Hi Juanes, did you ever get to the bottom of the problem? I've just joined the forum in the hope of finding some answers to the same problem on my TFG416S MY2010. It seems only one wheel will disengage the parking brake at a time. Of course, everything seems to be electric, so I'm not sure which way to go first, and am starting to think I will need the Jungheinrich engineer.... which I imagine won't be cheap. Thanks, Jon.