect HO2S 1 connector. Connect a jumper wire between ground and ground circuit terminal at HO2S 1 harness connector. If voltage is about 450 mV, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If voltage is not about 450 mV, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Check for a short to ground or short to sensor ground circuit in HO2S 1 signal circuit. If circuit is shorted, go to next step. If circuit is okay, go to step 7 .
Repair circuit as necessary. After repairs, go to step 8 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0131 until DTC P0131 test runs. If scan tool indicates FAILED THIS IGN, repeat step 2 . If scan tool does not indicate FAILED THIS IGN, system is okay.

Check HO2S pigtail wire for breaks, contamination or grounding on exhaust manifold. Check for intermittent ground in signal wire between sensor connector and sensor. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor. Check for fuel contamination, improper fuel pressure or exhaust leak, especially near oxygen sensor. Check for vacuum or crankcase leak, causing a lean condition. Check MAF sensor.

DTC P0131: HO2S CIRCUIT-LOW VOLTAGE-SENSOR 1 (3.8L "C", "F", "G", "H" & "W" BODIES)

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

PCM provides about 0.35 volt reference to HO2S 1. HO2S 1 sensor signal voltage varies from about one volt when exhaust is rich to about 0.1 volt when exhaust is lean. PCM reads and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If HO2S 1 voltage is out of predetermined range, DTC P0131 will set.

For duplication of DTC, ensure

No active TP sensor, EVAP system, misfire, IAT sensor, MAP sensor, fuel trim, fuel injector circuit, EGR sensor, ECT sensor, CKP sensor or MAF sensor DTCs are set.
System voltage is greater than 9 volts.
Closed loop commanded air/fuel ratio is 14.5-14.8:1.
TP angle is 3-40 percent.
HO2S 1 signal voltage remains less than 0.175 volt during closed loop operation or less than 0.6 volt during power enrichment mode of fuel control 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.
Start engine and allow it to reach operating temperature. Operate vehicle under conditions required to set DTC. Using scan tool, read HO2S 1 voltage. If voltage remains less than 0.3 volt, go to step 4 . If voltage does not remain less than 0.3 volt, go to next step.
Turn engine off. Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0131 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0131 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect HO2S 1 connector. Connect jumper wire between HO2S 1 harness connector ground circuit and chassis ground. If voltage is about 0.45 volt, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If voltage is not about 0.45 volt, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Check HO2S 1 signal circuit for short to ground. If circuit is shorted, go to next step. If circuit is okay, go to step 7 .
Repair HO2S 1 signal circuit. After repairs, go to step 8 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0131. If scan tool displays DTC P0131 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0131 FAILED THIS IGN, system is okay.

Ensure HO2S 1 sensor harness is routed correctly and not contacting exhaust system. Check for faulty PCM grounds. Check fuel system. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Perform injector balance test. See appropriate SYSTEM & COMPONENT TESTING article.

Check for vacuum leaks at intake manifold, throttle body, EGR system and crankcase ventilation system. Check for exhaust leaks in front of HO2S 1. Disconnect MAF sensor connector and see if lean condition is corrected. If lean condition is corrected, replace MAF sensor. Check for fuel contamination. If no faults are found, replace HO2S 1.

DTC P0131: HO2S CIRCUIT-LOW VOLTAGE-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.45 volt reference signal to the HO2S through the Bank 1 high signal circuit. When HO2S is cold, less than 392°F (200°C) , the sensor signal voltage will be about.45 volt and PCM will keep the system in "open loop". When HO2S is warm, sensor will swing from rich to lean rapidly, at least one switch every 2 seconds, if PCM is in good control of air/fuel mixture.

If sensor remains at lean voltage for greater than 40 seconds during this test, DTC will set. DTC will also set when there is a sensor circuit fault giving a false lean indication or air/fuel ratio is actually lean due to a vacuum leak or fuel control system fault.

For duplication of DTC, ensure

DTCs P0101, P0102, P0103, P0107, P0108, P0117, P0118, P0121, P0122, P0123, P0132 and P0134 are not set.
TP sensor angle is between 5.4 and 25 degrees.
Coolant temperature is 179°F (81.5°C) or greater.
Closed-loop fuel control is enabled.
Oxygen sensor is ready.
Engine speed is 800 RPM or greater.
MAP sensor value is greater than 32 kPa.
DTC P0151 test runs and passes.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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 P0134 is also present. If DTC P0134 is present, diagnose this DTC first. If DTC P0134 is not present, go to next step.
If DTC was set because vehicle ran out of fuel, clear DTC. System is okay. If vehicle did not run out of fuel, go to next step.
Start and warm engine until coolant temperature is at least 185°F (85°C). Using scan tool, select ENGINE 1 and note bank 1, sensor 1 oxygen sensor voltage. If voltage remains at less than.3 volt for 30 seconds or more, go to next step. If voltage does not remain at less than.3 volt for 30 seconds or more, fault is not present at this time. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect rear HO2S harness connector. Start engine. Measure voltage between HO2S terminals "A" and "B". If voltage remains at less than.3 volt for 30 seconds or more, diagnose using test for DTC P0133. If voltage does not remain at less than.3 volt for 30 seconds or more, go to next step.
Store fluid life index as indicated in scan tool. Turn ignition off. Wait 30 seconds, and then disconnect PCM connector C2. Measure resistance to ground at rear HO2S harness connector terminal "B". If resistance is greater than 10,000 ohms, go to next step. If resistance is not greater than 10,000 ohms, go to step 8 .
Measure resistance between rear HO2S harness connector terminals "A" and "B". If resistance is 5 ohms or less, go to step 9 . If resistance is greater than 5 ohms, go to step 10 .
Repair short to ground in rear H02S high signal circuit.
Repair rear HO2S high and low signal circuits for short together.
Check HO2S high and low signal circuit terminal contact at PCM harness connector C2. Repair as necessary. If terminal contacts are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

Check snapshot data for front long and rear long term fuel trim values. If both banks were lean, check for a condition that would cause lean engine operation. If only the rear bank was lean, check for a condition that would cause only the rear bank to be lean, such as an intermittent short to ground in HO2S high signal circuit. DO NOT solder HO2S wires.

DTC P0131: HO2S CIRCUIT-LOW VOLTAGE-BANK 1, SENSOR 1 (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" 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 0.1 volt with lean exhaust. HO2S produces no voltage and acts as an open circuit when temperature is less than 600°F (360°C). DTC P0131, P0132, an open sensor circuit or a cold sensor causes open loop operation. DTC P0131 determines if HO2S or circuit is shorted low by checking for a lean condition during steady throttle and power enrichment.

For duplication of DTC, ensure no TP, EVAP, IAT, MAP, ECT, MAF or misfire DTCs are set, no intrusive tests are in progress, no device controls are active and system voltage is at least 11.7-18 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.
Install scan tool. Start and warm engine to normal operating temperature. Monitor HO2S voltage using scan tool. If HO2S voltage is less than.086 volt, go to step 4 . If HO2S voltage is not less than.086 volt, go to next step.
DTC is intermittent. Check for signal wire shorted to ground or HO2S low circuit, faulty harness connections, exhaust leaks, or lean condition. Repair as necessary. After repairs, 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-p0100-p0134) .
Turn ignition off. Disconnect HO2S connector. Connect a jumper wire between HO2S ground circuit of HO2S connector (VCM side) and ground. Turn ignition on, with engine off. Monitor HO2S voltage using scan tool. If HO2S voltage is.35-.55 volt, go to next step. If HO2S voltage is not.35-.55 volt, go to step 6 .
Check for conditions that may cause HO2S to detect a lean condition. Repair as necessary. After repairs, go to step 10 . If no problem is found, go to step 8 .
Turn ignition off. Remove jumper wire. Disconnect VCM harness connector containing HO2S high signal circuit. Measure resistance between ground and HO2S high signal circuit. Measure resistance between HO2S high and low signal circuits. If resistance is infinite for both checks, go to step 9 . If resistance is not infinite for both checks, go to next step.
Repair HO2S high signal circuit for short to ground or short to HO2S low circuit. After repairs, go to step 10 .
Replace HO2S. After repairs, go to step 10 .
Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP system variation learn procedures. After repairs, go to step 10 .
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Using scan tool, observe Long Term (LT) fuel trim values at different RPM and air flow conditions. Scan tool should display fuel trim cells so that LT fuel trim values can be check in each cell to determine when DTC may have set. If DTC is set, LT fuel trim values will be about 158 or greater.

Check for mispositioned HO2S wire pigtail contacting exhaust manifold. Check for intermittent ground in wire between connector and sensor. Check for poor VCM to engine block ground. Check for lean fuel injectors. Check for water near in-tank fuel pump inlet that may be delivered to injectors. Water causes a lean exhaust and can cause DTC to set.

System will be lean if fuel pressure is too low. Monitor fuel pressure while driving vehicle at various speeds and loads to verify pressure. Check for an exhaust leak that can cause outside air to be pulled into exhaust and past sensor. Check for vacuum or crankcase leaks that can cause a lean condition and possibly high idle. If all above checks are okay, HO2S is faulty. DO NOT solder HO2S wires.

DTC P0131: HO2S CIRCUIT-LOW VOLTAGE-BANK 1, SENSOR 1 (4.8L, 5.3L & 6.0L "C" & "K" SERIES & 5.7L "F" & "Y" BODIES)

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

PCM supplies about 450 millivolts (mV) between HO2S high and low signal circuits. The HO2S voltage ranges from about 1000 mV when exhaust is rich to about 10 mV when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates voltage samples to determine amount of time sensor voltage is out of range. If PCM detects HO2S voltage is less than predetermined voltage, DTC P0131 will set.

For duplication of DTC, ensure

DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0200, P0335, P0336, P0351-P0358 or P1258 are not set.
AIR, EGR and catalyst diagnostics not active.
Ignition voltage is greater than 9 volts.
Fuel system is operating in "closed loop".
Fuel trim learn is enabled.
TP sensor angle is between 2 and 70 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and warm engine to normal operating temperature. Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage, with engine at idle. If HO2S voltage is less than 200 mV, go to step 4 . If HO2S voltage is not less than 200 mV, 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, and then enter DTC P0131. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect HO2S connector. Connect a fused jumper wire between PCM connector (harness side), HO2S low circuit and ground. If sensor voltage is 350-550 mV, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If sensor voltage is not 350-550 mV, go to next step.
Turn ignition off. Disconnect PCM harness connector C1. Check HO2S signal circuit for short to ground or short to sensor ground circuit. Repair circuit as necessary. After repairs, go to next step. If circuit(s) are okay, go to step 7 .
Repair HO2S signal circuit. After repairs, go to step 8 .
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, and then enter DTC P0131. 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.

