I have a 1999 Audi A6 Quattro and for some reason the CD player stopped working. The tape player and radio work fine, but whenever I put in a CD, it says "ERR 1". I looked in the manual and Error 1 is a dirty or scratched CD. When I saw that, I cleaned all my CD's and tried again, but it still didn't work. I've also tried different CD's and they didn't work either. Does anyone have any idea what might be wrong or how I can fix it without spending tons of money taking it to a shop?