Lexus GS430 User Manual page 34

KEYS AND DOORS
The electronic keys are required to deactivate the engine
immobilizer, and are essential for the engine immobilizer to
function correctly, so be careful not to lose these keys. If you
make your own duplicate key, you will not be able to cancel the
system or start the engine.
To protect items when using valet parking, turn the trunk lid
opener main switch to inoperative or lock the glove box if
necessary, and leave the electronic key (with the mechanical
key removed) with the attendant. For details, see "Trunk lid
opener main switch" on page 130.
If you should lose your electronic keys or if you need additional
electronic keys, duplicates can be made by a Lexus dealer
using the key number.
We recommend writing down the key number and storing it in
a safe place.
10