DONT take to dealer.NO NEED
mine did the same after fitting a new battery..
there is a simple fix tho,,i found out the answer here on this forum.
its a while since i did it so im not certain,, but its something like this,,
when putting card into reader ,,hold in start button for about 5 secs ,its then fixed,ie press it once
again check forum for EXACT fix ,
nothing is broken tho,just needs resetting,just like the electric front windows did