A control device is provided for a cooling liquid injection system for an internal combustion engine of a motor vehicle. The cooling liquid injection system includes at least two activatable injectors for introducing a cooling liquid into the internal combustion engine, which injectors can be controlled by the control device. The injectors can be supplied with cooling liquid by way of a common rail, and the control device is designed to receive an inclination variable, which characterizes an inclination of the rail, to determine an activation response for the injectors in dependence on the inclination variable, and to activate the injectors using the determined activation response in order to empty or fill the rail.