Cadillac 2000 DeVille Owner's Manual page 72

Master Key
There is a master key that works all of the lock cylinders
(driver's door, trunk, ignition and glove box).
There is also a VALET key which only operates the
driver's door and the ignition.
Both the master and VALET key have a transponder
embedded into the key for security and vehicle theft
deterrence. The keys also come with a bar code tag.
Keep the bar code tag in a safe place. If you lose your
key, you will be able to have a new one made using the
bar code tag. The replacement key must have a vehicle
theft deterrent system transponder embedded in it.
Your vehicle has a number of new features that
can help prevent theft. You can have a lot of
Valet Key
trouble getting into your vehicle if you ever lock
your keys inside. You may even have to damage
your vehicle to get in. So be sure you have
extra keys.
NOTICE:
2-3