Access and start/drive authorization system

Abstract

An access- and starting/driving-authorization system for a motor vehicle, having a portable transponder and a control unit accomodated in the motor vehicle, in order to control the smart master-key system and the engine control unit. In inquiry/response dialogs, the transponder and the control unit enabling or blocking access to the motor vehicle, and the starting and driving of the motor vehicle, using sets of code information that are matched to each other. Starting and driving the motor vehicle after forcibly entering the motor vehicle and replacing the engine control unit, including a vehicle immobilizer and a transponder of the control units relevant for starting and driving, is prevented in that the enabling of the motor-vehicle to be started and driven, after a successful starting/driving-authorization inquiry/response dialog, is rendered dependent on a preceding, successful access-authorization inquiry/response dialog.

Dependencies are inferred from the claim text.