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Home >> Chevrolet >> 2002 >> Impala Base, 3.4 E >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 3.4L >> System Tests >> Mil Inoperative >> Diagnostic Procedures
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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. Attempt to start engine. Does engine start? If yes, go to next step. If no, go to step  9.
  3. Inspect the fuse supplying voltage to the MIL. Is fuse open? If yes, go to step  7. If no, go to next step.
  4. Turn OFF ignition. Disconnect PCM connector containing the MIL control circuit. Turn ON ignition, with engine OFF. Probe MIL control circuit in PCM harness connector with a fused jumper wire connected to ground. Is MIL ON? If yes, go to step  16. If no, go to next step.
  5. Turn ignition off. Remove Instrument Panel (IP). Probe the MIL ignition positive voltage circuit at the IP harness connector with a test light connected to a good ground. Is test light illuminated? If yes, go to next step. If no, go to step  8.
  6. Test the MIL control circuit for an open or high resistance and repair as necessary. Did you find and correct the condition? If yes, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. If no, go to step  14.
  7. Repair the short to ground in the MIL ignition positive voltage circuit. After repairs, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  8. Repair the open in the MIL ignition positive voltage circuit. After repairs, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  9. Inspect PCM fuse and ignition 1 main fuse. Is one or both of the fuses open? If yes, go to step  12. If no, go to next step.
  10. Turn OFF ignition. Disconnect PCM. Turn ON ignition, with engine OFF. Connect a test light between PCM ignition positive voltage circuits and a good ground. Does the test light illuminate while probing all PCM ignition positive voltage circuits? If yes, go to next step. If no, go to next step  12.
  11. Connect a test light from PCM battery positive voltage circuit and good ground. Does the test light illuminate? If yes, go to step  13. If no, go to next step.
  12. Locate and repair open or short to ground in PCM ignition feed circuits or PCM battery positive voltage circuit. After repairs, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  13. Inspect for a poor PCM ground or a poor PCM ground connection. Repair the condition as necessary. Did you find and correct the condition? If yes, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. If no, go to step  15.
  14. Inspect for poor connections at the IP and repair as necessary. Did you find and correct the condition? If yes, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. If no, go to step  16.
  15. Inspect for poor connections at PCM and repair as necessary. Did you find and correct the condition? If yes, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. If no, go to step  17.
  16. Replace the IP. When complete, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  17. Replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. When complete, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
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