No, it is illegal for a dealer to void warranty if additional equipment is added to a car. However, if the installation of this equipment causes any damage to the vehicle then the warranty can be voided. For this reason, only the most talented DIYers among us should consider fitting a remote starter alone, and 99% of buyers should get theirs fitted by a professional company. It's expensive, we know; but a whole lot less expensive if your warranty is voided and vehicle is damaged or stolen.