Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Ecm power source circuit / Circuit description
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

Other materials:
Circuit description
The speed sensor detects wheel speed and transmits the appropriate
signals to the ecu. These signals are used for control
of the abs control system. Each of the front and rear rotors has
48 serrations.
When the rotors rotate, the magnetic field generated by the permanent
magnet in the spe ...
Driving the vehicle
The following procedures
should be observed to
ensure safe driving:
Driving procedure
■ Driving
1. With the brake pedal
depressed, shift the shift
lever to D.
2. Release the parking brake.
If the parking brake is in automatic
mode, the parking brake will be
released automatically.
3. Gradually re ...
Check and replace ecu
Notice:
start an inspection of the connector from the backside
of the connector on the wire harness side with
the connector connected to the ecu.
When no measurement condition is specified, perform
the inspection with the engine stopped and also
the ignition switch on.
First check the ec ...


