Mechanics

99 CRANKS WONT START

1999 GMC Jimmy

Engine Mechanical problem
1999 GMC Jimmy 6 cyl Four Wheel Drive Automatic 125000 miles

I turned on ignition and no power to fuel pump, I hooked up red test wire and no power at fuel pump, I inspected wire harness from fuse panel to pump and see no obvious signs of wear, connectors fit snug. Fuel pump relay checks out ok. Hooked up scanner and get codes: P0452 & P0001. Would a faulty fuel regulator or fuel pressure sensor prevent the fuel pump from working? How would I correct these faults and what else should I check for the fuel pump?
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Christo4
December 29, 2009.



Hook up a voltmeter at the pump, is there 12volt at the connection? If yes, replace pump.

Merlin2021
Dec 30, 2009.
I checked the connection with a voltmeter at the fuel pump and there's no power.

Tiny
Christo4
Dec 30, 2009.
Check fuse and relay in the power distribution center under the hood.
Fuel System Electrical Circuit 1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step. 2. Turn ignition off. If fuel pump runs continuously, go to step 26. If fuel pump does not run, go to next step. 3. Inspect ECM B fuse (20-amp), located in underhood fuse/relay center. If fuse is okay, go to next step. If fuse is open, go to step 21. 4. Turn ignition on. Install scan tool. Using scan tool, command fuel pump relay on. If fuel pump operates, go to IGNITION SYSTEM. If fuel pump does not operate, go to next step. 5. Remove fuel pump relay. Using a fused jumper wire, jumper fuel pump positive feed circuit to fuel pump relay ignition feed circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If fuel pump operates, go to next step. If fuel pump does not operate, go to step 7. 6. Using a test light connected to ground, probe fuel pump relay control circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. Using scan tool, command fuel pump on. If test light illuminates, go to step 8. If test light does not illuminate, go to step 9. 7. Using a test light connected to ground, probe ignition feed circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step 10. If test light does not illuminate, go to step 11. 8. Using a test light connected to battery positive, probe ground circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step 12. If test light does not illuminate, go to step 13. 9. Check for an open or short to ground in fuel pump relay control circuit. Repair as necessary. After repairs, go to step 31. If circuit is okay, go to step 14. 10. Reinstall fuel pump relay. Disconnect fuel pump harness connector. Using a test light connected to ground, probe fuel pump positive feed circuit at fuel pump harness connector (body harness side). See appropriate wiring diagram in WIRING DIAGRAMS article. Using scan tool, command fuel pump on. If test light illuminates, go to step 15. If test light does not illuminate, go to step 16. 11. Repair open in fuel pump relay ignition feed circuit. After repairs, go to step 31. 12. Replace fuel pump relay. After repairs, go to step 31. 13. Repair open in fuel pump relay ground circuit. After repairs, go to step 31. 14. Check for poor connections at VCM. Repair as necessary. After repairs, go to step 31. If connections are okay, go to step 17. 15. Using a test light connected to battery positive, probe ground circuit at fuel pump harness connector (body harness side). See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step 18. If test light does not illuminate, go to step 19. 16. Repair open or short to ground in fuel pump positive feed circuit. After repairs, go to step 31. 17. Replace VCM. Perform VCM relearn procedures. After repairs, go to step 31. 18. Check fuel pump positive feed and ground circuits at fuel pump harness connector for poor connections. Repair as necessary. After repairs, go to step 31. If connections are okay, go to step 20.19. Repair open in fuel pump ground circuit. After repairs, go to step 31. 20. Replace fuel pump. After repairs, go to step 31. 21. Turn ignition off. Disconnect fuel pump harness connector. Remove fuel pump relay. Using a test light connected to battery positive, probe fuel pump positive feed circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 23. 22. Repair short to ground in fuel pump positive feed circuit. After repairs, go to step 31. 23. Using a test light connected to battery positive, probe ignition positive feed circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 25. 24. Repair short to ground in fuel pump relay ignition feed circuit. After repairs, go to step 31. 25. Check fuel pump positive feed circuit in fuel pump wiring harness (tank side) for a short to ground. Repair as necessary. After repairs, go to step 31. If circuit is okay, go to step 20. 26. Remove fuel pump relay. If fuel pump continues to run, go to step 30. If fuel pump does not run, go to next step. 27. Turn ignition off. Using a test light connected to ground, probe fuel pump relay control circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step 29. If test light does not illuminate, go to next step. 28. Replace fuel pump relay. After repairs, go to step 31. 29. Repair fuel pump relay control circuit for a short to ground. After repairs, go to step 31. 30. Repair fuel pump positive feed circuit for a short to power. After repairs, go to step 31. 31. Using scan tool, clear DTCs. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, go to step 4. 32. Allow engine to reach normal operating temperature. Using scan tool, check for DTCs. If any DTCs are present, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If no DTCs are present, system is okay.
12/30/2009 .

Merlin2021
Dec 30, 2009.