What does it mean?
C1231 is a Chassis (ABS, traction control, steering) fault code. It indicates: Drive Test: Steering Angle Sensor .
Symptoms
- Stability control and ABS lamps on after a service or alignment job
- Message that the stability system is unavailable until the vehicle is driven
- Code remains stored until a correct road test is completed
- Stability control intervening on gentle bends or on a straight road
- Steering wheel slightly off centre while the vehicle tracks straight
Likely causes
- Sensor zero point never learned after a battery disconnect, module replacement or steering repair
- Wheel alignment out, so the steering wheel is not centred when the vehicle runs straight
- Steering angle disagreeing with the yaw rate and wheel speed data during the road test
- Signal dropouts from a worn clock spring or loose connector during driving
- Play in the steering rack, track rods or intermediate shaft so the reported angle lags the road wheels
- Calibration procedure started but not finished, for example the drive test was cut short
- Sensor itself drifting once it warms up
How to fix it
- Check the alignment and confirm the steering wheel is centred before any calibration attempt
- Read the live steering angle straight ahead on level ground; it should be close to zero
- Perform the zero point reset and then carry out the specified drive test, holding a steady straight run before making turns
- Graph steering angle against yaw rate and lateral acceleration during the road test and look for disagreement
- Wiggle test the clock spring connector and column wiring while watching the live angle
- Check the steering linkage and intermediate shaft for play that would delay the angle change
- Replace the sensor if the angle still steps or drifts after a correct calibration