brakes HUMMER H2 2009 User Guide

Using ABS
Do not pump the brakes. Just hold the brake pedal
down rmly and let antilock work. The brakes might
vibrate or some noise might be heard, but this is normal.
Braking in Emergencies
ABS allows the driver to steer and brake at the same
time. In many emergencies, steering can help more than
even the very best braking.
StabiliTrak®System
The vehicle has the StabiliTrak system which combines
antilock brake, traction and stability control systems
and helps the driver maintain directional control of the
vehicle in most driving conditions.
When the vehicle is started and begins to move, the
system performs several diagnostic checks to insure
there are no problems. The system may be heard or felt
while it is working. This is normal and does not mean
there is a problem with the vehicle. The system should
initialize before the vehicle reaches 20 mph (32 km/h).
In some cases, it may take approximately two miles of
driving before the system initializes.If the system fails to turn on or activate, the StabiliTrak
light along with one of the following messages will be
displayed on the Driver Information Center (DIC):
TRACTION CONTROL OFF, SERVICE TRACTION
CONTROL, STABILITRAK OFF, SERVICE
STABILITRAK. If these DIC messages appear, make
sure the StabiliTrak system has not been turned off using
the StabiliTrak on/off button. If this clears the message(s),
the vehicle does not need servicing. If this does not
clear the message(s), then turn the vehicle off, wait
15 seconds, and then turn it back on again to reset the
system. If any of these messages still appear on the
Driver Information Center (DIC), the vehicle should be
taken in for service. For more information on the DIC
messages, seeDriver Information Center (DIC) on
page 3-46.
The StabiliTrak light will
ash on the instrument
panel cluster when the
system is both on and
activated.
The system may be heard or felt while it is working; this
is normal.
4-6

Traction Control Operation
The traction control system is part of the
StabiliTrak system. Traction control limits wheel
spin by reducing engine power to the wheels (engine
speed management) and by applying brakes to
each individual wheel (brake-traction control) as
necessary.
The traction control system is enabled automatically
when the vehicle is started. It will activate and the
StabiliTrak light will ash if it senses that any of the
wheels are spinning or beginning to lose traction while
driving. If the traction control is turned off, only the
brake-traction control portion of traction control will work.
The engine speed management will be disabled. In this
mode, engine power is not reduced automatically and the
driven wheels can spin more freely. This can cause the
brake-traction control to activate constantly.
Notice:If the wheel(s) of one axle is allowed to
spin excessively while the StabiliTrak, ABS
and brake warning lights and any relevant DIC
messages are displayed, the transfer case could bedamaged. The repairs would not be covered by the
vehicle warranty. Reduce engine power and do
not spin the wheel(s) excessively while these lights
and messages are displayed.
The traction control system may activate on dry or
rough roads or under conditions such as heavy
acceleration while turning or abrupt upshifts/downshifts
of the transmission. When this happens, a reduction
in acceleration may be noticed, or a noise or vibration
may be heard. This is normal.
If cruise control is being used when StabiliTrak activates,
the cruise control automatically disengages. The
cruise control can be re-engaged when road conditions
allow. SeeCruise Control on page 3-12.
StabiliTrak may also turn off automatically if it determines
that a problem exists with the system. If the problem does
not clear itself after restarting the vehicle, see your
dealer/retailer for service.
4-8

Traction Control System (TCS)
The vehicle has a Traction Control System (TCS) that
limits wheel spin. This is especially useful in slippery road
conditions. The system operates only if it senses that any
of the wheels are spinning or beginning to lose traction.
When this happens, TCS applies the brakes to limit wheel
spin and also reduces engine power. The system may be
heard or felt while it is working, but this is normal.
TCS can operate on dry roads under some conditions.
When this happens, the system may be heard while it is
working or a reduction in acceleration may be noticed.
This is normal and does not mean there is a problem with
the vehicle. Examples of these conditions include hard
acceleration in a turn, an abrupt upshift or downshift of
the transmission or driving on rough roads.
If cruise control is being used when TCS begins to limit
wheel spin, the cruise control automatically disengages.
The cruise control can be re-engaged when road
conditions allow. SeeCruise Control on page 3-12.SERVICE TRACTION CONTROL comes on in the
Driver information Center (DIC) when a Traction Control
System or Antilock Brake System problem has been
detected and the vehicle needs service. SeeDIC
Warnings and Messages on page 3-56. When this
message is on, the system will not limit wheel spin.
Adjust your driving accordingly.
The traction control system automatically comes on
whenever the vehicle is started. To limit wheel
spin, especially in slippery road conditions, the system
should always be left on. But the traction control
system can be turned off if needed. It may be necessary
to turn the system off if the vehicle is stuck in sand,
mud, ice, or snow, and you want to “rock” the vehicle to
attempt to free it. SeeIf Your Vehicle is Stuck in
Sand, Mud, Ice, or Snow on page 4-39.
4-9

