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

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    On–vehicle inspection
    1. Inspect pressure switch no.1. Magnetic clutch control: inspect pressure switch operation.  Set on the manifold gauge set.  Connect the positive (+) lead from the ohmmeter to terminal 4 and the negative (–) lead to terminal 1.  Check continuity between termin ...

    Have the malfunction repaired immediately. (vehicles with a smart key system)
    After taking the specified steps to correct the suspected problem, check that the warning message and light go off. ■Warning buzzer ...

    Follow the correction procedures. (vehicles with a smart key system and with a drive monitor display)
    After taking the specified steps to correct the suspected problem, check that the warning light turns off. ■SRS warning light This warning light system monitors the airbag sensor assembly, front impact sensors, side impact sensors (front door), side impact sensors (front), side impac ...