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Engine Controls Self-Diagnostics - 3.1L & 3.4L: Other Chevrolet Malibu V facelift

Testing & Diagnostics 5 illustrations ~10571 words

Code Types

There are 3 types of DTC categories

  1. Type "A" Emissions related. Illuminates MIL the first time DTC sets.
  2. Type "B" Emissions related. Illuminates MIL if fault is active for 2 consecutive driving cycles.
  3. Type "C" Non-emissions related. Does not illuminate MIL, but will illuminate SERVICE light.

Freeze Frame/Failure Records

PCM stores one freeze frame record for the first failed test that sets a DTC and illuminates MIL. Freeze frame will not be overwritten unless a misfire or fuel trim DTC is set. Failure records are stored when any DTC is set. Some PCMs can store up to 5 failure records. Failure records will be stored for all types of codes, whether or not the MIL is illuminated.

Typical data includes

  1. Air/fuel ratio.
  2. Airflow rate.
  3. Fuel trim.
  4. Engine speed.
  5. Engine load.
  6. Engine coolant temperature.
  7. Vehicle speed.
  8. Throttle position angle.
  9. Manifold absolute pressure.
  10. Injector base pulse width.
  11. Loop status.

Monitors

  1. Comprehensive Component Monitor Monitors PCM systems for opens, shorts grounds and out-of-range sensors. Also monitors rationality of sensors. Rationality is whether the sensors value is consistent with the operating conditions of the other sensors.
  2. Misfire Monitor Monitors engine misfire using crankshaft sensor to determine location and severity of misfire. A catalyst damaging misfire will flash the MIL, and a non-catalyst damaging misfire is a normal type "B" code.
  3. Fuel Trim Monitor Monitors short and long term fuel trim for being at maximum lean or rich limit.
  4. Oxygen Sensor Monitor Monitors all oxygen sensors for maximum voltage level, minimum voltage level and lean rich/rich lean switching rate.
  5. Oxygen Sensor Heater Monitor Monitors oxygen sensor heater by watching sensor's time-to-activity after a cold start.
  6. Catalyst Monitor Monitors catalyst efficiency by comparing activity rate of precatalyst oxygen sensor and postcatalyst oxygen sensor.
  7. EVAP Monitor Monitors EVAP system for large leaks, small leaks and purge flow.

Duplicating Failure Conditions

Freeze frame and failure records data contain the conditions present when DTC set. Review and record freeze frame and failure records data. Clear DTCs using scan tool. Turn ignition off and wait 15 seconds. Operate the vehicle under the same conditions noted in freeze frame and failure records data, as closely as possible. Vehicle must also be operating within conditions for running the DTC. See CODE ENABLE CRITERIA in appropriate DTC test. Monitor DTC Status for the DTC being tested. The scan tool will indicate Ran, when the enabling conditions have been satisfied long enough for the DTC to run. The scan tool will also indicate whether the DTC passed or failed. An alternate method is to drive the vehicle with the DVOM connected to a suspected circuit. An abnormal reading on the DVOM when the problem occurs, may help you locate the problem.

Control Module & Component Power & Grounds

Many vehicles have multiple circuits supplying power to control modules. Other components may have separate power circuits that may also need to be tested. Check connections at module or component connectors, fuses, and any intermediate connections between power source and the module or component. Ensure that the circuit can carry the current necessary to operate the component. Test all control module ground and system ground circuits. Control module may have multiple ground circuits. Other components may have separate grounds that may also need to be tested. Check grounds for clean and tight connections at the ground connection. Check the connections at the component and in splice packs, where applicable. Ensure that the circuit can carry the current necessary to operate the component.

Temperature Sensitivity

An intermittent condition may occur when a component or connection reaches normal operating temperature. Condition may occur only when component or connection is cold, or hot. Use freeze frame and failure records, scan tool snapshot or vehicle data recorder to help diagnose this type of intermittent. If intermittent is related to heat, check for high ambient temperatures, underhood or engine generated heat, circuit generated heat due to a poor connection, or high electrical load. If intermittent is related to cold, check for low ambient temperatures or water intrusion.

Disconnect Battery

Note. On many OBD-II systems, PCM will retain memory for an extended period of time with battery disconnected. Memory may be retained for several days.

Disconnecting PCM power or battery ground will clear all PCM memory including DTCs, freeze frame, failure records, adaptive learning and system monitors.

Warm-up Cycles

If fault that caused DTC to set is repaired, PCM will begin to count warm-up cycles. After 40 consecutive warm-up cycles with no further faults, PCM will automatically clear DTC from memory.

POWERTRAIN CONTROL MODULE REPROGRAMMING

After replacing PCM or if program needs to be updated, refer to latest Techline information on PCM reprogramming. After reprogramming, perform CRANKSHAFT POSITION SENSOR SYSTEM VARIATION LEARN PROCEDURE , RESETTING GM OIL LIFE SYSTEM , INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE under INSPECTION/MAINTENANCE PROCEDURES and PROGRAMMING THEFT DETERRENT SYSTEM COMPONENTS .

CRANKSHAFT POSITION SENSOR SYSTEM VARIATION LEARN PROCEDURE

Crankshaft position system variation compensating values are stored in PCM non-volatile memory after a learn procedure has been performed. If actual crankshaft position system variation is not within crankshaft position system variation compensating values stored in PCM, DTC P0300 may set. See DIAGNOSTIC AIDS under DTC P0300: ENGINE MISFIRE DETECTED.

Crankshaft position system variation learn procedure should be performed if any of the following conditions are true

  1. DTC P1336 is set.
  2. PCM has been replaced.
  3. Engine has been replaced.
  4. Crankshaft has been replaced.
  5. Crankshaft harmonic balancer has been replaced.
  6. Crankshaft position sensor has been replaced.

Note. The scan tool crankshaft position system variation learn function will be inhibited if engine coolant temperature is less than 158°F (70°C). Allow engine to warm to at least 158°F (70°C) before attempting crankshaft position system variation learn procedure.

The scan tool crankshaft position system variation learn function will be inhibited if any powertrain DTCs other than DTC P1336 are set before or during the crankshaft position system variation learn procedure. Diagnose and repair any DTCs set.

The crankshaft position system variation learn function will be inhibited if PCM detects a malfunction involving the camshaft position signal circuit, the 3X reference circuit, or the 24X reference circuit. If a malfunction has been indicated, perform one of the following tests diagnose system or sensor

  1. «DTC P0336: CRANKSHAFT POSITION SENSOR CIRCUIT»(ref-125754-S05150490442001110800000)
  2. «DTC P0341: CAMSHAFT POSITION (CMP) SENSOR CIRCUIT»(ref-125754-S06687474812001101200000)
  3. «DTC P1374: CRANKSHAFT POSITION (CKP) HIGH-TO-LOW RESOLUTION FREQUENCY CORRELATION»(ref-125754-S08532857562001101200000)

The scan tool crankshaft position system variation learn function will not be enabled until engine coolant temperature reaches 158°F (70°C). Selecting crankshaft position system variation learn procedure on scan tool will command PCM to enable CKP system variation learn fuel cutoff and allow crankshaft position system variation compensating values to be stored in PCM. PCM must detect an engine speed of 5150 RPM during crankshaft position system variation learn procedure to store crankshaft position system variation compensating values and complete procedure.

