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P code powertrain High severity

P0628 Fuel Pump ""A"" Control Circuit Short to Ground

The OBD2 code P0628 indicates a short circuit in the fuel pump "A" control circuit, meaning there is an unintended connection to ground that affects the fuel pump's operation

Definition

The OBD2 code P0628 indicates a short circuit in the fuel pump "A" control circuit, meaning there is an unintended connection to ground that affects the fuel pump's operation

Common causes

  • Damaged wiring or connectors
  • Shorted fuel pump control circuit
  • Faulty fuel pump relay
  • Malfunctioning fuel pump
  • Corroded or loose electrical connections
  • Faulty engine control module (ECM)

Common misdiagnoses

  • Faulty fuel pump
  • Bad fuel pump relay
  • Wiring issues or shorts in the harness
  • Defective engine control module (ECM)
  • Fuel pressure regulator problems
  • Faulty ignition switch
  • Bad ground connections
  • Incorrectly installed aftermarket components

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide additional context for the issue

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring and connectors associated with the fuel pump control circuit. Look for signs of damage, fraying, corrosion, or loose connections

  3. 3. Pay special attention to areas where the wiring may be exposed to heat or moving parts

  4. 4. Test the Fuel Pump Relay

    Locate the fuel pump relay and test it for proper operation. You can swap it with a similar relay in the fuse box (if applicable) to see if the problem persists

  5. 5. Check the relay for continuity and proper voltage supply

  6. 6. Check the Fuel Pump Fuse

    Inspect the fuel pump fuse for continuity. If the fuse is blown, replace it and see if the issue is resolved. If it blows again, further investigation is needed

  7. 7. Measure Voltage at the Fuel Pump

    Use a multimeter to measure the voltage at the fuel pump connector while the ignition is in the "ON" position (but the engine is not running). You should see battery voltage

  8. 8. If there is no voltage, trace the wiring back to the relay and PCM (Powertrain Control Module) to identify where the break or short may be occurring

  9. 9. Check for Ground Issues

    Ensure that the ground connection for the fuel pump is secure and free of corrosion. A poor ground can cause erratic behavior in the fuel pump circuit

  10. 10. Inspect the PCM

    If all wiring and components appear to be in good condition, the issue may lie within the PCM itself. Check for any signs of damage or water intrusion

  11. 11. If necessary, consult a professional to test the PCM for proper operation

  12. 12. Perform a Visual Inspection of the Fuel Pump

    If accessible, inspect the fuel pump for any signs of damage or failure. A malfunctioning fuel pump can sometimes cause circuit issues

  13. 13. Clear Codes and Test Drive

    After performing repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code reappears

  14. 14. Consult a Professional

    If you are unable to identify or resolve the issue after these steps, it may be best to consult a professional mechanic who has experience with OBD-II diagnostics.Safety Precautions - Always take necessary safety precautions when working on a vehicle, especially when dealing with fuel systems. Work in a well-ventilated area and avoid open flames or sparks. By following these troubleshooting steps, you should be able to identify the cause of the P0628 code and take appropriate action to resolve the issue