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P code powertrain High severity

P0629 Fuel Pump ""A"" Control Circuit Short to Battery

The OBD2 code P0629 indicates a short circuit in the fuel pump "A" control circuit to the battery, which means there is an electrical issue causing the fuel pump to receive constant power, potentially leading to...

Definition

The OBD2 code P0629 indicates a short circuit in the fuel pump "A" control circuit to the battery, which means there is an electrical issue causing the fuel pump to receive constant power, potentially leading to improper operation or damage

Common causes

  • Shorted wiring or connectors in the fuel pump circuit
  • Faulty fuel pump relay
  • Defective fuel pump
  • Malfunctioning engine control module (ECM)
  • Poor ground connection
  • Corroded or damaged connectors
  • Incorrectly installed or damaged wiring harness

Common misdiagnoses

  • Fuel pump failure
  • Fuel pump relay issue
  • Wiring harness problems
  • Engine control module (ECM) failure
  • Fuel pressure regulator malfunction
  • Shorted wiring or connectors
  • Faulty fuel pump driver module
  • Battery or charging system issues
  • Grounding problems
  • Injector issues

Troubleshooting steps

  1. 1. Check the Code and Freeze Frame Data

    Use an OBD-II scanner to confirm the P0629 code and check for any additional codes that may provide more context about the issue

  2. 2. Review freeze frame data to understand the conditions under which the code was set

  3. 3. Inspect Wiring and Connectors

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

  4. 4. Pay special attention to areas where the wiring may be exposed to heat, moisture, or abrasion

  5. 5. 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

  6. 6. Check for proper voltage and ground at the relay terminals

  7. 7. Check the Fuel Pump

    If the relay is functioning correctly, test the fuel pump itself. You can do this by applying direct power to the pump to see if it operates

  8. 8. If the pump does not work when powered directly, it may need to be replaced

  9. 9. Measure Voltage and Ground

    Use a multimeter to measure the voltage at the fuel pump connector while the ignition is in the "ON" position. You should see battery voltage

  10. 10. Check for a good ground connection at the fuel pump connector

  11. 11. Inspect the Fuel Pump Control Module

    If your vehicle has a fuel pump control module, inspect it for faults. Check for proper power and ground at the module

  12. 12. If necessary, test the module according to the manufacturer's specifications

  13. 13. Check for Short Circuits

    Use a multimeter to check for continuity in the fuel pump control circuit. Look for any shorts to battery voltage or ground

  14. 14. If a short is found, trace the wiring to locate the source of the short and repair it

  15. 15. Clear Codes and Test Drive

    After performing repairs, clear the trouble codes using the OBD-II scanner

  16. 16. Take the vehicle for a test drive to see if the code returns. Monitor the fuel pump operation during this time

  17. 17. Consult a Professional

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician for further diagnosis.Additional Tips: - Always refer to the vehicle's service manual for specific wiring diagrams and troubleshooting procedures. - Ensure that you have the proper tools and safety equipment when working on the vehicle's electrical system. By following these steps, you should be able to identify and resolve the issue related to the P0629 code