WARNINGBlock drive wheels when performing the crankshaft position system variation learning procedure in order to prevent personal injury. Set vehicle parking brake when instructed by scan tool. Quickly increase accelerator pedal position until reaching wide open throttle and hold. During learn procedure, PCM will automatically control injector operation. When engine has reached a certain RPM, PCM will stop fuel injectors from pulsing until learn procedure is finished. When PCM has learned the crankshaft variation, fuel injectors will return to normal operation and engine will begin to accelerate again. Release throttle when engine reaches the second fuel cutoff. Leaving the throttle open during the fuel cutoff learn procedure will allow the engine to decelerate at an even rate.
  1. Block drive wheels.
  2. Ensure hood is closed.
  3. Start engine and allow engine coolant temperature to reach at least 158° F (70°C).
  4. Turn ignition off.
  5. Using scan tool, select and enable CRANKSHAFT POSITION SYSTEM VARIATION LEARN PROCEDURE.
  6. Set parking brake when instructed by scan tool.
  7. Start engine.
  8. Press and hold brake pedal firmly.
  9. Ensure transaxle is in Park.
  10. Slowly depress accelerator pedal until fuel cutoff is reached at 5150 and hold. Release accelerator pedal after second fuel cutoff has been reached.
  11. Crankshaft position system variation compensating values are learned when engine RPM decreases back to idle.
  12. Using scan tool, observe DTC status for DTC P1336.
  13. If scan tool indicates that DTC P1336 ran and passed, crankshaft position system variation learn procedure is complete. If scan tool indicates that DTC P1336 failed or did not run, check for other DTCs. If no other DTCs are set, repeat crankshaft position system variation learn procedure as necessary.

With Driver Information Center

Press MODE button until light appears on Driver Information Center (DIC). Press and hold RESET button for 3 seconds. Oil life percentage should change to 100 percent.

Without Driver Information Center

Turn ignition on. Fully press and release accelerator pedal slowly 3 times within 5 seconds. If CHANGE OIL SOON light flashes, system is resetting. Turn ignition off. Start engine. Oil life will change to 100 percent. If CHANGE OIL SOON light comes back on, system has not reset. Repeat procedure.

PROGRAMMING THEFT DETERRENT SYSTEM COMPONENTS

If replacing a PCM with a replacement part, after programming, these modules will learn incoming fuel continue password immediately upon receipt of a password message. Once a password message is received and a password is learned, a learn procedure must be performed to change this password again. A PCM which has been previously installed in another vehicle will have learned the other vehicle's fuel continue password and will require a learn procedure after programming to learn current vehicle's password.

  1. Turn ignition on, engine off.
  2. Attempt to start engine, then release key to ON position (vehicle will not start).
  3. Observe SECURITY telltale, after approximately 10 minutes telltale will turn off.
  4. Turn ignition off and wait 5 seconds.
  5. Repeat steps 1 through 4 2 more times for a total of 3 cycles in 30 minutes. Vehicle is now ready to relearn Passlock™ sensor data code and/or passwords on next ignition switch transition from OFF to CRANK position.
  6. Start engine. Vehicle has now learned Passlock™ sensor data code and/or password.
  7. Using scan tool, clear any DTCs if needed.

DRIVE CYCLES

See INSPECTION/MAINTENANCE SYSTEM CHECK .

Procedure

  1. Perform «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM. If DTC or driveability problems were repaired using powertrain diagnostic system check, go to step 3 . If no DTC or driveability problems were repaired using powertrain diagnostic system check, go to next step.
  2. Check for applicable Technical Service Bulletins (TSB) for software updates that may prevent Inspection/Maintenance (I/M) readiness. Perform any reprogramming or repairs indicated by TSBs. If reprogramming or repair service was required, see «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-125754-S27378901382002011800000) . If reprogramming or repair service is not required, go to next step.
  3. Using scan tool, observe I/M SYSTEM STATUS display. If more than one test indicates a NO status, see «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-125754-S27378901382002011800000) . If only one test indicates a NO status, go to appropriate I/M system set procedure for indicated system.

Enable Criteria

  1. Barometric Pressure (BARO) is more than 65 kPa.
  2. Engine Coolant Temperature (ECT) is less than 86°F (30°C).
  3. Intake Air Temperature (IAT) is less than 90°F (32°C).
  4. Difference between IAT and ECT is less than 7°F.
  5. Battery voltage is 10-18 volts.
  6. Fuel level is 1/4-3/4.
  1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-125754-S12473422642002011800000) . After performing inspection/maintenance system check, go to next step.
  2. Preprogram scan tool with vehicle information before ignition is turned on. Ensure vehicle meets conditions under «ENABLE CRITERIA»(ref-125754-S00876019412002011800000) . Turn off all accessories, such as A/C, blower fan, etc. Set vehicle parking brake. Ensure transmission is in Park. Start engine. Allow engine to idle for 2 minutes. Go to next step.
  3. Accelerate at part throttle to 55 MPH with this speed maintained until engine reaches operating temperature. This may be up to 8-10 minutes depending on start-up coolant temperature. Continue operation under these conditions for an additional 6 minutes. Go to next step.
  4. Reduce vehicle speed to 45 MPH with this speed maintained for one additional minute. Perform 4 decelerations of 25 seconds each from 45 MPH while the following criteria is maintained: Throttle is closed. No brake application on either M/T or A/T. No clutch actuation on M/T. No manual downshift. Vehicle speed remains more than 25 MPH. After each deceleration period, vehicle is returned to 45 MPH under part throttle acceleration and speed is maintained for 15 seconds. When complete, go to next step.
  5. Accelerate at part throttle to 45-55 MPH. Maintain this speed for 2 minutes. Decelerate to zero MPH. Allow engine to idle for 2 minutes while the following criteria is maintained: Service brake depressed. A/T in Drive. M/T in neutral with clutch pedal depressed. When complete, go to next step.
  6. Using scan tool, observe I/M SYSTEM STATUS display. If all I/M SYSTEM STATUS indicators update to YES, go to next step. If all I/M SYSTEM STATUS indicators do not update to YES, see INSPECTION/MAINTENANCE SET PROCEDURE for indicated systems.
  7. Using scan tool, observe emission related DTC portion of I/M SYSTEM STATUS display. If scan tool indicates any emission related DTCs, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate emission related DTCs, system is okay.
  1. Barometric Pressure (BARO) is more than 65 kPa.
  2. Engine coolant is 203-212°F (95-100°C).
  3. Intake Air Temperature (IAT) is 59-167°F (-15-75°C).
  4. Engine is in closed loop.
  5. Engine has run for 6-8 minutes off idle.
  6. Battery voltage is 10-18 volts.
  1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-125754-S12473422642002011800000) . After performing inspection/maintenance system check, go to next step.
  2. Ensure vehicle is operating within enable criteria. Turn all accessories off. Start engine and allow to idle. Operate vehicle in the following manor: Accelerate at part throttle to 55 MPH and maintain speed for 5 minutes. Decelerate to zero MPH and allow engine to idle for 2 minutes while service brake is depressed, A/T in Drive and M/T in neutral with clutch pedal depressed. Using scan tool, monitor I/M SYSTEM STATUS. If CATALYST SYSTEM STATUS is YES, go to step 5 . If CATALYST SYSTEM STATUS is not YES, go to next step.
  3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate any failed DTCs, go to next step.
  4. Using scan tool, monitor DTC P0420. Operate vehicle within code enable criteria for DTC P0420. See «DTC P0420: CATALYST SYSTEM LOW EFFICIENCY»(ref-125754-S09069843022001101200000) under DIAGNOSTIC TESTS. Operate vehicle within code enable criteria until scan tool indicates diagnostic test has run. Using scan tool, observe I/M SYSTEM STATUS. If catalyst system status is YES, go to next step. If catalyst system status is not YES, see «DIAGNOSTIC AIDS»(ref-125754-S04914265992002011800000) .
  5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate any DTCs are set, system is okay.
  1. Barometric Pressure (BARO) is more than 65 kPa.
  2. Engine Coolant Temperature (ECT) is 176-230°F (80-110°C).
  3. Intake Air Temperature (IAT) is less than 149°F (65°C).
  1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-125754-S12473422642002011800000) . After performing inspection/maintenance system check, go to next step.
  2. Ensure vehicle is within enable criteria. Turn off all of accessories. Start engine and allow to idle. Accelerate at part throttle to 45 MPH and maintain speed for one minute. Perform 4 decelerations of 25 seconds each from 45 MPH while following criteria is maintained: Throttle is closed No brake application on either manual or automatic transmission No clutch actuation on a manual transmission No manual downshift Vehicle speed remains more than 25 MPH. After each deceleration period, vehicle is returned to 45 MPH under part throttle acceleration and speed is maintained for 15 seconds. Using scan tool, observe I/M SYSTEM STATUS display. If EGR system status updates to YES, go to step 5 . If EGR system status did not update to YES, go to next step.
  3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate any failed DTCs, go to next step.
  4. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine if DTCs P0401, P0404, P0405 and P1404 have run. For those DTCs that have not run, see CODE ENABLE CRITERIA in appropriate DTC under DIAGNOSTIC TESTS. Operate vehicle to meet code enable criteria until DTC(s) runs. Using scan tool, observe I/M SYSTEM STATUS display. If EGR system status updated to YES, go to next step. If EVAP system status did not update to YES, see «DIAGNOSTIC AIDS»(ref-125754-S03590206302002011800000) .
  5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate any DTCs are set, system is okay.