Check for HO2S pigtail wire for breaks, contamination or grounding on exhaust manifold. Check for intermittent ground in signal wire between sensor connector and sensor.

Check for lean injector(s). Perform injector balance test. See appropriate SYSTEM & COMPONENT TESTING article. Check for fuel contamination, improper fuel pressure or exhaust leak, especially near HO2S. Check for vacuum or crankcase leak, causing a lean condition.

DTC P0132: O2S CIRCUIT-HIGH VOLTAGE-SENSOR 1 (1.9L SATURN)

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

When Oxygen Sensor (O2S) temperature reaches about 600°F (316°C) , it becomes an electrical source that responds to the oxygen content in the exhaust. PCM produces a bias voltage of about 450 mV on the oxygen sensor circuit. When sensor is cold, its internal resistance is extremely high, therefore, the PCM recognizes the bias as an open circuit. As the sensor warms up, the internal resistance decreases. When sensor reaches about 600°F (316°C) , it starts producing a voltage based on the oxygen content in the exhaust stream. This voltage is used by the PCM to determine a rich or lean oxygen sensor signal and adjusts the fuel mixture accordingly.

DTC will set if O2S voltage is greater than 787 mV for 90 seconds, or when O2S voltage is greater than 587 mV in decel fuel cut-off mode for 30 seconds when the system is in "closed loop", no other engine sensor or misfire DTCs have been set or when commanded air/fuel ratio is about 14.7:1. O2S signal is continuously monitored once these conditions are met.

Connect scan tool. Operate engine at 1500 RPM for one minute. Check ECT reading. Ensure ECT reads greater than 140°F (60°C). Monitor O2S reading. If O2S reading is constantly greater than 750 mV, go to next step. If O2S reading is not constantly greater than 750 mV, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect O2S harness connector. Check O2S reading. If O2S reading is 391-491 mV, check for rich system or faulty O2S. If O2S reading is not 391-491 mV, go to next step.
Measure voltage on O2S signal circuit at O2S harness connector. If voltage reading is greater than 750 mV, check signal circuit for short to voltage. If voltage reading is not greater than 750 mV, check for faulty terminal connection or PCM.

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

If system is commanding lean (engine running rich), with O2S signal about 900 mV and short term fuel trim is in the 100s, the system is nearing or at maximum correction. Review scan tool history decel rich fault. A total of 30 seconds under deceleration per ignition cycle will set a decel rich fault to YES, if rich condition occurs. Check for high fuel pressure, leaking injector, faulty EVAP canister purge, O2S contamination, malfunctioning or faulty EGR valve, engine oil contamination, shorted injector, vacuum leak to MAP sensor or ECT sensor reading is colder than actual temperature, causing possible high O2S voltage.

DTC P0132: O2S CIRCUIT-HIGH VOLTAGE-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.

For duplication of DTC, ensure

DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
Airflow is greater than 3 gm/s.
ECT is greater than 158°F (70°C).
Engine is operating in closed loop.
TP sensor angle is 5-50 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Ensure engine is at normal operating temperature. Using scan tool, observe O2S 1 sensor voltage. If voltage remains greater than 1042 mV, go to step 4 . If voltage does not remain greater than 1042 mV, go to next step.
Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Observe O2S 1 sensor voltage. If voltage remains greater than 1042 mV, go to next step. If voltage does not remain greater than 1042 mV, go to step 7 .
Turn ignition on, with engine off. Disconnect O2S 1 connector. Measure voltage between ground and O2S 1 harness connector. Observe O2S 1 voltage. If voltage is less than 600 mV, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If voltage is not less than 600 mV, go to next step.
Check for short to ground in O2S 1 signal circuit. Repair as necessary. After repairs, go to step 7 . If wiring is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Reconnect O2S 1 harness connector. Using scan tool, 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 P0132. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

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 P0132: HO2S CIRCUIT-HIGH VOLTAGE-BANK 1, SENSOR 1 (3.0L "V" BODY)

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

For duplication of DTC, ensure engine is running and rear HO2S sensor diagnostic is not 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.
Start engine and operate to normal operating temperature. Using scan tool, monitor HO2S voltage. If HO2S voltage value on scan tool remains greater than 1083 mV, go to step 4 . If HO2S voltage value on scan tool does not remain greater than 1083 mV, go to next step.
Turn ignition on, with engine off. Review FREEZE FRAME data for this DTC and note parameters. Clear DTCs. Turn ignition off for 15 seconds. Operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Check for DTCs. If DTC P0132 is set, go to next step. If DTC P0132 is not set, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition on, with engine off. Disconnect HO2S connector. Check for signs of water or corrosion. Repair as necessary. If HO2S voltage value on scan tool is 375-525 mV, go to step 14 . If HO2S voltage value on scan tool is not 375-525 mV, go to next step.
Using DVOM, measure voltage between ground and signal circuit at HO2S harness connector. If voltage is 900-1100 mV, go to next step. If voltage is not 900-1100 mV, go to step 11 .
Using DVOM, measure voltage between ground and low circuit at HO2S harness connector. If voltage is 700-800 mV, go to step 22 . If voltage is not 700-800 mV, go to next step.
Continue to monitor DVOM voltage from HO2S low circuit between harness connector and ground. Disconnect 3 other HO2S. As each sensor is disconnected, recheck voltage on DVOM. If disconnecting one of the other sensors restores voltage to 700-800 mV, go to step 14 . If disconnecting one of the other sensors does not restore voltage to 700-800 mV, go to next step.
Leave all HO2S disconnected. Turn ignition off. Disconnect ECM connector located in engine compartment relay center. Turn ignition on. Using DVOM, measure voltage between ground and HO2S low circuit at ECM harness connector. If any voltage is present, go to step 15 . If no voltage is present, go to next step.
Using DVOM, check harness continuity of HO2S low circuit. If continuity is present, go to next step. If continuity is not present, go to step 16 .
Using DVOM, check harness continuity between HO2S low circuit and ground. If continuity is present, go to step 17 . If continuity is not present, go to step 21 .
Leave all HO2S disconnected. Turn ignition off. Disconnect ECM connector located in engine compartment relay center. Turn ignition on. Using DVOM, measure voltage between ground and HO2S signal circuit at ECM harness connector. If any voltage is present, go to step 18 . If no voltage is present, go to next step.
Using DVOM, check harness continuity of HO2S signal circuit. If continuity is present, go to next step. If continuity is not present, go to step 19 .
Using DVOM, check harness continuity between HO2S signal circuit and ground. If continuity is present, go to step 20 . If continuity is not present, go to step 21 .
Replace shorted HO2S. After repairs, go to step 23 .
Repair short to voltage in HO2S low circuit. After repairs, go to step 23 .
Repair open or high resistance in HO2S low circuit. After repairs, go to step 23 .
Repair short to ground in HO2S low circuit. After repairs, go to step 23 .
Repair short to voltage in signal circuit. After repairs, go to step 23 .
Repair open or high resistance in signal circuit. After repairs, go to step 23 .
Repair short to ground in signal circuit. After repairs, go to step 23 .
Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 23 . 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. Operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Check for DTCs. If DTC P0132 is set, go to step 2 . If DTC P0132 is not set, go to next step.
If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.

DTC P0132: HO2S CIRCUIT HIGH VOLTAGE 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.

Powertrain Control Module (PCM) supplies about.45 volt to Heated Oxygen Sensor 1 (HO2S 1). The HO2S 1 varies voltage from about one volt when exhaust is rich to about.10 volt when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects HO2S 1 voltage is greater than predetermined voltage, DTC P0132 will set.

For duplication of DTCs, ensure no active TP, MAP, MAF, ECT, IAT, CKP sensor, misfire, fuel injector circuit, EVAP, fuel trim or EGR DTCs are present, system voltage is greater than 9 volts, closed loop commanded air/fuel ratio is 14.5-14.8:1, and throttle angle is 3-40 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine and operate vehicle within conditions required for setting this DTC. Using scan tool, observe HO2S 1 voltage. If voltage remains greater than 950 mV, go to step 5 . If voltage does not remain greater than 950 mV, go to next step.
Operate vehicle in DECEL FUEL MODE (vehicle speed greater than 25 MPH, TP angle less than 3 percent) while monitoring HO2S 1 on scan tool. If voltage remains greater than 800 mV, go to step 5 . If voltage does not remain greater than 800 mV, go to next step.
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0132 until DTC P0132 test runs. If scan tool indicates FAILED THIS IGN, go to next step. If scan tool does not indicate FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect HO2S 1 connector. Connect a jumper wire between ground and ground circuit terminal at HO2S 1 harness connector. If voltage is about 450 mV, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If voltage is not about 450 mV, go to next step.
Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Using DVOM, measure voltage between ground and signal circuit terminal at HO2S 1 harness connector. If voltage is greater than 600 mV, go to next step. If voltage is not greater than 600 mV, go to step 8 .
Repair short to voltage is HO2S 1 signal circuit. After repairs, go to step 9 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0132 until DTC P0132 test runs. If scan tool indicates FAILED THIS IGN, go to step 2 . If scan tool does not indicate, FAILED THIS IGN, system is okay.

Check fuel pressure. Perform injector balance test. See appropriate SYSTEM & COMPONENT TESTING article. Check for leaking fuel pressure regulator by removing vacuum hose and checking for fuel presence. If fuel is present, replace regulator. Check EVAP canister for fuel saturation. Check MAF sensor. See appropriate SYSTEM & COMPONENT TESTING article.

DTC P0132: HO2S 1 CIRCUIT HIGH VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

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

PCM provides about 0.45 volt reference to HO2S 1. HO2S 1 sensor signal voltage varies from about one volt when exhaust is rich to about 0.1 volt when exhaust is lean. PCM reads and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If HO2S 1 voltage is out of predetermined range, DTC P0132 will set.

For duplication of DTC, ensure no TP, IAT, MAP, EGR, ECT, CKP, MAF sensor, EVAP system, fuel trim, and fuel injector circuit DTCs are set, system voltage is greater than 9 volts, closed loop commanded air/fuel ratio is 14.5-14.8:1, and throttle angle is 3-40 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine and allow it to reach operating temperature. Operate vehicle under conditions required to set DTC. Using scan tool, read HO2S 1 voltage. If voltage remains greater than 0.8 volt, go to step 5 . If voltage does not remain greater than 0.8 volt, go to next step.
Operate vehicle in deceleration fuel mode (vehicle speed greater than 25 MPH and TP angle less than 3 percent) while monitoring HO2S 1 voltage. If voltage remains greater than 0.11 volt, go to step 5 . If voltage does not remain greater than 0.11 volt, go to next step.
Turn engine off. Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0132 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0132 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Disconnect HO2S 1 harness connector. Connect a jumper wire between HO2S 1 harness connector ground circuit and chassis ground. If voltage is about 0.45 volt, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If voltage is not about 0.45 volt, go to next step.
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Using a DVOM, measure voltage between PCM harness connector HO2S 1 signal circuit and chassis ground. If voltage is greater than 0.6 volt, go to next step. If voltage is not greater than 0.6 volt, go to step 8 .
Repair short to voltage in HO2S 1 signal circuit. After repairs, go to step 9 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Turn ignition on, engine off. 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 P0132. If scan tool displays DTC P0132 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0132 FAILED THIS IGN, system is okay.

