In the field of braking and driving stabilisation systems, development has progressed a long way. Systems such as ABS, ASR and ESP have long been part of the standard equipment of a new car. Common to all systems is that they require the vehicle speed or the speed of the individual wheels as an input variable. So-called wheel speed sensors are used for this purpose, which measure the speed of each individual wheel and pass it on to the ABS control unit, for example. Since this sensor technology is also constantly being developed further, there is a need to understand the differences between the individual variants and to learn the system-dependent diagnostic strategies.