Malfunction Indicator Lamp: Service and Repair

The check engine lamp will be illuminated when the ignition switch is in the ON position. When engine is started, the Check Engine lamp should go OFF. If lamp remains ON, a code has been stored in the Electronic Control Unit. After diagnosis and repair, place ignition switch in OFF position, then clear codes stored in the Electronic Control System memory by disconnecting the the battery ground cable for at least 16 seconds.