DTC P0629: Fuel Pump Relay Control Circuit High: Description

The Engine Control Module (ECM) provides ignition 1 voltage to the coil side of the fuel pump relay. When you turn ON the ignition switch, the ECM energizes the fuel pump relay, which applies power to the fuel pump. The ECM applies a low current signal of approximately 7 volts to the fuel pump relay control circuit with the key ON and the engine OFF. The ECM uses this signal to detect the integrity of the fuel pump relay control circuit. 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 2 seconds. The ECM monitors the voltage on the fuel pump relay control circuit. If the ECM detects an incorrect voltage on the fuel pump relay control circuit, a fuel pump relay control DTC sets.