To provide a method for prohibiting an error produced by a supervision method of a sensor of a conventional technique.

The method of supervising the sensor using a differential voltage evaluation is provided so as to detect a short to a ground and/or a supply voltage UB. A first resistor R1 and a second resistor R2 are attached to the sensor. A sum voltage is determined from one voltage UP of one terminal of the sensor and the other voltage UM of the other terminal, and this sum voltage is compared with the supply voltage UB. Then a ratio a between the determined sum voltage and the supply voltage UB is obtained. The occurrence of branching at a plus terminal and/or a minus terminal of the sensor is detected depending on the ratio a value.