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Fuel System Electrical Circuit

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
  2. Check fuel pump relay fuse, located in underhood relay block. If fuse is okay, go to next step. If fuse is faulty, go to step  20 .
  3. Install scan tool. Turn ignition on. Using scan tool, command fuel pump relay on. If fuel pump operates, diagnose fuel system. See BASIC FUEL SYSTEM CHECKS  . If fuel pump does not operate, go to next step.
  4. Remove fuel pump relay. Using a fused jumper wire, jumper fuel pump relay ignition feed terminal and fuel pump feed terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. If fuel pump operates, go to next step. If fuel pump does not operate, go to step  6 .
  5. Using a test light connected to ground, probe fuel pump relay control terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. Using scan tool, command fuel pump on. If test light illuminates, go to step  7 . If test light does not illuminate, go to step  8 .
  6. Using a test light connected to ground, probe fuel pump relay ignition feed terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step  9 . If test light does not illuminate, go to step  10 .
  7. Using a test light connected to battery positive, probe fuel pump relay ground terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step  11 . If test light does not illuminate, go to step  12 .
  8. Check for an open or short to ground in fuel pump relay control circuit. Repair as necessary. After repairs, go to step  25 . If circuit is okay, go to step  13 .
  9. Reinstall fuel pump relay. Disconnect fuel pump harness connector at fuel pump. Using a test light connected to ground, probe fuel pump harness connector feed terminal (body side). Using scan tool, command fuel pump on. If test light illuminates, go to step  14 . If test light does not illuminate, go to step  15 .
  10. Repair open in ignition feed circuit to fuel pump relay. After repairs, go to step  25 .
  11. Check for poor connections at fuel pump relay. Repair as necessary. If connections are okay, replace fuel pump relay. After replacing fuel pump relay, go to step  25 .
  12. Repair open in ground circuit to fuel pump relay. After repairs, go to step  25 .
  13. Check connections and terminals at PCM. Repair as necessary. After repairs, go to step  25 . If connections and terminals are okay, go to step  16 .
  14. Using a test light connected to battery positive, probe fuel pump ground terminal (body side). If test light illuminates, go to step  17 . If test light does not illuminate, go to step  18 .
  15. Repair open in fuel pump feed circuit. After repairs, go to step  25 .
  16. Turn ignition off. Replace PCM. Perform PCM relearn procedures. After replacing PCM, go to step  25 .
  17. Check for an open in fuel pump feed circuit and ground circuit. Repair as necessary. After repairs, go to step  25 . If circuit is okay, go to step  19 .
  18. Repair open in fuel pump ground circuit. After repairs, go to step  25 .
  19. Replace fuel pump. After replacing fuel pump, go to step  25 .
  20. Disconnect fuel pump harness connector at fuel pump. Remove fuel pump relay. Turn ignition off. Using a test light connected to battery positive, probe fuel pump feed terminal. If test light illuminates, go to next step. If test light does not illuminate, go to step  22 .
  21. Repair short to ground in fuel pump circuit. After repairs, go to step  25 .
  22. Using a test light connected to battery positive, probe fuel pump relay ignition feed terminal. If test light illuminates, go to next step. If test light does not illuminate, go to step  24 .
  23. Repair short to ground in fuel pump relay ignition feed circuit. After repairs, go to step  25 .
  24. Check for short to ground in fuel pump feed circuit. Repair as necessary. After repairs, go to next step. If circuit is okay, go to step  19 .
  25. Using scan tool, clear DTCs. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and stalls, go to step  2 .
  26. Allow engine to reach normal operating temperature. Check for DTCs. If DTCs are present, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If DTCs are not present, system is okay.
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