A method for checking the operational capability of a fuel tank ventilation valve (7) of a fuel tank ventilation system of a motor vehicle with an internal combustion engine (1) having an intake manifold pressure-based detection of filling levels is thereby characterized in that the fuel tank ventilation valve (7) is selectively activated to open or close and in correlation to this the operational capability of the fuel tank ventilation valve (7) is suggested from the thereby resulting intake manifold pressure (ps).