Ensure HO2S 1 sensor harness is routed correctly and not contacting exhaust system. Check for open or short in HO2S 1 signal or ground circuits. Check for internally shorted HO2S 1. Check HO2S 1 for silicon (powdery white deposit) contamination. Check for faulty PCM grounds. Check fuel system. See BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article. Perform injector balance test. See appropriate SYSTEM & COMPONENT TESTING article.

Check EVAP canister for fuel saturation. Disconnect MAF sensor connector and see if rich condition is corrected. If rich condition is corrected, replace MAF sensor. Check for fuel in fuel pressure regulator vacuum line.

DTC P0132: HO2S CIRCUIT-HIGH VOLTAGE-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.45 volt reference signal to the HO2S through the Bank 1 high signal circuit. When HO2S is cold, less than 392°F (200°C), the sensor signal voltage will be about.45 volt and PCM will keep the system in "open loop". When HO2S is warm, sensor will swing from rich to lean rapidly, at least one switch every 2 seconds, if PCM is in good control of air/fuel mixture.

If sensor stays at rich voltage for greater than 40 seconds during this test, DTC P0132 will set. DTC will also set when there is a sensor circuit fault giving a false rich indication or air/fuel ratio is actually rich due to a fuel control system fault.

For duplication of DTC, ensure

DTCs P0101, P0102, P0103, P0107, P0108, P0117, P0118, P0121, P0122, P0123, P0132 and P0134 are not set.
TP sensor angle between 5.4 and 25 degrees.
Coolant temperature is at 180°F (82°C) or greater.
Closed loop control is enabled.
Oxygen sensor is ready.
Engine speed is 800 RPM or greater.
MAP sensor value is greater than 32 kPa.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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 P0134 is also present, diagnose this DTC first. If DTC P0134 is not present, go to next step.
Start and warm engine until coolant temperature is at 185°F (85°C) or greater. Using scan tool, select ENGINE 1 and note oxygen sensor voltage. If voltage remains greater than.6 volt for 30 seconds or more, go to next step. If voltage is not as specified, fault is not present at this time. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn engine off. Disconnect rear HO2S sensor harness connector. Start engine. Using DVOM, measure voltage between sensor terminals "A" and "B". If voltage remains greater than.6 volt for 30 seconds or more, diagnose using DTC P0133 test. If voltage is not as specified, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, and then disconnect PCM harness terminal C2. Turn ignition on, with engine off. If voltage reading is greater than 0.1 volt, go to next step. If voltage is not as specified, go to step 7 .
Repair short to ground in HO2S high signal circuit.
Check terminal contact at PCM connector C2 to HO2S high and low signal circuits. Repair as necessary. If terminal contacts are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

Check snapshot data for front and rear long term fuel trim values. If both banks were rich, check for a condition that would cause a rich engine operation. If only the rear bank was rich, check for a condition that would cause only the rear bank to be rich, such as an intermittent short to voltage in HO2S high signal circuit. DO NOT solder HO2S wires.

DTC P0132: HO2S CIRCUIT-HIGH VOLTAGE-BANK 1, SENSOR 1 (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" 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 0.1 volt with lean exhaust. HO2S produces no voltage and acts as an open circuit when temperature is less than 600°F (316°C). DTC P0131, DTC P0132, an open sensor circuit or a cold sensor causes open loop operation. DTC P0132 determines if HO2S or circuit is shorted high by checking for a rich condition during steady throttle.

For duplication of DTC, ensure no active TP, IAT, MAP, ECT, MAF sensor, EVAP system and misfire DTCs are present, device control is not active, system voltage is between 11.7 and 18 volts, and no intrusive tests are in progress.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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. Warm engine to normal operating temperature. Monitor HO2S voltage using scan tool. If HO2S voltage is fixed greater than 976 mV, go to step 4 . If HO2S voltage is not fixed greater than 976 mV, go to next step.
DTC is intermittent. Check for any conditions that may cause a rich condition. Repair as necessary. After repairs, go to step 10 . If no problems are found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect HO2S harness connector. Connect jumper wire between ground and HO2S low signal circuit of HO2S harness connector (VCM side). Turn ignition on, with engine off. Monitor HO2S voltage using scan tool. If HO2S voltage is 351-551 mV, go to next step. If HO2S voltage is not 351-551 mV, go to step 6 .
HO2S is contaminated or detecting a rich condition. Check for any conditions that may cause a rich condition. Repair as necessary. After repairs, go to step 10 . If no problems are found, go to step 8 .
Turn ignition off. Remove jumper wire. Disconnect VCM harness connector containing HO2S high signal circuit. Turn ignition on. Measure voltage between ground and HO2S high signal circuit at VCM harness connector. If voltage is greater than 20 mV, go to next step. If voltage is not greater than 20 mV, go to step 9 .
Repair short to voltage in HO2S high signal circuit. After repairs, go to step 10 .
Replace HO2S. After repairs, go to step 10 .
Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP system variation learn procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

System will be rich if fuel pressure is too high. VCM can compensate for some increase in fuel pressure, but if pressure is too high, DTC may set. Check for rich or leaking injector. Check for fuel contaminated oil. Check for fuel saturation in EVAP canister purge. If full of fuel, check canister control and hoses. Check for leaking fuel pressure regulator diaphragm by checking vacuum line to regulator for fuel.

Check for an intermittent TP sensor output that will cause system to go rich due to false indication of throttle moving. Check for false rich indication due to silicon contamination of HO2S indicated by DTC accompanied by lean driveability conditions and a powdery white deposit on sensor.

Check for internally shorted HO2S as indicated by a voltage of greater than one volt on scan tool. Disconnect HO2S. If voltage changes from greater than one volt to about.45 volt, replace HO2S. DO NOT solder HO2S wires.

DTC P0132: HO2S CIRCUIT-HIGH VOLTAGE-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.

For duplication of DTC, ensure

DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0200, P0335, P0336, P0351-P0358, and P1258 are not set.
AIR, EGR and catalyst diagnostics are not active.
Ignition voltage is greater than 9 volts.
Fuel system is operating in closed loop.
Fuel trim learn is enabled.
TP angle is between 2 and 70 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine and allow it to reach normal operating temperature. Using scan tool, monitor HO2S voltage. If voltage is greater than 775 mV go to step 4 . If voltage is not greater than 775 mV, go to next step.
Turn engine off. Turn ignition on. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 15 seconds. Start engine and allow it to reach operating temperature. Operate vehicle under conditions required to set DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0132 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0132 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Monitor HO2S voltage on scan tool. If voltage is greater than 775 mV, go to next step. If voltage is not greater than 775 mV, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
While monitoring HO2S voltage, remove HO2S heater fuse (15-amp) located in underhood electrical center. If voltage drops to 350-550 mV, go to next step. If voltage does not drop to 350-550 mV, go to step 7 .
Reinstall fuse. Disconnect HO2S. Using a jumper wire, jumper HO2S low signal circuit (PCM side) to ground. Monitor HO2S voltage on scan tool. If voltage is 350-550 mV, go to step 10 . If voltage is not 350-550 mV, go to step 8 .
Turn ignition off. Disconnect PCM harness connector C1. Disconnect HO2S. Turn ignition on. Check for voltage on HO2S signal circuit at PCM harness connector. If voltage is present, go to next step. If voltage is not present, go to step 9 .
Repair short to voltage in HO2S signal circuit. After repairs, go to step 11 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 11 .
Replace HO2S. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

System will be rich if fuel pressure is too high. PCM can compensate for some increase in fuel pressure, but if pressure is too high, DTC may set. Check for rich or leaking injector. Check for fuel contaminated oil. Check for fuel saturation in EVAP canister purge. If full of fuel, check canister control and hoses. Check for leaking fuel pressure regulator diaphragm by checking vacuum line to regulator for fuel.

Check for an intermittent TP sensor output that will cause system to go rich due to false indication of moving throttle. Check for false rich indication due to silicon contamination of HO2S indicated by DTC accompanied by lean driveability conditions and a powdery white deposit on sensor.

Disconnect MAF sensor. If rich condition is corrected, check for improper installation. System will remain rich if MAF sensor is installed backwards. Replace MAF sensor if necessary.

DTC P0132: HO2S CIRCUIT-VOLTAGE HIGH-BANK 1, SENSOR 1 (5.7L "F" & "Y" BODIES)

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

PCM supplies about 450 millivolts (mV) between HO2S high and low signal circuits. The HO2S voltage ranges from about 1000 mV when exhaust is rich to about 10 mV when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates voltage samples to determine amount of time sensor voltage is out of range. If PCM detects HO2S voltage is greater than predetermined voltage, DTC P0132 will set.

For duplication of DTC, ensure

DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0200, P0335, P0336, P0351-P0358, P1120, P1220, P1221 and P1258 are not set.
AIR, EGR and catalyst diagnostics are not active.
Ignition voltage is greater than 9 volts.
Fuel system is operating in closed loop.
Fuel trim learn is enabled.
TP sensor angle is between 2 and 70 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and warm engine to normal operating temperature. Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage with engine speed greater than 1200 RPM. If HO2S voltage is greater than 775 mV, go to step 4 . If HO2S voltage is not as specified, 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, SPECIFIC, and then DTC P0132. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition on, with engine off. Monitor HO2S voltage with scan tool. If voltage is greater than 775 mV, go to next step. If voltage is not greater than 775 mV, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
While monitoring HO2S voltage, remove HO2S heater fuse. If HO2S voltage drops to within a range of 350-550 mV, go to next step. If voltage does not drop to within specified range, go to step 7 .
Reinstall fuse. Disconnect HO2S connector. Connect a fused jumper wire between ground and HO2S connector (PCM side), low signal circuit. If reading is 350-550 mV, go to step 10 . If reading is not as specified, go to step 8 .
Turn ignition off. Disconnect PCM harness connector C1. Disconnect HO2S connector. Turn ignition on. Using DVOM, check for voltage between ground and HO2S signal circuit at PCM harness connector. If voltage is present, go to next step. If voltage is not present, go to step 9 .
Repair short to voltage in HO2S signal circuit. After repairs, go to step 11 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 11 .
Replace HO2S. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0132. 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.

