Method and apparatus for monitoring function of ultrasonic sensors

The invention relates to a method for monitoring the function of ultrasonic sensors (1-12) of a vehicle (100), wherein an ultrasonic sensor (1-12) of the vehicle (100) emits ultrasonic signals (120) and receives reflected ultrasonic echoes (122) again. According to the invention, a current amplitude of a ground echo received by an ultrasonic sensor (1-12) and a current vehicle position are to be determined. In a further step, a reference threshold value or details of an anticipated ground echo amplitude are retrieved from a digital map on the basis of the current vehicle position, the digitalmap being provided by a central device (200). The current amplitude of the received ground echo is then compared with a threshold value. The threshold value is not reached, malfunction of the ultrasound sensor (1-12) is assumed, the threshold value being predetermined by the reference threshold value or the threshold value being determined by the details of an anticipated ground echo amplitude. Further aspects of the inve