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Engine Controls Self-Diagnostics - 2.2L & 2.4L: Other Oldsmobile Alero I

Testing & Diagnostics 4 illustrations ~9896 words

Code Types

There are 4 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.
  4. Type "D" Non-emissions related. Does not illuminate MIL or 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.

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.

ALTERNATE FUEL ENGINE CONTROL UNIT

After replacing AF ECU or if program needs to be updated (flashed), refer to latest Techline information on AF ECU reprogramming.

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 and PROGRAMMING THEFT DETERRENT SYSTEM COMPONENTS .

CRANKSHAFT POSITION SENSOR SYSTEM VARIATION LEARN PROCEDURE

CAUTIONBefore performing crankshaft position system variation learn procedure, always set parking brake and block drive wheels in order to prevent personal injury. Release throttle immediately when engine starts to decelerate in order to eliminate over-revving engine. Once learn procedure has been completed, control module will return engine control to operator and engine will respond to throttle position.

Note. Battery must be fully charged and in good condition. Scan tool connection at Data Link Connector (DLC) should be clean and tight before starting crankshaft position system variation learn procedure.

  1. Close hood.
  2. Block drive wheels and set vehicle parking brake.
  3. Put vehicle in Park or Neutral.
  4. Turn all accessories off.
  5. Connect a scan tool.
  6. Start and run engine until engine is at normal operating temperature 165°F (74°C) on 2.2L or 185°F (85°C) on 2.4L.
  7. With engine still running, use scan tool to enable CRANKSHAFT POSITION SYSTEM VARIATION LEARNING PROCEDURE.
  8. Press and hold brake pedal firmly and raise engine speed to specified value of 3920 RPM, releasing throttle as soon as engine cuts out.
  9. Using scan tool, verify that crankshaft variation has been learned.

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(tm) sensor data code and/or passwords on next ignition switch transition from OFF to CRANK position.
  6. Start engine. Vehicle has now learned Passlock(tm) sensor data code and/or password.
  7. Using scan tool, clear any DTCs if needed.

DRIVE CYCLES

See INSPECTION/MAINTENANCE SYSTEM CHECK (GASOLINE) or INSPECTION/MAINTENANCE SYSTEM CHECK (CNG) .

Conditions For Updating I/M System Status

Each system requires at least one, sometimes several, diagnostic tests. Results of these tests are reported by a Diagnostic Trouble Code (DTC). System monitor is complete when either all DTCs comprising monitor have run and passed, or any one DTC comprising monitor have illuminated the Malfunction Indicator Light (MIL). Once all tests are completed, I/M System Status display will indicate YES in COMPLETED column.

For example, when HO2S Heater Test indicates YES, all oxygen sensor heaters have been diagnosed. If vehicle has four heated oxygen sensors, all four heater circuits have been diagnosed. I/M System Status will indicate NO under COMPLETED column when any required tests for that system have not run.

Following is a list of conditions that would set I/M System Status indicator to NO

  1. Vehicle is new from factory and has not yet been driven through necessary drive cycles to complete tests.
  2. Battery has been disconnected or discharged below operating voltage.
  3. Control module power or ground has been interrupted.
  4. Control module has been reprogrammed.
  5. Control module DTCs have been cleared as part of a service procedure.

Enable Criteria

  1. BARO is more than 72 kPa.
  2. ECT is 167-257°F (75-125°C).
  3. IAT is -4 to 176°F (-20 to 80°C).
  4. Engine is in closed loop.
  5. Engine has run 6-8 minutes off idle.
  6. Battery voltage is 9-16 volts.
  1. BARO is more than 75 kPa.
  2. Fuel level is 1/4-3/4.
  3. Battery voltage is 9-16 volts.
  4. Test will initiate only after a cold start. PCM considers engine to be cold if ECT is 41-84°F (5-29°C), IAT is 41-84°F (5-29°C) and difference between ECT and IAT is less than 13°F (7°C).
  1. ECT is more than 167°F (75°C).
  2. Engine is in closed loop.
  3. Engine has been running more than one minute
  4. Battery voltage is 10-16 volts.
  1. ECT is less than 104°F (40°C).
  2. ECT is less than 104°F (40°C).
  3. Difference between ECT and IAT is less than 13°F (7°C).
  4. Battery voltage is 11.6-16.0 volts.

SUMMARY

If no DTC(s) are present and driveability symptoms exist proceed to appropriate TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).

MIL INOPERATIVE (GASOLINE)

  1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK (GASOLINE)»(ref-98416-S22656642022001052200000) under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
  2. Inspect fuse that supplies voltage to MIL (BCM/CLU fuse on "J" body and IPC/BFC ACC fuse on "N" body). If fuse is open, go to step 10 . If fuse is okay, go to next step.
  3. Turn ignition off. Disconnect PCM. Turn ignition on, engine off. Connect fused jumper wire (3-amp) between MIL control circuit (Brown/White wire) and ground. See WIRING DIAGRAMS article. Observe MIL. If MIL illuminated, go to step 9 . If MIL is not illuminated, go to next step.
  4. If fuse in jumper wire opened, go to step 11 . If fuse in jumper wire did not open, go to next step.
  5. Remove Instrument Panel Cluster (IPC). Check MIL control circuit (Brown/White wire) for open between PCM and IPC. If problem was found, repair as necessary. After repairs, go to step 14 . If problem was not found, go to next step.
  6. Using test light connected to ground, probe MIL ignition supply voltage circuit (Pink wire on "J" body and Purple wire on "N" body) at IPC harness connector. See WIRING DIAGRAMS article. If test light is on, go to step 8 . If test light is off, go to next step.
  7. Repair open in MIL ignition supply voltage circuit. See WIRING DIAGRAMS article. After repairs, go to step 14 .
  8. Check IPC connector for poor connections. If problem was found, repair as necessary. After repairs, go to step 14 . If problem was not found, go to step 12 .
  9. Check PCM connector for poor connections. If problem was found, repair as necessary. After repairs, go to step 14 . If problem was not found, go to step 13 .
  10. Repair short to ground in MIL ignition supply voltage circuit (Pink wire on "J" body and Purple wire on "N" body). See WIRING DIAGRAMS article. After repairs, go to step 14 .
  11. Repair short to voltage in MIL control circuit (Pink wire on "J" body and Purple wire on "N" body). See WIRING DIAGRAMS article. After repairs, go to step 14 .
  12. Replace IPC. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs, go to step 14 .
  13. Replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
  14. Operate system to verify repair.

