Fuel Pump Circuit Troubleshooting
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 Undercover 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. 3 and body ground.
Is there battery voltage?
YES -
Go to step 13.
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 the engine wire harness 13P connector.
10. Disconnect driver's under-dash fuse/relay box connector F (33P).
11. Connect PGM-FI main relay 1 4P connector terminal No. 2 to body ground with a jumper wire.
12. Check for continuity between driver's under-dash fuse/relay box connector F (33P) terminal No. 12 and body ground.
Is there continuity?
YES -
Replace the driver's under-dash fuse/relay box; USA models Drivers Under-dash Fuse/Relay Box (Drivers MICU) Removal and Installation (USA models), Canada models Drivers Under-dash Fuse/Relay Box (Drivers MICU) Removal and Installation (Canada 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; USA models Drivers Under-dash Fuse/Relay Box (Drivers MICU) Removal and Installation (USA models), Canada models Drivers Under-dash Fuse/Relay Box (Drivers MICU) Removal and Installation (Canada models).
13. 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 14.
NO -
- Check the No. B9 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; USA models Drivers Under-dash Fuse/Relay Box (Drivers MICU) Removal and Installation (USA models), Canada models Drivers Under-dash Fuse/Relay Box (Drivers MICU) Removal and Installation (Canada models).
14. Turn the ignition switch to LOCK (0).
15. Connect PGM-FI main relay 2 4P connector terminal No. 4 to body ground with a jumper wire.
16. Jump the SCS line with the HDS.
17. Disconnect PCM connector A (49P).
18. Check for continuity between body ground and PCM connector terminal A30.
Is there continuity?
YES -
Go to step 19.
NO -
Repair an open in the wire between PGM-FI main relay 2 and the PCM (A30).
19. Reinstall PGM-FI main relay 2.
20. Connect PCM connector terminal A7 to body ground with a jumper wire.
21. Turn the ignition switch to ON (II).
22. Measure the voltage between PCM connector terminal A30 and body ground.
Is there battery voltage?
YES -
Go to step 23.
NO -
Replace PGM-FI main relay 2.
23. Turn the ignition switch to LOCK (0).
24. Reconnect PCM connector A (49P).
25. Turn the ignition switch to ON (II), and measure the voltage between driver's under-dash fuse/relay box connector F (33P) terminal No. 33 and body ground within 2 seconds.
Is there battery voltage?
YES -
Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM, then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM Service and Repair.
NO -
Go to step 26.
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. 33 and body ground after 2 seconds.
Is there battery voltage?
YES -
Go to step 27.
NO -
Replace the driver's under-dash fuse/relay box; USA models Drivers Under-dash Fuse/Relay Box (Drivers MICU) Removal and Installation (USA models), Canada models Drivers Under-dash Fuse/Relay Box (Drivers MICU) Removal and Installation (Canada models).
27. Turn the ignition switch to LOCK (0).
28. Remove the rear seat cushion.
29. Remove the access panel from the floor.
30. Turn the ignition switch to ON (II), and measure the voltage between fuel tank unit 4P connector terminal No. 1 and body ground within 2 seconds.
Is there battery voltage?
YES -
Go to step 35.
NO -
Go to step 31.
31. Turn the ignition switch to LOCK (0).
32. Remove PGM-FI main relay 2.
33. Connect PGM-FI main relay 2 4P connector terminals No. 1 and No. 2 with a jumper wire.
34. Turn the ignition switch to ON (II), and measure the voltage between fuel tank unit 4P connector terminal No. 1 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 (D5) and the fuel tank unit 4Pconnector.
- If the wire is OK, replace the driver's under-dash fuse/relay box; USA models Drivers Under-dash Fuse/Relay Box (Drivers MICU) Removal and Installation (USA models), Canada models Drivers Under-dash Fuse/Relay Box (Drivers MICU) Removal and Installation (Canada models).
35. Turn the ignition switch to LOCK (0).
36. Check for continuity between fuel tank unit 4P connector terminal No. 3 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 G602.