Hummer 2003 H2 Owner's Manual page 116

3. Turn the ignition key to LOCK.
4. Remove the key and take it with you. If you can
leave your vehicle with the ignition key in your
hand, your vehicle is in PARK (P).
2-34
D
While still pressing
the button, move the
lever forward as far
as it will go. Let go
of the button and
the lever.
Leaving Your Vehicle With the Engine
Running
CAUTION:
It can be dangerous to leave your vehicle with
the engine running. Your vehicle could move
suddenly if the shift lever is not fully in PARK (P)
with the parking brake firmly set. With your
transfer case in NEUTRAL, your vehicle will
be free to roll, even if your shift lever is in
PARK (P). So be sure the transfer case is in a
--
drive gear not in NEUTRAL. And, if you leave
the vehicle with the engine running, it could
overheat and even catch fire. You or others could
be injured. Don't leave your vehicle with the
engine running unless you have to.