I had to reinstall my factory head unit, they pulled the codes, and then my after market was reinstalled. It was a complete pain. Let me preface this by saying though, that the installation of my after market was questionable (read: pretty illegal) allowing me the functionality of the navigation system while the car was moving as well as being able to play DVD's while the vehicle is in motion as well. In order to do this, the speed sensor has this 1.5" screw through it thereby making the system believe that the parking brake is still on.