MIL INOPERATIVE (CNG)

  1. If you have been sent to this procedure from another diagnostic procedure, go to next step. If you have not been sent to this procedure from another diagnostic procedure, perform alternative fuels engine controls diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK (CNG)»(ref-98416-S35966354722001121000000) under SELF-DIAGNOSTIC SYSTEM. After performing alternative fuels engine controls diagnostic system check, go to next step.
  2. Turn ignition on. If Malfunction Indicator Light (MIL) is illuminated continuously, go to next step. If MIL is not illuminated continuously, go to step 5.
  3. Using scan tool, communicate with Alternate Fuel Engine Control Unit (AF ECU) and command MIL off. If MIL is illuminated, go to «MIL ON STEADY (CNG)»(ref-98416-S27318219852001121000000). If MIL is not illuminated, go to next step.
  4. MIL malfunction is not present at this time. If a MIL operational symptom is still present, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK (CNG)»(ref-98416-S35966354722001121000000) under SELF-DIAGNOSTIC SYSTEM. If a MIL operational symptom is no longer present, problem may be intermittent. See «INTERMITTENT TROUBLE CODE DETERMINATION»(ref-98416-S26615447012001090600000) under ON-BOARD DIAGNOSTICS in SELF-DIAGNOSTIC SYSTEM.
  5. Crank engine for at least 10 seconds. If engine starts and runs, go to next step. If engine fails to start and run, go to step 9.
  6. Observe operation of other Instrument Panel Cluster (IPC) gauges and/or indicator lights. If all IPC indicators and gauges (except MIL) operate properly, go to next step. If all IPC indicators and gauges do not operate properly, go to step 13.
  7. Turn ignition on. Using scan tool, select ALT. FUELS DATA LIST and observe GASOLINE MIL COMMAND data parameter. If PCM is commanding MIL ON, go to next step. If PCM is not commanding MIL ON, go to step 11.
  8. Turn ignition off. Disconnect AF ECU connectors. AF ECU is located behind left front fascia, below headlight. (Scheme 15) Turn ignition on. Connect a fused jumper between AF ECU Blue connector C001 terminal No. 2 (Brown/White wire) and ground. (Scheme 16) If MIL illuminates, go to step 14. If MIL does not illuminate, go to step 10. If fused jumper blows, repair short to voltage in Brown/White wire between AF ECU and IPC connector C1 terminal "D". (Scheme 17)
  9. Fault is in gasoline control (PCM) system. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK (GASOLINE)»(ref-98416-S22656642022001052200000) under SELF-DIAGNOSTIC SYSTEM. After repairing gasoline control system, go to step 17.
  10. Check for open in Brown/White wire between AF ECU Blue connector C001 terminal No. 2 and IPC connector C1 terminal "D". Repair as necessary. After repairs, go to step 17. If circuit is okay, go to step 13.
  11. Check for open or short to voltage in Brown wire between AF ECU Blue connector C001 terminal No. 22 and PCM connector C2 terminal No. 46. (Scheme 16)and (Scheme 18). Check for short to voltage in Brown/White wire between AF ECU Blue connector C001 terminal No. 2 and IPC connector C1 terminal "D". (Scheme 17) Repair as necessary. After repairs, go to step 17. If circuit is okay, go to next step.
  12. Check for poor connections at PCM. Repair as necessary. After repairs, go to step 17. If connections are okay, go to step 15.
  13. Replace IPC. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION in ANALOG INSTRUMENT PANELS - CAVALIER & SUNFIRE article. After repairs, go to step 17.
  14. Check for poor connections at AF ECU. Repair as necessary. After repairs, go to step 17. If connections are okay, go to step 16.
  15. Replace PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - CARS article. Program (flash) PCM with correct vehicle software and calibration. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-98416-S14337562862001053000000) under PROGRAMMING. To perform CKP variation learn procedure, a switch-over to gasoline operation is necessary. Remove CNG fuse (20-amp) located in underhood fuse block to perform switch-over. Perform CKP system variation learn procedure. See «CRANKSHAFT POSITION SENSOR SYSTEM VARIATION LEARN PROCEDURE»(ref-98416-S03844968162001053000000) under PROGRAMMING. After performing repairs and procedures, go to step 17.
  16. Replace AF ECU. See ALTERNATE FUEL ENGINE CONTROL UNIT under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - CARS article. Program (flash) AF ECU with correct vehicle software and calibration. See «ALTERNATE FUEL ENGINE CONTROL UNIT»(ref-98416-S41433800582001121100000) under PROGRAMMING. After performing repairs and procedures, go to next step.
  17. Remove all test equipment except scan tool. Reconnect any disconnected components. Using scan tool, clear DTCs from AF ECU and PCM. Turn ignition off and wait 30 seconds. Start engine and operate vehicle. Monitor FIL and MIL operation. Observe vehicle performance and driveability. After operating vehicle check for DTCs in AF ECU and PCM. If vehicle operates on CNG with normal driveability, no FIL/MIL illumination and no set DTCs, system is okay. If vehicle does not operate on CNG with normal driveability, or FIL/MIL are illuminated or DTCs are set, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK (CNG)»(ref-98416-S35966354722001121000000) under SELF-DIAGNOSTIC SYSTEM.

Scheme 15

Scheme 15
Scheme 15

Scheme 16

Scheme 16
Scheme 16

Identifying Instrument Panel Cluster Connector Terminals. Scheme 17

Scheme 17: Identifying Instrument Panel Cluster Connector Terminals
Scheme 17: Identifying Instrument Panel Cluster Connector Terminals

Scheme 18

Scheme 18
Scheme 18

MIL ON STEADY (GASOLINE)

  1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK (GASOLINE)»(ref-98416-S22656642022001052200000) under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
  2. Turn ignition off. Disconnect PCM. Turn ignition on, engine off. Observe MIL. If MIL is illuminated, go to next step. If MIL is not illuminated, go to step 5 .
  3. Remove Instrument Panel Cluster (IPC). Check MIL control circuit (Brown/White wire) for short to ground between PCM and IPC. See WIRING DIAGRAMS article. If problem was found, repair as necessary. After repairs, go to step 6 . If problem was not found, go to next step.
  4. Replace IPC. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs, go to step 6 .
  5. Replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
  6. Operate system to verify repair.

