Here are the procedures for testing the fuel pump circuit.
Fuel Pump Electrical Circuit
1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to POWERTRAIN DIAGNOSTIC SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article.
2. Connect scan tool. Turn ignition on. Using scan tool, command fuel pump on and off. If fuel pump turns on and off, check for intermittent problem. See appropriate TROUBLE SHOOTING - NO CODES article. If fuel pump does not turn on and off, go to next step.
3. Using scan tool, command fuel pump on and off. If fuel pump relay clicks, go to step 9. If fuel pump relay does not click, go to next step.
4. Turn ignition off. Disconnect fuel pump relay located in underhood accessory wiring junction block. Turn ignition on. Using test light connected to ground, probe fuel pump relay control circuit at relay cavity. Using scan tool, command fuel pump on. If test light turns on and off, go to next step. If test light does not turn on and off, go to step 6.
5. Connect test light between fuel pump relay control circuit and fuel pump relay ground circuit at relay cavities. Using scan tool, command fuel pump on. If test light turns on and off, go to step 19. If test light does not turn on and off, go to step 22.
6. If test light remains illuminated, go to next step. If test light does not remain illuminated, go to step 8.
7. Disconnect PCM. Check fuel pump relay control circuit for short to voltage. Repair as necessary. After repairs, go to step 27. If circuit is okay, go to step 26.
8. Disconnect PCM. Check fuel pump relay control circuit for open or short to ground. Repair as necessary. After repairs, go to step 27. If circuit is okay, go to step 20.
9. Turn ignition on. If fuel pump runs continuously, go to next step. If fuel pump does not run continuously, go to step 11.
10. Turn ignition off. Disconnect fuel pump relay located in underhood accessory wiring junction block. Turn ignition on. If fuel pump runs continuously, go to step 21. If fuel pump does not run continuously, go to step 25.
11. Check F/PMP fuse (15-amp) located in underhood accessory wiring junction block. If fuse is open, go to next step. If fuse is okay, go to step 14.
12. Remove fuel pump access panel (if equipped; fuel tank may need to be lowered). Check for short to ground in fuel pump power feed circuit between fuel pump and fuse. Repair as necessary. After repairs, go to step 27. If circuit is okay, go to next step.
13. Reconnect all components. Install NEW F/PMP fuse. Using scan tool command fuel pump on. If fuse blows, go to step 24. If fuse does not blow, check for intermittent problem. See appropriate TROUBLE SHOOTING - NO CODES article.
14. Turn ignition off. Disconnect fuel pump relay located in underhood accessory wiring junction block. Turn ignition on. Using test light connected to ground, probe fuel pump relay battery feed circuit at fuel pump relay cavity. If test light illuminates, go to next step. If test light does not illuminate, go to step 23.
15. Connect fused jumper wire between fuel pump relay battery feed circuit and fuel pump power feed circuit at fuel pump relay cavities. If fuel pump runs, go to step 19. If fuel pump does not run, go to next step.
16. Remove fuel pump access panel. Check fuel pump power feed circuit for open or high resistance between fuel pump and fuel pump relay. Repair as necessary. After repairs, go to step 27. If circuit is okay, go to next step.
17. Check fuel pump ground circuit for open or high resistance. Repair as necessary. After repairs, go to step 27. If circuit is okay, go to next step.
18. Check for poor connections at fuel pump. Repair as necessary. After repairs, go to step 27. If connections are okay, go to step 24.
19. Check for poor connections at fuel pump relay. Repair as necessary. After repairs, go to step 27. If connections are okay, go to step 25.
20. Check for poor connections at PCM. Repair as necessary. After repairs, go to step 27. If connections are okay, go to step 26.
21. Repair short to voltage in fuel pump power supply circuit. After repairs, go to step 27.
22. Repair open in fuel pump relay ground circuit. After repairs, go to step 27.
23. Repair fuel pump relay battery feed circuit. After repairs, go to step 27.
24. Replace fuel pump. Replace F/PMP fuse (15-amp) if necessary. After repairs, go to step 27.
25. Replace fuel pump relay. After repairs, go to step 27.
26. Replace PCM. Perform PCM relearn procedure. After repairs, go to next step.
27. Operate system and verify repair. If system operation is okay, testing is complete. If system operation is not okay, go to step 2.
Saturday, August 3rd, 2019 AT 4:38 PM
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