Self-Diagnostic Feature

The control unit's self-diagnostic feature (with internal memory) detects malfunctions in the control unit or in emission-related components and stores fault codes. The control unit provides a substitute value if a failure occurs in the engine (coolant) temperature sensor, intake air temperature sensor, airflow meter or the exhaust gas oxygen sensor.

These substitute values are canceled when normal engine operation is resumed. To aid in trouble shooting, stored fault codes and sensor values can be monitored via the control unit and actuated components.