MIL ON STEADY (CNG)

  1. If you have been sent to this procedure from another diagnostic procedure, go to next step. If you have not been sent to this procedure from another diagnostic procedure, perform alternative fuels engine controls diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK (CNG)»(ref-98416-S35966354722001121000000) under SELF-DIAGNOSTIC SYSTEM. After performing alternative fuels engine controls diagnostic system check, go to next step.
  2. Turn ignition on. If Malfunction Indicator Light (MIL) is illuminated continuously, go to next step. If MIL is not illuminated, go to «MIL INOPERATIVE (CNG)»(ref-98416-S00253493842001121000000).
  3. Using scan tool, communicate with Alternate Fuel Engine Control Unit (AF ECU) and command MIL off. If MIL is illuminated, go to step 5. If MIL is not illuminated, go to next step.
  4. MIL malfunction is not present at this time. If a MIL operational symptom is still present, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK (CNG)»(ref-98416-S35966354722001121000000) under SELF-DIAGNOSTIC SYSTEM. If a MIL operational symptom is no longer present, problem may be intermittent. See «INTERMITTENT TROUBLE CODE DETERMINATION»(ref-98416-S26615447012001090600000) under ON-BOARD DIAGNOSTICS in SELF-DIAGNOSTIC SYSTEM.
  5. Using scan tool, select ALT. FUELS DATA LIST and observe GASOLINE MIL COMMAND data parameter while the MIL is commanded OFF. If a gasoline MIL command request present, go to step 7. If a gasoline MIL command request is not present, go to next step.
  6. Check for short to ground in Brown/White wire between AF ECU Blue connector C001 terminal No. 2 and IPC connector C1 terminal "D". (Scheme 16)and (Scheme 17). Check for internally shorted Instrument Panel Cluster (IPC). Repair as necessary. After repairs, go to step 9. If circuit is okay, go to step 8.
  7. Check for short to ground in Brown wire between AF ECU Blue connector C001 terminal No. 22 and PCM connector C2 terminal No. 46. (Scheme 16)and (Scheme 18). Repair as necessary. After repairs, go to step 9. If circuit is okay, go to next step.
  8. Replace AF ECU. See ALTERNATE FUEL ENGINE CONTROL UNIT under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - CARS article. Program (flash) AF ECU with correct vehicle software and calibration. See «ALTERNATE FUEL ENGINE CONTROL UNIT»(ref-98416-S41433800582001121100000) under PROGRAMMING. After performing repairs and procedures, go to next step.
  9. Remove all test equipment except scan tool. Reconnect any disconnected components. Using scan tool, clear DTCs from AF ECU and PCM. Turn ignition off and wait 30 seconds. Start engine and operate vehicle. Monitor FIL and MIL operation. Observe vehicle performance and driveability. After operating vehicle check for DTCs in AF ECU and PCM. If vehicle operates on CNG with normal driveability, no FIL/MIL illumination and no set DTCs, system is okay. If vehicle does not operate on CNG with normal driveability, or FIL/MIL are illuminated or DTCs are set, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK (CNG)»(ref-98416-S35966354722001121000000) under SELF-DIAGNOSTIC SYSTEM.

Code Enable Criteria

  1. DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0502, P0506, P0507 or P1441 is not set.
  2. Engine run time is more than 40 seconds.
  3. Engine speed is between 900-6375 RPM for M/T, 600-6375 RPM for A/T.
  4. Torque Converter Clutch (TCC) is stable to within 2.5 percent.
  5. Engine speed is stable within 50 RPM.
  6. IAC valve is stable within 5 counts.
  7. Conditions are present for 1.5 seconds.

DTC sets when MAP sensor or TP sensor is out of an expected range defined by engine calibration for 14 seconds.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel (CNG).
  2. Engine has been running for more than 5 seconds.
  3. No AF ECU DTCs are set.
  4. DTCs P1215, P1432 and P1433 may be set.
  5. TP sensor angle is less than 70 percent.

DTC will set when AF ECU detects MAP sensor pressure changes less than 6 kPa when TP sensor angle changes by more than 20 percent.

  1. DTCs P0122 or P0123 are not set.
  2. Engine speed is less than 1000 RPM.
  3. Engine speed is more than 1000 RPM, and throttle position is more than 15 percent.

DTC sets when MAP sensor voltage is less than 0.2 volt for at least 6.25 seconds.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine speed is more than 500 RPM.
  3. DTCs P0121, P0122, P0123 are not set.
  4. Throttle Position (TP) angle is less than 4 percent when engine speed is less than 1200 RPM or TP angle is more than 20 percent when engine speed is more than 1300 RPM.

DTC will set when AF ECU detects a MAP sensor signal voltage of less than 0.098 volts for at least 4 continuous seconds. When DTC is set, AF ECU will switch to gasoline fuel operation. AF ECU will not attempt alternative fuel operation until next key cycle.

  1. DTCs P0122 or P0123 are not set.
  2. Throttle position is less than 12 percent.
  3. Vehicle speed is less than one MPH (2 km/h).
  4. Engine run time is more than 20 to 40 seconds.

DTC sets when MAP sensor voltage is more than 3.8 volts for at least 1.25 seconds.

DTC will run when the following conditions are met

  1. Engine is operating on alternative fuel.
  2. Engine speed is more than 500 RPM.
  3. DTCs P0121, P0122, P0123 are not set.
  4. Throttle Position (TP) angle is less than 4 percent.

DTC will set when AF ECU detects MAP sensor signal voltage more than 4.8 volts for at least 4 continuous seconds. When DTC is set, AF ECU will switch to gasoline fuel operation. AF ECU will not attempt alternative fuel operation until next key cycle.

  1. DTCs P0117, P0118, P0125, P0502, or P0503 are not set.
  2. Engine run time is more than 320 seconds.
  3. Vehicle speed sensor indicates vehicle speed is more than 15 MPH.

IAT sensor signal voltage indicates intake air temperature is more than 262°F (128°C) for 3.13 seconds.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine has been operating for more than 1.5 minutes.
  3. Vehicle speed is more than one MPH.

DTC will set when AF ECU detects IAT sensor signal voltage less than 0.019 volt for at least 5 continuous seconds.

  1. DTCs P0117, P0118, P0125, P0502, or P0503 are not set.
  2. Engine run time is more than 320 seconds.
  3. Vehicle Speed Sensor (VSS) indicates that vehicle speed is more than 15 MPH.

DTC sets when IAT sensor signal voltage indicates IAT is more than 262°F (128°C) for 3.125 seconds.

  1. DTCs P0117, P0118, P0125, P0502, or P0503 are not set.
  2. Engine run time is more than 320 seconds.
  3. Vehicle Speed Sensor (VSS) indicates that vehicle speed is less than 15 MPH (24 km/h).

DTC sets when IAT sensor signal voltage indicates intake air temperature is less than -38°F (-39°C) for 3 seconds.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine has been operating for more than 1.5 minutes when engine start-up temperature is more than 32°F (0°C).
  3. Engine has been operating for more than 10 minutes when engine start-up temperature is 32°F (0°C) or less.
  4. Vehicle speed is less than one MPH for at least 10 seconds.
  5. Calculated air flow is less than 250 grams per second for at least 10 seconds.

DTC will set when AF ECU detects IAT sensor signal voltage is more than 4.8 volts for at least 5 continuous seconds.

  1. DTCs P0117, P0118, P0125, P0502, or P0503 are not set.
  2. Engine run time is more than 320 seconds.
  3. Engine Coolant Temperature (ECT) is more than -40°F (-40°C).
  4. Vehicle speed sensor indicates vehicle speed is less than 15 MPH.

IAT sensor signal voltage indicates IAT is less than -40°F (-40°C) for 3.13 seconds.

  1. Engine has been running more than 128 seconds.

DTC sets when ECT sensor indicates an engine coolant temperature more than 280°F (138°C) for more than 6.25 seconds.

