Abstract: The invention relates to a method for servicing an air conditioner, particularly in a motor vehicle. According to the method, a test gas is applied at a defined pressure to the air conditioner cooling circuit that is depleted of coolant in order to perform a tightness test, and changes in the pressure are recorded and evaluated during a certain interval. The aim of the invention is to further develop such a method in such a way that the same can be carried out in a highly automated manner, rapidly, and without harming the environment. The aim is achieved by using a gas mixture of nitrogen and hydrogen as a test gas and inspecting the cooling circuit by means of a hydrogen probe once a drop in pressure has been recorded.