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A-1, Mil Inoperative

WARNING: This page is about a different car, the 1996 Pontiac Firebird and 1996 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . After performing OBD system check, go to next step.
  2. Turn ignition on with engine off. If Malfunction Indicator Light (MIL) illuminates, go to step 4). If MIL does not illuminate, go to next step.
  3. Start engine. If engine starts, go to step 5). If engine does not start, go to step 6).
  4. Install Tech 1 scan tool. Turn ignition on. Using scan tool, command MIL to turn on and off. If MIL turns on and off as commanded, go to step 24). If MIL does not turn on and off as commanded, go to next step.
  5. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Using a test light connected to ground, probe MIL driver circuit (Brown/White wire). See Figure . If MIL illuminates, go to step 7). If MIL does not illuminate, go to step 8).
  6. Inspect ignition and battery fuses. If fuses are okay, go to step 9). If fuses are faulty, go to step 10).
  7. Using a test light connected to ground, probe PCM harness connector ignition feed terminal No. 3 (Pink wire). See Figure . If test light illuminates, go to step 11). If test light does not illuminate, go to step 12).
  8. If test light illuminated, go to step 13). If test light did not illuminate, go to step 19).
  9. Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Using a test light connected to ground, probe PCM harness connector ignition feed circuit No. 2 (Pink wire). See Figure . If test light illuminates, go to test 18). If test light does not illuminate, go to step 19).
  10. Check for short to ground in fuse circuit that was open. See Figure . Repair as necessary and replace fuse. After repairs, go to step 22).
  11. Check for faulty PCM connections. If connections are okay, replace PCM and then perform OBD system check. After repairs, go to step 22).
  12. Repair open in ignition feed circuit No. 3 (Pink). See Figure . After repairs, go to step 22).
  13. Repair short to voltage in MIL control circuit (Brown/White wire). See Figure . After repairs, go to step 22).
  14. Check for open in MIL control circuit. Repair as necessary. After repairs, go to step 22). If circuit is okay, go to next step.
  15. Check for open in ignition feed circuit or fuse to MIL. See Figure . Repair as necessary. After repairs, go to step 22). If circuit or fuse is okay, go to next step.
  16. Check for an open MIL bulb. If light bulb is faulty, go to step 22). If light bulb is okay, go to next step.
  17. Replace instrument cluster assembly. After replacing instrument cluster, go to step 22).
  18. Using test light connected to ground, probe battery feed circuit (Orange wire). See Figure . If test light illuminates, go to step 20). If test light does not illuminate, go to step 21).
  19. Repair open in ignition feed circuit No. 2 (Pink wire). See Figure . After repairs, go to step 22).
  20. Check for faulty PCM ground connection at engine block. After repairs, go to step 22). If connections were okay, go to step 11).
  21. Repair open in battery feed circuit (Orange wire). See Figure . After repairs, go to next step.
  22. Start and warm engine to normal operating temperature. Check if any DTCs are set. Diagnose any DTC present. See TESTS W/CODES article.
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