Control Unit

The Electronic Control Assembly (ECA) monitors engine operating conditions by input received from engine switches and sensors. Control of output actuators determines fuel mixture and idle speed. For ECA location, see ELECTRONIC CONTROL ASSEMBLY (ECA) LOCATIONS table.

The engine control system consists of the ECA, relays, sensors, switches and actuators. The ECA sends out electrical reference signals to engine sensors and then analyzes the return signals. The engine sensors supply the ECA with specific information, in the form of electrical signals, to determine engine operating conditions. In the event of a sensor or actuator failure, the ECA initiates an alternative strategy called Failure Mode Effects Management (FMEM) to allow the vehicle to maintain driveability.

The CHECK ENGINE light will remain on whenever FMEM is in operation. FMEM substitutes a fixed sensor signal and continues to monitor the failed sensor. If the signals from a faulty sensor return to within operating limits, the ECA will resume using the sensor's signal.