Table A1-7A Fuel System Diagnosis (Fuel Pump Relay Check)

Diagnostic Chart:

Wiring Diagram:

Circuit Description

The Powertrain Control Module (PCM) will energize the fuel pump relay for 2 seconds when the ignition switch is turned to the ON position. When the fuel pump relay is energized the fuel pump will operate and pressurize the fuel system. When the fuel pump relay is de-energized, the fuel pump stops operating. If the engine is being cranked, or is running, the fuel pump will continue to operate, as long as the PCM is receiving ignition reference pulses. The fuel pump will stop after 2 seconds if ignition reference pulses are not detected.

Diagnostic Aids

An intermittent malfunction may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation. Inspect the wiring harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connections before component replacement.

Test Description

The numbers below refer to the step numbers in the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable.

This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. Checks fuel pump operation with ignition switch in the ON position.

3. Checks fuel pump relay switch for power.