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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 383 (Engine Controls - System & Component Testing - 3.4L) >> Fuel Systems >> Fuel Pump Electrical Circuit Diagnosis (ALERO & Grand Am) >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS in SELF-DIAGNOSTICS - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article. After performing diagnostic system check - engine controls, go to next step.
  2. Install a scan tool. Turn ignition switch to RUN position, engine OFF. Using a scan tool, command the fuel pump relay ON and OFF. Does the fuel pump turn ON and OFF? If yes, go to INTERMITTENTS in TROUBLE SHOOTING - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article. If no, go to next step.
  3. Using a scan tool, command the fuel pump relay ON and OFF. Do you hear a click when you command the fuel pump relay ON and OFF? If yes, go to step  9. If no, go to next step.
  4. Turn ignition switch to OFF position. Disconnect the fuel pump relay. Turn ignition switch to RUN position, engine OFF. Probe the fuel pump relay control circuit using a test light connected to a good ground. Using a scan tool, command the fuel pump ON and OFF. Does the test light turn ON and OFF? If yes, go to next step. If no, go to step  6.
  5. Connect the test light between the fuel pump relay control circuit and the fuel pump relay ground circuit. Using a scan tool, command the fuel pump ON and OFF. Does the test light turn ON and OFF? If yes, go to step  21. If no, go to step  24.
  6. Does the test light remain illuminated with each command? If yes, go to next step. If no, go to step  8.
  7. Test the fuel pump relay control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  29. If no, go to step  28.
  8. Test the fuel pump relay control circuit for a short to ground or an open. Did you find and correct the condition? If yes, go to step  29. If no, go to step  22.
  9. Turn ignition switch to RUN position, engine OFF. Does the fuel pump operate continuously? If yes, go to next step. If no, go to step  11.
  10. Turn ignition switch to OFF position. Disconnect the fuel pump relay. Turn ignition switch to RUN position, engine OFF. Does the fuel pump operate continuously? If yes, go to step  23. If no, go to step  27.
  11. Is the FP-INJR fuse open? If yes, go to next step. If no, go to step  14.
  12. Disconnect the fuel pump harness in-line connector, located near the fuel tank. Test the fuel pump and the fuel injectors supply voltage circuit for a grounded circuit. Replace the FP-INJR fuse if necessary. Did you find and correct the condition? If yes, go to step  29. If no, go to next step.
  13. Lower the fuel tank if necessary. Test or inspect the fuel tank electrical harness for the following:
    • Damage to the harness.
    • A grounded circuit.

    Replace the FP-INJR 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 switch to OFF position. Disconnect the fuel pump relay. Turn ignition switch to RUN position, engine OFF. Probe the fuel pump relay ignition 1 voltage circuit using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  25.
  15. Connect a 10-amp fused jumper wire between the ignition 1 voltage circuit and the fuel pump supply voltage circuit in the fuel pump cavity. Does the fuel pump operate? If yes, go to step  21. If no, go to next step.
  16. Disconnect the fuel pump harness in-line connector located near the fuel tank. Test the fuel pump supply voltage circuit for an open or high resistance between the fuel pump relay and the in-line connector. Did you find and correct the condition? If yes, go to step  29. If no, go to next step.
  17. Check the ground circuit for being tight, corrosion on the terminals, or damage to the wiring harness. Test the fuel pump ground circuit for an open or high resistance between the body pass through connector and ground. If yes, go to step  29. If no, go to next step.
  18. Check for poor connections at the fuel pump in-line connector to the 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 the fuel tank. Test or inspect the fuel tank harness for the following:
    • Damage to the harness.
    • An 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 a NEW fuel pump fuse. Using a scan tool, command the fuel pump ON. Is the fuel pump fuse open? If yes, go to step  29. If no, go to INTERMITTENTS in TROUBLE SHOOTING - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article.
  21. Check for poor connections at the fuel pump relay. Did you find and correct the condition? If yes, go to step  29. If no, go to step  27.
  22. Check for poor connections at the PCM harness connector. Did you find and correct the condition? If yes, go to step  29. If no, go to step  28.
  23. Repair short to voltage in the fuel pump supply voltage circuit. After repair, go to step  29.
  24. Repair open in the fuel pump relay ground circuit. After repair, go to step  29.
  25. Repair open in the fuel pump relay ignition 1 voltage circuit. After repair, go to step  29.
  26. Check for poor connections at the fuel pump, within the fuel tank, before replacing the fuel pump. Repair as necessary. If fuel pump connections are okay, replace the fuel pump. Replace the fuel pump fuse if necessary. After repair, go to step  29.
  27. Check the fuel pump prime circuit for a short to voltage. Repair as necessary. If fuel pump prime circuit is okay, replace the fuel pump relay. Did you complete the repair? If yes, go to step  29.
  28. Replace the PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE under PROGRAMMING in SELF-DIAGNOSTICS - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article.
  29. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step  2.
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