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 PGM-FI main relay 2 (FUEL PUMP) (A).
3. Turn the ignition switch ON (II).
4. Measure 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 5.
NO - Replace the PGM-FI main relay 1 (FI MAIN).
5. 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 6.
NO
- Check the No.1 FUEL PUMP (15 A) fuse in the driver's under-dash fuse/relay box.
- Replace the driver's under-dash fuse/relay box
6. Turn the ignition switch OFF.
7. Connect PGM-FI main relay 2 (FUEL PUMP) 4P connector terminal No.3 to body ground with a jumper wire.
8. Jump the SCS line with the HDS.
9. Disconnect PCM connector A (44P).
10. Check for continuity between body ground and PCM connector terminal A11.
Is there continuity?
YES - Go to step 11.
NO - Repair open in the wire between PGM-FI main relay 2 (FUEL PUMP) and the PCM (A11).
11. Reinstall PGM-FI main relay 2 (FUEL PUMP).
12. Connect PCM connector terminal A6 to body ground with jumper wire.
13. Turn the ignition switch ON (II).
14. Measure voltage between PCM connector terminal A11 and body ground.
Is there battery voltage?
YES - Go to step 15.
NO - Replace PGM-FI main relay 2 (FUEL PUMP).
15. Turn the ignition switch OFF.
16. Reconnect PCM connector A (44P).
17. Open the SCS line with the HDS.
18. Turn the ignition switch OFF.
19. Turn the ignition switch ON (II), and measure voltage between PCM connector terminal A11 and body ground within the first 2 seconds after the ignition switch was turned on.
Is there battery voltage?
YES - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.
NO - Go to step 20.
20. Turn the ignition switch OFF.
21. Remove the driver's second row seat.
22. Cut the carpet at the dotted line (A). Be careful not to cut the wire harness under the carpet.
23. Remove the access panel from the floor.
24. Measure voltage between fuel pump 5P connector terminal No.5 and body ground within the first 2 seconds after the ignition switch was turned on.
Is there battery voltage?
YES - Go to step 30.
NO - Go to step 25.
25. Turn the ignition switch OFF.
26. Remove PGM-FI main relay 2 (FUEL PUMP).
27. Connect PGM-FI main relay 2 (FUEL PUMP) 4P connector terminals No.1 and No.2 with a jumper wire
28. Turn the ignition switch ON (II).
29. Measure voltage between fuel pump 5P connector terminal No.5 and body ground within the first 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 fuel pump 5P connector.
30. Turn the ignition switch OFF.
31. Check for continuity between fuel pump 5P connector terminal No.4 and body ground.
Is there continuity?
YES - Replace the fuel pump.
NO - Repair open in the wire between the fuel pump 5P connector and G603.