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. Check MAF sensor. Disconnect MAF connector and see if rich condition is corrected. If rich condition is corrected, check for incorrectly installed MAF sensor or faulty MAF sensor. Check HO2S wires for breaks or contamination. Check TP sensor. See appropriate SYSTEM & COMPONENT TESTING article.

DTC P0133, P1133 OR P1134: O2S CIRCUIT-SLOW RESPONSE-SENSOR 1 (1.9L SATURN)

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

After achieving "closed loop" fuel control, a commanded air/fuel ratio of 14.7:1, RPM between 1500-3200 and airflow between 7-25 grams per second, PCM will continuously monitor the front O2S signal for 100 seconds. During this time, the PCM counts the number of rich-to-lean and lean-to-rich switches. Voltage reading should be less than 300 mV and greater than 600 mV, to be considered a switch. The number of switches along with the time to achieve these switches are used to calculate the average response time to perform each switch. This information is also used to calculate if the proper ratio of the switches is correct.

The 3 DTCs are used to identify different types of faults that can occur with the O2S.

P0133 (O2S Response Too Slow) This DTC is set if average response time of the switches from the sensor is too slow after the 100 second test time performed. If the lean-to-rich time is less than 94 ms or the rich-to-lean time is less than 125 ms this DTC will set.
P1133 (Too Few Rich-To-Lean And Lean-To-Rich Switches) If less than 10 switches take place during the test, this DTC will set.
P1134 (Rich-To-Lean Or Lean-To-Rich Ratio Error) If the transition ratio of the sensor is greater than 2.8 or less than 0.6, this DTC will set.

O2S wiring and connections should be checked if any these DTCs are set. Contamination is the most likely cause of these DTCs to set. Contamination could be caused by fuel, improper use of RTV sealant, engine oil or coolant contamination. Correct source of contamination before replacing sensor.

DTC P0133: O2S CIRCUIT-SLOW RESPONSE-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 O2S 1 switches from rich to lean and from lean to rich. PCM then adds amount of time O2S 1 took to complete all switches. With this information, an average time for all switches can be determined. WheDO NOT average time to switch is too slow, DTC P0133 will set.

For duplication of DTC, ensure

DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
ECT is greater than 167°F (75°C).
Engine speed is 1800-2300 RPM.
Engine is operating in closed loop.
TP sensor angle is 8-15 percent.
Evaporative emission control system is commanded open for greater than 80 percent.
Purge learned memory is greater than about 0.86.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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 O2S 1 for the following: LEAN/RICH AVG. (ms). RICH/LEAN AVG. (ms). RICH/LEAN-to-LEAN/RICH RATIO (greater than, less than). If AVG. values are less than 249 ms, or RATIO is greater than 0.2 or less than 6.0, go to next step. If readings are not as specified, go to step 17 .
Turn ignition off. Check O2S 1 for proper installation. Check condition of O2S 1 circuits and connections. If a problem is found, go to step 9 . If no problems are found, go to next step.
Check exhaust manifold for leaks. Repair as necessary. After repairs, go to step 3 . If no leaks are found, go to next step.
Disconnect O2S 1 connector. Turn ignition on. Using scan tool, monitor O2S 1 voltage. If voltage is 407-509 mV, go to next step. If voltage is not 407-509 mV, go to step 10 .
Connect a jumper wire between ground and signal circuit terminal at O2S 1 harness connector (PCM side). If voltage is less than 200 mV, go to next step. If voltage is 200 mV or greater, 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 condition as necessary. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is found, 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. Measure voltage between ground and signal circuit at O2S 1 harness connector. If voltage is greater than 407 mV, go to next step. If voltage is not greater than 407 mV, go to step 13 .
Turn ignition off. Reconnect O2S 1 connector. Disconnect PCM harness connectors. Measure resistance between ground and O2S 1 ground circuit terminal at PCM harness 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. Measure resistance of signal circuit between O2S 1 harness connector and PCM harness connector. If resistance is less than 5 ohms, go to step 15 . If resistance is not less than 5 ohms, repair open in sensor signal circuit. After repairs, go to step 17 .
Check O2S 1 low signal circuit terminal connection at PCM harness connector. Repair as necessary. After repairs, go to step 17 . If low signal circuit terminal is okay, go to step 16 .
Check O2S 1 signal circuit terminal connection at PCM harness connector. Repair as necessary. After repairs, go to step 17 . If signal circuit terminal is okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, 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, and then enter DTC P0133. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

DTC P0133: HO2S CIRCUIT-SLOW RESPONSE-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 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. PCM counts number or times a rich-to-lean and lean-to-rich response is indicated and adds amount of time it takes to complete all transitions. PCM uses this information to determine average time for each transition. If average response time is slow, DTC P0133 will set.

For duplication of DTC, ensure

No active TP, MAP, MAF, IAT, ECT, CKP, EGR sensor, misfire, fuel injector circuit, EVAP system and fuel trim DTCs are set.
Engine has been running in closed loop fuel mode for at least one minute.
Engine speed is 1000-3000 RPM.
ECT is greater than 122°F (50°C).
EVAP purge duty cycle is less than 35 percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If any other HO2S DTCs (except P1133 or P1134) are set, diagnose affected DTCs. Start engine and allow it to reach operating temperature. Operate vehicle within conditions required to set DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0133 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0133 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
If scan tool also displays DTC P1133 or P1134 FAILED THIS IGN, go to step 8 . If scan tool does not display these DTCs, go to next step.
Visually inspect exhaust system for leaks near HO2S 1. Repair as necessary. After repairs, go to step 13 . If no leaks are 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 jumper wire between HO2S 1 harness connector low signal circuit and chassis ground. Using scan tool, read HO2S 1 voltage. If voltage is about 0.45 volt, go to next step. If voltage is not as specified, go to step 10 .
Connect a jumper wire between chassis ground and high and low signal circuits at HO2S 1 harness connector (PCM side). If voltage is less than 0.3 volt, go to step 12 . If voltage 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 in HO2S 1 low signal circuit or grounded HO2S 1 high signal circuit. After repairs, go to step 13 .
Repair open in HO2S 1 high signal circuit or faulty PCM connections as necessary. After repairs, go to step 13 .
Replace HO2S 1. 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 P0133. If scan tool displays DTC P0133 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0133 FAILED THIS IGN, system is okay.

Check for faulty connections or damaged harness. If connections and harness appear okay, observe HO2S 1 display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

DTC P0133: HO2S 1 CIRCUIT-SLOW RESPONSE-SENSOR 1 (3.5L "W" BODY)

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

For duplication of DTC, ensure

DTCs P0131, P0132 or P0135 are not set.
No active fuel trim, fuel injector circuit, misfire, EVAP, EGR, AIR, TP, IAT, MAP, ECT, CKP or MAF sensor DTCs are present.
System voltage is greater than 9 volts.
System is in closed loop.
Engine has been running for at least 3.3 seconds.
ECT is greater than 167°F (75°C).
Engine speed is 1000-3000 RPM.
MAF is 15-40 grams per 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.
Using scan tool, check for additional DTCs. If DTC P0140 is set, go to step 4 . If DTC P0140 is not set, go to next step.
If any powertrain component DTCs are set, diagnose applicable DTCs. If no powertrain component DTCs are set, go to step 5 .
HO2S is contaminated. Repair cause of contamination and replace affected HO2S. After repairs, go to step 18 .
Using scan tool, store DTC information from PCM, and then clear DTCs. Reset fuel trim values. Start engine and allow it to reach normal operating temperature. Operate engine under conditions required to set this DTC. If scan tool indicates this DTC ran and failed this ignition, go to step 7 . If scan tool indicates this DTC ran and passed this ignition, go to next step.
Condition that set this DTC is not present at this time. Check for the following: Exhaust leaks between engine and HO2S. Poor HO2S connector terminal contact. HO2S connector water intrusion. Improperly torqued HO2S. Faulty HO2S heater. Poor PCM harness connections. HO2S high or low circuit intermittently open, shorted, or excessive circuit resistance. Contaminated HO2S. Repair as necessary. After repairs, go to step 18 . If no problems are found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check for exhaust leaks between engine and HO2S. Check for poor harness connections at HO2S and PCM. Repair as necessary. After repairs, go to step 18 . If no problem is found, go to next step.
Turn ignition off. Disconnect HO2S. Using a jumper wire, jumper HO2S low circuit (PCM side) to ground. Turn ignition on, with engine off. Using scan tool, monitor HO2S voltage. If voltage is 351-551 mV, go to next step. If voltage is not 351-551 mV, go to step 13 .
Using a jumper wire, jumper HO2S high signal circuit to ground. Using scan tool, monitor HO2S voltage. If voltage is less than 20 mV, go to next step. If voltage is not less than 20 mV, go to step 14 .
Remove jumper wire from HO2S low signal circuit. Using test light connected to 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 heater ignition feed and ground circuits at HO2S harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 16 .
Check for any conditions that may contaminate HO2S. Repair as necessary. After repairs, go to step 17 .
Check HO2S high signal circuit for short to low signal circuit, ground or ignition voltage source. Repair as necessary. After repairs, go to step 18 .
Check HO2S high or low signal circuits for an 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 repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off and wait 15 seconds. Operate vehicle under conditions required to set DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
Using scan tool, review CAPTURED INFO. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

HO2S 1 requires an outside source of air for proper operation. Air is supplied through HO2S wiring. Check wires and connections for breaks or contamination. DO NOT solder HO2S wiring. Solder will obstruct air path.

DTC P0133: HO2S 1 CIRCUIT-SLOW RESPONSE-SENSOR 1 (3.8L "C", "F", "G", "H" & "W" BODIES)

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

Powertrain Control Module (PCM) continuously monitors Heated Oxygen Sensor 1 (HO2S 1) activity for 100 seconds. During the monitor period, PCM counts number of times HO2S 1 switches from rich to lean and from lean to rich. PCM then adds amount of time HO2S 1 took to complete all switches. With this information, an average time for all switches can be determined. WheDO NOT average time to switch is too slow, DTC P0133 will set.

