Abstract: Predicting a refill requirement for wash substances for performing a vehicle wash using a wash system for the car wash for performing the vehicle washing, wherein the control module is for providing a refill data set for predicting a refill requirement for washing substances. The control module comprises at least one measuring device for detecting current fill level data for each of the washing substances and a data link between the at least one measuring device and the control module for transmitting the detected fill level data to the control module. The control module is designed to perform a prediction function for calculating a refill data set, in which a prediction of the refill requirement is encoded, based on planning data, which represent planned vehicle washes at the washing system taking into account washing-substance-specific consumption data.