EFI Main Relay (ECHO)
EFI main relay may also be referred to as EFI relay. EFI fuse supplies constant battery voltage to one side of EFI main relay. When ignition is turned on, voltage is supplied to other side of EFI main relay from the ignition switch. EFI main relay is then energized and provides battery voltage to circuit opening relay and various other electrical components. EFI main relay also provides battery voltage to +B terminal of Engine Control Module (ECM) when ignition is turned on. For EFI main relay location, see EFI MAIN RELAY LOCATION table.