Steering in Emergencies
There are times when steering can be more effective
than braking. For example, you come over a hill and nd
a truck stopped in your lane, or a car suddenly pulls out
from nowhere, or a child darts out from between parked
cars and stops right in front of you. These problems can
be avoided by braking — if you can stop in time. But
sometimes you cannot stop in time because there is no
room. That is the time for evasive action — steering
around the problem.
The vehicle can perform very well in emergencies like
these. First apply the brakes. SeeBraking on page 4-4.
It is better to remove as much speed as possible
from a collision. Then steer around the problem, to the
left or right depending on the space available.
An emergency like this requires close attention and a
quick decision. If holding the steering wheel at the
recommended 9 and 3 o’clock positions, it can be turned
a full 180 degrees very quickly without removing either
hand. But you have to act fast, steer quickly, and just as
quickly straighten the wheel once you have avoided the
object.
The fact that such emergency situations are always
possible is a good reason to practice defensive driving
at all times and wear safety belts properly.
4-12

Off-Road Recovery
The vehicle’s right wheels can drop off the edge of a
road onto the shoulder while driving.
If the level of the shoulder is only slightly below the
pavement, recovery should be fairly easy. Ease off the
accelerator and then, if there is nothing in the way, steer
so that the vehicle straddles the edge of the pavement.
Turn the steering wheel 3 to 5 inches, 8 to 13 cm,
(about one-eighth turn) until the right front tire contacts
the pavement edge. Then turn the steering wheel to go
straight down the roadway.
Passing
Passing another vehicle on a two-lane road can be
dangerous. To reduce the risk of danger while passing:
Look down the road, to the sides, and to crossroads
for situations that might affect a successful pass.
If in doubt, wait.
Watch for traffic signs, pavement markings, and
lines that could indicate a turn or an intersection.
Never cross a solid or double-solid line on your side
of the lane.
Do not get too close to the vehicle you want to
pass. Doing so can reduce your visibility.
Wait your turn to pass a slow vehicle.
When you are being passed, ease to the right.
Loss of Control
Let us review what driving experts say about what
happens when the three control systems — brakes,
steering, and acceleration — do not have enough friction
where the tires meet the road to do what the driver has
asked.
In any emergency, do not give up. Keep trying to steer
and constantly seek an escape route or area of less
danger.
4-13

Brake and Accelerator Operation
Techniques for Off-Road Driving
For logs, walls, rocks, severe ditches,
hills, sand, etc.
1. Bring the vehicle to a complete stop. Do not rev the
engine.
2. Select the proper transmission and transfer case
gear range; usually 1 (First) gear, 4LO LOCK for
such obstacles.
3. If wheel spin is experienced, maintain steady throttle,
with your foot off the brake pedal, to allow the
Traction Control System (TCS) to control the wheel
spin. TCS might not operate if the brakes are
applied.
4. If wheel spin cannot be controlled by the TCS, fully
press the brake pedal with your left foot so all
wheel spin is stopped.
5. Back away from the obstacle so that a new
approach can be tried.
6. As the rst wheel crosses the obstacle, be prepared
to alternate the brake and accelerator pedal to
maintain control and avoid tire drop-off from
obstacles. Repeat this process for the other wheels.
For mounds, washouts, loose up-hill
slopes, ditches, etc.
When wheel spin occurs as the vehicle is moving, the
driver may notice a slight shaking or shuddering of
the vehicle. This should be stopped as soon as possible
to prevent damage to vehicle components. This is the
indication that a loss of traction is occurring on this
terrain. The operator should:
1. Reduce speed and apply the brakes.
2. Assess the terrain properly and adjust vehicle
speed and gear ranges accordingly: 4HI position
for higher speeds and 4LO LOCK for more torque
and lower speeds. Transmission 1 (First) gear
is generally recommended.
3. Apply slight pressure to the brake when the shaking
or shuddering sensation is felt, keeping the vehicle
moving in a controlled manner.
4. Be prepared to alternate between braking and
accelerating through the adverse terrain.
4-21

