Chart A-1, No Service Engine Soon Light: Notes

The SERVICE ENGINE SOON light is attached to the IPC. It is powered by CPS circuit No. 439. PCM completes the ground to turn the light on. The light will be on while engine is not running. With the engine running, a steady light indicates a PCM code is set

1. SERVICE ENGINE SOON light should be on.
2. Using a test light connected to battery voltage, probe each of the system ground circuits to be sure a good ground is present. See WIRING DIAGRAMS article in this section to identify system ground circuits.