Circuit Description

The engine control module (ECM) provides a ground to the coil side of the fuel pump relay. When the ignition switch is first turned On, the ECM energizes the fuel pump relay, which applies power to the fuel pump. The ECM enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the ECM de-energizes the fuel pump relay after 3 seconds. If the ECM detects low voltage on the fuel pump relay control circuit, this DTC sets.