Diagnostic System

The ECM of the CCC system is equipped with a self-diagnostic system which detects system failures or abnormalities. When a malfunction occurs, ECM will light the amber "CHECK ENGINE" lamp located on instrument panel. When malfunction is detected 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 lamp to flicker or go out after 10 seconds when fault goes away. However, the associated trouble code will be retained in ECM memory. "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 fault does not recur within 50 ignition cycles, related trouble code will be erased from ECM memory.

As a bulb and system check, the "CHECK ENGINE" lamp will glow when ignition switch is turned on and engine is not running. When engine is started, the lamp should go out after 1-4 seconds. If not, a malfunction has been detected in CCC system.