For duplication of DTC, ensure

No HO2S 1 heater circuit, EVAP system, misfire, fuel trim, fuel injector circuit, EGR pintle position, TP, IAT, MAP, ECT, CKP or MAF sensor DTCs are set.
Engine has been running in closed loop fuel control for at least one minute.
Engine speed is 1000-3000 RPM.
Engine coolant temperature is greater than 122°F (50°C).
MAF is 10-30 grams per 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 any other HO2S related DTCs (except P1133 or P1134) are set, diagnose affected DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required to set DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0133 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0133 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
If scan tool also displays DTC P1133 or P1134 FAILED THIS IGN, go to step 8 . If scan tool does not display these DTCs, go to next step.
Visually inspect exhaust system for leaks near HO2S 1. Repair as necessary. After repairs, go to step 13 . If no leaks are 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 low signal circuit and chassis ground. Using scan tool, read HO2S 1 voltage. If voltage is about 0.45 volt, go to next step. If voltage is not about 0.45 volt, go to step 10 .
Connect a jumper wire between chassis ground and HO2S 1 harness connector high and low signal circuits. If voltage is less than 0.3 volt, go to step 12 . If voltage 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 in HO2S 1 low signal circuit or grounded HO2S 1 high signal circuit. After repairs, go to step 13 .
Repair open in HO2S 1 high signal circuit or faulty PCM connections as necessary. After repairs, go to step 13 .
Replace HO2S 1. 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 P0133. If scan tool displays DTC P0133 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0133 FAILED THIS IGN, system is okay.

DTC P0133: HO2S CIRCUIT-SLOW RESPONSE-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.45 volt reference signal to the HO2S through the Bank 1 high signal circuit. When HO2S is cold, less than 392°F (200°C), the sensor signal voltage will be about.45 volt and PCM will keep the system in "open loop". When HO2S is warm, sensor will swing from rich to lean rapidly, at least one switch every 2 seconds, if PCM is in good control of air/fuel mixture. If oxygen sensor is slow to respond to changes on exhaust oxygen content, DTC P0133 will set.

For duplication of DTC, ensure DTCs P0117, P0118, P0121, P0122, P0123, P0135 and P1133 are not set, this test has not been completed this ignition cycle, coolant level is okay, and ignition voltage is 9-16 volts.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
If you are referred here from another DTC, go to step 4 . If not, go to next step.
If any other DTCs are present, diagnose affected DTCs first. If other DTCs are not present, go to next step.
Start and warm engine until coolant temperature reaches about 185°F (85°C) or greater. Using scan tool, select ENGINE 1 and note bank 1 sensor 1 voltage display. Increase engine speed to 1200-2000 RPM for about 2 minutes. After 2 minutes rear HO2S reading should swing rapidly within.3-.6 volt range. If voltage reading is within range, go to next step. If voltage reading is out of range, go to step 6 .
With engine speed still at 1200-2000 RPM, note LOOP STATUS on scan tool. If system is in "closed loop", go to step 10 . If system is not in "closed loop", go to step 9 .
If HO2S voltage remains between.3 and.6 volt longer than the time is swings out of range, go to step 9 . If not, go to next step.
Check terminal contact for HO2S high and low signal voltage at PCM connector C2. Repair as necessary. If terminal contacts are okay, go to next step.
Check terminal contact at rear oxygen sensor. Repair as necessary. If terminal contact is okay, go to next step.
Replace rear HO2S. Check for possible oxygen sensor contamination such as, leaded fuel, incorrect gasket sealer or over rich operation.
Check for possible causes of extended rich or lean operation. Repair as necessary.

DO NOT solder oxygen sensor wires.

DTC P0133: HO2S CIRCUIT-SLOW RESPONSE-BANK 1, SENSOR 1 (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" 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 0.1 volt with lean exhaust. VCM monitors activity for 100 seconds after closed loop. During monitored period, VCM counts how often HO2S switches between rich and lean. VCM determines average switching time. If average switching time is too slow, DTC P0133 will set.

HO2S produces no voltage and acts as an open circuit when temperature is less than 600°F (316°C). 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 checking response time.

For duplication of DTC, ensure

DTCs P0131, P0132, P0134 and P0135 are not set.
No active EVAP system, TP, IAT, MAP, ECT, MAF sensor, misfire DTCs are set.
No intrusive tests are in progress.
No device control active.
System voltage is 11.7-18 volts.
System is in closed loop.
Engine coolant temperature is greater than 135°F (57°C).
Engine is running.
MAF is 15-55 grams per second.
Engine speed is 1100-3000 RPM.
EVAP canister purge is enabled.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Check if any other HO2S DTCs are set. If any other HO2S DTCs are set, go to step 4 . If no other HO2S DTCs are set, go to next step.
If any powertrain component DTCs are set, diagnose applicable DTC. If no powertrain component DTCs are set, go to step 5 .
HO2S is contaminated. Repair condition causing contamination and replace affected HO2S. After repairs, go to step 18 .
Using scan tool, store VCM information, and then clear DTCs. Reset fuel trim values. Start engine and allow it to reach normal operating temperature. Operate vehicle under conditions required to set DTC. If scan tool indicates that DTC P0133 failed this ignition, go to step 7 . If scan tool does not indicate that DTC P0133 failed this ignition, go to next step.
Condition that set this DTC is not present at this time. Check for the following: Exhaust leaks between engine and HO2S. Poor HO2S connector terminal contact. HO2S connector water intrusion. Improperly torqued HO2S. Faulty HO2S heater. Poor PCM harness connections. HO2S high or low circuit intermittently open, shorted, or excessive circuit resistance. Contaminated HO2S. Repair as necessary. After repairs, go to step 18 . If no problems are found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Check exhaust system for leaks between HO2S and engine. Check for poor harness connections at HO2S and VCM. Repair as necessary. After repairs, go to step 18 . If no problem is found, go to next step.
Turn ignition off. Disconnect HO2S. Using jumper wire, jumper HO2S low signal circuit to ground. Turn ignition on. Using scan tool, monitor HO2S voltage. If voltage is 351-551 mV, go to next step. If voltage is not 351-551 mV, go to step 13 .
Using jumper wire, jumper HO2S high signal circuit to ground. Using scan tool, monitor HO2S voltage. If voltage is less than 20 mV, go to next step. If voltage is not less than 20 mV, go to step 14 .
Remove jumper wire from HO2S low circuit. Using a test light connected to 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 heater ignition feed and heater ground circuits at HO2S harness connector (engine harness side). If test light illuminates, go to next step. If test light does not illuminate, go to step 16 .
Check for any conditions that may cause HO2S contamination. Repair as necessary. After repairs, go to step 17 .
Repair HO2S high signal circuit for short to low signal circuit or short to ignition voltage source. After repairs, go to step 18 .
Check HO2S high and low circuits for an open or high resistance. Repair as necessary. After repairs, go to step 18 .
Repair HO2S ignition feed circuit. After repairs, go to step 18 .
Repair HO2S heater ground circuit. After repairs, go to step 18 .
Replace HO2S. After repairs, go to next step.
Using scan tool, reset fuel trim values. Start engine and allow it to reach normal operating temperature. Operate vehicle under conditions required to set DTC. If scan tool indicates this test ran and passed, system is okay. If scan tool does not indicate this test ran and passed, go to step 2 .

Check HO2S heater operation. Check for contaminated fuel, exhaust leaks, obstructed air intake and vacuum leaks. Check for faulty connections at VCM and HO2S. DO NOT solder HO2S wires.

DTC P0133: HO2S CIRCUIT-SLOW RESPONSE-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.

For duplication of DTC, ensure

DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0200, P0335, P0336, P0351-P0358 and P1258 are not set.
Engine coolant temperature is greater than 149°F (65°C).
Ignition voltage is greater than 9 volts.
AIR, EGR and catalyst diagnostics are not active.
Fuel system is operating in closed loop.
Engine speed is 1200-3000 RPM.
MAF is 23-50 grams per second.
EVAP canister purge duty cycle is greater than zero percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start engine and allow it to reach normal operating temperature. Operate vehicle under conditions required to set this DTC. If scan tool indicates DTC P0133 failed this ignition, go to next step. If scan tool does not indicate DTC P0133 failed this ignition, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
If DTC P0153 also failed this ignition, go to step 8 . If DTC P0153 did not fail this ignition, go to next step.
Check exhaust systems for leaks. Repair as necessary. After repairs, go to step 14 . If no leaks are found, go to next step.
Check HO2S for proper installation. Check condition of wiring and connections at HO2S and PCM. Repair as necessary. After repairs, go to step 14 . If no problem is found, go to next step.
Disconnect HO2S. Using jumper wire, jumper HO2S low signal circuit to ground. Using scan tool, monitor HO2S voltage. If voltage is 350-550 mV, go to next step. If voltage is not 350-550 mV, go to step 10 .
Using jumper wire, jumper HO2S high and low signal circuits to ground. Using scan tool, monitor HO2S voltage. If voltage is less than 200 mV, go to step 13 . If voltage is not less than 200 mV, go to step 9 .
HO2S is contaminated. Locate and repair condition causing contamination and replace HO2S. After repairs, go to step 14 .
Remove jumper wire from HO2S low signal circuit. Measure voltage between ground and HO2S low signal circuit. If voltage is about 5 volts, go to step 12 . If voltage is not about 5 volts, go to step 11 .
Repair HO2S high signal circuit for a short to ground or short to voltage. After repairs, go to step 14 .
Repair open in HO2S low signal circuit or faulty PCM harness connections. After repairs, go to step 14 .
Repair open in HO2S high signal circuit or poor PCM harness connections. After repairs, go to step 14 .
Replace HO2S. After repairs, go to next step.
Using scan tool, clear DTCs. Start engine and allow it to reach normal operating temperature. Select SPECIFIC DTC option and monitor for DTC P0133. Operate vehicle under conditions required to set DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
Using scan tool, review CAPTURED INFO. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

A malfunction in HO2S heater circuit will cause this DTC to set. Check for intermittent opens or shorts. HO2S 1 requires an outside source of air for proper operation. Air is supplied through HO2S wiring. Check wires and connections for breaks or contamination. DO NOT solder HO2S wiring. Solder will obstruct air path.

DTC P0133: HO2S CIRCUIT-SLOW RESPONSE-BANK 1, SENSOR 1 (5.7L "F" & "Y" BODIES)

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

PCM continuously monitors HO2S activity for 100 seconds. During this period, PCM counts number of times HO2S responds from rich to lean and from lean to rich, and adds amount of time it took to complete transition. With this information, an average time for all transitions can be determined. If average response time is too slow, DTC P0133 will set.

A lean to rich transition is determined when HO2S voltage changes from less than 300 mV to more than 600 mV. A rich to lean transition is determined when HO2S voltage changes from greater than 600 mV to less than 300 mV. A sensor that responds too slowly is most likely defective and should be replaced.

