Patent ID: 7164213

Claim:
A theft prevention system for a motor vehicle, comprising: a theft prevention apparatus connected through a wireless link to a portable unit storing a first identification code, and storing first, second, and third identification codes; an engine control apparatus connected to said theft prevention apparatus through a communication line and storing a second identification code; and a third apparatus connected to said theft prevention apparatus through said communication line and storing a third identification code; said theft prevention apparatus comprising: permitting means for checking the first identification code sent from said portable unit, checking the third identification code received from said third apparatus through said communication line, and permitting said theft prevention apparatus or said engine control apparatus to register or update the second identification code based on checked results over the first identification code and the third identification code; and equalizing means for equalizing information of the second identification codes stored in said theft prevention apparatus and said engine control apparatus when said permitting means permits said theft prevention apparatus or said engine control apparatus to register or update the second identification code.