Malfunction Indicator Lamp: Description and Operation

The Check Engine Light (CEL), also known as the Malfunction Indicator Light (MIL), is mounted in the dash and reads CHECK ENGINE or SERVICE SOON. The CEL will ILLUMINATE when the engine is operating in Failure Mode Effects Management (FMEM). The light will stay ON as long as there is a fault in the system. The CEL can also be used to retrieve fault codes from the Electronic Engine Control (EEC) system when the self test mode is entered.