U0126 – Lost Communication With Steering Angle Sensor means the Powertrain Control Module (PCM), ABS module, or Vehicle Dynamics Control Module (VDCM) has stopped receiving data from the Steering Angle Sensor (SAS). This sensor reports how far and how quickly you turn the steering wheel—critical information for ABS, traction control, stability control, and electric power steering. When communication is lost, these systems may shut down or enter failsafe mode. This guide explains what U0126 means, the symptoms to expect, common causes, diagnosis steps, and the best repair solutions.
What Does U0126 Mean?
U0126 is a generic OBD-II communication fault indicating that the SAS is no longer communicating over the CAN bus. The steering angle sensor constantly sends real-time data to stability and traction control systems. If the CAN network cannot deliver this information, the ABS and ESC modules cannot perform yaw corrections, brake interventions, or traction adjustments.
Because the sensor is essential for vehicle stability and modern steering systems, losing communication can significantly affect handling and safety. U0126 often appears alongside other stability control codes such as U0122 or U0124.
Quick Reference
- OBD-II Family: U-Code (Network Communication)
- Scope: Generic
- System: Steering / Stability Control / CAN Bus
- Difficulty Level: Moderate
- Estimated Repair Cost: €120–€500+
- Last Updated: 21 November 2025
Real-World Example / Field Notes
A vehicle arrived with the traction control and electric power steering lights illuminated. The steering felt heavy, especially at low speeds. Diagnostics showed U0126 in the ABS, EPS, and PCM. The cause was a broken ground wire in the steering column harness where repeated tilt adjustments stressed the wiring. Repairing the ground and securing the harness restored full steering and stability control operation.
Another case involved an SUV where the ESC light would turn on during hard cornering. The SAS connector under the steering column was slightly loose from a previous repair. Road vibrations caused intermittent communication loss, triggering U0126. Securing the connector resolved the intermittent faults.
Symptoms of U0126 – Lost Communication With Steering Angle Sensor
- ESC/traction light on: Stability control disabled.
- ABS warning light: ESC relies heavily on SAS data.
- EPS/steering warning: Electric steering may reduce assist.
- Heavy or inconsistent steering feel: EPS may revert to failsafe mode.
- No steering angle data: Live data in scan tool frozen at 0°.
- Vehicle pulls or feels unstable: ESC unable to correct yaw.
- Multiple U-codes: Network instability when SAS drops offline.
Common Causes of U0126
Most Common Causes
- Loss of power or ground at the Steering Angle Sensor
- Steering column wiring damage (tilt/telescoping wear)
- Corroded or loose SAS connector
- CAN bus wiring issues (opens, shorts, water intrusion)
- Faulty Steering Angle Sensor
Less Common Causes
- Poor chassis grounding affecting steering electronics
- Rodent damage under dash
- Aftermarket accessories interfering with column wiring
- Failed CAN terminating resistor
- Internal failure in ABS/ESC module disrupting communication
Diagnosis: Step-by-Step Guide
Diagnosing U0126 involves verifying the SAS power supply and checking CAN bus communication reliability. Follow these steps carefully.
Tools You’ll Need
Advanced scan tool, multimeter, wiring diagrams, backprobe kit, CAN breakout box, oscilloscope (recommended), and a battery/alternator tester.
- Scan all modules: Confirm U0126 across multiple modules and note whether the SAS responds at all.
- Inspect steering column: Look for damaged or over-stressed wiring caused by tilt/telescoping movement.
- Check SAS connector: Inspect for loose pins, corrosion, or moisture.
- Verify power and ground: Use wiring diagrams to confirm proper voltage supply.
- Measure CAN-H and CAN-L voltage: Expect ~3.5V (H) and ~1.5V (L). Abnormal values indicate wiring faults.
- Test network termination: With ignition off, CAN-H to CAN-L should read ~60 ohms.
- Continuity testing: Check wiring continuity from SAS to ABS/VDCM.
- Wiggle test: Move steering column harness while monitoring live SAS data for dropouts.
- Check for aftermarket devices: Remove Bluetooth dongles, alarms, or remote-start wiring if spliced into column.
- Oscilloscope analysis: A distorted waveform indicates noise or wiring interference affecting communication.
Pro Tip: Steering column wiring often fails exactly where the harness bends during tilt or reach adjustments. Even slight insulation wear can cause intermittent U0126 faults long before a complete failure.
Possible Fixes & Repair Costs
- Repair damaged steering column wiring: €60–€200
- Clean or replace SAS connector: €20–€80
- Replace Steering Angle Sensor: €150–€350+
- Repair CAN wiring near column or dash: €80–€200
- Fix poor chassis grounds: €20–€80
- Charging system repair (if voltage-related): €120–€400
Can I Still Drive With U0126?
Driving is possible, but less safe. With the SAS offline, the stability and traction control systems cannot correctly interpret vehicle direction. Hard cornering, slippery surfaces, or emergency maneuvers may become risky. If steering assist feels inconsistent or multiple warning lights are active, avoid driving until repairs are completed.
Related Codes
- U0151 – Instrument Panel Communication Fault
- U0141 – Steering System Network Communication Fault
- U0121 – Lost Communication With Anti-Lock Brake System (ABS) Control Module
- U0102 – Lost Communication With Transfer Case Control Module
- U0101 – Lost Communication With TCM
- U0100 – Lost Communication With ECM/PCM "A"
- U0195 – Lost Communication With Audio AMP
- U0194 – Lost Communication With Audio Display
- U0188 – Lost Communication With Video Display
- U0185 – Lost Communication With TV/Telematics Unit
Key Takeaways
- U0126 means the Steering Angle Sensor is not communicating over CAN.
- Wiring damage in the steering column is the most common cause.
- ESC, traction control, and ABS may be disabled.
- Driving becomes less stable and may be unsafe in slippery conditions.
FAQ
Where is the Steering Angle Sensor located?
Usually inside the steering column, at the base of the steering shaft, or built into the clock spring assembly.
Does U0126 mean the SAS needs replacement?
Not always. Many cases are caused by wiring, connector corrosion, or poor grounding rather than a failed sensor.
Can low voltage trigger U0126?
Yes. Steering and stability systems are sensitive to voltage drops and charging system issues.
Is it safe to drive with the SAS not communicating?
It’s possible but not ideal. Stability control is a key safety system and may be disabled.
Can a wheel alignment cause U0126?
An alignment itself won’t cause U0126, but a misaligned steering wheel may reveal an SAS calibration issue that existed before the code appeared.