Fuel Pump Control System

Fuel Pump Control Input And Output Chart:

CIRCUIT OPERATION
The ECM supplies the ground circuit for the fuel pump relay for a few seconds after the ignition switch is turned on. If the ECM receives a 1° signal from the crank angle sensor, that indicates that the engine is on or starting and the circuit is continuously supplied. The relay closes, providing voltage to the fuel pump.

If the 1° signal is not present, indicating a stalled engine, the ECM does not supply the ground circuit thereby preventing excessive battery discharge.

Single Pole Normally Open Relay:

FUEL PUMP RELAY
The fuel pump relay, located in the relay box near the battery, allows voltage to be applied to the fuel pump. The ECM supplies the ground circuit to the relay allowing the windings to close the switch internally. Battery voltage is then applied to the fuel pump.

Fig. 16 Fuel Pump Operation:

Refer to the chart for fuel pump relay operation.