Circuit Description
WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.
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.