Method for configuring a functionality of real and/or simulated control units, comprising a functionality belonging to a functionality class, such that the functionality has one or more functions and parameters dependent on the functionality class. The functionality is further assigned to at least one control unit. The functionality class has categories, including an else category and a default category and its functionalities each belong to a category. A predetermined value is stored for parameter and if the functionality is assigned to the default category, the predetermined value is adopted for the parameter. If the predetermined value of the parameter changes, the change is adopted for all functionalities which have already been assigned to the default category. And the control unit assigned to the functionality is configured with the function and the values of the parameters of the functionality.