Fuel Pump Electrical Circuit

When the ignition switch is in the ON position, before engaging the starter, the Powertrain Control Module (PCM) energizes the fuel pump relay for 2 seconds, causing the fuel pump to pressurize the fuel system. If the PCM does not receive ignition reference pulses, engine cranking or running, within 2 seconds, the PCM shuts OFF the fuel pump relay, causing the fuel pump to stop.