There is a longitudinal acceleration failure due to an offset / mounting position being out of the limit. The longitudinal acceleration (Ax) offset is estimated by a kind of low pass filtering. The offset is initialized with the offset of the last ignition cycle. A failure is set immediately when the offset exceeds the limit of 2.25 m/sē and compensation was active for at least 10km.
In addition, there is a check for a sudden change in the signal offset due to, for example, a misalignment of the HU after an accident. It compares the stored offset to the new offset after a learning distance of 10km. The allowed misalignment is 10deg (equals 1.73 m/sē offset difference).