Chevrolet 1998 Tracker Owner's Manual page 62

One key is used for the
ignition, the doors and
all other locks.
When a new vehicle is delivered, the dealer removes
the metal plate from the key ring and gives it to the
first owner.
The metal plate has a code on it that tells your dealer or
a qualified locksmith how to make extra keys. Keep the
code in a safe place.
If
you
lose
your keys, you'll be able
1
:o
have new ones made easily using this code.
NOTICE:
Your vehicle has a number of features that can
help prevent theft. However, you can have a lot
of
trouble getting into your vehicle if you ever lock
your key inside. You may even have to damage
your vehicle to get in. So be sure you have an
extra key.