Method and device for testing the functionality of an object recognition device of a motor vehicle

The method involves producing sensor data (12) of a motor vehicle based on characteristics of a sensor e.g. ultrasonic sensor. Determined surrounding is stimulated by providing the appropriate sensor data. Surrounding data (30) is computed based on the sensor data by the simulation of the surroundings. A recognition unit (10) is operated with the sensor data, and an appropriate recognition result (16) is determined for each simulated surrounding. Another sensor data (38) is produced based on a function of a comparison result (22) of the recognition result with a target recognition result (20). An independent claim is also included for a device for making a functional check of a recognition unit.