A method for determining a filling stop during a filling process of an operating fluid container whose operating fluid container interior can be filled with an operating fluid via a filling pipe opening into said interior, wherein a pressure sensor for determining a pressure within the filling pipe is arranged in the filling pipe, wherein the method has the following method steps: acquiring the time profile of pressure values acquired by means of the pressure sensor; and outputting a filling stop signal in accordance with the time profile of the pressure values. In addition, the present invention discloses an operating fluid container system having an operating fluid container and a filling pipe, opening into an operating fluid container interior, for filling the operating fluid container with an operating fluid, wherein the operating fluid container system has a pressure sensor arranged within the filling pipe and is coupled via a data line to an electronic control device for transmitting data, representing the pressure within the filling pipe, to the electronic control device, wherein the control device is designed to carry out the method according to the invention for determining a filling stop.