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:

    Inspection procedure
    Hint: read freeze frame data using the hand-held tester or the obd ii scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the ...

    Steering wheel audio switches
    Some audio features can be controlled using the switches on the steering wheel. Operation may differ depending on the type of audio system or navigation system. For details, refer to the manual provided with the audio system or navigation system. Operating the audio system using the steering whe ...

    What to do if... (Troubleshooting)
    If there is a problem with the hands-free system or a Bluetooth® device, first check the table below. ► When using the hands-free system with a Bluetooth® device ► When registering/connecting a cellular phone ► When making/receiving a call ► When using the p ...