volvo stereo code?

[ashleeandroid]

I am about to purchase a used 2000 Volvo cross country station wagon. When I test drove the car, the stereo would not work. I had a cd with me, and it would go into the player, but nothing would show on the screen and it wouldn't play. The dealer called me later and told me that Volvo's have codes that you have to punch into the stereo to get them to work...he said the stereos will lock up when the battery goes dead or is replaced. Has anyone heard of anything like this, because it sounds a little weird to me.