Abstract: A vehicle device comprising a base vehicle and a seat unit being releaseably connectable to the base vehicle is described. The base vehicle comprises an electronic control means and a vehicle-side wireless communication means, and the seat unit comprises at least one sensor, a battery, an electronic unit, and a seat-side wireless communication means. In order to provide the electronic control means of the base vehicle with the necessary information about the seat unit in an energy-saving manner, the electronic unit reads-out the status of the at least one sensor in a certain time-scheme and transmits a sensor related signal via the seat-side wireless communications means only if the status of the sensor changed since the previous read-out.