EFI Main Relay (LS400)

EFI main relay may also be referred to as EFI relay. EFI fuse No. 1 supplies constant battery voltage to one side of EFI main relay. EFI main relay is energized by MREL terminal of Engine Control Module (ECM). When EFI main relay is energized, EFI main relay provides battery voltage to circuit opening relay, through EFI fuse No. 2 and to data link connector No. 1 and various other electrical components. EFI main relay also provides battery voltage to +B and +B1 terminals of ECM. EFI main relay is located in fuse/relay box at driver's side of engine compartment, just in front of strut tower.