When you turn ON the ignition switch, the engine control module (ECM) energizes the fuel pump relay which powers the fuel pump ON. The fuel pump remains ON as long as the engine is cranking or running and the ECM receives ignition reference pulses. If there are no ignition reference pulses, the ECM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position or if the engine stops.

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

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Description and Operation:

Fuel System Description

Electrical Information Reference

Scan Tool Reference

Special Tools Required

J 43244 Relay Puller Pliers

1. Ignition ON, command the Fuel Pump Relay ON and OFF with a scan tool. You should hear a click when you command the fuel pump relay ON and OFF.
2. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

1. Ignition OFF, the fuel pump should not be operating.

⇒	If the fuel pump operates continuously, test for a short to voltage in the fuel pump supply voltage circuit. If the circuit tests normal, replace the fuel pump relay.

2. Ignition OFF, remove the fuel pump relay from the electrical center with the J 43244 relay puller pliers.
3. Test for less than 5 ohms of resistance between the relay ground circuit and ground.

⇒	If greater than the specified range, test the relay ground circuit for an open/high resistance.

4. Ignition ON, load test for B+ between the ignition 1 voltage circuit and ground .

⇒	If less than the specified range, test the ignition 1 voltage circuit for a short to ground or an open/high resistance.

5. Connect a 15 amp fused jumper wire between the ignition 1 voltage circuit and the supply voltage circuit. The fuel pump should operate.

⇒	If the fuel pump does not operate, test for the following conditions:

•	An open/high resistance in the motor circuit of the fuel pump.

•	An open/high resistance in the ground circuit of the fuel pump.

⇒	If the above circuits test normal, replace the fuel pump.

6. Ignition OFF, connect a test lamp between the relay control circuit and the ignition 1 voltage circuit.
7. Ignition ON, use a scan tool to command the fuel pump relay ON and OFF. The test lamp should turn ON and OFF with each command.

⇒	If the test lamp remains ON, test for a short to ground on the control circuit. If the circuit tests normal, replace the ECM.

⇒	If the test lamp remains OFF, test for a short to voltage or an open/high resistance on the relay control circuit. If circuit tests normal, replace the ECM.

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

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

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

2. Measure for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

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

3. Connect a 20 amp fused jumper wire between relay terminal 85 and B+. Connect a jumper wire between relay terminal 86 and ground. Measure for less than 2 ohms between terminals 30 and 87 of the relay.

⇒	If greater than the specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.