WOMS
P code powertrain Medium severity

P071E Transmission Mode Switch "B" Circuit Low

The OBD2 code P071E indicates that there is a low voltage or an open circuit in the Transmission Mode Switch "B" circuit, which affects the transmission's ability to determine the selected mode

Definition

The OBD2 code P071E indicates that there is a low voltage or an open circuit in the Transmission Mode Switch "B" circuit, which affects the transmission's ability to determine the selected mode

Common causes

  • Faulty transmission mode switch
  • Damaged wiring or connectors
  • Short circuit in the circuit
  • Open circuit in the circuit
  • Corroded connectors
  • Faulty transmission control module (TCM)
  • Poor ground connection

Common misdiagnoses

  • Faulty Transmission Control Module (TCM)
  • Faulty Transmission Range Sensor
  • Wiring issues or shorts in the circuit
  • Faulty Transmission Fluid Temperature Sensor
  • Incorrectly installed or malfunctioning transmission
  • Faulty Engine Control Module (ECM)
  • Issues with the vehicle's battery or charging system
  • Faulty or corroded connectors in the transmission circuit

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 Mode Switch

    Locate the Transmission Mode Switch (TMS) and visually inspect it for any signs of damage, corrosion, or loose connections

  3. 3. Ensure that the switch is properly mounted and that there are no broken wires or connectors

  4. 4. Test the Switch

    Use a multimeter to test the resistance and continuity of the Transmission Mode Switch. Compare the readings to the specifications in the vehicle’s service manual

  5. 5. If the switch is faulty, it may need to be replaced

  6. 6. Check Wiring and Connectors

    Inspect the wiring harness and connectors associated with the Transmission Mode Switch for any signs of wear, fraying, or damage

  7. 7. Ensure that all connectors are securely attached and free of corrosion

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

    Check the TCM for any signs of damage or corrosion. Ensure that it is properly connected

  9. 9. If possible, perform a software update or reset the TCM to see if that resolves the issue

  10. 10. Check for Ground Issues

    Ensure that the ground connections related to the Transmission Mode Switch and TCM are secure and free of corrosion. Poor grounding can lead to low voltage readings

  11. 11. Test Voltage Supply

    Use a multimeter to check the voltage supply to the Transmission Mode Switch. Ensure that it is receiving the correct voltage as specified in the service manual

  12. 12. Inspect Related Components

    Check other components that may be related to the transmission system, such as the transmission fluid level and condition, as low or dirty fluid can affect transmission performance

  13. 13. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code reappears

  14. 14. 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 transmission systems and can perform more advanced diagnostics.Conclusion By following these troubleshooting steps, you can systematically identify and address the cause of the P071E code. Always refer to the specific service manual for your vehicle for detailed procedures and specifications