Malfunction Indicator Lamp: Service and Repair

The check engine lamp will be illuminated when the ignition switch is placed in the "ON" position. When the engine is started, the lamp should go "OFF." If the lamp remains "ON" for 10 seconds or constantly after the engine is started, the self diagnosis system has detected a problem and has stored a code in the system Powertrain Control Module (PCM). After diagnosis and repair, the PCM memory can be cleared of codes as follows:

Remove the PCM fuse or disconnect the battery ground cable for approximately 30 seconds, with ignition switch in the "OFF" position. It should be noted, if battery ground cable is disconnected to clear codes, components such as clocks, electronically tuned radios etc., will have to be reset.

On vehicles that are equipped as such, the PCM power feed is connected by a pigtail, in-line fuse holder, at the positive battery terminal. To clear codes within the PCM system and protect the components that need resetting, disconnect the in-line fuse.