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:
Basic inspection
When the malfunction is not confirmed in the dtc check, troubleshooting
should be carried out in all the
possible circuits considered as causes of the problem. In many cases, by
carrying out the basic engine check
shown in the following flowchart, the location causing the problem can be found ...
Air outlets
■ Location of air outlets
The air outlets and air volume changes according to the selected airflow mode.
: Some models
■ Adjusting the position of and opening and closing the air outlets
► Front center outlets
Direct air flow to the left or right, up or down.
► Fron ...
If your vehicle overheats
The following may indicate that your vehicle is overheating.
● Vehicles without a multi-information display: The high engine coolant temperature
warning light comes on or a loss of power is experienced.
Vehicles with a multi-information display: The engine coolant temperature gauge&n ...


