WOMS
P code powertrain Medium severity

P071F Transmission Mode Switch "B" Circuit High

The OBD2 code P071F indicates that there is a high voltage signal detected in the Transmission Mode Switch "B" circuit, which may suggest a malfunction in the switch or its wiring

Definition

The OBD2 code P071F indicates that there is a high voltage signal detected in the Transmission Mode Switch "B" circuit, which may suggest a malfunction in the switch or its wiring

Common causes

  • Faulty transmission mode switch
  • Wiring issues (shorts or open circuits)
  • Poor connections or corroded terminals
  • Faulty transmission control module (TCM)
  • Malfunctioning engine control module (ECM)
  • Software issues or glitches in the TCM/ECM
  • Grounding problems in the circuit

Common misdiagnoses

  • Faulty transmission control module (TCM)
  • Defective transmission range sensor
  • Wiring issues or short circuits
  • Faulty transmission fluid temperature sensor
  • Malfunctioning shift solenoids
  • Incorrectly installed or damaged transmission components
  • Software issues or outdated firmware in the TCM
  • Battery or charging system problems affecting electronic components

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 Transmission Mode Switch

    Visual Inspection: Check the transmission mode switch for any visible damage, corrosion, or loose connections

  3. 3. Wiring and Connectors

    Inspect the wiring harness and connectors for fraying, breaks, or poor connections. Pay special attention to the pins in the connector

  4. 4. Test the Transmission Mode Switch

    Multimeter Testing: 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. Functionality Check

    If possible, manually operate the switch to see if it responds correctly and if the readings change as expected

  6. 6. Check for Short Circuits

    Inspect the wiring for any signs of short circuits to ground or to other wires. A short can cause the circuit to read high

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

    Check the TCM for any signs of damage or corrosion. Ensure that it is securely connected and that there are no issues with the pins or connectors

  8. 8. Check for Ground Issues

    Ensure that the ground connections related to the transmission mode switch and TCM are clean and secure. Poor grounding can lead to erroneous readings

  9. 9. Look for Software Updates

    Check if there are any software updates available for the vehicle’s TCM. Sometimes, manufacturers release updates that can resolve specific issues

  10. 10. Clear Codes and Test Drive

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

  11. 11. Seek Professional Help

    If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic or technician who has experience with transmission systems and OBD-II diagnostics. By following these steps, you should be able to identify the cause of the P071F code and take appropriate action to resolve it