2008 LEXUS GS450h smart key will need to be programmed to your vehicle before it will work for you. Programming can only be done at an automotive locksmith shop or your local Lexus dealership, where they will also be able to cut the emergency key blade to match your original. There are no onboard programming instructions for 2008 LEXUS GS450h smart keys. They can only be programmed using special diagnostic equipment. This smart key comes with battery and is tested for functionality before sending.