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P codepowertrainMedium severity

P1139Water In Fuel Indicator Circuit Malfunction

The OBD2 code P1139 indicates a malfunction in the water in fuel indicator circuit, which suggests a problem with the system that detects the presence of water in the fuel

Definition

The OBD2 code P1139 indicates a malfunction in the water in fuel indicator circuit, which suggests a problem with the system that detects the presence of water in the fuel

Common causes

  • Faulty water in fuel sensor
  • Damaged wiring or connectors
  • Corroded terminals
  • Faulty engine control module (ECM)
  • Contaminated fuel
  • Poor ground connection
  • Short circuit in the indicator circuit

Common misdiagnoses

  • Fuel system issues
  • Fuel filter blockage
  • Fuel pump failure
  • Contaminated fuel
  • Faulty fuel injectors
  • Electrical issues in the fuel system
  • Sensor malfunctions unrelated to water in fuel
  • Engine control module (ECM) problems

Troubleshooting steps

  1. 1.Check the Fuel System

  2. 2.Inspect the fuel system for any signs of water contamination. This can include checking the fuel filter and fuel lines for water accumulation

  3. 3.If water is present, drain the fuel filter and replace it if necessary

  4. 4.Inspect the Water in Fuel Sensor

  5. 5.Locate the water in fuel sensor and inspect it for any physical damage or corrosion

  6. 6.Ensure that the electrical connections to the sensor are secure and free of corrosion

  7. 7.Test the Sensor

  8. 8.Use a multimeter to test the resistance of the water in fuel sensor. Compare the readings to the specifications provided in the vehicle’s service manual

  9. 9.If the sensor is out of specification, it may need to be replaced

  10. 10.Check Wiring and Connectors

  11. 11.Inspect the wiring and connectors leading to the water in fuel sensor for any signs of damage, fraying, or corrosion

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

  13. 13.Scan for Additional Codes

  14. 14.Use an OBD-II scanner to check for any other related trouble codes that may provide additional context for the issue

  15. 15.Address any other codes that may be present, as they could be related to the P1139 code

  16. 16.Clear the Code

  17. 17.After performing the necessary repairs, clear the trouble codes using an OBD-II scanner

  18. 18.Take the vehicle for a test drive to see if the code reappears

  19. 19.Monitor the System

  20. 20.After clearing the code, monitor the vehicle’s performance and check for any signs of water in the fuel system

  21. 21.If the code returns, further investigation may be needed, possibly involving the vehicle’s ECU or other related components

  22. 22.Consult the Service Manual

  23. 23.Refer to the vehicle’s service manual for specific diagnostic procedures and specifications related to the water in fuel indicator circuit

  24. 24.Seek Professional Help

  25. 25.If you are unable to resolve the issue after performing these steps, consider seeking assistance from a qualified mechanic or technician who has experience with diesel fuel systems. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P1139 code