Patent attributes
A propellant anti-theft system can not only perform permission/stop of operation of a vehicle in a simple and easy manner without using a key, but also suppress the theft and reuse of vehicle parts. The system includes a portable device and an on-board device installed on the vehicle, and further includes an engine control device, a switch and various units, all of which are connected to the on-board device. The on-board device includes a transmitter receiver, a storage circuit and a control circuit. The portable device includes a transmitter receiver, a storage circuit and a control circuit. The control circuit of the on-board device compares common data possessed by itself and common data stored in microprocessor units of the engine control device and the various units, and unlocks a steering locking section included in the various units and outputs an engine starting permission signal to the engine control device when both of the individual pieces of common data coincide with each other.