Abstract: In a method for checking a first ultrasonic sensor of a motor vehicle for an occlusion, a measuring signal of the first ultrasonic sensor is acquired by an evaluation unit, and from the measuring signal, a decay time of a natural oscillation of the diaphragm of the first ultrasonic sensor, brought about by an excitation pulse, is ascertained. From the measuring signal of either the first ultrasonic sensor or a second ultrasonic sensor, an echo produced by an object located in a sensing range of the first ultrasonic sensor is ascertained, and a distance value of the object is determined on the basis of the echo. An occlusion is signaled if the decay time is less than a predetermined threshold value which would be exceeded if ice and/or dirt were to adhere directly to the diaphragm, and if the distance value is less than a predetermined maximum value.

Abstract: In a method for checking a first ultrasonic sensor of a motor vehicle for an occlusion, a measuring signal of the first ultrasonic sensor is acquired by an evaluation unit, and from the measuring signal, a decay time of a natural oscillation of the diaphragm of the first ultrasonic sensor, brought about by an excitation pulse, is ascertained. From the measuring signal of either the first ultrasonic sensor or a second ultrasonic sensor, an echo produced by an object located in a sensing range of the first ultrasonic sensor is ascertained, and a distance value of the object is determined on the basis of the echo. An occlusion is signaled if the decay time is less than a predetermined threshold value which would be exceeded if ice and/or dirt were to adhere directly to the diaphragm, and if the distance value is less than a predetermined maximum value.