U0126
Lost Communication With Steering Angle Sensor Module
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Code U0126 means the vehicle's electronic network has lost communication with the steering angle sensor (SAS) module. This sensor tells the rest of the vehicle's computers exactly what position the steering wheel is in at all times. This information is critical for electronic stability control, ABS optimization, adaptive headlights, and advanced driver-assistance features like lane-keeping assist.
Without accurate steering angle data, the stability control system cannot determine if the car is going where the driver intends, so it shuts down entirely as a safety precaution. You'll typically see ESC, ABS, and possibly lane-assist warning lights on the dashboard. One of the most common causes is simply a weak or recently disconnected battery — the SAS module may need a proper power cycle and recalibration to resume normal operation.
This code should be addressed within the week. While the vehicle remains drivable with basic steering and braking intact, the loss of stability control and related safety systems is significant. Start by checking battery condition and performing a steering angle sensor calibration with a scan tool. If the code persists, a technician should inspect the steering column wiring and the sensor module itself.
Severity
Symptoms
- •Electronic Stability Control (ESC/VSC) warning light on
- •ABS warning light may illuminate
- •Power steering assist may feel reduced or inconsistent
- •Lane departure or lane-keeping assist systems disabled
- •Steering wheel position may not register correctly after turns
- •Check engine light may be on
Likely Causes
The steering angle sensor is a precision component mounted in the steering column. Internal wear, electrical faults, or contamination can cause it to stop transmitting position data on the CAN bus.
The wiring harness running through the steering column is subject to flexing every time the wheel is turned. Over time, wires can break or connectors can develop loose pins, interrupting communication.
An open or short circuit on the CAN bus segment that serves the steering angle sensor will prevent it from communicating. If multiple U-codes are present, a shared bus fault is likely.
A dead or weak battery is a surprisingly common trigger for U0126. Low voltage can cause the SAS module to reset or fail to initialize properly, especially after a battery has been disconnected.
Power interruptions during operation or voltage spikes can corrupt the module's internal software, requiring reprogramming with a dealer-level scan tool to restore communication.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Check and charge or replace the vehicle battery
- Inspect steering column wiring and SAS module connector for damage
- Perform a steering angle sensor calibration with a scan tool
- Repair CAN bus wiring faults if multiple U-codes are present
- Replace the steering angle sensor module