Abstract: The invention relates to a method for checking the operability of a cyclically controlled regeneration valve in a tank venting system of a motor vehicle which utilizes the realization that during operation of the system significant pressure variations are generated in a discharge line arranged between an adsorption filter and the regenerating valve whenever the duty ratio of the regeneration valve is within a certain range. If the regeneration valve is operated at such a duty ratio, the pressure variations in the discharge line are recorded and the extreme pressure valves are determined in an evaluation device for a specified time period after which the difference between the maximum and the minimum pressures is determined and if this difference is below a predetermined threshold, the regeneration valve is indicated as being defective.