WOMS
C code chassis High severity

C1139 Wheel Speed Sensor Center Tone Ring Missing Tooth Fault

The OBD2 code C1139 indicates that there is a fault related to the wheel speed sensor, specifically that a tooth is missing from the center tone ring, which can affect the sensor's ability to accurately read wheel speed

Definition

The OBD2 code C1139 indicates that there is a fault related to the wheel speed sensor, specifically that a tooth is missing from the center tone ring, which can affect the sensor's ability to accurately read wheel speed

Common causes

  • Damaged or missing tone ring
  • Misaligned tone ring
  • Faulty wheel speed sensor
  • Wiring issues (shorts, breaks, or corrosion)
  • Poor electrical connections
  • Wheel bearing failure
  • Incorrect installation of components
  • Contamination or debris on the tone ring or sensor

Common misdiagnoses

  • Faulty wheel speed sensor
  • Damaged wiring or connectors
  • ABS control module failure
  • Incorrectly installed tone ring
  • Brake system issues
  • Wheel bearing problems
  • Tire size discrepancies
  • Calibration errors in the ABS system

Troubleshooting steps

  1. 1. Visual Inspection

    Check the Tone Ring: Inspect the tone ring for any visible damage, such as missing teeth, cracks, or excessive wear

  2. 2. Sensor Condition

    Examine the wheel speed sensor for any signs of damage, corrosion, or dirt buildup that could affect its operation

  3. 3. Wiring and Connectors

    Inspect the wiring and connectors leading to the wheel speed sensor for fraying, corrosion, or loose connections

  4. 4. Clean the Sensor and Tone Ring

    If dirt or debris is present, clean the wheel speed sensor and tone ring carefully. Use a soft cloth and appropriate cleaning solution to avoid damaging components

  5. 5. Check Sensor Alignment

    Ensure that the wheel speed sensor is properly aligned with the tone ring. Misalignment can lead to incorrect readings

  6. 6. Test the Wheel Speed Sensor

    Use a multimeter to test the resistance of the wheel speed sensor. Compare the readings to the manufacturer’s specifications

  7. 7. If available, use a scan tool to monitor the wheel speed sensor's output while the vehicle is in motion. The readings should change as the wheel rotates

  8. 8. Inspect the ABS Module

    If the tone ring and sensor are in good condition, check the ABS module for any faults. This may require specialized diagnostic equipment

  9. 9. Check for Other Codes

    Look for any additional OBD-II codes that may provide more context or indicate related issues. Address any other codes found

  10. 10. Test Drive the Vehicle

    After performing the above checks and repairs, take the vehicle for a test drive to see if the code reappears. Monitor the ABS and traction control systems for proper operation

  11. 11. Consult Repair Manual

    Refer to the vehicle’s service manual for specific diagnostic procedures and specifications related to the wheel speed sensor and tone ring

  12. 12. Professional Diagnosis

    If the issue persists after performing these steps, consider seeking help from a professional mechanic or technician who has access to advanced diagnostic tools.Conclusion Addressing the C1139 code involves a systematic approach to inspect, clean, and test the components involved. By following these troubleshooting steps, you can often identify and resolve the underlying issue