Malfunction Indicator Lamp (MIL) Inoperative

Malfunction Indicator Lamp (MIL) Inoperative

Circuit Description

Ignition 1 voltage is supplied directly to the malfunction indicator lamp (MIL). The engine control module (ECM) turns the MIL ON by grounding the MIL control circuit. There should be a steady MIL with the ignition ON and the engine OFF.

MIL Operation

The MIL is located on the instrument panel (I/P).

MIL Function
* The MIL informs the driver that a malfunction has occurred and the vehicle should be taken in for service as soon as possible.
* The MIL illuminates during a bulb test and a system test.
* A DTC will be stored if a MIL is requested by a diagnostic.

MIL Illumination
* The MIL will illuminate with ignition switch ON and the engine not running.
* The MIL will turn OFF when the engine is started.
* The MIL will remain ON if the self-diagnostic system has detected a malfunction.
* The MIL may turn OFF if the malfunction is not present.
* If the MIL is illuminated and then the engine stalls, the MIL will remain illuminated so long as the ignition switch is ON.
* If the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition switch is cycled OFF, then ON.

Test Description

The numbers below refer to the step numbers on the diagnostic table.
4. This step determines if the condition is with the MIL control circuit or the ECM.
5. This step determines if a voltage is constantly being applied to the control circuit.