Fuel Pump: Testing and Inspection

Fuel Pump Circuit Troubleshooting

If you suspect a problem with the fuel pump, check that the fuel pump actually runs; when it is on, you will hear some noise if you listen to the fuel fill port with the fuel fill cap removed. The fuel pump should run for 2 seconds when the ignition switch is turned to ON (II). If the fuel pump does not make noise, check as follows:

1. Turn the ignition switch to LOCK (0).

2. Remove PGM-FI main relay 2 (A) from auxiliary under-hood fuse/relay box.

3. Turn the ignition switch to ON (II).






4. Measure the voltage between PGM-FI main relay 2 4P connector terminal No. 4 and body ground.

Is there battery voltage?
YES - Go to step 9.

NO - Go to step 5.






5. Turn the ignition switch to LOCK (0).

6. Disconnect the under-hood fuse/relay box 8P connector.

7. Turn the ignition switch to ON (II).

8. Measure the voltage between under-hood fuse/relay box 8P connector terminal No. 6 and body ground.

Is there battery voltage?
YES - Repair open in the wire between the under-hood fuse/relay box and PGM-FI main relay 2.

NO -
- Replace PGM-FI main relay 1.

- If needed, replace the under-hood fuse/relay box.







9. Measure the voltage between PGM-FI main relay 2 4P connector terminal No. 2 and body ground.

Is there battery voltage?
YES - Go to step 10.

NO -
- Repair open in the wire between the under-dash fuse/relay box and PGM-FI main relay 2.

- Check the No. 2 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.

- If needed, replace the under-dash fuse/relay box.







10. Turn the ignition switch to LOCK (0).

11. Jump the SCS line with the HDS.

12. Disconnect PCM connector A (44P).

13. Check for continuity between PGM-FI main relay 2 4P connector terminal No. 3 and PCM connector terminal A15.

Is there continuity?
YES - Go to step 14.

NO - Repair open in the wire between PGM-FI main relay 2 and the PCM (A15).






14. Reinstall PGM-FI main relay 2.

15. Connect PCM connector terminal A6 to body ground with a jumper wire.






16. Turn the ignition switch to ON (II).

17. Measure the voltage between PCM connector terminal A15 and body ground.

Is there battery voltage?
YES - Go to step 18.

NO - Replace PGM-FI main relay 2.






18. Turn the ignition switch to LOCK (0).

19. Reconnect PCM connector A (44P).

20. Exit the SCS mode with the HDS.

21. Turn the ignition switch to LOCK (0).

22. Turn the ignition switch to ON (II), and measure the voltage between PGM-FI main relay 2 4P connector terminal No. 3 and body ground.

Is there battery voltage?
YES - Update the PCM if it does not have the latest software, PCM Update or substitute a known-good PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM, Service and Repair then go to step 23.

NO - If needed, replace the under-hood fuse/relay box, then go to step 23.






23. Turn the ignition switch to LOCK (0).

24. Disconnect the fuel tank unit subharness 4P connector. Service and Repair

25. Turn the ignition switch to ON (II), and measure the voltage between floor wire harness C651 4P connector terminal No. 3 and body ground within 2 seconds.

Is there battery voltage?
YES - Go to step 30.

NO - Go to step 26.






26. Turn the ignition switch to LOCK (0).

27. Remove PGM-FI main relay 2.

28. Connect PGM-FI main relay 2 4P connector terminals No. 1 and No. 2 with a jumper wire.






29. Turn the ignition switch to ON (II), and measure the voltage between floor wire harness C651 4P connector terminal No. 3 and body ground within 2 seconds.

Is there battery voltage?
YES -
- Repair open in the wire between the floor wire harness C651 4P connector and the fuel pump.

- Replace PGM-FI main relay 2.


NO - Repair open in the wire between PGM-FI main relay 2 and the floor wire harness C651 4P connector.






30. Turn the ignition switch to LOCK (0).

31. Check for continuity between floor wire harness C651 4P connector terminal No. 4 and body ground.

Is there continuity?
YES -
- Repair open in the wire between the floor wire harness C651 4P connector and the fuel pump.

- Replace the fuel pump. Fuel Pump/Fuel Gauge Sending Unit Replacement


NO - Repair open in the wire between the floor wire harness C651 4P connector and G601.