Non Scan Tool Service Bay Test

  1. Barometric Pressure (BARO) is more than 75 kPa.
  2. Fuel level is 15-85 percent.
  3. Battery voltage is 10-18 volts.
  4. Engine Coolant Temperature (ECT) is 39-86°F (4-30°C).
  5. Intake Air Temperature (IAT) is 39-86°F (4-30°C).
  6. Difference between ECT and IAT is less than 14°F (8°C).

Scan Tool Service Bay Test

  1. BARO is more than 65 kPa.
  2. Engine Coolant Temperature (ECT) is less than 158°F (70°C).
  3. Fuel level is 25-75 percent.
  4. Battery voltage is 10-18 volts.
  1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-125754-S12473422642002011800000) . After performing inspection/maintenance system check, go to next step.
  2. Using scan tool, select SPECIAL FUNCTIONS. Determine if vehicle is equipped with a Service Bay Test for EVAP system. If vehicle is equipped with EVAP Service Bay Test, go to next step. If vehicle is not equipped with EVAP Service Bay Test, go to step 5 .
  3. Ensure vehicle is within enable criteria. Turn off all accessories. Following directions on scan tool, perform EVAP Service Bay Test. If EVAP system passed Service Bay Test, go to step 8 . If EVAP system did not pass Service Bay Test, go to next step.
  4. Observe scan tool Service Bay Test for an indication of why test did not pass (e.g., failed DTC, test aborted, etc.). Refer to appropriate service information for diagnosis and repair of condition as necessary. After repairs, see «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-125754-S27378901382002011800000) .
  5. Ensure vehicle is within enable criteria. Turn off all of accessories. Once engine is started, DO NOT turn engine off for remainder of procedure until test is complete. Start and idle engine. Operate vehicle in following manner: Accelerate at part throttle to 45 MPH. Maintain speed until engine reaches operating temperature (may be up to 8-10 minutes). Continue operating conditions for an additional 3 minutes after engine reaches operating temperature, or until I/M SYSTEM STATUS indicator updates to YES. If EVAP SYSTEM STATUS updates to YES, go to step 8 . If EVAP SYSTEM STATUS does not update to YES, go to next step.
  6. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate any failed DTCs, go to next step.
  7. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine if DTCs P0440, P0442, P0446 and P1441 have run. For those DTCs that have not run, see CODE ENABLE CRITERIA in appropriate DTC under DIAGNOSTIC TESTS. Operate vehicle to meet code enable criteria until DTC(s) runs. Using scan tool, observe I/M SYSTEM STATUS display. If EVAP SYSTEM STATUS updated to YES, go to next step. If EVAP SYSTEM STATUS did not update to YES, see «DIAGNOSTIC AIDS»(ref-125754-S15996485412002011800000) .
  8. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate any DTCs are set, system is okay.
  1. Engine Coolant Temperature (ECT) is more than 176°F (80°C).
  2. Engine is running in closed loop.
  3. Engine has been running for more than 4 minutes.
  4. Battery voltage is 10-18 volts.
  1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-125754-S12473422642002011800000) . After performing inspection/maintenance system check, go to next step.
  2. Verify vehicle is within enable criteria. Turn off all accessories. Start and idle engine. Accelerate at part throttle to 45-55 MPH. Maintain this speed for 6 minutes or until I/M SYSTEM STATUS updates to YES. M/T may require operation in 4th or 5th gear. Using scan tool, review I/M SYSTEM STATUS display. If HO2S SYSTEM STATUS update to YES, go to step 5 . If HO2S SYSTEM STATUS does not update to YES, go to next step.
  3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate any failed DTCs, go to next step.
  4. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine if DTCs P0133, P0140, P1133 and P1134 have run. For those DTCs that have not run, see CODE ENABLE CRITERIA in appropriate DTC under DIAGNOSTIC TESTS. Operate vehicle to meet code enable criteria until DTC(s) runs. Using scan tool, observe I/M SYSTEM STATUS display. If HO2S SYSTEM STATUS updated to YES, go to next step. If HO2S SYSTEM STATUS did not update to YES, see «DIAGNOSTIC AIDS»(ref-125754-S35457284412002011800000) .
  5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate any DTCs are set, system is okay.
  1. Engine Coolant Temperature (ECT) is less than 90°F (32°C).
  2. Intake Air Temperature (IAT) is less than 90°F (32°C).
  3. Difference between IAT and ECT is less than 7°F.
  4. Battery voltage is 10-18 volts.
  1. Perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-125754-S12473422642002011800000) . After performing inspection/maintenance system check, go to next step.
  2. Preprogram scan tool with vehicle information before ignition is turned on. Verify vehicle is within enable criteria. Set vehicle parking brake. Ensure transmission is in Park or Neutral. Turn off all of accessories. Start the engine. Allow engine to idle for 2 minutes or until I/M SYSTEM STATUS indicator updates to YES. Using scan tool, observe I/M SYSTEM STATUS display. If HO2S HEATER SYSTEM STATUS updated to YES, go to step 5 . If HO2S HEATER SYSTEM STATUS did not update to YES, go to next step.
  3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate any failed DTCs, go to next step.
  4. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine if DTCs P0135 and P0141 have run. For those DTCs that have not run, see CODE ENABLE CRITERIA in appropriate DTC under DIAGNOSTIC TESTS. Operate vehicle to meet code enable criteria until DTC(s) runs. Using scan tool, observe I/M SYSTEM STATUS display. If HO2S HEATER SYSTEM STATUS updated to YES, go to next step. If HO2S HEATER SYSTEM STATUS did not update to YES, see «DIAGNOSTIC AIDS»(ref-125754-S26209054922002011800000) .
  5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If scan tool does not indicate any DTCs are set, system is okay.

