In a method for operating a cooling and heating circuit of a motor vehicle driven by an internal combustion engine, a first cooling medium path is provided through a bypass conduit, a second cooling medium path is provided through a main cooler of the internal combustion engine, a third cooling medium is provided through a heating heat exchanger, and a fourth cooling medium path is provided through a heat accumulator. The cooling medium flows through the paths are subdivided by an electrically operated valves, and the cooling medium flows are generated by at least one pump. The valves are controlled by a control unit based on operational and environmental parameters as well as nominal values, and a third control valve which is controlled by the control unit is arranged in the fourth cooling medium path. The circuit is operated so that the third control valve is closed completely or partially when a reference temperature of a remaining cooling and heating circuit exceeds a nominal value provided in the control unit, and the third control valve is opened when the reference temperature is below the nominal value.