EFI Main Relay (Corolla)

The EFI fuse supplies constant battery voltage to EFI main relay. EFI fuse may also be referred to as F-HTR fuse. EFI main relay may also be referred to as EFI relay or F-HTR relay. When ignition is turned on, voltage is supplied through IGN fuse to EFI main relay. EFI main relay is then energized and provides battery voltage to circuit opening relay, data link connector No. 1 and various other electrical components. The EFI main relay also provides battery voltage to +B terminal of Engine Control Module (ECM) when ignition is turned on. See EFI MAIN RELAY LOCATION  table.