Toyota Corolla (E120): 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 supplying power to terminal +b of the ecm.

If the ignition switch is turned off, the ecm continues to switch on the efi relay for a maximum of 2 seconds for the initial setting of the isc valve.

Wiring diagram

Inspection procedure

    Share this page:

    Other materials:

    Fail–safe chart
    If any of the following codes is recorded, the ecm enters the fail–safe mode. Check for intermittent problems Hand–held tester only: by putting the vehicle’s ecm in the check mode, the 1 trip detection logic is possible instead of the 2 trip detection logic, and the sensitivity to de ...

    Light control switch circuit
    Wiring diagram Inspection procedure 1 Check headlamp dimmer switch assy (light control switch) 2 Check wire harness (tvip ecu  light control switch) Disconnect the tvip ecu and light control switch connectors.  check the continuity between the terminals of the tvip e ...

    If the vehicle battery is discharged
    The following procedures may be used to start the engine if the vehicle’s battery is discharged. You can also call your Toyota dealer or a qualified repair shop. If you have a set of jumper (or booster) cables and a second vehicle with a 12-volt battery, you can jump start your vehicle by fo ...