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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 119 (Engine Control System - Basic Diagnostic Procedures) >> No-Start Diagnosis >> No Start - Engine Cranks Okay (3.5L - Intrigue) >> Fuel Pump Electrical Circuit Diagnosis

Fuel Pump Electrical Circuit Diagnosis

WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 2002 Saturn SL2, 2002 Saturn SL1, 2002 Saturn SL, 2002 Saturn SC2, and 2002 Saturn SC1. However, it is still accessible from the selected car via links, so may be relevant.
  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS in appropriate SELF-DIAGNOSTICS article.
  2. Turn ignition on. Using scan tool, command fuel pump relay on and off. If fuel pump turns on and off, check for intermittent problem. See appropriate TROUBLE SHOOTING - NO CODES article. If fuel pump does not turn on and off, go to next step.
  3. Using scan tool, command fuel pump relay on and off. If fuel pump relay clicks, go to step  9. If fuel pump relay does not click, go to next step.
  4. Turn ignition off. Disconnect fuel pump relay located in underhood accessory wiring junction block. Turn ignition on. Using test light connected to ground, probe fuel pump relay control circuit at relay cavity. Using scan tool, command fuel pump relay on and off. If test light turns on and off, go to next step. If test light does not turn on and off, go to step  6.
  5. Connect test light between fuel pump relay control circuit and ground circuit at relay cavities. Using scan tool, command fuel pump relay on and off. If test light turns on and off, go to step  21. If test light does not turn on and off, go to step  24.
  6. If test light remains illuminated with each command, go to next step. If test light does not turn on at all, go to step  8.
  7. Disconnect PCM. Check fuel pump relay control circuit for short to voltage. Repair as necessary. After repairs, go to step  29. If circuit is okay, go to step  28.
  8. Disconnect PCM. Check fuel pump relay control circuit for open or short to ground. Repair as necessary. After repairs, go to step  29. If circuit is okay, go to step  22.
  9. Turn ignition on. If fuel pump runs continuously, go to next step. If fuel pump does not run continuously, go to step  11.
  10. Turn ignition off. Disconnect fuel pump relay located in underhood accessory wiring junction block. Turn ignition on. If fuel pump runs continuously, go to step  23. If fuel pump does not run continuously, go to step  27.
  11. Check F/PMP fuse (15-amp) located in underhood accessory wiring junction block. If fuse is open, go to next step. If fuse is okay, go to step  14.
  12. Disconnect the fuel pump harness in-line connector located near fuel tank. Check supply voltage circuit of fuel pump for a short to ground. Replace fuel pump fuse if necessary. Did you find and correct the condition? If yes, go to step  29. If no, go to next step.
  13. Lower fuel tank, if necessary. Check or inspect fuel tank electrical harness for damage to harness, or a grounded circuit. Replace fuel pump fuse, if necessary. Did you find and correct the condition? If yes, go to step  29. If no, go to step  20.
  14. Turn ignition off. Disconnect fuel pump relay located in underhood accessory wiring junction block. Turn ignition on. Using test light connected to ground, probe fuel pump relay battery feed circuit at fuel pump relay cavity. If test light illuminates, go to next step. If test light does not illuminate, go to step  25.
  15. Connect fused jumper wire between fuel pump relay battery feed circuit and fuel pump power feed circuit at fuel pump relay cavities. If fuel pump runs, go to step  21. If fuel pump does not run, go to next step.
  16. Disconnect fuel pump harness in-line connector located near fuel tank. Check supply voltage circuit of the fuel pump for an open or high resistance between fuel pump relay and in-line connector. Did you find and correct the condition? If yes, go to step  29. If no, go to next step.
  17. Check fuel pump ground circuit for open or high resistance. Repair as necessary. After repairs, go to step  29. If circuit is okay, go to next step.
  18. Inspect for poor connections at fuel pump in-line connector to body pass-through connector. Did you find and correct the condition? If yes, go to step  29. If no, go to next step.
  19. Lower fuel tank. Test or inspect fuel tank electrical harness for damage to harness or open circuit. Did you find and correct the condition? If yes, go to step  29. If no, go to step  26.
  20. Connect all disconnected components. Install new fuel pump fuse. Using scan tool, command fuel pump on. If fuel pump fuse opens, go to step  26. If fuse is okay, problem is intermittent.
  21. Check for poor connections at fuel pump relay. Repair as necessary. After repairs, go to step  29. If connections are okay, go to step  27.
  22. Check for poor connections at PCM. Repair as necessary. After repairs, go to step  29. If connections are okay, go to step  28.
  23. Repair short to voltage in fuel pump power supply circuit. After repairs, go to step  29.
  24. Repair open in fuel pump relay ground circuit. After repairs, go to step  29.
  25. Repair fuel pump relay battery feed circuit. After repairs, go to step  29.
  26. Replace fuel pump. Replace F/PMP fuse (15-amp) if necessary. After repairs, go to step  29.
  27. Replace fuel pump relay. After repairs, go to step  29.
  28. Replace PCM. Perform PCM relearn procedure. After repairs, go to next step.
  29. Operate system and verify repair. If system operation is okay, testing is complete. If system operation is not okay, go to step  2.
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