For DTC to run, the engine must be operating on alternative fuel and running for more than 5 seconds. DTC will set when AF ECU detects ECT sensor signal voltage of less than 0.019 volt for at least 5 continuous seconds.

  1. Engine has been running more than 60 seconds.

ECT sensor temperature is less than -40°F (-40°C) for more than 6.25 seconds.

For DTC to run, engine must be operating on alternative fuel with engine running for more than 5 seconds when Intake Air Temperature (IAT) is more than 32°F (0°C) or engine running for more than 10 minutes when IAT is less than 32°F (0°C). DTC will set when AF ECU detects ECT sensor signal voltage of more than 4.8 volts for at least 5 continuous seconds.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine has been operating for more than 2 seconds.
  3. No AF ECU DTCs are set.
  4. DTCs P1215, P1432 and P1433 can be set.
  5. Engine MAP is less than 45 kPa.
  6. TP sensor angle has changed less than 2 percent for 2 continuous seconds.

DTC will set when TP sensor angle (percent) is more than specified at given engine speed. For specifications, see THROTTLE POSITION SENSOR ANGLE SPECIFICATIONS table.

TP Sensor AngleEngine RPM
30500
401500
502000
603000
703500
804000
904600

THROTTLE POSITION SENSOR ANGLE SPECIFICATIONS

  1. Engine is running.

DTC sets when TP sensor signal voltage is less than 0.1 volt for more than 2 seconds.

For DTC to run, engine must be operating on alternate fuel. DTC will set when AF ECU detects TP sensor signal voltage of less than 0.09 volt for at least one continuous second.

  1. Engine is running.
  2. DTCs P0107 or P0108 are not set.
  3. Manifold Absolute Pressure (MAP) is less than 60 kPa.
  4. Engine speed is less than 1500 RPM.

DTC sets when TP sensor signal voltage is more than 4.8 volts for more than 2 seconds.

For DTC to run, engine must be operating on alternate fuel. DTC will set when AF ECU detects TP sensor signal voltage of more than 4.9 volts for at least one continuous second.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0130, P0131, P0132, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0325, P0336, P0420, P0440, P0442, P0446, P0452, P0453, P0480, P0502, P0503, or P1441 are not set.
  2. Engine has run more than 30 seconds and less than 20 minutes.
  3. Minimum Intake Air Temperature (IAT) is more than 19°F (-7°C).
  4. Engine coolant temperature at start up is less than 95°F (35°C).

DTC sets when

  1. Average airflow is more than 15 grams per second.
  2. Vehicle has traveled more than 0.5 mile at speeds more than 25 MPH.
  3. Enough airflow has entered engine, and engine coolant temperature has not risen to 104°F (40°C) for 30 seconds.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. AF ECU DTCs P0112, P0113, P0117, P0118 are not set.
  3. This DTC has not tested this ignition cycle.
  4. Engine has been operating for more than 8.5 minutes.
  5. Vehicle speed is more than 5 MPH.
  6. Desired gas flow is more than 0.5 grams per second.
  7. Intake Air Temperature (IAT) is more than 5°F (-15°C).
  8. Engine coolant temperature at engine start-up is 1-91°F (-17°C to 33°C).

DTC will set when AF ECU detects engine coolant temperature that has not increased above start-up temperature by 77°F (25°C).

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0130, P0131, P0132, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0325, P0336, P0420, P0440, P0442, P0446, P0452, P0453, P0480, P0502, P0503 (A/T), or P1441 are not set.
  2. Engine has run more than 30 seconds and less than 20 minutes.
  3. Minimum Intake Air Temperature (IAT) is more than 19°F (-7°C).
  4. Engine coolant temperature at start up is less than 149°F (65°C).

DTC sets when

  1. Average airflow is more than 15 grams per second.
  2. Vehicle has traveled more than 1.5 miles at speeds more than 25 MPH.
  3. Enough airflow has entered engine and engine coolant temperature has not risen to 158°F (70°C) for 30 seconds.
  1. DTCs P0105, P0107, P0108, P0117, P0118, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0325, P0336, P0440, P0442, P0446, P0452, P0453, P0502, P0601, P0602, P1133, P1441, or P1621 are not set.
  2. Engine has been running more than 100 seconds.
  3. Engine speed is between 1200-3400 RPM.
  4. TP angle is 10-40 percent.
  5. ECT is more than 140°F (60°C).
  6. Above conditions have been met for 2 seconds.

DTC sets when engine is not in closed loop for 5 seconds out of 12.5 seconds.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Engine Coolant Temperature (ECT) is more than 158°F (70°C).
  3. Battery voltage is more than 10 volts.
  4. Fuel level is more than 10 percent.
  5. Engine run time is more than 10 seconds.
  6. Engine is operating in closed loop.
  7. Throttle Position (TP) angle is 8-50 percent.
  8. Manifold Absolute Pressure (MAP) is more than 25 kPa.
  9. Engine has been in specified conditions for 4 seconds.

DTC sets when O2S1 voltage is less than 52 millivolts for 125 seconds.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine speed is more than 500 RPM.
  3. Engine coolant temperature is more than 160°F (70°C).
  4. AF ECU determines O2S has been at operating temperature for at least 2 minutes. ECT must be more than 104°F (40°C) and calculated mass air flow must be more than 6 grams per second for 2 minutes for AF ECU to determine O2S is at operating temperature.
  5. AF ECU is operating in closed loop fuel control.

DTC will set when AF ECU monitors an O2S signal voltage of less than 0.02 volts (20 mV) for 6 continuous seconds.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Engine Coolant Temperature (ECT) is more than 158°F (70°C).
  3. Battery voltage is more than 10 volts.
  4. Fuel level is more than 10 percent.
  5. Engine run time is more than 10 seconds.
  6. Engine is operating in closed loop.
  7. Throttle Position (TP) angle is 8-50 percent.
  8. Manifold Absolute Pressure (MAP) sensor is more than 25 kPa.
  9. Engine has met specified conditions for 4 seconds.

DTC sets when O2S1 voltage is more than 946 millivolts for 50 seconds, or O2S1 voltage is more than 1042 millivolts for 50 seconds while in deceleration mode.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine speed is more than 500 RPM.
  3. Engine coolant temperature is more than 160°F (70°C).
  4. AF ECU determines O2S has been at operating temperature for at least 2 minutes. Engine coolant temperature must be more than 104°F (40°C) and calculated mass air flow must be more than 6 grams per second for 2 minutes for AF ECU to determine O2S is at operating temperature.
  5. AF ECU is operating in closed loop fuel control.

