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(sl) 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 wire c ...

    Replacement
    1. Disconnect battery negative terminal 2. Remove engine under cover rh 3. Remove starter assy Disconnect the starter connector.  open the terminal cover. remove the nut, then disconnect the starter wire.  remove the 2 bolts, then remove the starter. 4. Install starter a ...

    Overhaul
    1. Remove oil filler cap sub–assy Remove the oil filler cap from the cylinder head cover. 2. Remove oil filler cap gasket Using a screwdriver, remove the gasket from the oil filler cap. 3. Remove ventilation valve sub–assy Remove the ventilation valve from the cyl ...