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Home >> Saturn >> 2003 >> L300 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Diagnostic Procedures >> Fuel Systems >> Fuel Pump Electrical Circuit Diagnosis >> Diagnostic Procedure
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Diagnostic Procedure

  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 - 3.0L SATURN "L" SERIES article.
  2. Install a scan tool. Turn ignition on, with engine off. Command the fuel pump relay ON and OFF with a scan tool. Does the fuel pump turn ON and OFF? If yes, seeDIAGNOSTIC AIDS  . If no, go to next step.
  3. Command the fuel pump relay ON and OFF with a scan tool. Do you hear a click when you command the fuel pump relay ON and OFF? If yes, go to step  5 . If no, go to next step.
  4. Turn ignition off. Disconnect fuel pump relay. Connect a test light between the fuel pump relay control circuit and the battery positive voltage, switch side of the fuel pump relay. Turn ignition on, with engine off. With a scan tool, command the fuel pump relay ON and OFF. Does the test light turn ON and OFF? If yes, go to step  15 . If no, go to step  17 .
  5. Turn ignition on, with engine off. Does the fuel pump operate continuously? If fuel pump operates continuously, go to next step. If fuel pump does not operate continuously, go to step  7 .
  6. Turn ignition off. Disconnect fuel pump relay. Turn ignition on, with engine off. Does the fuel pump operate continuously? If fuel pump operates continuously, go to step  16 . If fuel pump does not operate continuously, go to step  19 .
  7. If fuel pump fuse is open, go to next step. If fuse is not open, go to step  10 .
  8. Test the fuel pump supply voltage circuit for a grounded circuit between the fuel pump fuse and the fuel pump. Replace fuel pump fuse if necessary. If you found and corrected a short to ground in the fuel pump supply voltage circuit, go to step  20 . If no short to ground was found, go to next step.
  9. Install all disconnected electrical components. Install a new fuel pump fuse. Using a scan tool. command the fuel pump ON. If the fuel pump fuse opened, go to step  18 . If fuel pump fuse did not open, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.0L SATURN "L" SERIES article.
  10. Turn ignition off. Disconnect fuel pump relay. Turn ignition on, with engine off. Probe the battery voltage circuit of the fuel pump relay switch side with a test light that is connected to a good ground. If the test light illuminates, go to next step. If test light does not illuminate, go to step  19 .
  11. Connect a 15-amp fused jumper wire between the fuel pump relay battery voltage circuit and the fuel pump supply voltage circuit. If the fuel pump operates, go to step  15 . If fuel pump does not operate, go to next step.
  12. Test the fuel pump supply voltage circuit for an open or high resistance between the fuel pump relay and the fuel pump. If you found and corrected an open or high resistance condition, go to step  20 . If no open or high resistance was found, go to next step.
  13. Test the ground circuit of the fuel pump for an open or high resistance. Ensure that harness connections are tight, corrosion free and wiring harness is not damaged. If you found and corrected an open or high resistance, go to step  20 . If no open or high resistance was found, go to next step.
  14. Inspect for poor connections at the fuel pump. If you found and corrected a poor connection at the fuel pump, go to step  20 . If fuel pump connections are okay, go to step  18 .
  15. Inspect for poor connections at the fuel pump relay. If you found and corrected a poor connection at the fuel pump relay, go to step  20 . If fuel pump relay connections are okay, go to step  19 .
  16. Repair the short to voltage in the fuel pump supply voltage circuit. After repair is complete, go to step  20 .
  17. Repair the open fuel pump relay ground circuit. After repair is complete, go to step  20 .
    18. NOTE: Inspect for poor connections at the fuel pump, within the fuel tank, before replacing the fuel pump.
  18. Replace the fuel pump. See FUEL PUMP MODULE under FUEL SYSTEMS in REMOVAL & INSTALLATION - SATURN "L" SERIES article. Replace fuel pump fuse if necessary. Did you complete the replacement? If yes, go to step  20 .
  19. Replace the fuel pump relay. Did you complete the replacement? If yes, go to next step.
  20. 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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