DTC will set when AF ECU senses O2S signal voltage of more than one volt (1000 mV) for continuous 3 seconds. When DTC is set, AF ECU will operate in open loop fuel control.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201-P0204, P0300, P0301-P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Engine coolant temperature is more than 158°F (70°C).
  3. Battery voltage is more than 10 volts.
  4. Fuel level is more than 10 percent.
  5. Engine run time is more than 10 seconds.
  6. Engine speed is between 1600-2450 RPM.
  7. Engine is operating in closed loop.
  8. Throttle Position (TP) angle is 9-18 percent.
  9. Evaporative emissions control system is commanded open more than 36 percent.
  10. Purge learned memory is more than approximately 0.78.
  11. Diagnostic completes when 30 seconds of accumulated time has been spent in specified conditions.

DTC sets when average O2S1 response times are more than 1119 milliseconds for rich to lean sweeps, or 760 milliseconds for lean to rich sweeps. Or sum of rich to lean and lean to rich is more than 1235 milliseconds.

For DTC to run, the following conditions must be met

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0506, P0507, P0601 are not set.
  2. Engine is operating on alternative fuel.
  3. Engine Coolant Temperature (ECT) is more than 167°F (75°C).
  4. Engine speed is 1600-2200 RPM.
  5. Engine is operating in closed loop.
  6. Engine has been operating for at least 120 seconds with engine speed of more than 450 RPM.
  7. Throttle Position (TP) angle is 9-23 percent.
  8. TP angle changes less than 3 percent per second.
  9. Evaporative emissions control system is commanded open for more than 80 percent.
  10. Purge learned memory is more than approximately 0.86.
  11. Diagnostic completes when 30 seconds of accumulated time has been spent in the above conditions.

DTC will set when average O2S 1 response times are more than 1174 milliseconds (mS) for rich to lean sweeps, or 1008 mS for lean to rich sweeps. DTC will also set when cycle time is more than 1491 mS.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Fuel level is more than 10 percent.
  3. Engine Coolant Temperature (ECT) is more than 158°F (70°C).
  4. Engine speed is between 1600 RPM and 2450 RPM.
  5. Engine is operating in closed loop.
  6. Throttle Position (TP) angle is 9-18 percent.
  7. Evaporative emissions control system is commanded OPEN more than 36 percent.
  8. Purge learned memory is more than approximately 0.78.
  9. Diagnostic completes when 30 seconds accumulated time has been spent in specified conditions.

DTC sets when average O2S1 response times are more than 1119 milliseconds for rich to lean sweeps or 760 milliseconds for lean to rich sweeps. Or sum of rich to lean and lean to rich is more than 1235 milliseconds.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Battery voltage is more than 10 volts.
  3. Fuel level is more than 10 percent.
  4. Engine coolant temperature is more than 158°F (70°C).
  5. Airflow is more than 3 grams per second.
  6. Throttle Position (TP) angle is 8-56 percent.
  7. Manifold Absolute Pressure (MAP) is more than 25 kPa.
  8. Engine run time is more than 30 seconds.

DTC sets when O2S1 voltage is 399-499 millivolts for 125 seconds.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine speed is more than 500 RPM.
  3. Engine has been operating for at least 2 minutes.
  4. AF ECU determines O2S has been at operating temperature for at least 2 minutes.
  5. Engine coolant temperature must be more than 104°F (40°C) and calculated mass air flow must be more than 6 grams per second for 2 minutes for AF ECU to determine O2S is at operating temperature.

DTC will set when AF ECU detects an O2S signal voltage stuck between 0.347 volt and 0.550 volt (in-active) for 9 continuous seconds or AF ECU detects an O2S signal voltage between zero and one volt that has not performed a rich/lean switch for 15 continuous seconds. When DTC is set, AF ECU will operate in open loop fuel control.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Engine coolant temperature (ECT) is more than 158°F (70°C).
  3. Battery voltage is more than 10 volts.
  4. Engine run time is more than 10 seconds.
  5. Throttle Position (TP) angle is 8-50 percent for 4 seconds.
  6. Manifold Absolute Pressure (MAP) is more than 25 kPa.

DTC sets when HO2S2 remains less than 43 millivolts for 150 seconds.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Engine Coolant Temperature (ECT) is more than 158°F (70°C).
  3. Battery voltage is more than 10 volts.
  4. Fuel level is more than 10 percent.
  5. Engine run time is more than 10 seconds.
  6. Engine is operating in closed loop.
  7. Throttle Position (TP) angle is between 8-50 percent for 4 seconds.
  8. Manifold Absolute Pressure (MAP) is more than 25 kPa.

DTC sets when HO2S2 voltage is more than 1042 millivolts for 50-75 seconds.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Battery voltage is more than 10 volts.
  3. Fuel level is more than 10 percent.
  4. Engine run time is more than 10 seconds.
  5. Airflow is more than 5.5 grams per second (2.2L) or 140 grams per second (2.4L).
  6. Engine Coolant Temperature (ECT) is more than 104°F (40°C).
  7. Throttle Position (TP) is 8-56 percent.
  8. Manifold Absolute Pressure (MAP) is more than 25 kPa.
  9. Engine is operating in closed loop.

DTC sets when HO2S2 remains within 425-460 millivolts for 125 seconds.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Ignition 1 signal is more than 10 volts.
  3. Engine Coolant Temperature (ECT) less than 113°F (45°C).
  4. Intake Air Temperature (IAT) less than 113°F (45°C).
  5. Difference between ECT and IAT is less than 45°F (7°C).
  6. Fuel level is more than 10 percent.
  7. Rear HO2S voltage is between 395-495 millivolts.

DTC sets when HO2S voltage does not go more than 600 millivolts or less than 300 millivolts 110-255 seconds after a cold start.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125 , P0131, P0132, P0133, P0134, P0201-P0204, P0300, P0301-P0304, P0325, P0341, P0446, P0502, P0503, P0506, P0507, P0601, P0602, P1133, or P1441 are not set.
  2. Engine Coolant Temperature (ECT) is 14-239°F (60-115°C).
  3. Intake air temperature is -13 to 239°F (-25 to 115°C).
  4. Manifold Absolute Pressure (MAP) is more than 26 kPa.
  5. Vehicle speed is less than 82 MPH.
  6. Engine speed is 55-3400 RPM.
  7. Barometric (BARO) pressure is more than 72 kPa.
  8. Fuel ethanol composition is less than 88 percent.
  9. Fuel level is more than 9.8 percent.

DTC sets when fuel trim index is more than 23 percent.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine coolant temperature is more than 102°F (49°C).
  3. AF ECU is operating in closed loop fuel control.

DTC will set when AF ECU monitors short term fuel trim at +50 percent for at least 5 continuous seconds or AF ECU monitors long term fuel trim at +45 percent for at least 5 continuous seconds.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125 , P0131, P0132, P0133, P0134, P0201-P0204, P0300, P0301-P0304, P0325, P0341, P0446, P0502, P0503, P0506, P0507, P0601, P0602, P1133, or P1441 are not set.
  2. Engine Coolant Temperature (ECT) is 140-239°F (60-115°C).
  3. Intake air temperature is -13 to 239°F (-25 to 115°C).
  4. Manifold Absolute Pressure (MAP) is more than 26 kPa.
  5. Vehicle speed is less than 82 MPH.
  6. Engine speed is 550-3400 RPM.
  7. Barometric pressure is more than 72 kPa.
  8. Fuel ethanol composition is less than 88 percent.
  9. Fuel level is more than 9.8 percent.

