if the system is functional a processing function s 3 defined for normal mode is started in which normal mode convertible top mechanism 2 is driven with maximum power and speed in the process an inquiry function s 4 constantly checks whether the convertible top 1 has already reached the final position if this is the case the system proceeds with a processing function s 15 that ends the monitoring function otherwise the convertible top 1 continues with the closing motion with the aid of a further processing function s 5 whereby the system permanently uses an inquiry function s 6 to check during the motion whether an obstruction is detected using the optical or the capacitive or another sensor system in the event of a positive inquiry result of inquiry function s 6 in other words when an obstruction situation is detected the convertible top motion is stopped at first by means of a subsequent processing function s 7 and a waiting time is started an inquiry function s 8 which is also called u201c timeout u201d function is used to check whether the obstruction situation is still present while the convertible top motion is stopped if the obstruction situation is no longer present the system returns to inquiry function s 4 in order to check.