Diagnostic Procedures
- Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
- Inspect the fuse that supplies voltage to the MIL. Is the fuse open? If yes, go to step 10. If no, go to next step.
- Turn ignition off. Disconnect PCM. Turn ignition on, with engine off. Connect a 3-amp fused jumper wire between the MIL control circuit and a good ground. Observe the MIL. Is MIL illuminated? If yes, go to step 9. If no, go to next step.
- Did the fuse in the jumper wire open? If yes, go to step 11. If no, go to next step.
- Remove the Instrument Panel Cluster (IPC). Test the MIL control circuit for an open between the PCM and IPC and repair as necessary. Did you find and correct the condition? If yes, go to step 14. If no, go to next step.
- Probe the MIL battery positive voltage circuit at the IPC harness connector with a test light connected to a good ground. Does the test light illuminate? If yes, go to step 8. If no, go to next step.
- Repair open in the MIL battery positive voltage circuit. After repairs, go to step 14.
- Inspect for poor connections at the harness connector of the IPC and repair as necessary. Did you find and correct the condition? If yes, go to step 14. If no, go to step 12.
- Inspect for poor connections at the harness connector of the PCM and repair as necessary. Did you find and correct the condition? If yes, go to step 14. If no, go to step 13.
- Repair short to ground in the MIL battery positive voltage circuit. After repairs, go to step 14.
- Repair short to voltage in the MIL control circuit. After repairs, go to step 14.
- Replace IPC. After replacing IPC, go to step 14.
- Replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE REPROGRAMMING under PROGRAMMING. After repairs, go to next step.
- Operate the system in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to step 2.