DTC sets when fuel trim index is less than -42 percent. Diagnostics have determined that a rich condition was not due to excessive vapor.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine coolant temperature is more than 120°F (49°C).
  3. AF ECU is operating in closed loop fuel control.

DTC will set when AF ECU monitors short term fuel trim at -50 percent for at least 5 continuous seconds or AF ECU monitors long term fuel trim at -45 percent for at least 5 continuous seconds.

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

DTC sets when PCM detects an incorrect voltage on fuel injector control circuit for 30 seconds.

  1. DTCs P0711, P0712 or P0713 are not set.

DTC sets when transmission fluid temperature is more than 260°F (130°C) for 10 minutes.

  1. DTCs P0105, P0107, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0137, P0138, P0140, P0171, P0172, P0325, P0336, P0502, P0503, P0506, P0507, P0601, P0602, P1133, P1137, P1138, P1171, P1336, or P1621 are not set.
  2. Engine speed is 469-5900 RPM.
  3. Battery voltage is 9-17 volts.
  4. Engine Coolant Temperature (ECT) is 20-254°F (-7 to 123°C).
  5. Engine has been running more than 5 seconds.
  6. Throttle Position (TP) has not increased more than 8 percent in one second.
  7. TP has not decreased more than 1.5 percent in one second.

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

  1. DTCs P0105, P0107, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0336, P0340, P0341, P0342, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133, or P1621 are not set.
  2. Engine speed is 469-6400 RPM.
  3. Battery voltage is 9-17 volts.
  4. Engine Coolant Temperature (ECT) is 20-254°F (-7 to 123°C).
  5. Engine has been running for more than 5 seconds.
  6. Throttle Position (TP) has not increased more than 8 percent in one second.
  7. TP has not decreased more than 1.5 percent in one second.

DTC sets when misfire total is more than 8 counts.

  1. Engine speed is 469-5906 RPM.
  2. Battery voltage is 9-17 volts.
  3. Engine Coolant Temperature (ECT) is 20-254°F (-7 to 123°C).
  4. Engine has been running more than 5 seconds.
  5. Fuel level is more than 10 percent.

DTC sets when PCM detects a crankshaft rotation speed variation indicating a misfire rate sufficient to cause emissions levels to exceed a mandated standard.

  1. DTCs P0105, P0107, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133, or P1621 are not set.
  2. Engine speed is 469-6400 RPM.
  3. Battery voltage is 9-17 volts.
  4. Engine Coolant Temperature (ECT) is 20-254°F (-7 to 123°C).
  5. Engine has been running more than 5 seconds.
  6. Throttle Position (TP) has not increased more than 8 percent in one second.
  7. TP has not decreased more than 1.5 percent in one second.

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

  1. DTCs P0122 or P0123 are not set.
  2. Engine run time is more than 20 seconds.
  3. Engine Coolant Temperature (ECT) is more than 131°F (56°C).
  4. Engine speed is 1600-6400 RPM.
  5. Manifold Absolute Pressure (MAP) is more than 60 kPa.

DTC sets when KS voltage and variation is not within normally expected ranges for more than 15 seconds.

  1. DTCs P0122 or P0123 are not set.
  2. Engine Coolant Temperature (ECT) is more than 140°F (70°C).
  3. Engine run time is more than 20 seconds.
  4. Manifold Absolute Pressure (MAP) is more than 60 kPa.
  5. Engine speed is 1800-6400 RPM.

DTC sets when KS is outside assigned range, or KS is not present.

  1. DTC P0341 is not set.
  2. Engine is running.

DTC sets when CKP re-sync counter goes more than 15 times within 4 minutes and 15 seconds.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel for an initial failure. AF ECU will run this DTC in gasoline mode after an initial alternative fuel mode failure.
  2. MAP sensor signal indicates 31.07 in. Hg (105.23 kPa) or less.
  3. Cam signal monitored indicates engine is cranking or running.

DTC will set when AF ECU detects no CKP reference signal when a cam sensor signal is detected. When DTC is set, engine will switch over to gasoline operation.

  1. Engine is running.
  2. DTC P0341 is not set.

DTC sets when CKP resync counter goes more than 15 times within 4 minutes and 15 seconds.

  1. Engine is running.

DTC sets when there is no change in cam activity for 30 crankshaft revolutions.

  1. Engine is running.

DTC sets when PCM sees more than 15 CMP sensor re-syncs in 256 seconds (4 minutes 16 seconds).

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0131, P0132, P0133, P0134, P0137, P0138, P0140, P0141, P0171, P0172, P0201-P0204, P0300, P0301-P0304, P0325, P0336, P0340, P0341, P0440, P0442, P0446, P0452, P0453, P0480, P0502, P0503, P0506, P0507, P0601, P0602, P1133, P1336, P1441, or P1621 are not set.
  2. Engine has been running more than 530 seconds after throttle has moved.
  3. BARO is more than 72 kPa.
  4. Vehicle is in closed loop operation.
  5. Vehicle has been driven at more than 1000 RPM for more than 35 seconds if vehicle has an automatic transmission.
  6. Vehicle has been driven at more than 1000 RPM for more than 45 seconds if vehicle has a manual transmission.
  7. Battery voltage is more than 9 volts.

With vehicle stopped

  1. Engine is idling less than 150 RPM from desired idle.
  2. Vehicle is in Drive (automatic transmission) or in Neutral (manual transmission).
  3. Throttle Position (TP) is zero percent.
  4. Engine Coolant Temperature (ECT) is 56-257°F (69-125°C).
  5. Intake Air Temperature (IAT) is -4 to 176°F (-20 to 80°C).
  6. Short Term (ST) fuel trim is between -28 to +28 percent.
  7. Catalytic temperature is more than 950°F (510°C).
  8. Specified conditions are present for up to 30 seconds.
  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0131, P0132, P0133, P0134, P0137, P0138, P0140, P0141, P0171, P0172, P0201-P0204, P0300, P0325, P0336, P0340, P0341, P0440, P0442, P0446, P0452, P0453, P0480, P0481, P0502, P0503, P0506, P0507, P0601, P0602, P1133, P1171, P1336, P1441, or P1621 are not set.
  2. Engine has been running more than 520 seconds after throttle has moved.
  3. Barometric (BARO) pressure is more than 72 kPa.
  4. Vehicle is in closed loop operation.
  5. Vehicle has been driven at more than 1200 RPM for more than 45 seconds.
  6. Battery voltage is more than 9 volts.