SUMMARY

If no Diagnostic Trouble Codes (DTC) are present and a no-start condition exists, proceed to appropriate BASIC DIAGNOSTIC PROCEDURES article. If no DTCs are present and a driveability condition exists, proceed to appropriate TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).

MIL Inoperative

  1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
  2. Attempt to start engine. If engine starts, go to next step. If engine does not start, go to step 9.
  3. Check fuse that supplies voltage to MIL. See «MIL SUPPLY VOLTAGE CIRCUIT IDENTIFICATION»(ref-125754-S06756030932002012600000) table. If fuse is open, go to step 7. If fuse is okay, go to next step.
  4. Turn ignition off. Disconnect PCM harness connectors. See «PCM LOCATION»(ref-125754-S10257283102002012300000). Turn ignition on. Connect fused jumper wire between ground and PCM harness connector C2 terminal No. 5 (Brown/White wire). (Scheme 20)or (Scheme 21). Observe MIL. If MIL illuminates, go to step 15. If MIL does not illuminate, go to next step.
  5. Turn ignition off. Remove Instrument Panel Cluster (IPC). See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Turn ignition on. Connect a test light between ground and appropriate IPC harness connector terminal. See «MIL SUPPLY VOLTAGE CIRCUIT IDENTIFICATION»(ref-125754-S06756030932002012600000) table. If test light illuminates, go to next step. If test light does not illuminate, go to step 8.
  6. Check for open or high resistance in Brown/White wire between PCM harness connector C2 terminal No. 46 and appropriate IPC harness connector terminal. See «MIL CONTROL CIRCUIT IDENTIFICATION»(ref-125754-S07014015362002012600000) table. Repair circuit as necessary, then perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM. If circuit is okay, go to step 14.
  7. Repair short to ground in MIL supply voltage circuit. After repair, perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM.
  8. Repair open in MIL supply voltage circuit. After repair, perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM.
  9. Check PCM fuse and ignition 1 main fuse. See WIRING DIAGRAMS article. If either fuse is open, go to step 12. If both fuses are okay, go to next step.
  10. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Connect a test light between ground and all ignition positive circuits. See WIRING DIAGRAMS article. If test light illuminates on all ignition positive circuits, go to next step. If test light does not illuminate on all ignition positive circuits, go to step 12.
  11. Connect test light between ground and PCM harness connector C1 terminal No. 20 (Orange wire). (Scheme 20)or (Scheme 21). If test light illuminates, go to step 13. If test light does not illuminate, go to next step.
  12. Repair open or short to ground in Orange wire or in ignition feed circuits. See WIRING DIAGRAMS article. After repairs, perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM.
  13. Check for a poor PCM ground or a poor PCM ground connection. See WIRING DIAGRAMS article. If a problem is found, repair as necessary, then perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM. If a problem is not found, go to step 15.
  14. Check for poor connections at IPC. If a problem is found, repair as necessary, then perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM. If a problem is not found, go to step 16.
  15. Check for poor connections at PCM. If a problem is found, repair as necessary, then perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM. If a problem is not found, go to step 17.
  16. Replace IPC. After repair, perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM.
  17. Replace PCM. After repair, perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM.
ApplicationFuse(1) IPC Connector Terminal (Wire Color)
Alero(2) IPC/BFC ACC (10-Amp)A2 (Purple)
Century(3) CLUSTER (10-Amp)B12 (Pink)
Grand Am(2) IPC/BFC ACC (10-Amp)A8 (Purple)
Grand Prix(3) I/P-IGN (10-Amp)Connector C2 Terminal "I" (Pink)
Impala & Monte Carlo(2) PCM, BCM/CLSTR (10-Amp)A8 (Purple)
Malibu(2) IPC/BFC ACC (10-Amp)B9 (Purple)
(1) (Scheme 22), (Scheme 23) or (Scheme 24). (2) Located in left instrument panel fuse block. (3) Located in instrument panel fuse block.
(2)Located in left instrument panel fuse block.
(3)Located in instrument panel fuse block.

MIL SUPPLY VOLTAGE CIRCUIT IDENTIFICATION

Application(1) IPC Connector Terminal
AleroB8
CenturyB5
Grand AmB6
Grand PrixConnector C1 Terminal "N"
Impala & Monte CarloB2
MalibuB11
(1) (Scheme 22), (Scheme 23) or (Scheme 24).

MIL CONTROL CIRCUIT IDENTIFICATION

Scheme 20

Scheme 20
Scheme 20

Scheme 21

Scheme 21
Scheme 21

Scheme 22

Scheme 22
Scheme 22

Scheme 23

Scheme 23
Scheme 23

Scheme 24

Scheme 24
Scheme 24

MIL Always On

  1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
  2. Using scan tool, check for DTCs. If any DTCs are set, perform appropriate test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-125754-S20756478142001101200000) . If no DTCs are set, go to next step.
  3. Turn ignition off. Observe MIL. If MIL is on, go to step 6 . If MIL is off, go to next step.
  4. Turn ignition on. Using scan tool, command MIL on and off several times. If MIL turns on and off with each command, no problem is indicated at this time. If MIL does not turn on and off with each command, go to next step.
  5. Repair short to ground in MIL control circuit (Brown/White wire) between PCM harness connector C2 terminal No. 46 and appropriate IPC harness connector terminal. See «MIL CONTROL CIRCUIT IDENTIFICATION»(ref-125754-S07014015362002012600000) table. After repairs, go to step 7 .
  6. Repair short to voltage in MIL control circuit (Brown/White wire) between PCM harness connector C2 terminal No. 46 and appropriate IPC harness connector terminal. See «MIL CONTROL CIRCUIT IDENTIFICATION»(ref-125754-S07014015362002012600000) table. After repairs, go to next step.
  7. Turn ignition on. Using scan tool, command MIL on and off several times. If MIL turns on and off with each command, perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-125754-S07490526332001101200000) under SELF-DIAGNOSTIC SYSTEM. If MIL does not turn on and off with each command, go to step 2 .

Code Enable Criteria

PCM will run diagnostic for this DTC when engine is running. DTC P0300 will set when PCM detects that HO2S heater control circuit current is greater than the capacity of PCM internal driver for more than 20 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0102, P0103, P0107, P0108, P0121, P0122, P0123, P0401, P0404, P0405, P0440, P0442, P0446, P1404, or P1441 are not set.
  2. Engine is running.
  3. Ignition 1 signal voltage is 9-18 volts.
  4. TP sensor angle is no more than 25 percent.
  5. TP sensor is steady for more than 1.5 seconds.
  6. MAP sensor value is no more than 63 kPa.
  7. MAP sensor is steady for more than 3 seconds.

DTC will set when actual MAF sensor signal is not within a predetermined range of calculated MAF value.

PCM will run diagnostic for this DTC under the following conditions

  1. Engine is running.
  2. IAC position parameter more than 2 counts.
  3. System voltage is greater than 8 volts.

DTC will set when MAF signal frequency is less than 1200 Hz for more than .5 second.

PCM will run diagnostic for this DTC under the following conditions

  1. Engine is running.
  2. IAC position parameter is more than 2 counts.
  3. System voltage is greater than 8 volts.

DTC will set when MAF signal frequency is more than 11,500 Hz for more than .5 second.

PCM will run diagnostic for this DTC under the following conditions

  1. DTC P0121, P0122, or P0123 are not set.
  2. Engine is running.
  3. Throttle angle is more than zero percent if engine speed is less than 1000 RPM.

