Vehicle antitheft device

Abstract

A vehicle antitheft device prevents an erroneous activation of a theft preventing function due to an activation of a system, which is capable of starting an engine in a state where a key is not inserted in an ignition key cylinder. A power source control device causes a starter motor to start the engine when the key is inserted into the ignition key cylinder or an authentication collation through a radio communication is completed. The vehicle antitheft device activates an alarm when an IG signal from the power source control device becomes an ON signal in an uninserted state of the key into the ignition key cylinder. A push start switch, which is push-operated at a time of an engine start, is connected to the power source control device and the vehicle antitheft device. The power source control apparatus turns an ACC signal and the IG signal supplied to the vehicle antitheft device to an ON state in that order when the collation with the portable equipment through a radio communication is completed after an operation of the push start switch. The vehicle antitheft device changes a security function to an unvigilant state when the ACC signal is changed to an ON state.

Dependencies are inferred from the claim text.