Circuit Opening Relay

Circuit opening relay controls the fuel pump circuit. When EFI main relay is energized, EFI main relay provides battery voltage to one side of circuit opening relay. When engine is cranking, circuit opening relay receives a start signal which energizes circuit opening relay. Circuit opening relay then provides voltage to fuel pump for fuel pump operation. When start signal is released from circuit opening relay and engine is running, the Engine Control Module (ECM) then uses engine speed input signal for controlling the ground circuit for circuit opening relay at ECM terminal FC. Circuit opening relay then provides voltage to fuel pump for fuel pump operation. Circuit opening relay is located in various places. See CIRCUIT OPENING RELAY LOCATIONS table. See Figure.