LEMON Manuals: Even more car manuals for everyone
Home >> Saturn >> 2002 >> SC2 Automatic, MP6 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Basic Diagnostic Procedures >> No-Start Diagnosis >> No Start - Engine Cranks Okay (3.1L & 3.4L) >> Fuel Pump Electrical Circuit Diagnosis (3.1L Malibu; 3.4L Alero & Grand Am)

Fuel Pump Electrical Circuit Diagnosis (3.1L Malibu; 3.4L Alero & Grand Am)

  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 in appropriate SELF-DIAGNOSTICS article.
  2. Install scan tool. Turn ignition on, with engine off. Using scan tool, command fuel pump relay on and off. Does fuel pump turn on and off? If yes, problem is intermittent. If no, go to next step.
  3. Command fuel pump relay on and off with 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 off. Disconnect fuel pump relay. Turn ignition on, with engine off. Probe control circuit of the fuel pump relay with a test light connected to a good ground. See WIRING DIAGRAMS article. Command fuel pump on and off with scan tool. Does test light turn on and off? If yes, go to next step. If no, go to step  6.
  5. Connect test light between the control circuit of the fuel pump relay and ground circuit of fuel pump relay. Command fuel pump on and off with a scan tool. Does 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 control circuit of the fuel pump relay 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 control circuit of the fuel pump relay 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 on, with engine off. Does the fuel pump operate continuously? If yes, go to next step. If no, go to step  11.
  10. Turn ignition off. Disconnect fuel pump relay. Turn ignition on, with engine off. Does fuel pump operate continuously? If yes, go to step  23. If no, go to step  27.
  11. Is the FP-INJ fuse open? If yes, go to next step. If no, go to step  14.
  12. Disconnect fuel pump harness in-line connector located near fuel tank. Test the supply voltage circuit of fuel pump and the fuel injectors for a grounded circuit. Replace the FP-INJ 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 damage to harness or a grounded circuit. Replace the FP-INJ 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 off. Disconnect fuel pump relay. Turn ignition on, with engine off. Probe the ignition 1 voltage circuit of the fuel pump relay with a test light connected to a good ground. Does 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 fuel pump supply voltage circuit in fuel pump cavity. Does the fuel pump operate? If yes, go to step  21. If no, go to next step.
  16. Disconnect fuel pump harness in-line connector located near fuel tank. Test the supply voltage circuit of fuel pump for an open or high resistance between fuel pump relay and in-line connector. Did you find and correct the condition? If yes, go to step  29. If no, go to next step.
  17. Ensure ground circuit is tight. Check for corrosion on terminals or damage to wiring harness. Check ground circuit of the fuel pump for an open or high resistance between the body pass-through connector and ground. Did you find and correct the condition? If yes, go to step  29. If no, go to next step.
  18. Inspect for poor connections at fuel pump in-line connector to 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 fuel tank. Test or inspect fuel tank electrical harness for damage to harness or 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. Command the fuel pump on with scan tool. Is fuel pump fuse open? If yes, go to step  26. If no, problem is intermittent.
  21. Inspect for poor connections at fuel pump relay. Did you find and correct the condition? If yes, go to step  29. If no, go to step  27.
  22. Inspect for poor connections at PCM harness. Did you find and correct the condition? If no, go to step  29. If no, go to step  28.
  23. Repair supply voltage circuit of fuel pump for a short to voltage. After repairs, go to step  29.
  24. Repair fuel pump relay ground circuit for an open ground. After repairs, go to step  29.
  25. Repair the ignition 1 voltage circuit of the fuel pump relay for an open circuit. After repairs, go to step  29.
    26. NOTE: Inspect for poor connections at fuel pump, within the fuel tank, before replacing fuel pump.
  26. Replace fuel pump. Replace fuel pump fuse if necessary. After repairs, go to step  29.
    27. NOTE: Before replacing fuel pump relay, inspect fuel pump prime circuit for a short to voltage.
  27. Replace fuel pump relay. After replacing relay, go to step  29.
  28. Replace PCM. After replacing PCM, go to next step.
  29. Operate the system in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to step  2.
scientia non olet · About LEMON Manuals