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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 162 (ENGINE CONTROLS - SYSTEM & COMPONENT TESTS - 2.2L)FUEL SYSTEMS (GASOLINE)FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSISDIAGNOSTIC PROCEDURE
1999 GMC Forward Control 5.7 R, Automatic

Diagnostic Procedure

1999 GMC Forward Control 5.7 R, AutomaticSECTION Diagnostic Procedure
WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
  2. Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON and OFF using a scan tool. Repeat the commands as necessary. Does the fuel pump turn ON and OFF? If yes, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article. If no, go to next step.
  3. Command the fuel pump relay ON and OFF using a scan tool. Do you hear the fuel pump relay 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. Remove 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. Test 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. 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  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. Remove 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. Inspect the P/P INJR fuse (Alero and Grand Am) or F/P INJ (Cavalier and Sunfire) fuse, located in the instrument panel fuse block. Is the fuse open? If yes, go to next step. If no, go to step  14.
    12. NOTE: The F/P INJR or F/P INJ fuse also supplies ignition voltage to the fuel injectors. Test all related circuits for a short to ground.
  12. Test the supply voltage circuit of the fuel pump for a short to ground between the F/P INJR or F/P INJ fuse and the fuel pump. Replace the F/P INJ fuse if necessary. Did you find and correct the condition? If yes, go to step  27. If no, go to next step.
  13. Connect all disconnected electrical components. Install a new F/P INJR or FP INJ fuse. Command the fuel pump relay ON using a scan tool. Inspect the F/P INJR or F/P INJ fuse. Is the F/P INJR or FP INJ fuse open? If yes, go to step  24. If no, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
  14. Turn ignition switch to OFF position. Remove the fuel pump relay from the engine compartment fuse block. Turn ignition switch to RUN position, engine OFF. Probe the fuel pump relay ignition 1 voltage circuit, switch side, 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 15-amp fused jumper wire between the fuel pump relay ignition 1 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. Test 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: Inspect the ground circuit for correct tightening, corrosion on the terminals, or damage to the wiring harness.
  17. Test the ground circuit of the fuel pump 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. Test for an intermittent and for a poor connection at the fuel sender cover. Did you find and correct the condition? If yes, go to step  27. If no, go to step  24.
  19. Test for an intermittent and for a poor connection 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. Test for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step  27. If no, go to step  26.
  21. Repair the short to voltage in the fuel pump supply voltage circuit. After repair, go to step  27.
  22. Repair the open or high resistance in the fuel pump relay ground circuit. After repair, go to step  27.
  23. Repair the open in the fuel pump relay ignition 1 voltage circuit. After repair, go to step  27.
    24. NOTE: Inspect for poor connections at the fuel pump, within the fuel tank, before replacing the fuel pump.
  24. Replace the fuel sender. See FUEL SENDER ASSEMBLY under FUEL SYSTEMS in appropriate REMOVAL & INSTALLATION article. Replace the F/P INJR or F/P INJ fuse if necessary. After repair, go to step  27.
  25. Replace the fuel pump relay. After repair, go to step  27.
  26. Replace the PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See PROGRAMMING in SELF-DIAGNOSTICS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
  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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