Patent ID: 7477136

Claim:
A theft deterrent system for a vehicle, the theft deterrent system comprising: a vehicular electronic key system, the vehicular electronic key system comprising: an on-board device, comprising an electronic device, and a portable electronic key for communicating with the on-board device and making mutual authentication therewith, the theft deterrent system further comprising: a warning device operatively connected to the on-board device, and a user operation switch operatively connected to the on-board device and adapted to be operated by a user for performing a predetermined switching operation, wherein the system is configured such that when the on-board device detects that the user operation switch has been operated, the on-board device communicates with the portable electronic key and, upon success of mutual authentication, switches the warning device into one of an armed operation stand-by state and an non-operable state in accordance with a user selected position of the user operation switch.