Then, with vehicle stopped

  1. Engine is idling at less than 150 RPM from desired idle.
  2. Vehicle is in Drive.
  3. Throttle Position (TP) is zero percent.
  4. Engine Coolant Temperature (ECT) is between 156-257°F (69-125°C).
  5. Intake Air Temperature (IAT) is -4-176°F (-20-80°C).
  6. Short Term (ST) fuel trim is 93-163 (-28 percent to +28 percent).
  7. Predicted catalyst temperature is 923-1117.5°F (495-603°C).
  8. Specified conditions are present for up to 30 seconds.
  1. DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0452, or P0453 are not set. The ignition voltage is between 10 and 18 volts.
  2. Barometric pressure is more than 75 kPa.
  3. Fuel level is 15-85 percent.
  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. Start-up ECT and IAT are within 16°F (9°C) of each other.
  7. Vehicle Speed Sensor (VSS) is less than 75 MPH.

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

  1. DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0452, or P0453 are not set.
  2. Ignition voltage is 10-18 volts.
  3. Barometric (BARO) pressure is more than 75 kPa.
  4. Fuel level is 15-85 percent.
  5. Engine Coolant Temperature (ECT) is 39-86°F (4-30°C).
  6. Intake Air Temperature (IAT) is 39-86°F (4-30°C).
  7. Start up ECT and IAT are within 16°F (9°C) of each other.
  8. Vehicle Speed Sensor (VSS) is less than 75 MPH.

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

  1. DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0452, or P0453 are not set.
  2. Ignition voltage is 10-18 volts.
  3. Barometric (BARO) pressure is more than 75 kPa.
  4. Fuel level is 15-85 percent.
  5. Engine Coolant Temperature (ECT) is 39-86°F (4-30°C).
  6. Intake Air Temperature (IAT) is 39-86°F (4-30°C).
  7. Start up ECT and IAT are within 16°F (9°C) of each other.
  8. Vehicle Speed Sensor (VSS) is less than 75 MPH.

DTC sets when fuel tank pressure is less than -10 in. H2O for as long as 30 seconds.

  1. Ignition is on.

DTC sets when FTP sensor voltage is less than 0.1 volt for more than 5 seconds.

  1. Ignition is on.

Fuel tank pressure sensor voltage is more than 4.9 volts. All conditions present for more than 5.0 seconds

  1. Ignition is on.

DTC sets when fuel level input has not changed more than 1.6 percent in 120 miles.

  1. Ignition is on and system voltage is 11-16 volts.

DTC will set when fuel level sensor is less than 3.5 percent for more than 25 seconds on "J" body or less than 4 percent for more than 20 seconds on "N" body.

  1. Ignition is on and system voltage is 11-16 volts.

On "J" body, DTC sets when fuel level sensor is more than 98 percent for more than 25 seconds.

On "N" body, DTC sets when fuel level sensor voltage is more than 3 volts or more than 100 percent for more than 20 seconds.

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

An improper voltage level has been detected on cooling fan relay control circuit. Specified conditions are present for at least 30 seconds.

  1. Ignition voltage is 9-18 volts.
  2. Engine speed is more than 80 RPM.
  3. PCM driver transitions from on to off or from off to on.

DTC sets when an improper voltage level has been detected on low speed cooling fan relay control circuit for at least 30 seconds.

  1. Ignition voltage is 9.0-18.0 volts.
  2. Engine speed is more than 80 RPM.
  3. PCM driver transitions from on to off or from off to on.

DTC sets when an improper voltage level has been detected on high speed cooling fan relay control circuit for at least 30 seconds.

  1. DTCs P0107, P0108, P0121, P0122, P0123, P0716, P0717 or DTC P1810 are not set.
  2. Transmission is in a Drive.
  3. TP angle is more than 12 percent.
  4. MAP is more than 50 kPa.
  5. Input speed is more than 2000 RPM.

DTC sets when output speed is less than 2 MPH for 3 seconds.

  1. DTCs P0107, P0108, P0122 or P0123 are not present.
  2. Engine speed is 1700-3600 RPM.
  3. Throttle Position (TP) is 0-1 percent.
  4. Engine vacuum is 21-24 in. Hg.
  5. Specified conditions are met for 5 seconds.

DTC sets when vehicle speed is less than 2 MPH.

  1. DTC P1810 must not be set.
  2. Engine run time is more than 5 seconds.
  3. Time since gear select lever change is more than 6 seconds.
  4. An increase in output speed of 500 RPM or more has not occurred for more than 5 seconds.

DTC sets when output speed drops more than 1200 RPM for 3 seconds.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0171, P0172, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0502, P0503, P1133, or P1441 are not set.
  2. ECT is more than 104°F (40°C).
  3. BARO is more than 72 kPa.
  4. Engine run time is more than 20 seconds.
  5. Ignition voltage is more than 11.3 volts.

DTC sets when

  1. Actual engine speed is 100 RPM less than desired engine speed for 19 seconds for M/T.
  2. Actual engine speed is 60 RPM less than desired engine speed for 13 seconds for A/T.
  3. IAC command is more than 145 counts.
  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0171, P0172, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0502, P0503, P1133, or P1441 are not set.
  2. ECT is more than 104°F (40°C).
  3. BARO is more than 72 kPa.
  4. Engine run time is more than 20 seconds.
  5. Ignition voltage more than 11.3 volts.

DTC sets when actual engine speed is 60 RPM more than desired engine speed for 13 seconds. IAC command is less than 2 counts.

  1. Engine speed more than 1500 RPM.
  2. System voltage 9.5-18.0 volts.

DTC sets when PCM detects a system voltage less than 10 volts for 5 seconds.

  1. Engine speed more than 1500 RPM.
  2. System voltage 9.5-18.0 volts.

DTC sets when PCM detects system voltage more than 16 volts for less than one second.

For DTC to run, ignition must be on. DTC will set when AF ECU detects and internal malfunction.

  1. Key On Test No generator, CKP sensors, or CMP sensor DTCs are set. Key is in RUN position. Engine is not running.
  2. Run Test No generator, CKP sensors, or CMP sensor DTCs are set. Engine is running.

DTC sets when

  1. Key On Test PCM detects a high signal voltage on generator turn on signal circuit for at least 5 seconds.
  2. Run Test PCM detects a low signal voltage on generator turn on signal circuit for at least 15 seconds.
  1. Key On Test No generator, CKP sensor, or CMP sensor DTCs are set. Key is in RUN position. Engine is not running.
  2. Run Test No generator, CKP sensors, or CMP sensor DTCs are set. Engine speed is less than 3000 RPM.

DTC sets when

  1. Key On Test PCM detects a PWM signal more than 65 percent for at least 5 seconds.
  2. Run Test PCM detects a PWM signal less than 5 percent for at least 15 seconds.
  1. System voltage is 8-18 volts.
  2. Engine run time is more than 5 seconds.
  3. Vehicle speed is more than 5 MPH.

