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P code powertrain Medium severity

P205C Reductant Tank Temperature Sensor Circuit Low

The OBD2 code P205C indicates that the reductant tank temperature sensor circuit is reading a low voltage or signal, suggesting a potential issue with the sensor or its wiring

Definition

The OBD2 code P205C indicates that the reductant tank temperature sensor circuit is reading a low voltage or signal, suggesting a potential issue with the sensor or its wiring

Common causes

  • Faulty reductant tank temperature sensor
  • Damaged wiring or connectors in the sensor circuit
  • Short circuit in the sensor circuit
  • Open circuit in the sensor circuit
  • Poor ground connection
  • Faulty engine control module (ECM)

Common misdiagnoses

  • Faulty Reductant Tank Temperature Sensor
  • Wiring issues or short circuits in the sensor circuit
  • Faulty Engine Control Module (ECM)
  • Incorrectly diagnosed fuel system issues
  • Misinterpretation of related OBDII codes
  • Issues with the DEF (Diesel Exhaust Fluid) system
  • Problems with the reductant pump or injector
  • Low DEF level or contamination in DEF

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are multiple issues

  2. 2. Inspect the Reductant Tank Temperature Sensor

    Locate the reductant tank temperature sensor and visually inspect it for any signs of damage, corrosion, or loose connections

  3. 3. Ensure that the sensor is properly connected and that the wiring harness is intact

  4. 4. Test the Sensor

    Use a multimeter to measure the resistance of the temperature sensor. Compare the readings to the manufacturer's specifications

  5. 5. If the resistance is outside the specified range, the sensor may be faulty and need replacement

  6. 6. Check the Wiring and Connectors

    Inspect the wiring leading to the sensor for any signs of wear, fraying, or damage

  7. 7. Check the connectors for corrosion or poor connections. Clean or repair as necessary

  8. 8. Test the Circuit

    With the multimeter, check the voltage at the sensor connector with the ignition on (engine off) and while the engine is running

  9. 9. Ensure that the voltage readings are within the expected range as per the vehicle's service manual

  10. 10. Inspect the Reductant Tank

    Check the reductant tank for any signs of contamination or issues that could affect the sensor's operation

  11. 11. Ensure that the tank is filled with the correct type of reductant (e.g., DEF - Diesel Exhaust Fluid)

  12. 12. Check for Ground Issues

    Ensure that the ground connection for the sensor circuit is secure and free of corrosion. A poor ground can lead to incorrect readings

  13. 13. Clear Codes and Test Drive

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

  14. 14. Take the vehicle for a test drive to see if the code returns. Monitor the performance of the SCR system

  15. 15. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the P205C code for your specific vehicle make and model. Manufacturers may have known issues or specific fixes

  16. 16. Seek Professional Help

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with diesel engines and SCR systems. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P205C code