MIL Circuit: Description

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunction detections by the ECM. When the power switch is turned 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 power switch is turned ON (IG), the MIL should illuminate. Then when the power switch is turned ON (READY), the MIL should turn off. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the intelligent tester.