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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    System description
    The ecm uses signals from the vehicle speed sensor and crankshaft position sensor to detect the actual gear position (1st, 2nd, 3rd or o/d gear). Then the ecm compares the actual gear with the shift schedule in the ecm memory to detect the mechanical trouble of the shift solenoid valves, th ...

    On–vehicle inspection
    1. Check fuel pump operation Connect the hand–held tester to the dlc3.  turn the ignition switch on and hand–held tester main switch on. Notice: do not start the engine.  select the active test mode on the hand–held tester.  please refer to the hand–held te ...

    Mechanical system tests
    1. Perform mechanical system tests Measure the stall speed. The object of this test is to check the overall performance of the transaxle and engine by measuring the stall speeds in the d and r positions. Notice: Do the test at normal operating atf temperature 50 to 80 °c (122 to ...