WOMS
U code network Medium severity

U2139 Lost Communication with the Steering Angle Sensor Module

The OBD2 code U2139 indicates that there is a loss of communication with the Steering Angle Sensor Module, which may affect the vehicle's stability control and steering functions

Definition

The OBD2 code U2139 indicates that there is a loss of communication with the Steering Angle Sensor Module, which may affect the vehicle's stability control and steering functions

Common causes

  • Faulty steering angle sensor
  • Damaged wiring or connectors
  • Poor electrical connections
  • Malfunctioning vehicle control module
  • Software issues or updates needed
  • Low battery voltage or power supply issues
  • Corrosion or dirt in connectors
  • Faulty CAN bus communication
  • Intermittent faults in the sensor or wiring

Common misdiagnoses

  • Faulty Steering Angle Sensor
  • Wiring or connector issues
  • Faulty Body Control Module (BCM)
  • Faulty Electronic Power Steering (EPS) module
  • Incorrectly calibrated steering angle sensor
  • Faulty ABS module
  • Software or firmware issues in the vehicle's control modules
  • Battery or charging system problems

Troubleshooting steps

  1. 1. Check for Other Codes

    Use an OBD-II scanner to check for any additional trouble codes. Sometimes, multiple codes can provide more context for the issue

  2. 2. Inspect Wiring and Connectors

    Visual Inspection: Check the wiring harness and connectors related to the steering angle sensor for any signs of damage, corrosion, or loose connections

  3. 3. Connector Pins

    Ensure that the pins in the connectors are not bent, corroded, or pushed back

  4. 4. Test the Steering Angle Sensor

    Sensor Functionality: If possible, test the steering angle sensor to ensure it is functioning correctly. This may involve using a multimeter or an oscilloscope to check the output signals

  5. 5. Calibration

    Some vehicles require the steering angle sensor to be calibrated after installation or repair. Check the vehicle’s service manual for calibration procedures

  6. 6. Check Power and Ground

    Power Supply: Verify that the steering angle sensor is receiving the correct voltage. Use a multimeter to check the power supply at the sensor connector

  7. 7. Ground Connection

    Ensure that the ground connection for the sensor is intact and providing a good ground

  8. 8. Inspect the CAN Bus

    Communication Lines: Since the steering angle sensor communicates over the CAN bus, check for any issues with the CAN wiring. Look for shorts, opens, or interference

  9. 9. CAN Bus Termination

    Ensure that the CAN bus is properly terminated at both ends

  10. 10. Check for Software Issues

    Updates: Check if there are any software updates available for the vehicle’s ECU that may address communication issues

  11. 11. Resetting the ECU

    Sometimes, resetting the ECU by disconnecting the battery for a few minutes can clear temporary communication faults

  12. 12. Inspect Related Modules

    Other Modules: Check if other modules that communicate with the steering angle sensor are functioning properly. A fault in another module can sometimes cause communication issues

  13. 13. Perform a System Scan

    Use a professional-grade scan tool to perform a complete system scan. This can help identify any hidden issues or communication problems between modules

  14. 14. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to the steering angle sensor or communication issues for your specific vehicle make and model. Manufacturers may have known fixes for common problems

  15. 15. 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 your vehicle’s specific systems. By following these troubleshooting steps, you should be able to identify the root cause of the U2139 code and take appropriate action to resolve the issue