Before Proceeding With Diagnosis, The Following Precautions Must Be Observed
- Ensure vehicle has a fully charged battery and functional charging system.
- Visually inspect connectors and circuit wiring being worked on.
- DO NOT disconnect battery or ECM unless directed to do so. Doing so will erase any fault codes stored in ECM.
- DO NOT cause short circuits when performing electrical tests. This will set additional fault codes, making diagnosis of the original problem more difficult.
- DO NOT use a test light in place of a voltmeter.
- When checking for spark, DO NOT hold coil wire more than1/4" from ground. Damage to vehicle electronics and/or ECM may result.
- DO NOT prolong testing of fuel injectors. Engine may hydrostatically (liquid) lock.
- When a vehicle has multiple fault codes, always repair lowest number fault code first.
RETRIEVING DTC(S)
Note. A scan tool is needed to perform diagnostic test.
- Connect and operate scan tool following manufacturer's instructions. Connect scan tool to Data Link Connector (DLC) located on left side of dash. (Scheme 1) Turn ignition on. Retrieve DTCs. Refer to appropriate diagnostic repair procedure. See DTC IDENTIFICATION table.
- Clear DTC(s) after repair is done following scan tool manufacturer's instructions, or by disconnecting negative battery cable for at least 15 seconds. Verify no DTCs are reset. Disconnect scan tool.
Scheme 1
CLEARING DTC(S)
After testing and repairs are completed, disconnect negative battery cable for at least 15 seconds to clear DTC(s).
DIAGNOSTIC PROCEDURE
Note. DTCs will be recorded at various operating times. Some DTCs require operation of sensor or switch for 5 seconds; other components require operation for 5 minutes or longer at normal operating temperature, vehicle speed, and load. Therefore, some DTC may not set in a service bay and may require road testing vehicle to duplicate the condition under which the DTC sets.
Diagnosis of computerized engine control system should be performed in the following order
- Ensure all engine systems other than computerized systems (i.e., compression, ignition, etc.) are operating properly. DO NOT proceed with testing unless all other problems have been repaired. If MIL light is on, see «RETRIEVING DTC(S)»(ref-16576-S00736652682000122900000) . For diagnosing hard codes, see «DIAGNOSTIC TROUBLE CODE (DTC) DEFINITION»(ref-16576-S32011127312000122900000) under DIAGNOSTIC TESTS to determine cause of malfunction.
- For diagnosing intermittent codes, proceed to INTERMITTENTS in «TESTS W/O CODES»(ref-16593) article. Inspect condition of system harness by conducting recommended voltage or continuity checks. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-16576-S33969347622000122900000) section for additional information on specific circuit configuration. Inspect condition of individual component. Repair or replace component as needed.
- Recheck system operation after repair is made. If DTC still exists, substitute with a known-good ECM. After repairs have been completed, clear DTCs. See «CLEARING DTC(S)»(ref-16576-S07254658492000122900000) .
DIAGNOSTIC TROUBLE CODE (DTC) DEFINITION
See DTC IDENTIFICATION table, then go to appropriate diagnostic procedure. Repair conditions which set DTC(s), beginning with lowest number first, then in ascending order.
| Code | Probable Cause |
|---|---|
| P0102 | Mass Airflow Sensor Circuit Low Input |
| P0103 | Mass Airflow Sensor Circuit High Input |
| P0112 | Intake Air Temp. Circuit Low Input |
| P0113 | Intake Air Temp. Circuit High Input |
| P0116 | Engine Coolant Temp. Sensor Circuit Range |
| P0117 | Engine Coolant Temp. Sensor Circuit Low Input |
| P0118 | Engine Coolant Temp. Sensor Circuit High Input |
| P0121 | TP Sensor Circuit Range |
| P0122 | TP Sensor Circuit Low Input |
| P0123 | TP Sensor Circuit High Input |
| P0130 | Front O2S Circuit Malfunction |
| P0131 | Front O2S Circuit Low Voltage |
| P0132 | Front O2S Circuit High Voltage |
| P0133 | Front O2S Circuit Slow Response |
| P0134 | Front O2S Circuit No Activity Detected |
| P0135 | Front O2S Heater Circuit Malfunction |
| P0136 | Rear O2S Circuit No Activity Detected |
| P0137 | Rear O2S Low Voltage |
| P0138 | Rear O2S High Voltage |
| P0141 | Rear O2S Heater Circuit Malfunction |
| P0201 | Injector No. 1 Circuit Malfunction |
| P0202 | Injector No. 2 Circuit Malfunction |
| P0203 | Injector No. 3 Circuit Malfunction |
| P0204 | Injector No. 4 Circuit Malfunction |
| P0300 | Random Misfire Detected |
| P0301 | Cylinder No. 1 Misfire Detected |
| P0302 | Cylinder No. 2 Misfire Detected |
| P0303 | Cylinder No. 3 Misfire Detected |
| P0304 | Cylinder No. 4 Misfire Detected |
| P0326 | Knock Sensor Circuit Range |
| P0335 | Crankshaft Position Sensor Circuit Malfunction |
| P0336 | Crankshaft Position Sensor Circuit Range |
| P0342 | Camshaft Position Sensor Circuit Low Input |
| P0343 | Camshaft Position Sensor Circuit High Input |
| P0421 (1) | Catalyst Efficiency Below Threshold |
| P0422 (2) | Catalyst Efficiency Below Threshold |
| P0441 | EVAP Purge Control System, Incorrect Purge Flow |
| P0444 | EVAP Purge Control Valve Circuit Open |
| P0445 | EVAP Purge Control Valve Circuit Shorted |
| P0501 | Vehicle Speed Sensor Range |
| P0506 | Idle RPM Lower Than Expected |
| P0507 | Idle RPM Higher Than Expected |
| P0562 (3) | System Voltage Low |
| P0563 (3) | System Voltage High |
| P0605 | Internal Control Module ROM Error |
| P1123 | Long Term Fuel Trim Additive Air, Too Rich |
| P1124 | Long Term Fuel Trim Additive Air, Too Lean |
| P1127 | Long Term Fuel Trim Multiplicative, Too Rich |
| P1128 | Long Term Fuel Trim Multiplicative, Too Lean |
| P1510 | Idle Control Valve Opening Coil Circuit Shorted |
| P1513 | Idle Control Valve Opening Coil Circuit Open |
| P1552 | Idle Control Valve Closing Coil Circuit Shorted |
| P1553 | Idle Control Valve Closing Coil Circuit Open |
| P1586 | Encoding Signal Circuit Out Of Range |
| P1605 | Acceleration/Rough Road Sensor Circuit Malfunction |
| P1606 | Acceleration/Rough Road Sensor Out Of Range |
| P1611 | MIL Request Signal Circuit Low Input |
| P1614 | MIL Request Signal Circuit High Input |
| P1624 (3) | Malfunction Of TCM Component |
| P1665 (3) | Power Stage Group "A" Malfunction |
| P1670 (3) | Power Stage Group "B" Malfunction |
| (1) California SOHC models. (2) Federal SOHC models. (3) Diagnostic information is not available from manufacturer. | |
| (1) | California SOHC models. |
| (2) | Federal SOHC models. |
| (3) | Diagnostic information is not available from manufacturer. |
DTC IDENTIFICATION