A housing for enclosing an electronic control unit is constructed of a resinous cover and a metallic case having heat conductivity higher than that of the resinous cover. The aim of the invention is to provide a method which prevents, to the greatest possible extent, warping of the drawn cylinder and other deviations from the ideal cylinder dimensions and to prevent, to the greatest possible extent, the outer surface of the drawn cylinder from being touched. Another feature of the invention is a process for the preparation the spray-dried composition. If, for the individual drive cycles, the corresponding tolerance ranges are not reached, then, in response to repeated measurement, these erroneous measurements are counted.