DTC sets when combination of TR switch signals is invalid for 5 seconds. see scheme 16

  1. Ignition switch is on and system voltage is 8-18 volts.

DTC sets if PCM detects an open brake switch or circuit (zero volts) for 15 minutes and the following conditions occur 8 times

  1. Vehicle speed is less than 5 MPH
  2. Then, vehicle speed is 5-20 MPH for 3 seconds
  3. Then, vehicle speed is more than 20 MPH for 6 seconds.
  1. Ignition is on.
  2. System voltage is 8-18 volts.

DTC sets if PCM detects a closed brake switch or circuit (12 volts) during vehicle deceleration and the following conditions occur 8 times

  1. Vehicle speed is more than 20 MPH for 6 seconds
  2. Then, vehicle speed is 5-20 MPH for 3 seconds
  3. Then, vehicle speed is less than 5 MPH.
  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201-P0204, P0300, P0301-P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Engine Coolant Temperature (ECT) is more than 158°F (70°C).
  3. Engine speed is 1600-2450 RPM.
  4. Engine is operating in closed loop.
  5. Throttle Position (TP) angle is between 9-18 percent.
  6. Evaporative emissions control system is commanded open for more than 36 percent.
  7. Purge learned memory is more than approximately 0.78.
  8. Fuel level is more than 10 percent.
  9. Diagnostic test completes when 30 seconds of accumulated time has been spent in specified conditions.

DTC sets when number of rich to lean counts is less than 2, or lean to rich counts is less than 2.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0336, P0440, P0446, P0452, P0453, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Engine is in power enrichment mode.
  3. Battery voltage is more than 10.0 volts.
  4. Engine Coolant Temperature (ECT) is more than 158°F (70°C).
  5. Fuel level is more than 10 percent.
  6. Engine has been running more than 10 seconds.

DTC sets when HO2S2 remains less than 400 millivolts for more than 5 seconds. Diagnostic then will run for 11 seconds after a 5-second delay.

  1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0172, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0446, P0452, P0453, P0506, P0507, P0601, P0602, or P1441 are not set.
  2. Engine is in Decel Fuel Cut-Off (DFCO) mode.
  3. Battery voltage is more than 10 volts.
  4. Engine Coolant Temperature (ECT) is more than 158°F (70°C).
  5. Fuel level is more than 10 percent.
  6. Engine has been running for more than 10 seconds.

DTC sets when HO2S2 remains at more than 648 millivolts for more than 10 seconds. Diagnostic then will run for 11 seconds after a 10-second delay in order to complete one test.

  1. DTCs P0131, P0132, P0133, P0134, or P1133 are not set.
  2. Engine Coolant Temperature (ECT) is more than 70°F (20°C).
  3. Engine has been running for more than 20 seconds.
  4. Engine is operating in a closed loop operation.

DTC sets when O2S1 voltage is less than 300 millivolts for 5 seconds and engine is in power enrichment mode.

For DTC to run, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. No AF ECU ECT, O2S or GMS DTCs are set.
  3. Engine speed is more than 500 RPM.
  4. Battery voltage is more than 10 volts.
  5. Fuel Pressure Sensor (FPS) indicates CNG fuel level is more than one-quarter full.
  6. Engine coolant temperature is 176-221°F (80-105°C).
  7. AF ECU is not operating in fuel cut-off mode (DFCO, speed limiting, etc.).

DTC will set when difference between Desired Gas Flow and Actual Gas Flow is more than 45 percent for 5 seconds. When DTC is set, AF ECU will switch-over to gasoline fuel operation. AF ECU will not attempt alternative fuel operation until next ignition key cycle.

DTC will run under 2 conditions, engine cranking and engine running. For DTC to run while engine is cranking, engine must be cranking on alternative fuel with engine speed 25-500 RPM and battery voltage more than 8 volts. For DTC to run while engine is running, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine has been operating for more than 10 seconds.
  3. Engine speed is more than 500 RPM.
  4. Battery voltage is more than 10 volts.

While engine is cranking, DTC will set when AF ECU detects GMS actual gas flow signal circuit frequency of less than 250 Hz for at least 0.5 continuous second. While engine is running, DTC will set when AF ECU detect GMS actual gas flow signal circuit frequency of less than 500 Hz for at least 0.5 continuous second. When DTC is set, AF ECU will switch-over to gasoline fuel operation. AF ECU will not attempt alternative fuel operation until next ignition key cycle.

DTC will run under 2 conditions, engine cranking and engine running. For DTC to run while engine is cranking, engine must be cranking on alternative fuel with engine speed 25-500 RPM and battery voltage more than 8 volts. For DTC to run while engine is running, the following conditions must be met

  1. Engine is operating on alternative fuel.
  2. Engine has been operating for more than 10 seconds.
  3. Engine speed is more than 500 RPM.
  4. Battery voltage is more than 10 volts.

While engine is cranking or running, DTC will set when AF ECU detects GMS actual gas flow signal circuit frequency of more than 2900 Hz for at least 0.5 continuous second. When DTC is set, AF ECU will switch-over to gasoline fuel operation. AF ECU will not attempt alternative fuel operation until next ignition key cycle.

For DTC to run, ignition must be on. DTC will set when AF ECU detects a control circuit fault for at least one second.

  1. DTCs P0336, P0340, or P0341 are not set.

DTC sets when PCM has not successfully learned crankshaft position system variation.

For DTC to run, engine must be operating on alternative fuel. DTC will set when AF ECU detects an FPS signal voltage of less than 0.50 volt for at least one second.

For DTC to run, engine must be operating on alternate fuel. DTC will set when AF ECU detects an FPS signal voltage of more than 4.7 volts for at least one second.

  1. DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0440, P0442, P0446, P0452, or P0453 are not set.
  2. Ignition voltage is 10-18 volts.
  3. Barometric (BARO) pressure is more than 75 kPa.
  4. Fuel level is 15-85 percent.
  5. Engine Coolant Temperature (ECT) is 39-86°F (4-30°C).
  6. Intake Air Temperature (IAT) is 39-86°F (4-30°C).
  7. Start-up ECT and IAT are within 16°F (9°C) of each other.
  8. Vehicle Speed Sensor (VSS) is less than 75 MPH.

DTC sets when PCM detects vacuum during a non-purge condition.

  1. Engine is running.

DTC sets when PCM has detected a loss of state of health serial data message from theft deterrent system.

  1. VTD system has allowed fuel delivery. PCM is in theft deterrent password learn mode.

DTC sets when PCM remains in theft deterrent password learn mode for more than 2 seconds.

  1. Ignition is on.

DTC sets when PCM detects an incorrect password from VTD system. Condition is present for less than one second.

  1. Ignition is cycled to on.

DTC sets when PCM receives a fuel disabled password from BCM or an undecided password was sent from BCM.

More articles — Engine Controls Self-Diagnostics - 2.2L & 2.4L