A bora 1.6L manual block car, when traveling to more than 10 thousand km, caused the dashboard damage due to the accident. The owner asked for the replacement of the dashboard assembly. After the replacement was completed, there was a failure of the burglar alarm lamp, which only lasted for 2S. However, vehicles can start normally before they are replaced. The FAW Volkswagen saloon car adopts the third generation of anti-theft system, which mainly consists of the anti-theft system control unit in the embedded instrument, the anti-theft warning lamp K117 (on the speed meter of the combined instrument), the matched engine control unit, the identification coil D2 on the ignition switch, and the matched transmission / response. The ignition key of the answer device is made up. Normally, when the ignition switch is turned on, the burglar alarm light K117 on the electronic antitheft combination meter will be lit and extinguished after 3S. If the following faults occur: the ignition key is equipped with error; the ignition key is not sent / responder; the ignition key is unauthorized; the engine control unit is unauthorized; the identification coil D2 is malfunction or the data line is malfunction and so on. When the ignition switch is opened, the burglar alarm K117 will shine or continue to shine.