Engine Malfunction Test

This test is constantly performed by ECM to detect system failures or malfunctions. When a malfunction occurs, ECM will light the amber "CHECK ENGINE" lamp located in right hand information center. When a malfunction occurs and lamp is turned on, a corresponding trouble code is stored in ECM memory. Malfunctions are recorded as "hard failures" or "intermittent failures".

• "Hard failures" cause "CHECK ENGINE" lamp to glow and remain on until malfunction is repaired. If the "CHECK ENGINE" lamp comes on and remains on during vehicle operation, cause of malfunction MUST be determined.
• "Intermittent failures" cause "CHECK ENGINE" lamp to flicker or go out after malfunction clears. "Intermittent failures" may be sensor related. If a sensor fails, ECM will use a substitute value in its calculations to continue engine operation. In this condition, service is not mandatory; but loss of driveability may be encountered. If the related sensor malfunction does not recur within 20 ignition cycles, related trouble code will be erased from ECM memory.