Patent ID: 6133649
Filing Date: 2000-10-17
Classification: B60R

Abstract:
A vehicle antitheft system which is set so as to prevent starting of an engine when a predetermined operation is carried out, and for which a setting is canceled so as to permit the starting of the engine when communication is carried out with a transponder provided in a key and transmitting an identification code and the identification code transmitted from the transponder matches a registered code which has been registered in advance, comprising:first judging means for, while differentiating in advance between main keys and auxiliary keys, judging whether a specific key which is any one of the main keys or auxiliary keys is inserted in a key cylinder, the specific key being equipped with a transponder which transmits an identification code corresponding to a registered code which has been registered in advance;second judging means for judging whether the specific key inserted in the key cylinder is a main key or an auxiliary key, by collating the registered code with the identification code;mode changing means for, on the basis of results of judgment of said second judging means, changing a mode when a predetermined combination operation of on-and-off operations of a switching means provided in a vehicle is carried out; andcode changing means for effecting at least one of registration of a code and erasure of a registered code after the mode has been changed.