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Diagnostic Procedure (With Feedback Fuel System)

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. 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, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS in SELF-DIAGNOSTICS - 5.7L CORVETTE article.
  2. Turn ignition ON, with the engine OFF. Command fuel pump relay ON and OFF with a scan tool. Repeat the commands as necessary. Does the fuel pump turn ON and OFF? If yes, see DIAGNOSTIC AIDS  . If no, go to next step.
  3. Command the fuel pump relay ON and OFF with 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  9 . If no, go to next step.
  4. Turn ignition OFF. Remove fuel pump relay. See Figure . Turn ignition ON, with the engine OFF. Probe control circuit of the fuel pump relay with a test light that is connected to a good ground. Command the fuel pump relay ON and OFF with 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 control circuit of fuel pump relay and ground circuit of fuel pump relay. Command fuel pump relay ON and OFF with a scan tool. Does the test light turn ON and OFF? If yes, go to step  21 . If no, go to step  25 .
  6. Does the test light remain illuminated with each command? If yes, go to next step. If no, go to step  8 .
  7. Test control circuit of fuel pump relay for a short to voltage. Did you find and correct the condition? If yes, go to step  30 . If no, go to step  29 .
  8. Test control circuit of fuel pump relay for a short to ground and for an open. Did you find and correct the condition? If yes, go to step  30 . If no, go to step  22 .
  9. Turn ignition ON, with the engine OFF. Does the fuel pump operate continuously? If yes, go to next step. If no, go to step  11 .
  10. Turn ignition OFF. Remove fuel pump relay. Turn ignition ON, with the engine OFF. Does the fuel pump operate continuously? If yes, go to step  24 . If no, go to step  28 .
  11. Inspect F/PMP fuse. Is the fuse open? If yes, go to next step. If no, go to step  15 .
  12. Remove left rear wheel house panel. Disconnect fuel pump harness in-line connector. Test supply voltage circuit of fuel pump between fuel pump relay and fuel pump harness in-line connector for a short to ground. Replace the F/PMP fuse if necessary. Did you find and correct the condition? If yes, go to step  30 . If no, go to next step.
  13. Remove left fuel tank. See FUEL TANKS (WITH FEEDBACK FUEL SYSTEM) under FUEL SYSTEMS in REMOVAL & INSTALLATION - CORVETTE article. Inspect fuel sender harness on top of the fuel tank for any damage to the harness or a short to ground in the fuel pump supply voltage circuit. Replace F/PMP fuse if necessary. Did you find and correct the condition? If yes, go to step  30 . If no, go to next step.
  14. Install all removed electrical components. Install a new F/PMP fuse. Command fuel pump relay ON with a scan tool. Inspect F/PMP fuse. Is the fuse open? If yes, go to step  23 . If no, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 5.7L CORVETTE article.
  15. Turn ignition OFF. Remove fuel pump relay. Turn ignition ON, with the engine OFF. Probe ignition 1 voltage circuit of fuel pump relay, switch side, with a test light that is connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  26 .
  16. Connect a 20-amp fused jumper wire between ignition 1 voltage circuit of fuel pump relay and supply voltage circuit of the fuel pump. Does the fuel pump operate? If yes, go to step  21 . If no, go to next step.
  17. Remove the left rear wheelhouse panel. Disconnect fuel pump harness in-line connector. Test supply voltage circuit of fuel pump between fuel pump relay and fuel pump harness in-line connector for an open and for high resistance. Did you find and correct the condition? If yes, go to step  30 . If no, go to next step.
    18. NOTE: Inspect the ground circuit for proper torque, corrosion on the terminals, and damage to the wiring harness.
  18. Test ground circuit of fuel pump for an open and for high resistance between fuel pump harness in-line connector and ground. Did you find and correct the condition? If yes, go to step  30 . If no, go to next step.
  19. Test for an intermittent and for a poor connection at fuel pump harness in-line connector. Did you find and correct the condition? If yes, go to step  30 . If no, go to next step.
  20. Remove the left fuel tank. See FUEL TANKS (WITH FEEDBACK FUEL SYSTEM) under FUEL SYSTEMS in REMOVAL & INSTALLATION - CORVETTE article. Inspect the fuel sender harness on top of the fuel tank for any damage to the harness or an open circuit. Did you find and correct the condition? If yes, go to step  30 . If no, go to step  23 .
  21. 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  30 . If no, go to step  28 .
  22. Test for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step  30 . If no, go to step  29 .
  23. Test for an intermittent and for a poor connection at the fuel pump connector within the fuel tank. Did you find and correct the condition? If yes, go to step  30 . If no, go to step  27 .
  24. Repair short to voltage in supply voltage circuit of fuel pump. Did you complete the repair? If yes, go to step  30 .
  25. Repair open or high resistance in ground circuit of fuel pump relay. Did you complete the repair? If yes, go to step  30 .
  26. Repair open in the ignition 1 voltage circuit of fuel pump relay. Did you complete the repair? If yes, go to step  30 .
  27. Replace fuel pump. See FUEL PUMP under FUEL SYSTEMS in REMOVAL & INSTALLATION - CORVETTE article. Replace the F/PMP fuse if necessary. Did you complete the replacement? If yes, go to step  30 .
  28. Replace fuel pump relay. Did you complete the replacement? If yes, go to step  30 .
  29. Replace the PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - CORVETTE article. After repair is complete, go to step  30 .
  30. Operate the system in order to verify the repair. Did you correct the condition? If yes, system okay. If no, go to step  2 .
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