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Home >> Pontiac >> 2002 >> Firebird Base, 2D Convertible, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P0650: Mil Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

  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. NOTE: If the MIL fuse is open, locate and repair a short to ground in the MIL battery positive voltage circuit or a shorted cluster.
  2. Inspect the MIL fuse, and replace as necessary. Was the fuse open? If yes, go to step  12. If no, go to next step.
    3. NOTE: If the jumper fuse opens, locate and repair a short to voltage in the MIL control circuit or a shorted cluster.
  3. Turn OFF the ignition. Disconnect the PCM. Install a 3-amp fused jumper between the MIL control circuit at the PCM harness connector and a good ground. Turn ON the ignition, with the engine OFF. Is the MIL illuminated? If yes, go to next step. If no, go to step  5.
  4. Leaving the ignition ON, remove the jumper. Is the MIL illuminated? If yes, go to step  7. If no, go to step  9.
  5. Remove the Instrument Panel Cluster (IPC). See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Test the MIL control circuit for an open, and repair as necessary. Did you find and correct the condition? If yes, go to step  12. If no, go to next step.
  6. Test the MIL battery positive voltage circuit for an open, and repair as necessary. Did you find and correct the condition? If yes, go to step  12. If no, go to step  8.
  7. Remove the instrument panel cluster. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Test the MIL control circuit for a short to ground, and repair as necessary. Did you find and repair the condition? If yes, go to step  12. If no, go to step  10.
  8. Inspect the cluster harness connector for faulty connections, and repair as necessary. Did you find and repair the condition? If yes, go to step  12. If no, go to step  10.
  9. Inspect the PCM and the PCM harness connector for faulty connections, and repair as necessary. Did you find and correct the connection? If yes, go to step  12. If no, go to step  11.
  10. Repair or replace the instrument panel cluster. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs, go to step  12.
  11. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  12. 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.
  13. 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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