Malfunction Indicator Lamp: Description and Operation

PURPOSE
The Malfunction Indicator Lamp (MIL) is used to alert the vehicle operator If exhaust influencing malfunctions are diagnosed from the control module .

OPERATION
The MIL will be illuminated when the ignition switch is placed in the ON position. After the engine is started, the lamp should go off. If the lamp remains on or comes on during engine operation there is one or more malfunctions in the emissions system or engine management system. The On Board Diagnostic (OBD) system should be checked and the malfunction corrected as soon as possible.

Extremely critical malfunctions are indicated immediately by the MIL.

Less critical malfunctions are indicated if they occur during two sequential "trips".