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 first turned on. If the fuel pump does not make noise, check as follows:| 1. | Turn the ignition switch OFF. |
| 2. | Remove the driver's side under cover. |
| 3. | Remove the relay holder (A) from the under-dash fuse/relay box, and remove the PGM-FI main relay 2 (blue) (B) from the relay holder (A), after reinstall the relay holder (A) to the under-dash fuse/relay box.
 BA |
| 4. | Turn the ignition switch ON (II). |
| 5. | Measure voltage between the PGM-FI main relay 2 4P connector terminal No. 4 and body ground.
 PGM-FI MAIN RELAY 24P CONNECTORTerminal side of female terminalsIGP1 (YEL/BLK) Is there battery voltage? YES - Go to 6. NO - Repair open in the wire between the PGM-FI main relay 1 and the PGM-FI main relay 2.n |
| 6. | Measure voltage between the PGM-FI main relay 2 4P connector terminal No. 1 and body ground.
 PGM-FI MAIN RELAY 24P CONNECTORTerminal side of female terminalsIG1 (YEL/BLK)*1 (BLK/YEL)*2*1 *2: With inertia switch : Without inertia switch Is there battery voltage? YES - Go to 7. NO - Repair open in the wire between the under-dash fuse/ relay box and PGM-FI main relay 2.n |
| 7. | Turn the ignition switch OFF. |
| 8. | Disconnect the negative cable from the battery. |
| 9. | Disconnect ECM/PCM connector E (31P). |
| 10. | Check for continuity between the PGM-FI main relay 2 4P connector terminal No. 3 and ECM/PCM connector terminal E1.
 PGM-FI MAIN RELAY 24P CONNECTORTerminal side of female terminalsIMOFPR (GRN/ YEL)ECM/PCM CONNECTOR E (31P)Wire side of female terminalsIMOFPR (GRN/YEL) Is there continuity? YES - Go to 11. NO - Repair open in the wire between the PGM-FI main relay 2 and the ECM/PCM (E1).n |
| 11. | Reinstall the PGM-FI main relay 2. |
| 12. | Reconnect the negative cable from the battery. |
| 13. | Turn the ignition switch ON (II). |
| 14. | Measure voltage between ECM/PCM connector terminal E1 and body ground.
 ECM/PCM CONNECTOR E (31P)Wire side of female terminalsIMOFRP (GRN/YEL)Is there battery voltage? YES - Go to 15. NO - Replace the PGM-FI main relay 2.n |
| 15. | Turn the ignition switch OFF. |
| 16. | Disconnect the negative cable from the battery. |
| 17. | Reconnect ECM/PCM connector E (31P). |
| 18. | Reconnect the negative cable from the battery. |
| 19. | 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 (II).
 ECM/PCM CONNECTOR E (31P)Wire side of female terminalsIMOFRP (GRN/YEL)Is there battery voltage? YES - Substitute a known-good ECM/PCM and recheck. If symptom/indication goes away, replace the original ECM/ PCM.n NO - Go to 20. |
| 20. | Turn the ignition switch OFF. |
| 21. | Remove the access panel from the floor. |
| 22. | Measure voltage between the fuel pump 5P connector terminal No. 5 and body ground within the first 2 seconds after the ignition switch was turned ON (II).
 FUEL PUMP 5P CONNECTORFUEL PUMP (YEL/GRN)Wire side of female terminals Is there battery voltage? YES - Go to 29. NO - Go to 23. |
| 23. | Turn the ignition switch OFF. |
| 24. | Remove the driver's side under cover. |
| 25. | Remove the relay holder (A) from the under-dash fuse/relay box, and remove the PGM-FI main relay 2 (blue) (B) from the relay holder (A), after reinstall the relay holder (A) to the under-dash fuse/relay box.
 BA |
| 26. | Connect the PGM-FI main relay 2 4P connector terminals No. 1 and No. 2 with a jumper wire.
 PGM-FI MAIN RELAY 24P CONNECTORTerminal side of female terminalsIG1 (YEL/BLK)*1 (BLK/YEL)*2*1: With inertia switch *2: Without inertia switchJUMPER WIREFUEL PUMP (YEL/ GRN) |
| 27. | Turn the ignition switch ON (II). |
| 28. | Measure voltage between the fuel pump 5P connector terminal No. 5 and body ground within the first 2 seconds after the ignition switch was turned ON (II).
 FUEL PUMP 5P CONNECTORFUEL PUMP (YEL/GRN)Wire side of female terminals Is there battery voltage? YES - Replace the PGM-FI main relay 2.n NO - Repair open in the wire between the PGM-FI main relay 2 and the fuel pump 5P connector.n |
| 29. | Turn the ignition switch OFF. |
| 30. | Check for continuity between the fuel pump 5P connector terminal No. 4 and body ground.
 FUEL PUMP 5P CONNECTORGND (BLK)Wire side of female terminals Is there continuity? YES - Replace the fuel pump.n NO - Repair open in the wire between the fuel pump 5P connector and G402.n |