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A-1, Malfunction Indicator Light (Mil) Inoperative

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  1. If MIL does not illuminate with ignition on and engine off, attempt to start engine. If engine starts, go to step 3). If engine does not start, check fusible links at battery. Also check PCM fuse. If fusible links or PCM fuse are blown, repair short to ground.
  2. If fusible links and PCM fuse are okay, turn ignition on and check power circuits to PCM, including keep-alive memory and ignition feed. See appropriate WIRING DIAGRAM in the WIRING DIAGRAMS  section at the end of this article for power terminal identification. If power to PCM power terminals is not available, check for open in power circuits. If power to PCM power terminals is available, check for poor PCM ground circuits. If circuits are okay, replace faulty PCM.
  3. Turn ignition off. Disconnect PCM connectors. Turn ignition on, and connect PCM MIL driver terminal to ground using a test light. See See appropriate WIRING DIAGRAM in the WIRING DIAGRAMS  section at the end of this article for power terminal identification.
  4. If MIL is now on, repair MIL driver terminal connections at PCM, or replace faulty PCM. If MIL stays off when test light is used to ground MIL driver terminal, check for blown instrument panel fuse, faulty bulb, open in MIL driver circuit between PCM and bulb, short in driver circuit to voltage or open in ignition feed to MIL.
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