@jacekpk thanks for very detailed explanation. I have similar issue, flap is stuck and see error on VCDS. My flap stuck and ventilation blows to window, not to central two ventilation only to central ventilation newt to doors, blows slightly to legs(do know how to explain this better). When trying to get to motor flap get unstuck and everything was working normally for one month. When second stuck occurred tried to put WD40 do flap mechanism but after 2 days stuck again. Possible that it stuck more easily when heating is on but not sure. Anybody had similar issue? Motor is working, cannot know does it stuck because of flap or motor is faulty. I can try to unscrew motor a little bit, any other idea?