Operating method for a vehicle

The method involves determining (S1) filling value of urea containing liquid in a container of vehicle at two different points of time. The difference between filling values in different points of time is determined (S2) with respect to a reference amount, to achieve liquid decrease between points of time in close-to-reality. The reduction of pollutants in exhaust gas of vehicle is determined to restrict (S4) the vehicle operation, if the liquid decrease falls below reference amount over a preset size and/or over a defined time domain.