DTC will set when MAP sensor signal voltage is less than 0.1 volt (12 kPa) for more than 67 crankshaft revolutions.

PCM will run diagnostic for this DTC under the following conditions

  1. DTC P0121, P0122 or P0123 are not set.
  2. Engine has been running for a length of time that is determined by start-up engine coolant temperature. Length of time ranges from 2 minutes at less than 86°F (30°C) to one second at more than 86°F (30°C).
  3. Throttle angle is less than 2 percent if engine speed is less than 3000 RPM.
  4. Throttle angle is less than 30 percent if engine speed is more than 3000 RPM.

DTC will set when MAP sensor signal voltage is more than 4.3 volts for more than 67 crankshaft revolutions.

PCM will run diagnostic for this DTC under the following conditions

  1. DTC P0101, P0102, P0103, P0117, P0118, P0125, P0128, P0502, P0503, P1114 or P1115 are not set.
  2. Engine has been running for more than 10 seconds.
  3. Vehicle speed is more than 25 MPH.

DTC will set when IAT signal voltage indicates intake air temperature is more than 275°F (135°C) for 20 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTC P0101, P0102, P0103, P0117, P0118, P0125, P0128, P0502, P0503, P1114 or P1115 are not set.
  2. Vehicle speed is less than 35 MPH.
  3. Mass Airflow (MAF) value is less than 12 grams per second.
  4. Engine coolant temperature is more than 140°F (60°C).
  5. Engine run time more than 3 minutes.
  6. IAT signal voltage indicates an intake air temperature less than -35°F (-37°C).
  7. Conditions present for at least 20 seconds.

DTC will set when IAT signal voltage indicates intake air temperature is less than -35°F (-37°C) for 20 seconds.

PCM will run diagnostic for this DTC when engine is running. DTC will set when ECT sensor circuit indicates an engine coolant temperature of more than 283°F (140°C). Condition must be present for more than 15 seconds.

PCM will run diagnostic for this DTC when engine is running. DTC will set when ECT sensor circuit indicates an engine coolant temperature of less than -36°F (-38°C). Condition must be present for more than 15 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTC P0107, P0108, P0122, P0123, P1106, P1107, P1121, or P1122 are not set.
  2. Engine has been running longer than 2 minutes.
  3. Engine coolant temperature is more than 167°F (75°C).
  4. MAP reading is less than 50 kPa for a TP sensor skewed high test, or more than 70 kPa for a TP sensor skewed low test.
  5. MAP reading is steady for at least 5 seconds.

DTC P0121 will set when

  1. TP sensor reading is more than predicted value when MAP is less than 50 kPa.
  2. TP sensor reading is less than predicted value when MAP is more than 70 kPa.
  3. Conditions are present for 5 seconds.

PCM will run diagnostic for this DTC when ignition is on. DTC P0122 will set when TP sensor signal voltage is less than .1 volts for more than one second.

PCM will run diagnostic for this DTC when ignition is on. DTC P0123 will set when TP sensor signal voltage is more than 4.9 volts for longer than one second.

PCM will run diagnostic for this DTC under the following conditions

  1. This diagnostic will only run once per ignition cycle within enabling conditions.
  2. DTCs P0112, P0113, P0117, P0118, P1111, P1112, P1114 or P1115 are not set.
  3. Minimum air temperature is more than 19°F (-7°C).
  4. Start up engine coolant temperature is less than 104°F (40°C).
  5. In region 1, air temperature is more than 50°F (10°C) and start-up coolant temperature is more than 14°F (-10°C).
  6. In region 2, air temperature is more than 19°F (-7°C) and start-up coolant temperature is 19-50°F (-7 to 10°C).
  7. In region 3, air temperature is more than 19°F (-7°C) and start-up coolant temperature is 19-50°F (-7 to 10°C).

In region 1, DTC will set when the following conditions exist

  1. Engine run time is more than 6 seconds to achieve closed loop temperature of 14°F (-10°C).
  2. Calibrated minimum amount of air flow has been exceeded.
  3. Maximum idle time has been less than 5 seconds.

In region 2, DTC will set when the following conditions exist

  1. Engine run time is more than 154 seconds to achieve closed loop temperature of 14°F (-10°C).
  2. Calibrated minimum amount of air flow has been exceeded.
  3. Maximum idle time has been less than 120 seconds.

In region 3, DTC will set when the following conditions exist

  1. Engine run time is more than 287 seconds to achieve closed loop temperature of 14°F (-10°C).
  2. Calibrated minimum amount of air flow has been exceeded.
  3. Maximum idle time has been less than 225 seconds.

Diagnostic will only run once per ignition cycle under the following enabling conditions

  1. DTCs P0112, P0113, P0117, P0118, P1111, P1112, P1114, or P1115 are not set.
  2. Engine coolant temperature is more than -40 to 172°F (-40 to -7°C).
  3. Air temperature is more than 19°F (-7°C).
  4. Engine has been running for more than 2 minutes and less than 30 minutes.
  5. Vehicle speed has been more than 15 mph for more than one mile.
  6. Mass airflow average reading is more than 15 grams per second.

DTC P0128 will set when length of time for engine coolant to reach a preset temperature has been exceeded.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201-P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
  2. Engine has been running for at least 4 minutes.
  3. Engine coolant temperature is at least 158°F (70°C).
  4. Engine RPM is 550-3000 RPM.
  5. Mass airflow is 8-35 grams per second.
  6. Throttle angle is 3-35 percent.
  7. Ignition voltage is 9-18 volts.

DTC will set when PCM detects an active HO2S with an improper voltage amplitude.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201-P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
  2. System voltage is more than 9 volts.
  3. Closed loop commanded air/fuel ratio is 12:1-16.5:1.
  4. Throttle angle is 3-35 percent.

DTC will set when HO2S 1 signal voltage remains less than 175 mV during normal closed loop operation, or HO2S 1 signal voltage remains less than 600 mV during power enrichment mode fuel control operation. Either condition must be present for 50 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201-P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
  2. System voltage is more than 9 volts.
  3. Closed loop commanded air/fuel ratio is 12:1-16.5:1.
  4. Throttle angle is 3-35 percent.

DTC will set when HO2S 1 signal voltage remains more than 975 mV during normal closed loop operation, or HO2S 1 signal voltage remains more than 200 mV during deceleration fuel mode operation. Either of these conditions must be present for 50 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201- P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
  2. Transmission is not in Park or Neutral.
  3. Engine has been running for at least 4 minutes.
  4. Mass airflow is 8-35 grams per second.
  5. Engine speed is 550-3000 RPM.
  6. Throttle angle is 3-35 percent.
  7. System voltage is 9-18 volts.
  8. Engine coolant temperature is more than 158°F (70°C).

DTC will set when HO2S 1 lean to rich average transition response time was more than 95 milliseconds, or HO2S 1 rich to lean average transition response time was more than 105 milliseconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTC P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201- P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
  2. Engine has been running for at least 4 minutes.
  3. Ignition voltage is 90-18 volts.

DTC will set when HO2S 1 signal voltage remains between 408-512 mV for more than 30 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201- P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
  2. System voltage more than 9 volts and less than 18 volts.
  3. Engine run time more than 4 minutes.
  4. Engine coolant temperature more than 158°F (70°C).
  5. Engine speed is 650-2500 RPM.
  6. Airflow is 4-26 grams per second.

