CAN network

U0126 — Lost Communication with Steering Angle Sensor Module

Severity: medium Drive with care, to a shop

What U0126 means

U0126 means a control module, usually the ABS/ESC unit or a gateway, has stopped receiving messages from the steering angle sensor over the CAN bus. This sensor tells the stability control system where the driver is steering, so ESC can compare that with the car's actual path. Without the signal, ESC shuts off and, on some cars, power steering assist is affected too.

Symptoms

  • ESC and ABS warning lights on, sometimes the check engine light too
  • Stability control disabled
  • Steering feels heavy or power assist is intermittent
  • Steering feel is abnormal
  • Several warning lights on at once
  • Features that rely on steering angle are unavailable

Possible causes

  1. Failed steering angle sensor or its module
  2. Damaged or corroded CAN bus wiring or connectors
  3. Poor power supply or ground at the sensor module
  4. Open or shorted CAN bus lines
  5. Failed clock spring
  6. Battery disconnected without recalibrating the sensor
  7. Module software error
  8. Another faulty module disrupting the bus

How to diagnose

  1. Scan all modules and note which ones are missing from the network
  2. Check battery voltage and look for other U-codes
  3. Check fuses, power, and ground at the steering angle sensor
  4. Inspect connectors and harness at the steering column and along the route to the ABS unit for corrosion, chafing, or moisture
  5. Measure CAN-H to CAN-L resistance at the diagnostic connector (about 60 ohms on a healthy bus) and check line voltages
  6. Watch the steering angle live data while turning the wheel
  7. Test the clock spring
  8. Unplug suspect modules one at a time, only following the manufacturer's documented procedure

Common fixes

  • Repair damaged CAN wiring or connectors
  • Restore power and ground to the sensor, replace blown fuses
  • Replace the steering angle sensor or clock spring, then calibrate
  • Update or reprogram module software
  • Perform a steering angle zero-point calibration after repairs or battery disconnection

Questions and answers

Can I drive with a U0126 code?

For a short distance, yes, if the steering works normally, but ESC and ABS are probably off. Drive carefully and get it diagnosed soon.

Do I need to calibrate after replacing the steering angle sensor?

Yes. The sensor must be calibrated with a scan tool, otherwise ESC may work incorrectly and the fault can return. Clear the codes and confirm the angle reading changes live.

Can U0126 appear after disconnecting the battery?

Yes, a battery disconnect can sometimes cause the sensor to lose calibration or trigger a communication glitch. Calibrating and clearing codes often fixes it, but if it returns, look for a wiring or sensor fault.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.