What does it mean?
C1266 is a Chassis (ABS, traction control, steering) fault code. It indicates: Steering Angle Sensor Circuit Failure .
Symptoms
- Stability, traction and often ABS warning lamps on together
- Steering angle missing from live data, or fixed at one value no matter how the wheel is turned
- ESP and traction control fully disabled
- Electric power steering assist reduced or in a fallback mode
- Adaptive headlights and steering-dependent driver assistance inoperative
Likely causes
- Open circuit in the steering angle sensor supply or ground so the module sees no sensor at all
- Connector left unplugged, damaged or partly seated after column, airbag or ignition switch work
- Internally broken clockspring cutting the sensor circuits
- Harness damage where the loom passes the column bracket or the pedal box
- Short circuit pulling the shared reference voltage down
- Internal sensor failure
- Faulty stability control module input
How to fix it
- Confirm the sensor connector is fully seated and the locking tab is engaged before anything else
- Check for reference voltage and a good ground at the sensor connector with the ignition on
- Test continuity of each sensor circuit from the connector to the module pin
- Inspect the clockspring and its pigtails, and check continuity through the full steering travel
- Unplug other devices on the shared reference if the voltage is low, to find the shorted component
- Repair the wiring, then perform the steering angle calibration
- Replace the sensor or clockspring assembly once the circuits and supplies are proven good