Chart A-1, No "Check Engine" Light: Notes

The CHECK ENGINE light should remain on when ignition switch is in ON position and engine is not running. Battery voltage is applied to indicator bulb. The ECM controls the indicator bulb and turns it on by providing a ground path through the Purple wire to ECM.

1. Checks to see if ECM is receiving power.
2. Checks to see if ECM is faulty.
3. Checks for an open in White/Blue wire between fuel injection relay and ECM.
4. Checks to see if ECM has a good ground.
5. Checks for an open in Black/White wire to instrument panel and Purple wire to ECM.
6. Checks to see if fuel injection relay switch is receiving power.
7. Checks to see if fuel injection relay coil is receiving power.
8. Checks to see if fuel injection relay or ECM is faulty, or circuit is open in Black wire between fuel injection relay and ground.