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Diagnostic Procedures

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  1. 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.
  2. Verify whether the Instrument Panel (IP) is operational. If the IP is completely inoperative, see appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Verify whether the MIL turns ON and OFF when commanded. Turn ON the ignition, with the engine OFF. Command the MIL ON and OFF using the scan tool. Repeat the commands as necessary. Does the MIL turn ON and OFF when commanded? If yes, see DIAGNOSTIC AIDS . If no, go to next step.
  3. Turn OFF the ignition. Disconnect the PCM connector C2 located on the opposite side of the manufacturer logo. Turn ON the ignition. Is the lamp OFF? If yes, go to next step. If no, go to step  5.
  4. Probe the lamp control circuit in the PCM harness connector with a fused jumper wire connected to ground. Is the lamp ON? If yes, go to step  6. If no, go to step  7.
  5. Repair the short to ground in the lamp control circuit. After repairs, go to step  9.
  6. Inspect for poor connections at the PCM. If you find a poor connection, repair the terminal as necessary. Did you find and correct the condition? If yes, go to step  9. If no, go to step  8.
  7. Test for the following conditions:
    • A faulty Instrument Panel Cluster (IPC). See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT.
    • An open ignition feed to the IPC. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT.
    • A control circuit open or shorted to battery voltage.

    Repair as necessary. After repairs, go to step  9.

  8. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  9. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  10. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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