Lost Communication with Steering Angle Sensor Module
Diagnostic trouble code U0126 indicates that the vehicle's control module has lost communication with the Steering Angle Sensor Module (SASM). This sensor is critical for electronic stability control (ESC), traction control, and steering assist systems. Communication typically occurs via the Controller Area Network (CAN) bus, and loss of this signal prevents related modules from receiving steering wheel position and rotation speed data. According to SAE J2012, U-codes from U0000 to U1000 correspond to data network communication faults.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Faulty steering angle sensor module (SASM)
- Open or short circuit in the CAN bus wiring (CAN-H and/or CAN-L lines)
- Incorrect CAN bus termination resistance
- Faulty powertrain control module (PCM/ECM) or ABS/ESC control module
- Corroded, loose, or damaged sensor connector
- Low voltage or power supply failure to the SASM
- Electromagnetic interference in the sensor wiring
3. Symptoms You Will Notice
- Illuminated check engine light or ESC warning light
- Loss of electronic stability control, traction control, or power steering assist
4. Step-by-Step Diagnosis
Scan for all stored codes and note any related U-codes
Inspect the SASM connector for corrosion, damage, or looseness
Check CAN bus wiring for opens, shorts, or high resistance
Measure CAN bus termination resistance (should be ~60 ohms between CAN-H and CAN-L)
Verify power and ground at the SASM connector
Test the SASM per manufacturer procedures or replace with a known-good unit
5. Frequently Asked Questions
Is it safe to drive?▼
No, it is not safe to drive with this code active. Loss of steering angle sensor communication can disable stability control and traction control, increasing the risk of loss of vehicle control, especially in emergency maneuvers or slippery conditions.
How much does it cost to fix?▼
Repair costs vary widely depending on the root cause. A simple wiring repair may cost $100-$200, while replacing the steering angle sensor module can range from $300 to $800 including labor. If the PCM or ABS module is faulty, costs can exceed $1,000.