Circuit Description

The MIL is used to indicate the ECM's detection of a vehicle malfunction.

The instrument panel GAUGE fuse provides the circuit power and the ECM provides the circuit ground that illuminates the MIL.

Operation of MIL should be checked visually:

When the ignition is first turned to ON, the MIL should be illuminated. If the MIL is always OFF or ON, use the hand-held tester or OBD II scan tool and follow the procedure below to determine cause of the problem.