Engine Control Module: Description and Operation

Fig. 66 Check Engine Light:

CALIFORNIA MODELS ONLY

The electronic control unit (ECU) for the FBC, contains a self-diagnostic system that will store failure codes associated with the fuel and emission control systems. The ECU will analyze signals from various sensors and actuators and detect any system malfunctions. An instrument panel "CHECK ENGINE" lamp will light to indicate when a system defect occurs. The technician can then extract these failure codes, follow the testing procedures and use the information to repair the malfunction.