For duplication of DTC, ensure

DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0200, P0335, P0336, P0351-P0358 or P1258 are not set.
Engine coolant temperature is greater than 122°F (50°C).
Ignition voltage is greater than 9 volts.
Fuel system is operating in closed loop.
Engine speed is at 1000-2300 RPM.
Engine airflow is 20-50 gm/s.
EVAP canister purge duty cycle is greater than zero percent.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(ref-132811-S27457185922002013000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
Start and warm engine to normal operating temperature. Using scan tool, select ENGINE 1 DATA LIST and operate vehicle within parameters when DTC was set. Using scan tool, select DTC INFO and monitor FAIL THIS IGN data. If scan tool indicates that DTC P0133 test failed, go to next step. If scan tool does not indicate that DTC P0133 test failed, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
If scan tool also indicates that P0153 test failed, go to step 8 . If scan tool does not indicate that P0153 test failed, go to next step.
Check exhaust system for leaks. Repair as necessary. After repairs, go to step 14 . If exhaust is okay, go to next step.
Ensure Bank 1 HO2S 1 is securely installed. Check terminals for corrosion or damaged wiring. Repair as necessary. After repairs, go to step 14 . If wiring and terminals are okay, go to next step.
Disconnect Bank 1 HO2S 1. 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 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 PCM connector (PCM side), Bank 1 HO2S 1 high and low signal circuits. Using scan tool, monitor voltage. If voltage is less than 200 mV, go to step 13 . If voltage is not less than 200 mV, go to step 9 .
Replace HO2S. Determine cause of sensor contamination, otherwise new sensor will be damaged. After repairs, go to step 14 .
Remove jumper wire from HO2S low signal circuit. Measure voltage between HO2S low signal circuit and battery ground. If voltage is about 5 volts, go to step 12 . If voltage is not about 5 volts, go to step 11 .
Repair HO2S high signal circuit for short to ground or short to voltage. After repairs, go to step 14 .
Repair open in HO2S low signal circuit or faulty PCM connections. After repairs, go to step 14 .
Repair open in HO2S high signal circuit or faulty PCM connections. After repairs, go to step 14 .
Replace Bank 1 HO2S 1 sensor. After repairs, go to next step.
Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0133. 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.

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 P0134: O2S CIRCUIT-INSUFFICIENT ACTIVITY-SENSOR 1 (1.9L SATURN)

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

When Oxygen Sensor (O2S) temperature reaches about 600°F (316°C), it becomes an electrical source that responds to the oxygen content in the exhaust. PCM produces a bias voltage of about 450 mV on the oxygen sensor circuit. When sensor is cold, its internal resistance is extremely high, therefore the PCM recognizes the bias as an open circuit. As the sensor warms up, the internal resistance decreases. When sensor reaches about 600°F (316°C), it starts producing a voltage based on the oxygen content in the exhaust stream. This voltage is used by the PCM to determine a rich or lean oxygen sensor signal and adjusts the fuel mixture accordingly.

DTC P0134 will set if O2S voltage is inactive (not reading outside 391-491 mV), engine has been running for at least one minute, TP sensor reads greater than 6.5 percent (off idle), no other engine sensor or misfire DTCs have been set or when commanded air/fuel ration is about 14.7:1. O2S signal is continuously monitored once these conditions are met.

Start and operate engine for more than 5 minutes. Connect scan tool. Ensure engine coolant temperature is greater than 140°F (60°C). O2S voltage should be varying from less than 391 mV to greater than 491 mV. If voltage is varying as specified, problem is intermittent. See «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) . If voltage is not varying as specified, go to next step.
Turn ignition on, with engine off. Disconnect O2S harness connector. Jumper O2S harness connector terminal to ground. If scan tool reads less than 100 mV, check for terminal tightness or faulty O2S. If scan tool does not read less than 100 mV, go to next step.
Remove jumper wire. Using a DVOM, measure voltage at O2S harness connector terminal. If voltage reading is.3-.6 volt (300-600 millivolt), replace PCM. If voltage reading is greater than.6 volt (600 millivolt), check for open ground circuit, terminal tightness or faulty PCM. If voltage reading is less than.3 volt (300 millivolt), check for open signal circuit, terminal tightness or faulty PCM.

PCM will not go into "closed loop" if this DTC has failed during the current ignition cycle. Use scan tool to review malfunction history diagnostic information. This data can be used to duplicate a problem. Check tightness of terminal connections. Normal scan tool readings in "closed loop" will show the O2S voltage varying between 10-999 mV. DTC can also set or cause false O2S reading of O2S ground becomes loose or corroded.

DTC P0134: O2S CIRCUIT-INSUFFICIENT ACTIVITY-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) supplies about.45 volt to Oxygen Sensor 1 (O2S 1). The O2S 1 supplies a varying voltage from about one volt when exhaust is rich to about.10 volt when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects O2S 1 voltage remains at or near.45 volt for an extended period, DTC P0134 will set.

For duplication of DTC, ensure

DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
Airflow is greater than 3 gm/s.
ECT is greater than 158°F (70°C).
TP sensor angle is 4-56 percent for 20 seconds.
Engine run time is greater than 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.
Ensure engine is at normal operating temperature. Start engine. Increase engine speed to 1200 RPM for 2 minutes. If scan tool indicates closed loop, go to next step. If scan tool does not indicate closed loop, go to step 4 .
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If scan tool indicates closed loop, go to step 12 . If scan tool does not indicate closed loop, go to next step.
Turn ignition on, with engine off. Disconnect O2S 1 connector. Connect a jumper wire between ground and sensor signal circuit terminal at O2S 1 harness connector. If voltage is less than 50 mV, go to next step. If voltage is not less than 50 mV, go to step 6 .
Turn ignition off. Inspect O2S 1 harness connector for faulty terminals or poor connection. Repair as necessary. After repairs, go to step 12 . If connector is okay, go to step 9 .
Turn ignition on, with engine off. Disconnect jumper wire. Using DVOM, measure voltage between ground and sensor signal circuit terminal at O2S 1 harness connector. If voltage is greater than 600 mV, go to step 10 . If voltage is not greater than 600 mV, go to next step.
If voltage reading is less than 300 mV, go to step 11 . If voltage reading is not less than 300 mV, go to next step.
Replace PCM. Program PCM using required equipment. After repairs, go to step 12 .
Replace oxygen sensor. After repairs, go to step 12 .
Check O2S 1 ground circuit for open or poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 8 .
Check O2S 1 signal circuit for open or poor connection at PCM. Repair as necessary. After repairs, go to next step. If circuit is okay, go to step 8 .
Reconnect oxygen sensor. Using scan tool, 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, and then enter DTC P0134. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

DTC P0134: HO2S CIRCUIT-INSUFFICIENT ACTIVITY-BANK 1, SENSOR 1 (3.0L "V" BODY)

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

For duplication of DTC, ensure engine is running, event counter value is greater than 20, and HO2S maximum value has been exceeded.

Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (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 exhaust leaks between bank 1 HO2S 1 and HO2S 2. If a leak is found, go to step 6 . If no leaks are found, go to next step.
Turn ignition off. Disconnect HO2S 1. Check connectors for contamination. If a problem is found, go to step 7 . If connectors are okay, go to next step.
Disconnect ECM harness connector C2. Check circuits between HO2S 1 harness connector and ECM harness connector for an open, short together, or short to ground. If a problem is found, go to step 8 . If circuits are okay, go to next step.
Replace HO2S 1. After repairs, go to step 9 .
Repair exhaust leak as necessary. After repairs, go to step 9 .
Repair connections as necessary. After repairs, go to step 9 .
Repair affected circuit as necessary. After repairs, go to next step.
Using scan tool, 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, and then enter DTC P0134. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Inspect for poor ECM to engine grounds. If fuel pressure is too low, this DTC may set. Check for lean injectors. Inspect for disconnected or damaged vacuum hoses and for vacuum leaks at intake manifold, throttle body and crankcase ventilation system.

DTC P0134: HO2S CIRCUIT-INSUFFICIENT ACTIVITY-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.

Powertrain Control Module (PCM) supplies about.45 volt to Heated Oxygen Sensor 1 (HO2S 1). The HO2S 1 generates a voltage that varies from about one volt when exhaust is rich to about.10 volt when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects HO2S 1 voltage remains at or near.45 volt for an extended period of time, DTC P0134 will set.

For duplication of DTC, ensure no active misfire, fuel injector circuit, EVAP system, fuel trim, EGR system, TP, IAT, MAP, ECT, MAF, or CKP sensor DTCs are set, engine is running, and HO2S 1 signal voltage remains at 400-500 mV for more than 10 seconds.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Ensure engine is at normal operating temperature. Start engine and increase engine speed to 1200 RPM for 2 minutes. Using scan tool, monitor HO2S 1 voltage. If voltage is varying outside the range of 400-500 mV, go to next step. If voltage is within the 400-500 mV range, go to step 4 .
Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0134 until DTC P0134 test runs. If scan tool indicates FAILED THIS IGN, go to next step. If scan tool does not indicate FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition on, with engine off. Disconnect HO2S 1 connector. Using a jumper wire, jumper signal and low circuits to ground at HO2S 1 harness connector. If voltage is less than 150 mV, go to step 8 . If voltage is not less than 150 mV, go to next step.
Turn ignition on, with engine off. Disconnect jumper wire. Using DVOM, measure voltage between heater ground circuit and sensor signal circuit terminals at HO2S 1 harness connector. If voltage is near 450 mV, go to next step. If voltage is not as specified, go to step 7 .
Turn ignition off. Disconnect PCM harness connector. Check continuity in ground circuit between PCM harness connector and HO2S 1 harness connector. If resistance is not greater than 5 ohms, go to step 9 . If resistance is greater than 5 ohms, repair open in ground circuit. After repairs, go to step 13 .
Turn ignition off. Disconnect PCM harness connector. Check continuity in signal circuit between PCM and HO2S 1 harness connectors. If resistance is not greater than 5 ohms, go to step 10 . If resistance is greater than 5 ohms, repair open in ground circuit. After repairs, go to step 13 .
Turn ignition off. Disconnect and inspect HO2S 1 connector. Inspect for damaged pins, corrosion and loose wires. Repair as necessary. After repairs, go to step 13 . If connector is okay, go to step 11 .
Check for poor HO2S 1 low circuit terminal connection at PCM harness connector. Repair as necessary. After repairs, go to step 13 . If connector is okay, go to step 12 .
Check for poor HO2S 1 signal circuit terminal connection at PCM harness connector. Repair as necessary. After repairs, go to step 13 . If connector is okay, go to step 12 .
Replace HO2S 1. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P0134 until DTC P0134 test runs. If scan tool indicates FAILED THIS IGN, go to step 2 . If scan tool does not indicate FAILED THIS IGN, system is okay.

Check for poor connection at PCM. Check for damaged wiring harness. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation.

