Malfunction Indicator Lamp: Testing and Inspection

The Malfunction Indicator Light (MIL) will come on when the Electronic Control Module (ECM) detects an irregularity in one or more of the following monitored circuits: the ECM, injector, fuel pump, oxygen sensor, air flow sensor, intake air temperature sensor, throttle position sensor, engine coolant temperature sensor, crank angle sensor, top dead center sensor or barometric pressure sensor circuits.

When an irregular signal returns to normal or is repaired and the ECM judges that it has returned to normal, the MIL will turn "OFF". When the ignition switch is turned "OFF" then malfunction indicator light will turn off until the ignition switch is turned back "ON" and the irregular signal is detected again. The ECM will retain a fault code corresponding to the detected irregularity for 50-100 starts after the irregularity was detected unless the battery or ECM are disconnected.