Vagcom lite
 

I got the free version and it hooked up fine to my 99.5 b5 but wont hook up to my friends 2000 jetta. Anyone know why?

I'm guessing that if it works with your car, but not your friends, there may be a problem with the OBDII in your friends car. have you tried a different code reader on the jetta to make sure the port functions?

the other possibility is "user error". RTFM? PEBKAC?