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Diagnostic Procedure

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  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 under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  2. Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON and OFF using a scan tool. Does the fuel pump turn ON and OFF? If yes, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Command the fuel pump relay ON and OFF using a scan tool. 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. Command the fuel pump relay ON and OFF using a scan tool. Does the test light turn ON and OFF? If yes, go to next step. If no, go to step  6.
  5. Connect a test light between the fuel pump relay control circuit and the fuel pump relay ground circuit. Command the fuel pump relay ON and OFF using a scan tool. Does the test light turn ON and OFF? If yes, go to step  19. If no, go to step  22.
  6. Does the test light remain illuminated with each command? If yes, go to next step. If no, go to step  8.
  7. Disconnect the Powertrain Control Module (PCM) harness connectors. Check the fuel pump relay control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  27. If no, go to step  26.
  8. Disconnect the Powertrain Control Module (PCM) harness connectors. Check 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  27. If no, go to step  20.
  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  21. If no, go to step  25.
  11. Is the F/PMP fuse (20-amp) open? F/PMP fuse is located in the left underhood junction block. If yes, go to next step. If no, go to step  14.
  12. Remove the fuel sender access panel, located under the rear compartment floor trim. Check the fuel pump supply voltage circuit for a grounded circuit between the fuel pump fuse and the fuel pump. Replace the fuel pump fuse if necessary. Did you find and correct the condition? If yes, go to step  27. If no, go to next step.
  13. Install all disconnected electrical components. Install a new F/PMP fuse. Command the fuel pump ON using a scan tool. Is the F/PMP fuse open? If yes, go to step  24. If no, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
  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 switch battery 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  23.
  15. Connect a 20-amp fused jumper wire between the fuel pump relay switch battery voltage circuit and the fuel pump supply voltage circuit. Does the fuel pump operate? If yes, go to step  19. If no, go to next step.
  16. Remove the fuel sender access panel. Check the fuel pump supply voltage circuit for an open or high resistance between the fuel pump relay and the fuel pump. Did you find and correct the condition? If yes, go to step  27. If no, go to next step.
    17. NOTE: Check the ground circuit for correct tightening, corrosion on the terminals, or damage to the wiring harness.
  17. Check the fuel pump ground circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  27. If no, go to next step.
  18. Check for poor connections at the fuel pump. Did you find and correct the condition? If yes, go to step  27. If no, go to step  24.
  19. Check for poor connections at the fuel pump relay. Did you find and correct the condition? If yes, go to step  27. If no, go to step  25.
  20. Check for poor connections at the PCM harness connectors. Did you find and correct the condition? If yes, go to step  27. If no, go to step  26.
  21. Repair the fuel pump supply voltage circuit for a short to voltage. After repair, go to step  27.
  22. Repair the open in the fuel pump relay ground circuit. After repair, go to step  27.
  23. Repair the open in the fuel pump relay switch battery voltage circuit. After repair, go to step  27.
  24. Check for poor connections at the fuel pump, within the fuel tank, before replacing the fuel pump. If connections are okay, replace the fuel pump. After repair, go to step  27.
  25. Replace the fuel pump relay. After repair, go to step  27.
  26. Replace PCM. Program replacement PCM. See POWERTRAIN CONTROL MODULE under PROGRAMMING in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After repair, go to next step.
  27. 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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