Turn ignition on, with engine off. Using scan tool, monitor HO2S 1 voltage. Voltage should gradually drop to less than 250 mV or rise to greater than 600 mV. If voltage is not as specified, disconnect HO2S 1 connector. Connector a test light between ignition feed circuit and heater ground circuit terminals at HO2S 1 harness connector. If test light does not illuminate, repair open ignition feed circuit. If test light illuminates, replace HO2S 1.

DTC P0134: HO2S CIRCUIT-INSUFFICIENT ACTIVITY-SENSOR 1 (3.5L "W" BODY)

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

Powertrain Control Module (PCM) supplies about 450 mV to Heated Oxygen Sensor 1 (HO2S 1). The HO2S 1 supplies a varying voltage from about 800 mV when exhaust is rich to about 50 mV when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects that HO2S 1 voltage remains at or near 450 mV for an extended period, DTC P0134 will set.

For duplication of DTC, ensure engine is running, and no active fuel trim, fuel injector circuit, misfire, EVAP system, EGR system, TP, IAT, MAP, ECT, CKP, or MAF sensor DTCs are present.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Using scan tool, clear DTCs. Reset fuel trim values. Start engine and allow it to reach normal operating temperature. Monitor HO2S 1 voltage on scan tool. If voltage is fixed at 351-551 mV, go to step 4 . If voltage is not as specified, go to next step.
DTC is intermittent. Faulty wiring and harness connections or exhaust leaks may have set this DTC. Repair as necessary. After repairs, go to step 17 . If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect HO2S 1 harness connector. Using jumper wires, jumper HO2S 1 high and low signal circuits to ground. Turn ignition on, with engine off. Monitor HO2S 1 voltage with scan tool. If voltage is less than 20 mV, go to step 7 . If voltage is not less than 20 mV, go to next step.
Turn ignition off. Remove jumper wires. Disconnect PCM harness connector containing HO2S 1 circuits. Measure resistance of HO2S 1 high and low signal circuits. If each circuit resistance is less than 5 ohms, go to next step. If either circuit resistance is not less than 5 ohms, go to step 9 .
Check for faulty PCM harness connections. Repair as necessary. After repairs, go to step 17 . If connections are okay, go to step 16 .
Remove jumper wires. Turn ignition on, with engine off. Connect a test light between heater ignition feed and heater ground circuits at HO2S 1 harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Turn ignition off. Reconnect HO2S 1 harness connector. Disconnect PCM harness connector containing HO2S 1 circuits. Measure resistance between HO2S 1 low signal circuit and any PCM ground circuit at PCM harness connector. 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 high resistance. After repairs, go to step 17 .
Repair HO2S 1 heater ignition feed or ground circuit. After repairs, go to step 17 .
Repair high resistance between HO2S 1 low circuit and PCM ground circuit. After repairs, go to step 17 .
Check for an exhaust leak upstream of HO2S 1. Repair as necessary. After repairs, go to step 17 . If no leaks are found, go to next step.
Allow engine to completely cool. Measure resistance between HO2S 1 low signal circuit and any PCM ground circuit at PCM harness connector. 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 1. Clean threads and apply anti-seize compound, and then reinstall. Measure resistance between HO2S 1 low signal circuit and any PCM ground circuit at PCM harness connector. 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 1. After repairs, go to step 17 .
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Turn ignition off and wait 15 seconds. Start engine and operate vehicle under conditions required to set this DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate 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.

Check for poor connection at PCM. Check for damaged wiring harness. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation.

HO2S 1 requires an outside source of air for proper operation. Air is supplied through HO2S 1 wiring. Check wires and connections for breaks or contamination. DO NOT solder HO2S 1 wiring. Solder will obstruct air path.

DTC P0134: HO2S CIRCUIT-INSUFFICIENT ACTIVITY-SENSOR 1 (3.8L "C", "F", "G", "H" & "W" BODIES)

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

For duplication of DTC, ensure engine is running and no active fuel trim, fuel injector circuit, misfire, EVAP system, EGR pintle position, TP, IAT, MAP, ECT, CKP, or MAF sensor DTCs are set.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Start engine and allow it to reach operating temperature. Place gear selector in Park or Neutral, and apply parking brake. Increase engine speed to greater than 1200 RPM for 2 minutes. Using scan tool, read HO2S 1 voltage. If voltage is varying outside of 400-500 mV range, go to next step. If voltage is not varying outside of 400-500 mV range, go to step 4 .
Turn ignition on. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0134 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0134 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition on. Disconnect HO2S 1 harness connector. Using jumper wires, jumper HO2S 1 signal and ground circuits to ground. Monitor HO2S 1 voltage with scan tool. If voltage is less than 150 mV, go to step 8 . If voltage is not less than 150 mV, go to next step.
Remove jumper wire from HO2S 1 signal circuit. Using DVOM, measure voltage between HO2S 1 harness connector signal and heater ground circuits. If voltage is about 4.5 volts, go to next step. If voltage is not about 4.5 volts, go to step 7 .
Turn ignition off. Disconnect PCM harness connectors. Measure resistance of HO2S 1 ground circuit between HO2S 1 and PCM. If resistance is greater than 5 ohms, repair circuit as necessary. After repairs, go to step 13 . If resistance is not greater than 5 ohms, go to step 9 .
Turn ignition off. Disconnect PCM harness connectors. Measure resistance of HO2S 1 signal and ground circuits between HO2S 1 and PCM. If either circuit resistance is greater than 5 ohms, repair circuit as necessary. After repairs, go to step 13 . If resistance in both circuits is not greater than 5 ohms, go to step 10 .
Check for faulty connection at HO2S 1. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
Check HO2S 1 ground circuit for faulty connection at PCM. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Check HO2S 1 signal circuit for faulty connection at PCM. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to step 12 .
Replace HO2S 1. After repairs, go to step 13 .
Replace PCM. Program replacement PCM using required equipment. 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 P0134. If scan tool displays DTC P0134 FAILED THIS IGN, go to step 2 . If scan tool does not display DTC P0134 FAILED THIS IGN, system is okay.

DTC P0134: HO2S CIRCUIT-INSUFFICIENT ACTIVITY-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.45 volt reference signal to the HO2S through the Bank 1 high signal circuit. When HO2S reaches operating temperature, it will generate a counter voltage that will vary based on the amount of oxygen in the exhaust. A lean exhaust will generate a low voltage and cause the reference voltage (.45 volt) to drop lower. A rich exhaust will generate a high voltage and cause the reference voltage to increase. If sensor cannot respond under the test conditions and generate a voltage greater than.61 volt or less than.31 volt, DTC P0134 will set.

For duplication of DTC, ensure DTCs P0117, P0118, P0121, P0122, P0123 and P0560 are not set, coolant temperature is 163°F (72.5°C) or greater, throttle angle is 1-81.6 degrees, calculated throttle position switch is open, and engine speed is 800 RPM or greater.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Start and warm engine until coolant temperature reaches about 185°F (85°C) or greater. Using scan tool, select ENGINE 1 and note HO2S 1 voltage display for 30 seconds. If voltage remains between.3 and.6 volt, go to next step. If voltage does not remain between.3 and.6 volt, go to step 6 .
Turn ignition off. Disconnect HO2S 1 harness connector. Start engine. Using DVOM, measure voltage between HO2S harness connector (sensor side) terminals "A" and "B". If voltage remains between.3 and.6 volt, diagnose using DTC P0133 test. If voltage does not remain between.3 and.6 volt, go to next step.
Store fluid life index as indicated on scan tool. Turn ignition off for 30 seconds, and then disconnect PCM harness connector C2. Using DVOM, measure resistance of HO2S 1 high signal circuit between PCM and HO2S 1 harness connectors. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, go to step 9 .
Measure resistance of HO2S 1 low signal circuit between PCM and HO2S 1 harness connectors. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, go to step 10 .
Turn ignition on, with engine off. Measure voltage between HO2S 1 harness connector terminals "C" and "D" (harness side). If voltage is greater than 10.5 volts, go to next step. If voltage is 10.5 volts or less, go to step 8 .
Using a jumper wire, jumper HO2S 1 heater ground circuit together at harness connectors. Set DVOM to amp scale. Connect DVOM to HO2S 1 heater ignition feed circuit in series at harness connectors. If amperage is 0.9-1.5 amps, go to step 14 . If amperage is not as specified, go to step 13 .
Measure voltage between ground and HO2S 1 heater ignition feed circuit at HO2S 1 harness connector. If voltage is 10.5 volts or greater, go to step 11 . If voltage is less than 10.5 volts, go to step 12 .
Repair open in HO2S 1 high signal circuit.
Repair open in HO2S 1 low signal circuit.
Repair open in HO2S 1 heater ground circuit.
Repair open or short to ground in HO2S 1 heater ignition feed circuit.
Replace HO2S 1.
Check terminal contacts at PCM harness connector C2. Repair as necessary. If terminal contacts are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment.

A loose HO2S 1 or poor exhaust ground may cause DTC to set. Clean HO2S 1 threads as necessary. DO NOT solder oxygen sensor wires. Replace sensor if harness is damaged.

DTC P0134: HO2S CIRCUIT-INSUFFICIENT ACTIVITY-BANK 1, SENSOR 1 (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K" & "L", "M", "P", "S" & "T" 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.

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 or HO2S circuit is open. DTC P0134 will set if VCM fails to detect minimum number of HO2S 1 voltage transitions greater than and less than bias voltage range of 300-600 mV.

