The control module enables the fuel pump relay when the ignition switch is turned ON. The control module will disable the fuel pump relay within 2 seconds unless the control module detects ignition reference pulses. The control module continues to enable the fuel pump relay as long as ignition reference pulses are detected. The control module disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the ignition remains ON.

The following conditions may cause the fuel pump fuse to open:

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Note: An open or a short to voltage in the control circuit will cause both the Ckt. Open Test Status and the Ckt. Short Volts Test Status parameters to display Fault.

Ignition ON, command the fuel pump relay ON and OFF with a Scan tool while observing the following control circuit status parameters:

Each parameter should toggle between OK and Not Run or Not Run and OK.

1. With the ignition OFF, remove the fuel pump relay from the rear electrical center.
2. With the ignition ON, engine OFF, probe the control circuit of the fuel pump relay with a test lamp that is connected to a good ground. Command the fuel pump relay ON and OFF with a scan tool. The test lamp should turn ON and OFF with each command.

⇒	If the test lamp does not turn ON and OFF, test for an open or a short to ground in the fuel pump relay control circuit. If the circuit tests normal, replace the control module.

⇒	If the test lamp remains illuminated with each command, test for a short to voltage in the control circuit of the fuel pump relay. If the circuit tests normal, replace the control module.

3. Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the fuel pump relay. Command the fuel pump relay ON and OFF with a scan tool.

⇒	If the test lamp does not turn ON and OFF, repair the open or the high resistance in the ground circuit of the fuel pump relay.

⇒	If the test lamp does turn ON and OFF, test for an intermittent and for a poor connection at the fuel pump relay, or a faulty fuel pump relay.

4. Inspect the fuel pump fuse.

⇒	If the fuel pump fuse is open, test for a short to ground in the supply voltage circuit of the fuel pump, or a faulty fuel sender.

5. With the ignition ON, engine OFF, probe the battery positive voltage circuit of the fuel pump relay with a test lamp that is connected to a good ground.

⇒	If the test lamp does not illuminate, repair the open in the battery positive voltage circuit.

6. Connect a 15A fused jumper wire between the battery positive voltage circuit of the fuel pump relay and the supply voltage circuit of the fuel pump.

⇒	If the fuel pump operates, test for an intermittent or poor connection at the fuel pump relay, or a faulty fuel pump relay.

⇒	If the fuel pump does not operate, test for an open or high resistance in the supply voltage circuit of the fuel pump, an open or high resistance in the ground circuit of the fuel pump, or a faulty fuel tank module.

7. If all circuits test normal, test or replace the fuel pump relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.