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 the driver's dashboard lower cover Driver's Dashboard Lower Cover Removal / Installation.
3. Remove PGM-FI main relay 2 (A) from the driver's under-dash fuse/relay box.
4. Turn the ignition switch to ON (II).
5. 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 14.
NO -
Go to step 6.
6. Turn the ignition switch to LOCK (0).
7. Remove PGM-FI main relay 1 (A) and the ETCS control relay (B) from the under-hood fuse/relay box.
8. Jump the SCS line with the HDS.
9. Disconnect ECM/PCM connector A (49P).
10. Disconnect the driver's under-dash fuse/relay box connector F (33P).
11. Disconnect the engine wire harness C101 connector at left side of engine compartment.
12. Connect PGM-FI main relay 1 4P connector terminal No. 2 to body ground with a jumper wire.
13. Check for continuity between driver's under-dash fuse/relay box connector F (33P) terminal No. 31 and body ground.
Is there continuity?
YES -
- Replace PGM-FI main relay 1.
- If needed, replace the driver's under-dash fuse/relay box Driver's Under-Dash Fuse/Relay Box (Driver's MICU) Removal and Installation (USA Models).
NO -
- Repair an open in the wire between the under-hood fuse/relay box and the driver's under-dash fuse/relay box.
- If the wire is OK, replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation.
14. 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 15.
NO -
- Check the No. 9 FUEL PUMP (20 A) fuse in the driver's under-dash fuse/relay box.
- If the fuse is OK, replace the driver's under-dash fuse/relay box Driver's Under-Dash Fuse/Relay Box (Driver's MICU) Removal and Installation (USA Models).
15. Turn the ignition switch to LOCK (0).
16. Connect PGM-FI main relay 2 4P connector terminal No. 3 to body ground with a jumper wire.
17. Jump the SCS line with the HDS.
18. Disconnect ECM/PCM connector A (49P).
19. Check for continuity between body ground and ECM/PCM connector terminal A16.
Is there continuity?
YES -
Go to step 20.
NO -
Repair an open in the wire between PGM-FI main relay 2 and the ECM/PCM (A16).
20. Reinstall PGM-FI main relay 2.
21. Connect ECM/PCM connector terminal A7 to body ground with a jumper wire.
22. Turn the ignition switch to ON (II).
23. Measure the voltage between ECM/PCM connector terminal A16 and body ground.
Is there battery voltage?
YES -
Go to step 24.
NO -
Replace PGM-FI main relay 2.
24. Turn the ignition switch to LOCK (0).
25. Reconnect all connectors.
26. Turn the ignition switch to ON (II), and measure the voltage between driver's under-dash fuse/relay box connector F (33P) terminal No. 22 and body ground within 2 seconds.
Is there battery voltage?
YES -
Update the ECM/PCM if it does not have the latest software ECM/PCM Update (M/T), or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away and the ECM/PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the ECM/PCM was substituted, replace the original ECM/PCM Service and Repair.
NO -
Go to step 27.
27. Turn the ignition switch to ON (II), and measure the voltage between driver's under-dash fuse/relay box connector F (33P) terminal No. 22 and body ground after 2 seconds.
Is there battery voltage?
YES -
Go to step 28.
NO -
Replace the driver's under-dash fuse/relay box Driver's Under-Dash Fuse/Relay Box (Driver's MICU) Removal and Installation (USA Models).
28. Turn the ignition switch to LOCK (0).
29. Remove the rear seat; sedan model Rear Seat Removal / Installation, sport wagon model Rear Seat Removal / Installation.
30. Remove the fuel tank unit access panel from the floor Fuel Tank Unit Removal/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.
34. Connect PGM-FI main relay 2 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.
NO -
- Repair an open in the wire between the driver's under-dash fuse/relay box (D10) and the fuel tank unit 4P connector.
- If the wire is OK, replace the driver's under-dash fuse/relay box Driver's Under-Dash Fuse/Relay Box (Driver's MICU) Removal and Installation (USA Models).
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 an open in the wire between the fuel tank unit 4P connector and G603 Front Passenger's Door Wire Harness (4-Door).