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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    Inspection procedure
    1 Inspect transmission wire(s1) Disconnect the transmission wire connector from the transaxle.  measure the resistance according to the value(s) in the table below. Standard: 2 Check harness and connector(transmission wire – ecm) Connect the transmission connec ...

    Purpose of the readiness tests
    The on–board diagnostic (obd ii) system is designed to monitor the performance of emission–related components and report any detected abnormalities in the form of diagnostic trouble codes (dtcs). Since the various components need to be monitored during different driving condition ...

    On–vehicle inspection
    1. Inspect drive belt Visually check the belt for excessive wear, frayed cords, etc. If any defect is found, replace the drive belt. Hint: cracks on the rib side of a belt are considered acceptable. If the missing chunks from the ribs are found on the belt, it should be replaced. 2 ...