2004 Lexus LS 430 User Guide 2 - Page 36

KEYS AND DOORS For your Lexus dealer to make you a new key with built-in transponder chip, your dealer will need your key number and master key. However, there is a limit to the number of additional keys your Lexus dealer can make for you. If you make your own duplicate key, you will not be able to cancel the system or start the engine. Deactivation using the key NOTICE Do not modify, remove or disassemble the engine immobilizer system. If any unauthorized changes or modifications are made, proper operation of the system cannot be guaranteed. 11L223 " 1 Type A 2 Type B The engine immobilizer system is a theft prevention system. When you insert the key in the ignition switch, the transponder chip in the key's head transmits an electronic code to the vehicle. The engine will start only when the electronic code in the chip corresponds to the registered ID code for the vehicle. The system is automatically set when the key is removed from the ignition switch. At this time, the security indicator light flashes. When you insert the key in the ignition switch, the security indicator light goes out and the system is canceled automatically, which enables the engine to start. The transponder chip of the flat key is in its key case. You can cancel the engine immobilizer system using the flat key. (For details, see pages 12 and 15.) 18