In a method and apparatus for diagnosing a malfunction in a clutch actuator of a motor vehicle, the actual position of the clutch actuator is measured by a position sensor. The rear clamping device is part of a slide that is arranged to be movable towards the front clamping device along a clamping path. Each results table includes a plurality of records. The delay locked loop may further include a delay line having a plurality of delay elements, the plurality of delay elements including a first selectable group and a second selectable group that is larger than the first selectable group.