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:

    Fuel pump shut off system
    To minimize the risk of fuel leakage when the engine stalls or when an airbag inflates upon collision, the fuel pump shut off system stops the supply of fuel to the engine. Follow the procedure below to restart the engine after the system is activated. ► Vehicles without a smart key syst ...

    Circuit description
    The seat belt buckle switch (lh) circuit consists of the airbag sensor assy center and front seat inner belt assy (lh). Dtc b0126/b0127/27 is recorded when a malfunction is detected in the seat belt buckle switch (lh) circuit. Wiring diagram ...

    Monitor description
    The battery supplies electricity to the ecm even when the ignition switch is off. This electricity allows the ecm store data such as dtc history, freeze frame data, fuel trim values, and other data. If the battery voltage falls below a minimum level, the ecm will conclude that there is a fault ...