A method and a device for operating a position sensor made of at least two parts that move in relation to one another. The first part of the position sensor has at least two sections magnetized in different directions, and the second part has at least one magnetic field sensor which detects the magnetic field of the first part and converts it into signals having two levels depending on the polarity of the component of the magnetic field in a predefined spatial direction. The levels are supplied to a signal-processing arrangement which evaluates them to determine the relative position of the first part in relation to the second part. Prior to disabling the at least one magnetic field sensor when the first part is at a standstill with respect to the second part, the level delivered by the magnetic field sensor is stored, detected again after the magnetic sensor is enabled again, compared with the stored level, and if the measured level does not coincide with the stored level, the level change is evaluated as a valid level change.