Fuel Pump Relay Circuit Check

Fuel Pump Relay Circuit Check




Circuit Description
When the ignition switch is turned ON, the engine control module (ECM) will activate the fuel pump relay and run the in-tank fuel pump. The fuel pump will operate as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.

If there are no reference pulses, the ECM will shut off the fuel pump within 2 seconds after the ignition switch is turned ON.

Diagnostic Aids
An intermittent problem may be caused by a poor connection, rubbed through wire insulation, or a broken wire inside the insulation.

Steps 1 - 10:

Steps 11 - 13:

Test Description
The number(s) below refer to step(s) on the diagnostic table.
3. This step checks for the engine control module (ECM) providing a ground for the operation of the fuel pump relay.
7. By confirming that the wiring is OK using steps 2 through 6, it can be determined that the fuel pump relay is at fault.
9. After determining that there is no ground being provided by the ECM to the fuel pump relay, the fault is either the ECM or the wiring between the ECM and the fuel pump relay.