Malfunction Indicator Lamp: Description and Operation

The instrument panel mounted ``Check Engine'' lamp is used to alert the operator of malfunctions within the C3 system. When the ignition is on with the engine stopped, the lamp is illuminated as a bulb check. When the engine is running, the lamp will be illuminated whenever the ECM senses a system malfunction. In addition, the lamp is used to access trouble codes stored in the ECM trouble code memory.