Hummer 2004 H2 Owner's Manual page 236

Another feature of this system is the Traction Control 2
(TC2) mode. TC2 should be selected for improved
traction and system performance when the vehicle is on
loose surfaces such as deep sand or mud.
TC2 only operates in the following transfer case modes:
•
4HI Lock
•
4LO Lock
•
4LO Lock and Rear Axle Lock
See Locking Rear Axle on page 4-11 for more
information on the rear axle lock.
4-10
To enter this mode,
press the TC2 button
located on the instrument
panel to the right of
the steering wheel.
It will not operate in 4HI. If the TC2 button is pressed
while in 4HI, the light will flash for about 15 seconds and
then go out. The light should also come on briefly
when you turn the ignition key to RUN; if it doesn't see
your dealer for service.
If you restart your engine, the system reverts to the
standard TCS mode.
When the traction off light is on, adjust your driving
accordingly.
The traction control system, as delivered from the
factory, will automatically come on whenever you start
your vehicle.
The traction off light will
come on when a Traction
Control System or
Anti-Lock Brake System
problem has been detected
and the vehicle needs
service. See Traction Off
Light on page 3-35.