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 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 (see REMOVAL AND INSTALLATION ), then remove PGM-FI main relay 2 (FUEL PUMP) (A) from the under-dash fuse/relay box.
   Fig 1: Identifying PGM-FI Main Relay 2 (Fuel Pump)

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
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.
   Fig 2: Measuring Voltage Between PGM-FI Main Relay 2 (Fuel Pump) 4P Connector Terminal No. 4 And Body Ground

   Courtesy of AMERICAN HONDA MOTOR CO., INC.

   Is there battery voltage? 

   YES  -Go to step  13.

   NO  -Go to step 6.

6. Turn the ignition switch to LOCK (0).
7. Disconnect under-hood fuse/relay box connector D (8P).
8. Jump the SCS line with the HDS.
9. Disconnect PCM connector A (49P).
10. Disconnect under-dash fuse/relay box connector G (21P).
11. Connect under-dash fuse/relay box connector G (21P) terminal No. 4 to body ground with a jumper wire.
    Fig 3: Connecting Under-Dash Fuse/Relay Box Connector G (21P) Terminal No. 4 To Body Ground With Jumper Wire

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
12. Check for continuity between under-hood fuse/relay box connector D (8P) terminal No. 6 and body ground.
    Fig 4: Checking Continuity Between Under-Hood Fuse/Relay Box Connector D (8P) Terminal No. 6 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -

    • Replace PGM-FI main relay 1.
    • If needed, replace the under-hood fuse/relay box (see REMOVAL AND INSTALLATION ).

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

13. Measure the voltage between PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 1 and body ground.
    Fig 5: Measuring Voltage Between PGM-FI Main Relay 2 (Fuel Pump) 4P Connector Terminal No. 1 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 14.

    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 (see REMOVAL AND INSTALLATION ).
14. Turn the ignition switch to LOCK (0).
15. Connect PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 3 to body ground with a jumper wire.
    Fig 6: Connecting PGM-FI Main Relay 2 (Fuel Pump) 4P Connector Terminal No. 3 To Body Ground With Jumper Wire

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
16. Jump the SCS line with the HDS.
17. Disconnect PCM connector A (49P).
18. Check for continuity between PCM connector terminal A16 and body ground.
    Fig 7: Checking Continuity Between PCM Connector Terminal A16 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 19.

    NO  -Repair an open in the wire between PGM-FI main relay 2 (FUEL PUMP) and the PCM (A16).

19. Remove the under-dash fuse/relay box (see REMOVAL AND INSTALLATION ), then reinstall PGM-FI main relay 2 (FUEL PUMP).
20. Reinstall the under-dash fuse/relay box.
21. Connect PCM connector terminal A7 to body ground with a jumper wire.
    Fig 8: Connecting PCM Connector Terminal A7 To Body Ground With Jumper Wire

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
22. Turn the ignition switch to ON (II).
23. Measure the voltage between PCM connector terminal A16 and body ground.
    Fig 9: Measuring Voltage Between PCM Connector Terminal A16 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 24.

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

24. Turn the ignition switch to LOCK (0).
25. Reconnect PCM connector A (49P).
26. Within 2 seconds after turning the ignition switch to ON (II), measure the voltage between under-dash fuse/relay box connector F (34P) terminal No. 10 and body ground.
    Fig 10: Measuring Voltage Between Under-Dash Fuse/Relay Box Connector F (34P) Terminal No. 10 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM (see PCM REPLACEMENT ).

    NO  -Go to step 27.

27. Within 2 seconds after turning the ignition switch to ON (II), measure the voltage between under-dash fuse/relay box connector F (34P) terminal No. 10 and body ground.
    Fig 11: Measuring Voltage Between Under-Dash Fuse/Relay Box Connector F (34P) Terminal No. 10 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 28.

    NO  -If needed, replace the under-dash fuse/relay box (see REMOVAL AND INSTALLATION ), then go to step 28.

28. Turn the ignition switch to LOCK (0).
29. Fold the driver's side rear seat forward, and pull back the carpet to expose the access panel.
30. Remove the access panel from the floor (see 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.
    Fig 12: Measuring Voltage Between Fuel Tank Unit 4P Connector Terminal No. 2 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    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.
    Fig 13: Connecting PGM-FI Main Relay 2 (Fuel Pump) 4P Connector Terminals No. 1 And No. 2 With Jumper Wire

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
35. 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.
    Fig 14: Measuring Voltage Between Fuel Tank Unit 4P Connector Terminal No. 2 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Replace PGM-FI main relay 2 (FUEL PUMP).

    NO  -Repair an 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 (see FUEL PUMP/FUEL GAUGE SENDING UNIT REPLACEMENT ).

NO  -Repair an open in the wire between the fuel tank unit 4P connector and G602 (see STARTER SUBHARNESS ('07-09 MODELS) ).