C1139Wheel 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
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.Visual Inspection
Check the Tone Ring: Inspect the tone ring for any visible damage, such as missing teeth, cracks, or excessive wear
2.Sensor Condition
Examine the wheel speed sensor for any signs of damage, corrosion, or dirt buildup that could affect its operation
3.Wiring and Connectors
Inspect the wiring and connectors leading to the wheel speed sensor for fraying, corrosion, or loose connections
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.Check Sensor Alignment
Ensure that the wheel speed sensor is properly aligned with the tone ring. Misalignment can lead to incorrect readings
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.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.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.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.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.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.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