Its nout to do with the single cd player as thats all that i have, mine occasionally doesnt recognise my iPhone 5 (probably twice out of 30 times) and i have to reset my phone and itll work. If you have a cd in when you plug your iPod in, press cd and it comes up with 6cd options, cd6 should be highlighted as that is your full iPods list of tracks, the other cd are for playlists, so if you have playlist these will say 'cd1' etc. Do you have a reciept to say the work was done at VW? As im not sure if they need coding or not!