For duplication of DTC, ensure

DTC P0135 is not set.
No active EVAP system, misfire, TP, IAT, MAP, ECT or MAF sensor DTCs are set.
No intrusive tests are in progress.
No device controls are active.
System voltage is 11.7-18 volts.
Engine run time is greater than 2 minutes.
Decel fuel cut-off mode is not active.
ECT is 137°F (58.5°C) or greater.
MAF is 13 grams per second.
System is in closed loop.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Using scan tool, store DTC information from VCM. Clear DTCs and reset fuel trim values. Start engine and allow it to reach normal operating temperature. Monitor HO2S 1 voltage on scan tool. If voltage is fixed at 351-551 mV, go to step 4 . If voltage is not as specified, go to next step.
Condition that set DTC is not present at this time. Check for exhaust leaks and condition of HO2S 1 related circuits and connections. Repair as necessary. After repairs, go to step 17 . If no problem is found, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition off. Disconnect HO2S 1 harness connector. Using jumper wires, jumper HO2S 1 high and low signal circuits to ground. Turn ignition on. Monitor HO2S 1 voltage with scan tool. If voltage is less than 20 mV, go to step 7 . If voltage is not less than 20 mV, go to next step.
Turn ignition off. Remove jumper wires. Disconnect VCM harness connector containing HO2S 1 circuits. Measure resistance of HO2S 1 high and low signal circuits between HO2S 1 and VCM. If resistance of both circuits is less than 5 ohms, go to next step. If resistance of either circuit is not less than 5 ohms, go to step 9 .
Check VCM harness connections. Repair as necessary. After repairs, go to step 17 . If connections are okay, go to step 16 .
Remove jumper wires from HO2S 1. Turn ignition on. Connect test light between HO2S 1 heater ignition feed and ground circuits at HO2S 1 harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
Turn ignition off. Reconnect HO2S 1 harness connector. Disconnect VCM harness connector containing HO2S 1 low signal circuit and VCM harness connector containing VCM ground circuits. Measure resistance between HO2S 1 low signal circuit and one of the VCM ground circuit terminals at VCM harness connector. 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 high resistance. After repairs, go to step 17 .
Repair HO2S 1 heater ignition feed or ground circuit. After repairs, go to step 17 .
Repair high resistance between HO2S 1 low signal circuit and VCM ground circuit. After repairs, go to step 17 .
Check for exhaust leaks upstream of HO2S 1. Repair as necessary. After repairs, go to step 17 . If no leaks are found, go to next step.
Allow engine to completely cool. Measure resistance between HO2S 1 low signal circuit and one of the VCM ground circuit terminals at VCM harness connector. 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 1. Clean threads and apply anti-seize compound, and then reinstall. Measure resistance between HO2S 1 low signal circuit and one of the VCM ground circuit terminals at VCM harness connector. 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 1. After repairs, go to step 17 .
Replace VCM. Program replacement VCM using required equipment. Perform Passlock® reprogramming and CKP system variation learn procedures. After repairs, go to next step.
Using scan tool, clear DTCs. Start engine and operate vehicle under conditions required to set this DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate 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.

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

With ignition on and engine off, HO2S voltage on scan tool should gradually decrease to less than.15 volt indicating heater is operating properly. If voltage does not decrease as specified, disconnect HO2S connector and connect a test light between HO2S connector terminals "C" and "D" (engine harness side). If test light illuminates, replace HO2S. If test light does not illuminate, repair open in HO2S heater ground circuit or HO2S ignition feed circuit.

Using scan tool, monitor signal voltage while wiggling HO2S related connectors and wiring harness with a warm engine running at part throttle in closed loop. If a failure is induced, signal voltage will change from normal fluctuating voltage of greater than.6 volt and less than.3 volt, to a fixed voltage of about.45 volt. A change in voltage will assist in isolating location of fault. DO NOT solder HO2S wires.

DTC P0134: HO2S CIRCUIT-INSUFFICIENT ACTIVITY-BANK 1, SENSOR 1 (4.8L, 5.3L & 6.0L "C" & "K" SERIES & 5.7L "F" & "Y" BODIES)

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

For duplication of DTC, ensure

DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0200, P0335, P0336, P0351-P0358 and P1258 are not set.
Ignition voltage is greater than 9 volts.
AIR, EGR and catalyst diagnostics are not active.
Fuel system is operating in closed loop.
Engine run time is greater than 70 seconds.

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
Start and warm engine to normal operating temperature. Increase engine speed to 1200 RPM for 2 minutes. Using scan tool, select ENGINE 1 and note HO2S 1 voltage. If voltage varies from less than 350 mV to greater than 550 mV, go to next step. If voltage does not vary as specified, go to step 4 .
Turn ignition on. Using scan tool, read and record FAILURE RECORDS data. Turn ignition off for 15 seconds. Start engine and operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0134 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0134 FAILED THIS IGN, see «DIAGNOSTIC AIDS»(/gmc/savana/i-1996-2002/remont/testing-diagnostics/#engine-control-system-tests-wcodes-dtc-p0100-p0134) .
Turn ignition on, with engine off. disconnect HO2S 1. Using jumper wires, jumper HO2S 1 high and low signal circuits to ground. Monitor HO2S 1 voltage with scan tool. If voltage is less than 200 mV, go to step 8 . If voltage is not less than 200 mV, go to next step.
Remove jumper wire from HO2S 1 low signal circuit. Measure voltage between ground and low signal circuit at HO2S 1 harness connector. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 7 .
Turn ignition off. Disconnect PCM harness connector C1. Check for continuity in HO2S 1 high signal circuit between HO2S 1 and PCM harness connectors. Repair open circuit if continuity is not present. After repairs, go to step 12 . If circuit is okay, go to step 10 .
Turn ignition off. Disconnect PCM harness connector C1. Check for continuity in HO2S 1 low signal circuit between HO2S 1 and PCM harness connectors. Repair open circuit if continuity is not present. After repairs, go to step 12 . If circuit is okay, go to step 10 .
Check HO2S 1 circuits for poor connections at HO2S 1 harness connector. Repair as necessary. After repairs, go to step 12 . If connections are okay, go to next step.
Replace HO2S 1. After repairs, go to step 12 .
Check HO2S 1 circuits for poor connections at PCM. Repair as necessary. After repairs, go to step 12 . If connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
Using scan tool, clear DTCs. Start engine and operate vehicle under conditions required to set this DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate 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.

Check for poor connection at PCM. Check for damaged wiring harness. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation. Ensure HO2S 1 is tight and properly installed.

See also:
• MAF SPECIFICATIONS
• CIRCUIT DESCRIPTION

Engine Control System - Tests W/codes - DTC p0100-p0134 GMC Savana I

MODEL IDENTIFICATION

DTC P0100: MAF SENSOR CIRCUIT (3.0L "V" BODY)

Circuit Description

Diagnostic Procedures

Diagnostic Aids

DTC P0101: MAF SYSTEM PERFORMANCE (3.0L "V" BODY)

DTC P0101: MAF SYSTEM PERFORMANCE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0101: MAF SYSTEM PERFORMANCE (3.5L "W" BODY & 4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0101: MAF SYSTEM PERFORMANCE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P0101: MAF SYSTEM PERFORMANCE (4.0L "G" BODY & 4.6L DEVILLE & ELDORADO)

DTC P0101: MAF SYSTEM PERFORMANCE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

DTC P0101: MAF SYSTEM PERFORMANCE (4.6L SEVILLE)

DTC P0101: MAF SYSTEM PERFORMANCE (5.7L "F" & "Y" BODIES)

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (3.5L "W" BODY)

DTC P0102: MAF SENSOR CIRCUIT-LOW-FREQUENCY (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0102: MAF SENSOR CIRCUIT-LOW FREQUENCY (5.7L "F" & "Y" BODIES)

DTC P0103: MAF SENSOR CIRCUIT-HIGH FREQUENCY (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0103: MAF SENSOR CIRCUIT-HIGH FREQUENCY (3.5L "W" BODY)

DTC P0103: MAF SENSOR CIRCUIT-HIGH FREQUENCY (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P0103: MAF SENSOR CIRCUIT-HIGH FREQUENCY (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0103: MAF SENSOR CIRCUIT-HIGH-FREQUENCY (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P","S" & "T" SERIES)

DTC P0103: MAF SENSOR CIRCUIT-HIGH-FREQUENCY (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0103: MAF SENSOR CIRCUIT-HIGH FREQUENCY (5.7L "F" & "Y" BODIES)

DTC P0105: MAP SENSOR CIRCUIT RANGE/PERFORMANCE (1.9L SATURN)

DTC P0105: MAP/TP SENSOR PERFORMANCE/RANGE (2.2L & 2.4L "J" BODY & 2.4L ALERO & GRAND AM "N" BODY)

DTC P0105: MAP/TP SENSOR PERFORMANCE/RANGE (2.2L "S" SERIES & CUTLASS & MALIBU 2.4L "N" BODY)

DTC P0105: MAP SENSOR CIRCUIT-INSUFFICIENT ACTIVITY (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0106: MAP SYSTEM PERFORMANCE (2.2L "J" BODY)

DTC P0106: MAP SYSTEM PERFORMANCE (2.4L "N" BODY)

DTC P0106: MAP SYSTEM PERFORMANCE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0106: MAP SYSTEM PERFORMANCE (4.3L, 5.0L & 5.7L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (1.9L SATURN)

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (2.2L "J" BODY & "S" SERIES & 2.4L "J" & "N" BODIES)

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (3.5L "W" BODY)

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0107: MAP SENSOR CIRCUIT-LOW VOLTAGE (5.7L "F" & "Y" BODIES)

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (1.9L SATURN)

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (2.2L "J" BODY, 2.2L "S" SERIES & 2.4L "J" & "N" BODIES)

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (3.5L "W" BODY)

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES TRUCKS)

DTC P0108: MAP SENSOR CIRCUIT-HIGH VOLTAGE (5.7L "F" & "Y" BODIES)

DTC P0110: IAT SENSOR CIRCUIT (3.0L "V" BODY)

DTC P0111: IAT SENSOR CIRCUIT PERFORMANCE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0112: IAT SENSOR CIRCUIT-HIGH TEMPERATURE (1.9L SATURN)

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (2.2L "J" BODY, 2.2L "S" SERIES & 2.4L "J" & "N" BODIES)

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (3.5L "W" BODY)

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (3.8L "C", "F", "G", "H" & "W" BODIES)

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

DTC P0112: IAT SENSOR CIRCUIT-LOW VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES & 5.7L "F" & "Y" BODIES)

DTC P0113: IAT SENSOR CIRCUIT-LOW TEMPERATURE (1.9L SATURN)

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (2.2L "J" BODY, 2.2L "S" SERIES & 2.4L "J" & "N" BODIES)

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (3.5L "W" BODY)

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (3.8L "C", "F", "G" & "H" BODIES)

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (3.8L "W" BODY)

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (4.3L, 5.0L, 5.7L & 7.4L "C", "G", "K", "L", "M", "P", "S" & "T" SERIES)

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (4.8L, 5.3L & 6.0L "C" & "K" SERIES)

DTC P0113: IAT SENSOR CIRCUIT-HIGH VOLTAGE (5.7L "F" & "Y" BODIES)

DTC P0115: ECT SENSOR CIRCUIT (3.0L "V" BODY)

DTC P0116: ECT SENSOR CIRCUIT PERFORMANCE (3.0L "V" BODY)

DTC P0116: ECT SENSOR CIRCUIT PERFORMANCE (4.0L "G" BODY & 4.6L "E" & "K" BODIES)

DTC P0117: ECT SENSOR CIRCUIT-HIGH TEMPERATURE (1.9L SATURN)

DTC P0117: ECT SENSOR CIRCUIT-LOW VOLTAGE (2.2L "J" BODY, 2.2L "S" SERIES & 2.4L "J" & "N" BODIES)

DTC P0117: ECT SENSOR CIRCUIT-LOW VOLTAGE (3.1L "N" & "W" BODIES & 3.4L "N" BODY & "U" SERIES)