MIL Circuit: Description

The Malfunction Indicator Lamp (MIL) is used to indicate vehicle malfunctions detected by the ECM. By turning the engine switch on (IG), power is supplied to the MIL circuit, and the ECM provides the circuit ground which illuminates the MIL.

The MIL operation can be checked visually. When the engine switch is first turned on (IG), the MIL should illuminate and should then turn off. If the MIL remains illuminated or does not illuminate, conduct the following troubleshooting procedure. If the ECM detects any trouble, the MIL illuminates. At this time, the ECM records a DTC in the memory.