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 first turned on. If the fuel pump does not make noise, check as follows:

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

2. Remove the under-dash fuse/relay box, Under-Dash Fuse/Relay Box Removal and Installation then remove PGM-FI main relay 2 (FUEL PUMP) (A) from the under-dash fuse/relay box.

3. Reinstall the under-dash fuse/relay box.






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

5. Measure the voltage between PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 4 and body ground.

Is there battery voltage?
YES - Go to step 12.

NO - Go to step 6.






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

7. Disconnect the under-hood fuse/relay box connector E (10P).

8. Disconnect C101 connector at left side of engine compartment.

9. Disconnect the under-dash fuse/relay box connector G (21P).

10. Connect under-dash fuse/relay box connector G (21P) terminal No. 4 to body ground with a jumper wire.






11. Check for continuity between under-hood fuse/relay box connector E (10P) terminal No. 5 and body ground.

Is there continuity?
YES -
- Replace PGM-FI main relay 1.

- If needed, replace the under-hood fuse/relay box. Under-Hood Fuse/Relay Box Removal and Installation


NO - Repair open in the wire between the under-hood fuse/relay box and the under-dash fuse/relay box.






12. Measure the voltage between PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 1 and body ground.

Is there battery voltage?
YES - Go to step 13.

NO -
- 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. Under-Dash Fuse/Relay Box Removal and Installation







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

14. Connect PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 3 to body ground with a jumper wire.






15. Jump the SCS line with the HDS.

16. Disconnect ECM connector A (44P).

17. Check for continuity between body ground and ECM connector terminal A15.

Is there continuity?
YES - Go to step 18.

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






18. Remove the under-dash fuse/relay box, Under-Dash Fuse/Relay Box Removal and Installation then reinstall PGM-FI main relay 2 (FUEL PUMP).

19. Reinstall the under-dash fuse/relay box. Under-Dash Fuse/Relay Box Removal and Installation

20. Connect ECM connector terminal A6 to body ground with a jumper wire.

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






22. Measure the voltage between ECM connector terminal A15 and body ground.

Is there battery voltage?
YES - Go to step 23.

NO - Replace PGM-FI main relay 2 (FUEL PUMP).






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

24. Reconnect ECM connector A (44P).

25. Open the SCS line with the HDS.

26. Turn the ignition switch to ON (II), and measure the voltage between under-dash fuse/relay box connector F (34P) terminal No. 10 and body ground within 2 seconds.

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

NO - Go to step 27.






27. Turn the ignition switch to ON (II), and measure the voltage between under-dash fuse/relay box connector F (34P) terminal No. 10 and body ground after 2 seconds.

Is there battery voltage?
YES - Go to step 28.

NO - If needed, replace the under-dash fuse/relay box, Under-Dash Fuse/Relay Box Removal and Installation then go to step 28.






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

29. Remove the rear seat cushion. Rear Seat Removal/Installation

30. Remove the rear floor upper cross-member, then remove the access panel from the floor. Fuel Tank Unit Removal and Installation

31. Turn the ignition switch to ON (II), and measure the voltage between fuel tank unit 4P connector terminal No. 2 and body ground within 2 seconds.

Is there battery voltage?
YES - Go to step 36.

NO - Go to step 32.






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

33. Remove PGM-FI main relay 2 (FUEL PUMP).

34. Connect PGM-FI main relay 2 (FUEL PUMP) 4P connector terminals No. 1 and No. 2 with a jumper wire.






35. Turn the ignition switch to ON (II), and measure the voltage between fuel tank unit 4P connector terminal No. 2 and body ground.

Is there battery voltage?
YES - Replace PGM-FI main relay 2 (FUEL PUMP).

NO - Repair open in the wire between PGM-FI main relay 2 (FUEL PUMP) and the fuel tank unit 4P connector.






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

37. Check for continuity between fuel tank unit 4P connector terminal No. 4 and body ground.

Is there continuity?
YES - Replace the fuel pump. Fuel Pump/Fuel Gauge Sending Unit Replacement

NO - Repair open in the wire between the fuel tank unit 4P connector and G601.