DTC will set when HO2S 1 heater current is not within calibrated range.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201- P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
  2. Closed loop commanded air/fuel ratio is 12:1-16.5:1.
  3. Throttle angle is 3-40 percent.

DTC will set when HO2S 2 signal voltage remains less than 30 mV during normal closed loop operation, or HO2S 2 signal voltage remains less than 550 mV during power enrichment mode fuel control operation. Either condition must be present for up to 2.5 minutes.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
  2. Closed loop commanded air/fuel ratio is 12:1-16.5:1.
  3. Throttle angle is 3-40 percent.

DTC will set when HO2S 2 signal voltage remains more than 999 mV during normal closed loop operation, or HO2S 2 signal voltage remains more than 200 mV during deceleration fuel mode operation.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
  2. Engine has been running for at least 4 minutes.
  3. System voltage should be 9-18 volts.
  4. This test only runs once per trip.
  5. TP sensor change of more than 8 percent occurs at least twice during test.

DTC will set when HO2S 2 signal voltage remains between 412 and 500 mV for 90 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTC P0101, P0102, P0103, P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449, or P1441 are not set.
  2. System voltage is 9-18 volts.
  3. Intake Air Temperature (IAT) and Engine Coolant Temperature (ECT) are less than 95°F (35°C) at start-up.
  4. IAT and ECT are within 10°F of each other at start-up.

DTC will set when HO2S 2 voltage remains within 150 mV of bias voltage (about 450 mV) for a longer time than it should. The time ranges from 100 to 130 seconds, depending on engine coolant temperature at start-up and average airflow since start-up.

PCM will run diagnostic for this DTC under the following conditions

  1. DTC P0101, P0102, P0103, P0107, P0108, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0401, P0403, P0404, P0405, P0410, P0440, P0442, P0446, P0506, P0507, P1404, or P1441 are not set.
  2. Engine Coolant Temperature (ECT) is 68-230°F (20-110°C).
  3. Intake Air Temperature (IAT) is 64-158°F (18-70°C).
  4. Manifold Absolute Pressure (MAP) is 2.1-15.2 psi (15-105 kPa).
  5. Vehicle speed is less than 82 MPH.
  6. Engine speed is 550-4000 RPM.
  7. Barometric Pressure (BARO) is more than 10.1 psi (70 kPa).
  8. Mass Airflow (MAF) is 2.8-150.0 grams per second.
  9. Fuel level is more than 10 percent.

DTC will set when average long term fuel trim value is more than 20 percent and all of the above conditions are present for 6 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTC P0101, P0102, P0103, P0107, P0108, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0120, P0122, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0401, P0403, P0404, P0405, P0410, P0412, P0418, P0440, P0442, P0446, P0506, P0507, P1404 or P1441 are not set.
  2. Engine Coolant Temperature (ECT) is 68-230°F (20-110°C).
  3. Intake Air Temperature (IAT) is 64-158°F (18-70°C).
  4. Manifold Absolute Pressure (MAP) is 2.1-15.2 psi (15-105 kPa).
  5. Vehicle speed is less than 82 MPH.
  6. Engine speed is 550-4000 RPM.
  7. Barometric pressure is more than 10.1 psi (70 kPa).
  8. Mass Airflow (MAF) is 2.8-150.0 grams per second.
  9. Fuel level is more than 10 percent.

DTC will set when average long term fuel trim value is less than -13 percent for 40 seconds.

PCM will run diagnostic for these DTCs under the following conditions

  1. Engine is running.
  2. Ignition voltage is 9-18 volts.

DTC will set when PCM detects an incorrect voltage on injector control circuit for 30 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. Ignition is on.
  2. System voltage is 9-18 volts.

DTC will set when PCM detects an incorrect voltage on fuel pump relay control circuit for less than one second.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0117, P0118, P0121, P0122, P0123, P0125, P0336, P0341, P0502, P0503, P1106, P1107, P1114, P1115, P1121, P1122, P1336, P1351, P1352, P1361, P1362, or P1374 are not set.
  2. Engine speed is 525-5900 RPM.
  3. System voltage is 9-18 volts.
  4. Engine coolant temperature is 21-255°F (-7-125°C).
  5. Throttle angle is steady.

DTC will set when The PCM is detecting a crankshaft rotation speed variation indicating a misfire rate sufficient to cause emissions levels to exceed mandated standard.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0117, P0118, P0121, P0122, P0123, P0125, P0336, P1114, P1115, P1121, P1122 P1336 are not set.
  2. Engine speed is 1000-5000 RPM.
  3. Throttle angle is more than 15 percent.
  4. Engine load is more than 40 percent.
  5. Engine coolant temperature is more than 153°F (60°C).
  6. Maximum spark retard is less than 15 degrees.
  7. System voltage is more than 9 volts.
  8. Engine run time is more than 30 seconds.

DTC will set when PCM detects a malfunction in integrated knock sensor diagnostic circuitry which will not allow proper diagnosis of knock sensor circuit for at least one second.

PCM will run diagnostic for this DTC under the following conditions

  1. DTC P0112, P0113, P0121, P0122, P0123, P0341, P0336, P0506 or P0507 are not set.
  2. Engine speed is 1000-5000 RPM.
  3. Engine has been running for a minimum of 30 seconds.
  4. Throttle angle is more than 15 percent.
  5. Engine load is more than 40 percent.
  6. Engine coolant temperature is more than 153°F (60°C).
  7. Maximum spark retard is less than 15 degrees.
  8. System voltage is more than 9 volts.

DTC will set when PCM detects a KS signal voltage within calculated average voltage range for at least 10 seconds.

PCM will run diagnostic for this DTC when engine is running and 3X reference pulses are being received for a minimum of 3 seconds. DTC P0336 will set when ratio of 24X reference pulses to 3X reference pulses received by PCM is incorrect.

PCM will run diagnostic for this DTC when engine is running (3X reference pulses are being received). DTC will set when CMP sensor reference pulse is not detected on every engine cycle.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0201-P0206, P0300, P0336, P0403, P0404, P0502, P0503, P0506, P0507, P1106, P1107, P1111, P1112, P1114, P1115. P1121, P1122, P1374 or P1404 are not set.
  2. System voltage is 10-18 volts.
  3. A/C status does not change.
  4. Transaxle range does not change.
  5. Throttle angle is less than one percent (deceleration).
  6. Intake air temperature is more than 176°F (80°C).
  7. Engine coolant temperature is more than 167°F (75°C).
  8. Engine speed is 1050-1300 RPM.
  9. Idle Air Control (IAC) position is steady.
  10. MAP is steady at 15-70 kPa.
  11. Vehicle speed is more than 35 MPH during deceleration.
  12. Barometric pressure is more than 70 kPa.
  13. Drive vehicle at a speed of more than 50 MPH, then allow vehicle to decelerate. When vehicle is decelerating while meeting all criteria listed above, PCM will enable test to run. As test is running, you will see DESIRED EGR parameter and EGR POSITION SENSOR on scan tool change from zero to a calibrated value more than zero.

DTC will set when MAP changes monitored during EGR flow test indicate insufficient EGR flow.

PCM will run diagnostic for this DTC under the following conditions

  1. Engine is cranking or running.
  2. System voltage is 9-18 volts.

DTC will set when PCM detects an electrical malfunction in EGR valve control circuit for more than 20 seconds.

PCM will run diagnostic for this DTC when system voltage is more than 11 volts and EGR valve is enabled. DTC will set when difference between EGR position sensor parameter and desired EGR position is more than 15 percent for longer than 20 seconds.

