A-1, Malfunction Indicator Light (Mil) Inoperative
- 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 ECM fuse. If fusible links or ECM fuse are blown, repair short to ground.
- If fusible links and ECM fuse are okay, turn ignition on and check power circuits to ECM, including keep-alive memory and ignition feed. See WIRING DIAGRAMS at the end of this article for power terminal identification. If power to ECM power terminals is not available, check for open in power circuits. If power to ECM power terminals is available, check for poor ECM ground circuits. If circuits are okay, replace faulty ECM.
- Turn ignition off. Disconnect ECM connectors. Turn ignition on, and connect ECM MIL driver terminal to ground using a test light. See WIRING DIAGRAMS at the end of this article for power terminal identification.
- If MIL is now on, repair MIL driver terminal connections at ECM, or replace faulty ECM. 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 ECM and bulb, short in driver circuit to voltage or open in ignition feed to MIL.