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P code powertrain Medium severity

P252C Fuel Pump Control Module Performance

The OBD2 code P252C indicates that the Fuel Pump Control Module is not performing as expected, which may affect the fuel pump's operation and overall engine performance

Definition

The OBD2 code P252C indicates that the Fuel Pump Control Module is not performing as expected, which may affect the fuel pump's operation and overall engine performance

Common causes

  • Faulty fuel pump control module
  • Wiring issues or damaged connectors
  • Poor ground connections
  • Faulty fuel pump
  • Low fuel pressure
  • Malfunctioning fuel pressure sensor
  • Software issues in the engine control module (ECM)
  • Electrical shorts or open circuits in the fuel pump circuit

Common misdiagnoses

  • Faulty fuel pump
  • Clogged fuel filter
  • Bad fuel pressure regulator
  • Electrical issues (wiring or connectors)
  • Faulty fuel pump relay
  • Engine control module (ECM) issues
  • Incorrectly diagnosed fuel system problems
  • Vacuum leaks
  • Faulty sensors (e.g., fuel level sensor)
  • Battery or charging system issues

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 more context and help identify related issues

  2. 2. Inspect the Fuel Pump Control Module

    Locate the FPCM and visually inspect it for any signs of damage, corrosion, or loose connections

  3. 3. Ensure that the module is securely mounted and that all connectors are clean and free of debris

  4. 4. Test the FPCM Power and Ground

    Use a multimeter to check for proper voltage and ground at the FPCM connector. Refer to the vehicle’s service manual for the correct specifications

  5. 5. If there is no power or ground, trace the wiring back to the battery and check for any breaks or shorts

  6. 6. Check Fuel Pump Operation

    Listen for the fuel pump operation when the ignition is turned on (you should hear a humming sound for a few seconds)

  7. 7. If the pump does not operate, it may be faulty or there may be an issue with the fuel pump relay or fuse

  8. 8. Inspect Wiring and Connectors

    Check the wiring harness and connectors leading to the FPCM and fuel pump for any signs of wear, fraying, or damage

  9. 9. Repair or replace any damaged wiring or connectors

  10. 10. Test the Fuel Pump Relay

    Test the fuel pump relay to ensure it is functioning correctly. You can swap it with a similar relay in the fuse box to see if the issue resolves

  11. 11. If the relay is faulty, replace it

  12. 12. Check Fuel Pressure

    Use a fuel pressure gauge to check the fuel pressure at the fuel rail. Compare the reading to the manufacturer’s specifications

  13. 13. If the pressure is too low, it could indicate a failing fuel pump, clogged fuel filter, or issues with the fuel lines

  14. 14. Inspect the Fuel Filter

    A clogged fuel filter can restrict fuel flow and cause performance issues. If it hasn’t been replaced recently, consider replacing it

  15. 15. Check for Software Updates

    Sometimes, manufacturers release software updates for the FPCM or engine control module (ECM) that can resolve performance issues. Check with a dealership for any available updates

  16. 16. Clear Codes and Test Drive

    After performing the necessary repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.1

  17. 17. Consult a Professional

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P252C code. Always refer to the vehicle’s service manual for specific procedures and specifications