Hello ! I have a question today about the expansion of an old standard installed radio. Since there the whole lamp should say goodbye I want to install there a new ( used but ok ). Now I got to hear from jmd that you have to disconnect the battery before the expansion otherwise after error messages appear ( zb airbag control etc ) .. the radio would probably also be a kind of control unit … sounds logical for me since also the display for the immobilizer da dri As a replacement radio, I would also have an original as I said …. I don’t usually know that you have to disconnect the battery … Ev knows of you if this is already the case with my year of construction..? I don’t have a chance for error messages and also not for having to have to be friendly because of such a dödel …. Thank you in advance ….