Malfunction Indicator Lamp (MIL) "ON" Steady
Malfunction Indicator Lamp (MIL) "ON" SteadyCircuit Description
The malfunction indicator lamp (MIL) should always be illuminated and steady with ignition "ON" and the engine "OFF". Ignition feed voltage is supplied directly to the MIL indicator. The Engine Control Module (ECM) turns the MIL "ON" by grounding the MIL driver circuit.
The MIL should not remain "ON" with the engine running and no DTC(s) set. A steady MIL with the engine running and no DTC(s) suggests a short to ground in the MIL driver circuit.
Diagnostic Aids
An intermittent may be caused by a poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Check for the following items:
- Poor connection or damaged harness - Inspect the ECM harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness.
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Chart.
2. If the MIL does not remain "ON" when the ECM is disconnected, the MIL driver wiring is not faulty.
3. If the MIL driver circuit is OK, the instrument panel cluster is faulty.
6. This vehicle is equipped with a ECM which utilizes an electrically erasable programmable read only memory (EEPROM). When the ECM is replaced, the new ECM must be programmed. Refer to ECM Replacement and Programming Procedures in Engine Control Module (ECM) and Sensors.
