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 glove box, then remove the PGM-FI main relay 2 (A).
3. Turn the ignition switch ON (II).
4. Measure voltage between PGM-FI main relay 2 4P connector terminal No.4 and body ground.
Is there battery voltage?
YES - Go to step 5.
NO - Repair open in the wire between PGM-FI main relay 1 and PGM-FI main relay 2.
5. Measure voltage between PGM-FI main relay 2 4P connector terminal No. land body ground.
Is there battery voltage?
YES - Go to step 6.
NO - Repair open in the wire between the under- dash fuse/relay box and PGM-FI main relay 2.
6. Turn the ignition switch OFF.
7. Disconnect ECM/PCM connector E (31P).
8. Check for continuity between PGM-FI main relay 2 4P connector terminal No.3 and ECM/PCM connector terminal E1.
Is there continuity?
YES - Go to step 9.
NO - Repair open in the wire between PGM-FI main relay 2 and the ECM/PCM (E1).
9. Reinstall PGM-FI main relay 2.
10. Turn the ignition switch ON (II).
11. Measure voltage between ECM/PCM connector terminal E1 and body ground.
Is there battery voltage?
YES - Go to step 12.
NO - Replace PGM-FI main relay 2.
12. Turn the ignition switch OFF.
13. Reconnect ECM/PCM connector E (31P).
14. Turn the ignition switch ON (II), and measure voltage between ECM/PCM connector terminal E1 and body ground within the first 2 seconds after the ignition switch was turned on.
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.
NO - Go to step 15.
15. Turn the ignition switch OFF.
16. Remove the rear seat cushion.
17. Remove the access panel from the floor.
18. 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 24.
NO - Go to step 19.
19. Turn the ignition switch OFF.
20. Remove PGM-FI main relay 2.
21. Connect the PGM-FI main relay 2 4P connector terminals No. 1 and No.2 with a jumper wire.
22. Turn the ignition switch ON (II).
23. 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 - Replace PGM-FI main relay 2.
NO - Repair open in the wire between PGM-FI main relay 2 and the fuel pump 5P connector.
24. Turn the ignition switch OFF.
25. 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 G501.