In a method for determining the charge of an activated carbon container of a tank venting system of a gasoline engine on the basis of the thermal influence of the tank venting system on the exhaust gas of the engine, an exhaust gas temperature measured downstream of a catalytic converter of the engine with the tank venting system activated is compared with a calculated or measured exhaust gas temperature obtained for the same location with the tank venting system inactivated and divided by the exhaust gas temperature measured with the tank venting system activated so as to obtain a temperature quotient on the basis of which the charge of the carbon container is determined.