California

Fuel Pump Wiring:

Power to the fuel pump is controlled by the ECM through the control relay. To test the relay refer to the CONTROL RELAY test procedure.

OPERATION TEST
To test the pump operation, connect a 12 Volt power source to the pump test connector.

Remove the fuel cap and listen through the fuel filler neck for the sound of the pump. If the pump operates during the operational test, continue with the harness test. If no pump sound is heard, check the ground circuit (step #1) and also test the control relay. If no faults are found, replace the fuel pump.

HARNESS TEST
1. Disconnect the fuel pump connector located on the fuel tank. Using an Ohmmeter, check the ground circuit of the fuel pump between the harness connector terminal 1 and ground.

Continuity:
Should exist.

2. Using an Ohmmeter, check for continuity between the fuel pump check connector and the fuel pump harness connector terminal 2.

Continuity:
Should exist.

3. Disconnect the ECM connector and the control relay connector. Using an Ohmmeter, check for continuity between the check connector and the ECM harness connector terminal 8 and the control relay harness connector terminal 5.

Continuity:
Should exist.

4. Measure the supply voltage of the control relay from the ignition switch. Using a voltmeter, measure the voltage between the control relay connector terminal 7 and ground with the ignition switch in the start position.

Voltage:
8 or more volts.

5. Using an Ohmmeter, check for continuity (short) to ground between the ECM harness connector terminal 8 and the control relay harness connector terminal 5.

Continuity:
Should not exist.

6. Using an Ohmmeter, check for continuity between the control relay terminal 1 and ground.

Continuity:
Should not exist.

7. Using an Ohmmeter, check for continuity between the control relay terminal 1 and the fuel pump connector 2.

Continuity:
Should exist.

If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, clear the trouble codes and road test the vehicle to confirm that the repair has corrected the problem and the code doesn't return.
If the trouble code returns, it is possible that there is an intermittent failure of the component or the ECM. Check for looseness at all harness junctions and test for an intermittent failure. If the same trouble code reoccurs, the ECM will need to be changed.