Diagnostic Procedures
- Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM.
- 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 OFF the ignition. Disconnect the PCM. See COMPONENT LOCATIONS . Turn ON the ignition, with the engine OFF. Connect a 3-amp fused jumper wire between the MIL control circuit and a good ground. Observe the MIL. Is the 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). See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Test the MIL control circuit for an open between the PCM and the 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 lamp connected to a good ground. Does the test lamp illuminate? If yes, go to step 8. If no, go to next step.
- Repair the 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 the short to ground in the MIL battery positive voltage circuit. Replace the fuse. After repairs, go to step 14.
- Repair the short to voltage in the MIL control circuit. After repairs, go to step 14.
- Repair or replace the IPC. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs, go to step 14.
- Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE 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.