Toyota Corolla (E120): Circuit description

The key unlock warning switch comes on when the ignition key is inserted in the key cylinder and goes off when the ignition key is removed.

Wiring diagram

Inspection procedure

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    Circuit description
    Refer to dtc p0120 Dtc no. Dtc detection condition Trouble area P0121 The following condition is met 4 times. After the vehicle speed has exceeded 19 mph (30 km/h) once, the throttle position sensor output value is out of normal range when the throttle ...

    Circuit description
    When the ignition switch is turned on, battery positive voltage is applied to the coilwhich closes the contacts of the efi main relay (marked: efi) and supplies power to terminal +b of the ecm. This signal causes current to flow to the coil, closing the contacts of the efi relay and supplyin ...

    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 ...