Diagnostic Systems

The ECM of the CCC system is equipped with a self-diagnosis system which detects system failures. When a malfunction occurs, the amber "CHECK ENGINE" light on instrument panel comes on and a corresponding trouble code is stored in ECM memory. Malfunctions are recorded as either "hard failures" or "intermittent failures".

"Hard failures" cause "CHECK ENGINE" light to come on, and stay on, until malfunction is repaired. When "CHECK ENGINE" light remains on during vehicle operation, cause of malfunction MUST be determined.

"Intermittent failures" cause light to flicker, and/or go out, 10 seconds after fault goes away. However, 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 driveability may suffer. If same or similar fault does not repeat within 50 ignition cycles, related trouble code will be erased from ECM memory.

As a bulb and system check, the "CHECK ENGINE" light will glow with ignition switch on and engine not running. When engine is started, light should go out within 4 seconds. If not, a malfunction has been detected in CCC system.