A remote vehicle control system may be used to permit a user control of one or more vehicle devices from a distance. A typical remote vehicle control system, for example, in a more modern vehicle may include a controller connected to a plurality of vehicle devices via a data communications bus, and a remote transmitter providing the controller with remote control signals. The vehicle devices, for example, may operate the engine starter, the door locks, the power windows, or the alarm system.
An example of such a system is U.S. Pat. No. 5,719,551 to Flick, which discloses a remote transmitter that can remotely control a number of vehicle devices. The controller in the Flick '551 patent is responsive to the remote transmitter and sends command codes over a data communications bus to the vehicle devices. Similarly, U.S. Pat. Nos. 6,275,147, 6,756,885, 6,756,886, and 6,812,829, to Flick also disclose a controller/transmitter used to remotely control a number of vehicle devices via command codes sent over a communications data bus.
U.S. Pat. No. 5,583,479 to Hettich et al. also discloses a vehicle controller connected to a number of vehicle devices via a data communications bus and a remote transmitter in communication with the controller. The Hettich et al. patent further discloses that if the alarm system is not deactivated correctly, then the vehicle devices will be impaired or prevented from working properly.
U.S. Pat. No. 6,232,873 to Dilz et al. discloses a vehicle security system that detects if an original control unit is no longer active. If the security system determines that the original control unit is no longer active, an alternate circuit that remains active in the vehicle activates an electronic immobilization system.
Although conventional remote vehicle control systems operating via the data communications bus have made significant advances in convenience for the user, the overall security may still be an issue. For example, a would-be thief gaining access to the data bus, such as from under the vehicle, may generate rogue commands on the data bus compromising vehicle security. The would-be thief could temporarily connect a rogue controller to the data bus and cause the windows to roll down or the doors to unlock. Once inside the vehicle, the would-be thief could again connect to the data communications bus and start the engine. Of course, if the vehicle had a vehicle security system, the would-be thief could disarm the vehicle security system via the data communications bus.