Fuel Pump: Testing and Inspection
Fuel Pump Circuit TroubleshootingIf 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 OFF.
2. Remove the under-dash fuse/relay box, 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 ON (II).
5. Measure voltage between PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 3 and body ground.
Is there battery voltage?
Yes - Go to step 10.
NO - Go to step 6.
6. Turn the ignition switch OFF.
7. Disconnect the under-hood fuse/relay box 10P connector.
8. Turn the ignition switch ON (II).
9. Measure voltage between under-hood fuse/relay box 10P connector terminal No. 5 and body ground.
Is there battery voltage?
Yes - Repair open in the wire between the under-hood fuse/relay box and the under-dash fuse/relay box.
NO -
- Replace PGM-FI main relay 1 C.
- If needed, replace the under-hood fuse/relay box.
10. Measure 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 11.
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.
11. Turn the ignition switch OFF.
12. Connect PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No. 4 to body ground with a jumper wire.
13. Jump the SCS line with the HDS.
14. Disconnect ECM/PCM connector A (44P).
15. Check for continuity between body ground and ECM/PCM connector terminal A15.
Is there continuity?
Yes - Go to step 16.
NO - Repair open in the wire between PGM-FI main relay 2 (FUEL PUMP) and the ECM/PCM (A15).
16. Remove the under-dash fuse/relay box, then reinstall PGM-FI main relay 2 (FUEL PUMP).
17. Reinstall the under-dash fuse/relay box.
18. Connect ECM/PCM connector terminal A6to body ground with a jumper wire.
19. Turn the ignition switch ON (II).
20. Measure voltage between ECM/PCM connector terminal A15 and body ground.
Is there battery voltage?
Yes - Go to step 21.
NO - Replace PGM-PI main relay 2 (FUEL PUMP).
21. Turn the ignition switch OFF.
22. Reconnect ECM/PCM connector A (44P).
23. Open the SCS line with the HDS.
24. Turn the ignition switch OFF.
25. Turn the ignition switch ON (II), and measure voltage between under-dash fuse/relay box 34P connector terminal No. 10 and body ground within 2 seconds.
Is there battery voltage?
Yes - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM, then go to step 26.
NO - If needed, replace the under-dash fuse/relay box, then go to step 26.
26. Turn the ignition switch OFF.
27. Remove the rear cushion.
28. Remove the rear floor upper cross-member, then remove the access panel from the floor.
29. Turn the ignition switch ON (II), and measure voltage between fuel tank unit 4P connector terminal No. 2 and body ground within 2 seconds.
Is there battery voltage?
Yes - Go to step 34.
NO - Go to step 30.
30. Turn the ignition switch OFF.
31. Remove PGM-FI main relay 2 (FUEL PUMP).
32. Connect PGM-FI main relay 2 (FUEL PUMP) 4P connector terminals No. 1 and No. 2 with a jumper wire.
33. Turn the ignition switch ON (II), and measure voltage between fuel tank unit 4P connector terminal No. 2 and body ground within 2 seconds.
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.
34. Turn the ignition switch OFF.
35. Check for continuity between fuel tank unit 4P connector terminal No. 4 and body ground.
Is there continuity?
Yes - Replace the fuel pump.
NO - Repair open in the wire between the fuel tank unit 4P connector and G601.