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Home >> Buick >> 2001 >> Century Limited >> Repair and Diagnosis (Single Page) >> Engine Performance >> Testing & Diagnosis >> Engine Control System - Basic Diagnostic Procedures >> No-Start Diagnosis >> No Start - Engine Cranks Okay (2.2L - Cavalier & SUNFIRE) >> Fuel Pump Electrical Circuit

Fuel Pump Electrical Circuit

  1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to POWERTRAIN DIAGNOSTIC SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article.
  2. Connect scan tool. 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 fuse/relay center. Turn ignition on. Using test light connected to ground, probe fuel pump relay control circuit. 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 fuel pump relay ground circuit. 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, go to next step. If test light does not illuminate 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 operates continuously, go to next step. If fuel pump does not operate continuously, go to step  11.
  10. Turn ignition off. Disconnect fuel pump relay. Turn ignition on. If fuel pump operates continuously, go to step  23. If fuel pump does not operate continuously, go to step  27.
  11. Check F/P-INJ fuse (20-amp) located in underhood fuse relay center. If fuse is open, go to next step. If fuse is okay, go to step  14.
  12. Disconnect fuel pump harness connector from rear body harness connector. Check fuel pump power supply circuit for short to ground between fuse and body harness connector. Repair as necessary. After repairs, go to step  29. If circuit is okay, go to next step.
  13. Lower fuel tank. Check fuel pump harness for damage or grounded circuit. Repair as necessary. After repairs, go to step  29. If harness is okay, go to step  20.
  14. Turn ignition off. Disconnect fuel pump relay located in underhood fuse relay center. Turn ignition on. Using test light connected to ground, probe fuel pump relay ignition feed circuit at 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 ignition feed circuit and fuel pump power supply circuit at relay cavities. If fuel pump operates, go to step  21. If fuel pump does not operate, go to next step.
  16. Disconnect fuel pump harness connector from rear body harness. Check fuel pump power supply circuit for open or high resistance between fuel pump relay and rear body harness connector. Repair as necessary. After repairs, go to step  29. If circuit is okay, go to next step.
  17. Check fuel pump ground circuit for open or high resistance between ground and body pass-through harness connector. Repair as necessary. After repairs, go to step  29. If circuit is okay, go to next step.
  18. Check for poor connections at fuel pump harness to body pass-through harness connector. Repair as necessary. After repairs, go to step  29. If connections are okay, go to next step.
  19. Lower fuel tank. Check fuel pump harness for damage, opens or poor connections. Repair as necessary. After repairs, go to step  29. If harness is okay, go to step  26.
  20. Reconnect all components. Install NEW F/P-INJ fuse (20-amp). Using scan tool, command fuel pump on. If fuse blows, go to step  26. If fuse does not blow, check for intermittent problem. See appropriate TROUBLE SHOOTING - NO CODES article.
  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 ignition feed circuit. After repairs, go to step  29.
  26. Replace fuel pump. 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 to verify repair. If system operation is okay, testing is complete. If system operation is not okay, go to step  2.
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