PCM will run diagnostic for this DTC when system voltage is more than 11 volts. DTC will set when EGR pintle position feedback voltage is less than .35 volt for longer than 20 seconds.

  1. Meet conditions for engine warm-up. Using scan tool catalyst data list, verify the following: DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0336, P0341, P0401, P0403, P0404, P0405, P0440, P0442, P0443, P0446, P0449, P0502, P0503, P0506, P0507, P1133, P1134, P1336, P1351, P1352, P1361, P1362, P1374, P1404 or P1441 are not set. Engine has been running for more than 10 minutes. Engine coolant temperature is 158-255°F (70-124°C). Barometric Pressure (BARO) is more than 75 kPa. Vehicle is in closed loop. Intake air temperature is -4 to 212°F (-20 to 100°C). Battery voltage is more than 10.7 volts.
  2. Warm catalyst as follows: Open hood. Place transmission in Park or Neutral. Set parking brake. Press and hold service brakes. Each time engine is started, diagnostic can run up to 18 times. After the 10 minute run time, and before the diagnostic runs the first time, engine must run an additional 5 minutes at 1500-2500 RPM. For any additional tests on the same ignition cycle, engine must be 1500-2500 RPM for one minute. In order to activate diagnostic, return to idle and place vehicle in Drive (A/T), or depress clutch pedal (M/T).
  3. Test catalyst as follows: Verify that transaxle is in Drive (A/T) or is in Neutral with clutch pedal depressed (MT). Within 60 seconds, air/fuel ratio will go lean for up to 7 seconds, and may then may go rich for up to 7 seconds. Use scan tool in order to determine if DTC P0420 has passed or failed this ignition cycle.

DTC will set when PCM determines that the catalyst's oxygen storage capacity is less than acceptable.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121 or P1122 are not set.
  2. System voltage is 10-18 volts.
  3. Barometric pressure is more than 75 kPa.
  4. Fuel level is 15-85 percent.
  5. Engine Coolant Temperature (ECT) and Intake Air Temperature (IAT) is 39-86°F (4-30°C).
  6. Start-up ECT and IAT are within 16°F of each other.
  7. Vehicle speed is less than 75 MPH.

DTC will set when EVAP system is not able to achieve or maintain vacuum during diagnostic test.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121 or P1122 are not set.
  2. Ignition voltage is 10-18 volts.
  3. Barometric pressure is more than 75 kPa.
  4. Fuel level is 15-80 percent.
  5. Engine Coolant Temperature (ECT) and Intake Air Temperature (IAT) are 39-86°F (4-30°C).
  6. Start-up ECT and IAT are within 16°F of each other.
  7. Vehicle speed is less than 75 MPH.

DTC will set when EVAP system can achieve vacuum, but a vacuum decay is detected during diagnostic test.

PCM will run diagnostic for this DTC when engine speed is more than 400 RPM and system voltage is 6-18 volts. DTC will set when PCM detects that commanded state of driver and actual state of control circuit do not match for 5 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0442, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121 or P1122 are not set.
  2. Ignition voltage is 10-18 volts.
  3. Barometric pressure is more than 75 kPa.
  4. Fuel level is 15-85 percent.
  5. Engine Coolant Temperature (ECT) and Intake Air Temperature (IAT) are between 39-86°F (4-30°C).
  6. Start-up ECT and IAT are 16°F of each other.
  7. Vehicle speed is less than 75 MPH.

DTC will set when FTP is less than 10 in. H2O for at least 30 seconds.

PCM will run diagnostic for this DTC when system voltage is 6-18 volts and engine speed is more than 400 RPM. DTC will set when PCM detects that the commanded state of the driver and actual state of the control circuit do not match. Conditions must be present for at least 5 seconds.

PCM will run diagnostic for this DTC when engine is running. DTC will set when FTP sensor voltage is less than .1 volt for more than 5 seconds.

PCM will run diagnostic for this DTC when engine is running. DTC will set when FTP sensor voltage is more than 4.9 volts for more than 5 seconds.

PCM will run diagnostic for this DTC when ignition is on. DTC will set when an improper voltage level has been detected on relay control circuit for 30 seconds or more.

PCM will run diagnostic for this DTC when ignition is on. DTC will set when an improper voltage level has been detected on relay control circuit for 30 seconds or more.

DTC will run under the following conditions

  1. Transaxle is not in Park or Neutral.
  2. DTCs P0106, P0107, P0108, P1106, P1107, P0121, P0122, P0123, P0716, P0717 or P1810 are not present.
  3. Input shaft speed is more than 1500 RPM.
  4. Throttle angle is more than 12 percent.
  5. Engine torque is 40-150 ft. lbs (54-203 N.m).

DTC will set when output shaft speed is less than 150 RPM for 2.5 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. Transaxle is not in Park or Neutral.
  2. No DTC P0502 or P1810.
  3. Engine speed is more than 500 RPM for 5 seconds and not in fuel shut off mode.
  4. Time since last gear change is more than 6 seconds.
  5. No output speed increase more than 250 RPM in 2 seconds.

DTC will set when output shaft speed drops more than 1500 RPM in 2 seconds.

MIL will illuminate after 2 consecutive ignition cycles with first failure signal. PCM commands maximum line pressure and disables shift adapts. PCM calculates vehicle speed using input speed sensor information and commanded gear.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0172, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0401, P0403, P0404, P0405, P0443, P1121, P01404, or P1441 are not set.
  2. Engine run time is more than 2 minutes.
  3. Engine Coolant Temperature (ECT) is more than 158°F (70°C).
  4. Intake Air Temperature (IAT) is more than -.4°F (-18°C).
  5. Barometric Pressure (BARO) is more than 70 kPa.
  6. Ignition voltage is 9-18 volts.
  7. Throttle Position (TP) sensor is less than 1.5 percent.
  8. Vehicle speed is less than 3 MPH.
  9. Above conditions are present for 5 seconds.

DTC will set when actual engine speed is 100 RPM less than desired engine speed. Diagnostic must fail 4 consecutive tests per key cycle.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0172, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0401, P0403, P0404, P0405, P0443, P1121, P01404, or P1441 are not set.
  2. Engine run time is more than 2 minutes.
  3. Engine Coolant Temperature (ECT) is more than 158°F (70°C).
  4. Intake Air Temperature (IAT) is more than -.4°F (-18°C).
  5. Barometric Pressure (BARO) is more than 70 kPa.
  6. Ignition voltage is 9-18 volts.
  7. Throttle Position (TP) sensor is less than 1.5 percent.
  8. Vehicle speed is less than 3 MPH.
  9. Above conditions are present for 5 seconds.

DTC will set when actual engine speed is 1500 RPM more than desired engine speed. Diagnostic must fail 4 consecutive tests per key cycle.

PCM will run diagnostic for this DTC under the following conditions

  1. System voltage is less than 11 volts.
  2. Engine speed is more than 1500 RPM.
  3. Vehicle speed is less than 25 MPH.

DTC will set when PCM detects system voltage is out of range for 2 seconds.

If PCM detects an internal program fault (check sum error), DTC P0601 will set.

DTC P0602 will set if PCM does not contain correct program(s) required to operate vehicle.

PCM will run diagnostic for this DTC when ignition is on. DTC will set when an improper voltage level has been detected on the MIL control circuit for at least 30 seconds.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0121, P0122, or P0123 are not set.
  2. Engine has been running for a length of time that is determined by start-up coolant temperature. The time ranges from 2 minutes at less than 86°F (30°C), to one second at more than 86°F (30°C).
  3. Throttle angle is less than 2 percent when engine speed is less than 3000 RPM.
  4. Throttle angle is less than 30 percent when engine speed is more than 3000 RPM.

