Chart A-5 Fuel Pump Relay

With ignition on, the ECM activates fuel pump relay, which energizes the in-tank electric fuel pump. The fuel pump will operate as long as ECM is receiving an ignition reference pulse. If there is no ignition reference pulse, fuel pump will stop within 2 seconds. If the fuel pump relay or ECM fail while engine is running, the fuel pump will continue to run through an oil pressure switch back-up circuit.