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

Electrical Information Reference

Scan Tool Reference

Special Tools Required

J 43244 Relay Puller Pliers

Ignition ON, command the fuel pump relay ON and OFF with a scan tool. Listen/feel for relay to click and for the fuel pump to turn ON and OFF.

1. Ignition OFF, remove the fuel pump relay from the underhood electrical center.
2. Connect a test lamp between the control circuit and a good ground.
3. 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 is always OFF, test the control circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Connect a test lamp between the control circuit 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 is always OFF, repair the open/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.

5. Inspect the fuel pump fuse.

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

6. Ignition ON, probe the battery positive voltage circuit 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.

7. Connect a 15-amp 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/high resistance in the supply voltage circuit of the fuel pump, an open/high resistance in the ground circuit of the fuel pump, an intermittent or poor connection at the fuel pump module cover, or a faulty fuel pump module.

1. Measure for 70-110 ohms of resistance between terminals 85 and 86 of the fuel pump relay.

⇒	If the resistance is not within the specified range, replace the fuel pump relay.

2. Measure for infinite resistance between the following terminals of the fuel pump relay:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If continuity is detected, replace the fuel pump relay.

3. Connect a 15-amp fused jumper wire from the positive terminal of the battery to relay terminal 85. Connect a jumper wire from the negative terminal of the battery to relay terminal 86. Measure for less than 2 ohms between terminals 30 and 87 of the relay.

⇒	If the resistance measures more than 2 ohms, replace the fuel pump relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.