My recently acquired 2013 L405 has an issue with the recirculating flap, I suspect likely caused by the previous owner forcing the flap open to change the cabin filter.

The flap will move upwards to the recirculating position when the recirc button is pressed but will not move down when disengaged. I can freely move it manually by hand back down to fresh air position and if recirc button is again pressed it will dutifully move upwards but will not come back down.
Given the flap moves upwards consistently, it does not appear to be a case of broken mating with the shaft but rather an issue with the motor reversal.

I do not have a GAP tool to try a motor recalibration myself but asking the question if what I described points likely to a recalibration issue or something else? Has anyone successfully “recalibrated” the motor to fix an issue as I have described?