I have a 2000 Sl500, and recently had some work done that involved disconnecting the battery. My car was missing the codecard for the radio, so the indie shop I use called the dealer and got the security code for my VIN. It would not activate the radio, so my mechanic pulled the radio and discovered that it was a rebuilt unit not original to the car. So he called the dealer again and got the code for the radio based on it's serial number. That code does not work either. So he told me to take the car to the dealer. What will they do to get the correct code?