Calibrage du capteur non effectué après réparation

A sensor that reads correctly but has never been told what "correct" means. The part is not faulty; the reference is missing — which is why this cause is on the list at all, and why it should be ruled out before anything is bought.

It is different from a sensor that has drifted. Drift is a part degrading over time. This is a zero point that was never established, or that was deliberately erased by the work just done.

The steering angle sensor is the classic case. It measures angle relative to straight ahead, and it has to be shown where straight ahead is. A wheel alignment, a steering rack, a clock spring, a battery disconnection or a module replacement can all lose that reference — after which the sensor is healthy and every reading is wrong by a fixed amount, which stability control cannot use.

Inertial sensors need it too, and with a condition attached: the car must be still, on level ground. A calibration performed on a slope teaches the car a lie it will keep.

The diagnostic question is a scheduling question. If the fault appeared immediately after work on the car, this is the first thing to eliminate — and it costs nothing but the scan tool time.