Chart A-1, No Malfunction Indicator Light (Mil): Notes

Malfunction Indicator Light (MIL) should remain on when ignition switch is in ON position and engine is not running. Battery voltage is applied to indicator bulb. ECM controls indicator bulb and turns it on by providing a ground path through Purple/Yellow wire to ECM.

1. Checks if ECM is receiving power.
2. Checks if ECM is faulty.
3. Checks for open in Blue/Black wire between main relay and ECM.
4. Checks if ECM has a good ground.
5. Checks for open in Black/White wire to instrument panel, and Purple/Yellow wire to ECM.
6. Checks if main relay switch is receiving power.
7. Checks if main relay coil is receiving power.
8. Checks if main relay or ECM is faulty, or for open in Blue wire between main relay and ECM.
9. Checks for a faulty ignition switch or open in Black/Blue or Black/White wires to IG-COIL METER fuse.