Toyota Corolla (E120): Circuit description

The ignition switch provides circuit power and the ecm provides the circuit ground that illuminates the mil.

Mil operation is checked visually: it should be illuminated when the ignition is first turned on. If the mil is off all of the time or on all of the time, use the procedure below to troubleshoot it. The mil is used to indicate the ecm’s detection of a vehicle malfunction.

Follow this procedure using the hand–held tester or an obd ii scan tool to determine the cause of the problem and to check the mil.

Wiring diagram

Inspection procedure

    Share this page:

    Other materials:

    Emission inspection and maintenance (I/M) programs
    Some states have vehicle emission inspection programs which include OBD (On Board Diagnostics) checks. The OBD system monitors the operation of the emission control system. If the malfunction indicator lamp comes on The OBD system determines that a problem exists somewhere in the emission cont ...

    Inspection procedure
    1 Check fuse(ecu–ig) Remove the ecu–ig fuse from the instrument panel j/b.  check the continuity of the ecu–ig fuse. Ok: continuity 2 Inspect terminal voltage(b) Remove the cruise control ecu assy with connector still connected.  turn the ignition switch ...

    Components
    ...