DTC will set when MAP sensor voltage is intermittently more than 4.2 volts.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0121, P0122, or P0123 are not set.
  2. Ignition is on.
  3. Throttle angle is more than zero percent when engine speed is less than 1000 RPM.
  4. Throttle angle is more than 10 percent when engine speed is more than 1000 RPM.

DTC will set when MAP sensor voltage is intermittently less than .1 volt.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0117, P0118, P0125, P0128, P0502, P0503, P1114, or P1115 are not set.
  2. Vehicle speed is less than 35 MPH.
  3. Mass airflow is less than 12 grams per second.
  4. Engine Coolant Temperature (ECT) is more than 140°F (60°C).
  5. Engine run time is more than 3 minutes.

DTC will set when IAT signal voltage indicates intake air temperature is intermittently less than -35°F (-37°C).

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0117, P0118, P0125, P0128, P0502, P0503, P1114, or P1115 are not set.
  2. Engine run time is more than 10 seconds.
  3. Vehicle speed is more than 25 MPH.

DTC will set when IAT signal voltage indicates intake air temperature is intermittently more than 275°F (135°C).

PCM will run diagnostic for this DTC when engine has been running for more than 5 seconds. DTC will set when PCM detects an intermittently high ECT sensor voltage.

PCM will run diagnostic for this DTC when engine is running. DTC will set when PCM detects an intermittently low ECT sensor temperature.

PCM will run diagnostic for this DTC when ignition is on. DTC will set when TP sensor intermittently indicates a TP sensor signal voltage of more than 4.9 volts for .5 second.

PCM will run diagnostic for this DTC when ignition is on. DTC will set when TP sensor intermittently indicates a TP sensor signal voltage of less than .95 volt for .5 second.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449 or P1441 are not set.
  2. System voltage is more than 9 volts.
  3. Engine is running in closed loop.
  4. Engine is running for at least 3.3 minutes.
  5. Engine Coolant Temperature (ECT) is more than 158°F (70°C).
  6. TP sensor angle is more than 2 percent.
  7. Engine speed is 1300-3000 RPM.
  8. Mass airflow is 13-29 grams per second.
  9. Above conditions are stable for 3 seconds.

DTC will set when PCM monitors fewer than 25 rich-to-lean and 25 lean-to-rich switches for HO2S 1 during a 100-second monitoring period.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0101, P0102, P0103, P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0410, P0440, P0442, P0443, P0446, P0449 or P1441 are not set.
  2. System voltage is more than 9 volts.
  3. Engine is running in closed loop.
  4. Engine has been running for at least 60 seconds.
  5. Engine Coolant Temperature (ECT) is more than 122°F (50°C).
  6. TP sensor angle is more than 2 percent.
  7. Engine speed is 1300-3000 RPM.
  8. Mass airflow is 13-29 grams per second.

DTC will set when the ratio of averages is not between 4.2 and 0.4 during the 100-second monitoring period.

PCM will run diagnostic for this DTC when DTC P0336, P0341 or P1374 are not set and engine coolant temperature is more than 156°F (69°C). DTC will set when crankshaft position system variation values are not stored in PCM memory.

PCM will run diagnostic for this DTC when engine speed is more than 600 RPM. DTC will set when PCM detects an open in IC circuit for 100 crankshaft revolutions.

PCM will run diagnostic for this DTC when engine is running. DTC will set when PCM detects an open in IC timing signal circuit. Condition must be present for 106 crankshaft revolutions.

PCM will run diagnostic for this DTC under the following conditions

  1. Engine speed is more than 600 RPM.
  2. DTC P1351 is not set.

DTC will set when PCM does not monitor IC pulses while IC mode spark advance is commanded. Condition must be present for 100 crankshaft revolutions.

PCM will run diagnostic for this DTC when engine is running. DTC will set when PCM detects a short to voltage in IC timing signal circuit. Condition must be present for 100 crankshaft revolutions.

PCM will run diagnostic for this DTC when engine is running and 24X pulses are being received. DTC will set when

  1. The ratio of 24X reference pulses to 3X reference pulses received by the PCM does not equal 8.
  2. The ratio of 24X reference pulses to CMP PCM input pulses received by the PCM equals 48.
  3. The conditions are present for more than 10 seconds.

PCM will run diagnostic for this DTC under the following conditions: engine load is less than 87 percent, engine speed is less than 5000 RPM, vehicle speed is greater than 10 MPH, misfire DTC is occurring and requesting MIL to be illuminated. DTC will set when PCM has detected an EBCM/EBTCM rough road sensing error.

PCM will run diagnostic for this DTC under the following conditions

  1. Engine load is less than 87 percent.
  2. Engine speed is less than 5000 RPM.
  3. Vehicle speed is more than 10 MPH.
  4. A misfire DTC is occurring and is requesting MIL to be illuminated.

DTC will set when PCM is detecting a loss of communication with EBCM/EBTCM for at least 5 seconds.

PCM will run diagnostic for this DTC when system voltage is more than 11 volts. DTC will set when EGR position sensor voltage is .2 volt more than EGR learned minimum position when desired EGR position is commanded to zero percent. Condition must be present twice.

PCM will run diagnostic for this DTC under the following conditions

  1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0442, P0443, P0446, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121, or P1122 are not set.
  2. Ignition voltage is 10-18 volts.
  3. Barometric pressure is more than 75 kPa.
  4. Fuel level is 15-85 percent.
  5. Engine Coolant Temperature (ECT) and Intake Air Temperature (IAT) are 39-86°F (4-30°C).
  6. Start-up ECT and IAT are within 16°F of each other.
  7. Vehicle speed is less than 75 MPH.

DTC will set when PCM detects vacuum during a non purge condition.

PCM will run diagnostic for this DTC when ignition voltage is 9-18 volts, engine speed is more than 80 RPM and PCM driver is activated. DTC will set when PCM detects an improper voltage level on control circuit for at least 30 seconds.

PCM will run diagnostic for this DTC when engine is running. DTC will set when PCM detects a voltage out of range/tolerance on the 5-volt reference 1 circuit and condition is present longer than 10 seconds.

PCM will run diagnostic for this DTC when engine is running. DTC will set when PCM detects an out of tolerance condition on 5-volt reference 2 circuit and condition is present for longer than 10 seconds.

PCM will run diagnostic for this DTC when ignition is on. DTC will set when the ODM has detected a voltage more than 33 volts, or excessive current is detected on any circuit to the ODM. Condition must be present for 30 seconds.

PCM will run diagnostic for this DTC when ignition is on. DTC will set when the ODM has detected a voltage more than 33 volts, or excessive current is detected on any circuit to the ODM. Condition must be present for 30 seconds.

PCM will run diagnostic for this DTC when ignition is on. DTC will set when the ODM has detected a voltage more than 33 volts, or excessive current is detected on any circuit to the ODM. Condition must be present for 30 seconds.

PCM will run diagnostic for this DTC when ignition is on. DTC will set when the ODM has detected a voltage more than 33 volts, or excessive current is detected on any circuit to the ODM. Condition must be present for 30 seconds.

PCM will run diagnostic for this DTC when ignition is on and system voltage is 9-18 volts. DTC will set when an improper voltage level has been detected on the hot coolant indicator control circuit. Condition must be present for at least 30 seconds.

More articles — Engine Controls Self-Diagnostics - 3.1L & 3.4L