Fuel Pump Electrical Circuit

When the key is turned ON without the engine running, the control module turns a fuel pump relay ON for 2 seconds. This builds up fuel pressure quickly. If the engine is not started within 2 seconds, the control module shuts the fuel pump OFF and waits until the engine starts. As soon as the engine is cranked, the control module turns the relay ON and runs the fuel pump. When the engine is cranking or running, the control module receives the Crankshaft Position (CKP) sensor reference pulses which in turn energize the fuel injectors. The VCM will also turn ON the fuel pump for 2 seconds when the ignition key is turned to the OFF position.