WOMS
P code powertrain High severity

P271C Transmission Fluid Temperature Sensor Range/Performance Problem (B)

The OBD2 code P271C indicates a problem with the transmission fluid temperature sensor's range or performance, specifically related to sensor B, suggesting that the sensor is providing readings that are outside the...

Definition

The OBD2 code P271C indicates a problem with the transmission fluid temperature sensor's range or performance, specifically related to sensor B, suggesting that the sensor is providing readings that are outside the expected range or not functioning correctly

Common causes

  • Faulty transmission fluid temperature sensor
  • Wiring issues (shorts, opens, or corrosion)
  • Poor electrical connections
  • Transmission control module (TCM) malfunction
  • Low transmission fluid level
  • Contaminated transmission fluid
  • Faulty transmission fluid temperature sensor circuit
  • Overheating transmission
  • Software issues in the TCM

Common misdiagnoses

  • Faulty transmission control module (TCM)
  • Transmission fluid issues (contamination or low level)
  • Faulty transmission fluid temperature sensor
  • Wiring or connector issues
  • Transmission solenoid problems
  • Internal transmission problems
  • Engine control module (ECM) issues
  • Incorrectly diagnosed overheating issues

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 other issues affecting the transmission

  2. 2. Inspect the Transmission Fluid

    Fluid Level: Check the transmission fluid level. Low fluid can cause overheating and sensor issues

  3. 3. Fluid Condition

    Inspect the fluid for contamination, burning smell, or discoloration. If the fluid is dirty or burnt, it may need to be changed

  4. 4. Examine the Transmission Fluid Temperature Sensor

    Visual Inspection: Check the wiring and connectors leading to the transmission fluid temperature sensor for any signs of damage, corrosion, or loose connections

  5. 5. Sensor Testing

    If possible, test the sensor using a multimeter to ensure it is functioning within the manufacturer’s specifications. Compare the readings to the expected values

  6. 6. Check for Wiring Issues

    Inspect the wiring harness for any signs of wear, fraying, or short circuits. Pay special attention to areas where the wiring may be exposed to heat or moving parts

  7. 7. Inspect the Transmission Control Module (TCM)

    Ensure that the TCM is functioning correctly. Sometimes, a software update or reprogramming may be necessary if the TCM is not processing the sensor data correctly

  8. 8. Look for Overheating Issues

    Check for any signs of overheating in the transmission. This could be due to a failing transmission cooler, blocked cooler lines, or other cooling system issues

  9. 9. Perform a Transmission Fluid Change

    If the fluid is old or contaminated, consider performing a transmission fluid change. This can sometimes resolve sensor performance issues

  10. 10. Clear Codes and Test Drive

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

  11. 11. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued updates or fixes for known issues related to the transmission fluid temperature sensor

  12. 12. Seek Professional Help

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or transmission specialist for further diagnosis and repair. By following these steps, you can systematically identify and address the underlying cause of the P271C code