Fuel Pump Relay Control Circuit

NAME OF CODE:
Fuel Pump Relay Control Circuit

WHEN MONITORED:
With the ignition key ON and battery voltage greater than 10 volts.

SET CONDITION:
An open or shorted condition is detected in the fuel pump relay control circuit.

THEORY OF OPERATION:
The fuel pump relay controls the 12-volt source to the fuel pump. The relay is located in the Power Distribution Center (PDC).

One side of the relay control coil is supplied with 12 volts when the ignition switch is turned to either the "RUN" or start position. The circuit is completed when the other side of the relay coil is grounded by the powertrain control module (PCM).

The PCM grounds the relay for about one second when the ignition switch is initially turned to the RUN or start position. Any additional grounding of the relay is performed only when the PCM detects engine rpm.

POSSIBLE CAUSES:
- Relay coil open or shorted
- Fused ignition switch output circuit open
- Fuel pump relay control circuit is open or shorted
- Inoperative circuit driver in powertrain control module