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 to ON (II). 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; A/T, M/T(except Si model), M/T (Si model), 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 -

Reconnect all connectors, and update the ECM if it does not have the latest software ECM/PCM Update, or substitute a known-good ECM, then recheck. If the symptom/indication goes away and the ECM was updated, troubleshooting is complete. If the symptom/indication goes away and the ECM was substituted, 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 -

Replace the under-dash fuse/relay box Under-Dash Fuse/Relay Box Removal And Installation.�

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

29. Remove the rear seat cushion.

30. Remove the rear floor upper cross-member, then remove the access panel from the floor.

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; 4-door, 2-door.