Driving Downhill
When off-roading takes you downhill, consider:
How steep is the downhill? Will I be able to maintain
vehicle control?
What is the surface like? Smooth? Rough?
Slippery? Hard-packed dirt? Gravel?
Are there hidden surface obstacles? Ruts? Logs?
Boulders?
What is at the bottom of the hill? Is there a hidden
creek bank or even a river bottom with large rocks?
If you decide you can go down a hill safely, try to keep
the vehicle headed straight down. Use a low gear
so engine drag can help the brakes so they do not have
to do all the work. Descend slowly, keeping the
vehicle under control at all times.
{CAUTION:
Heavy braking when going down a hill can cause
your brakes to overheat and fade. This could cause
loss of control and a serious accident. Apply the
brakes lightly when descending a hill and use a low
gear to keep vehicle speed under control.Things not to do when driving down a hill:
When driving downhill, avoid turns that take you
across the incline of the hill. A hill that is not too
steep to drive down might be too steep to drive
across. The vehicle could roll over.
Never go downhill with the transmission in
N (Neutral), called free-wheeling. The brakes will
have to do all the work and could overheat
and fade.
Vehicles are much more likely to stall when going uphill,
but if it happens when going downhill:
1. Stop the vehicle by applying the regular brakes and
apply the parking brake.
2. Shift to P (Park). While still braking, restart the
engine.
3. Shift back to a low gear, release the parking brake,
and drive straight down.
4. If the engine will not start, get out and get help.
4-29

Driving in Water
{CAUTION:
Driving through rushing water can be dangerous.
Deep water can sweep your vehicle downstream
and you and your passengers could drown. If it is
only shallow water, it can still wash away the
ground from under your tires, and you could lose
traction and roll the vehicle over. Do not drive
through rushing water.
Heavy rain can mean ash ooding, and ood waters
demand extreme caution.
Find out how deep the water is before driving through
it. Do not try it if it is deep enough to cover the wheel
hubs, axles, or exhaust pipe — you probably will not
get through. Deep water can damage the axle and
other vehicle parts. The vehicle is capable of depths up to
20 inches (50 cm). Know how to judge whether the water
is deeper than this before proceeding into it.If the water is not too deep, drive slowly through it. At
faster speeds, water splashes on the ignition system and
the vehicle can stall. Stalling can also occur if you get
the tailpipe under water. If the tailpipe is under
water, you will never be able to start the engine. When
going through water, remember that when the brakes
get wet, it might take longer to stop. SeeDriving in Rain
and on Wet Roads on page 4-34.
After Off-Road Driving
Remove any brush or debris that has collected on the
underbody, chassis, or under the hood. These
accumulations can be a re hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the engine and oil
coolers for mud accumulation. Thoroughly and carefully
clean these devices to allow proper cooling. Check
the body structure, steering, suspension, wheels, tires,
and exhaust system for damage and check the fuel
lines and cooling system for any leakage.
The vehicle requires more frequent service due to
off-road use. Refer to the Maintenance Schedule for
additional information.
4-32

Driving in Rain and on Wet Roads
Rain and wet roads can reduce vehicle traction
and affect your ability to stop and accelerate. Always
drive slower in these types of driving conditions
and avoid driving through large puddles and
deep-standing or owing water.
{CAUTION:
Wet brakes can cause crashes. They might not
work as well in a quick stop and could cause
pulling to one side. You could lose control of the
vehicle.
After driving through a large puddle of water or a
car/vehicle wash, lightly apply the brake pedal until
the brakes work normally.
Flowing or rushing water creates strong forces.
Driving through owing water could cause your
vehicle to be carried away. If this happens, you
and other vehicle occupants could drown. Do not
ignore police warnings and be very cautious about
trying to drive through owing water.
Hydroplaning
Hydroplaning is dangerous. Water can build up under
your vehicle’s tires so they actually ride on the
water. This can happen if the road is wet enough and
you are going fast enough. When your vehicle is
hydroplaning, it has little or no contact with the road.
There is no hard and fast rule about hydroplaning.
The best advice is to slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet weather driving tips
include:
Allow extra following distance.
Pass with caution.
Keep windshield wiping equipment in good shape.
Keep the windshield washer uid reservoir lled.
Have good tires with proper tread depth. SeeTires
on page 5-57.
Turn off cruise control.
4-34

Hill and Mountain Roads
Driving on steep hills or through mountains is different
than driving on at or rolling terrain. Tips for driving
in these conditions include:
Keep the vehicle serviced and in good shape.
Check all uid levels and brakes, tires, cooling
system, and transmission.
Going down steep or long hills, shift to a
lower gear.
{CAUTION:
If you do not shift down, the brakes could get so
hot that they would not work well. You would then
have poor braking or even none going down a hill.
You could crash. Shift down to let the engine
assist the brakes on a steep downhill slope.
{CAUTION:
Coasting downhill in N (Neutral) or with the ignition
off is dangerous. The brakes will have to do all the
work of slowing down and they could get so hot
that they would not work well. You would then
have poor braking or even none going down a hill.
You could crash. Always have the engine running
and the vehicle in gear when going downhill.
Stay in your own lane. Do not swing wide or cut
across the center of the road. Drive at speeds
that let you stay in your own lane.
Top of hills: Be alert — something could be in your
lane (stalled car, accident).
Pay attention to special road signs (falling rocks
area, winding roads, long grades, passing or
no-passing zones) and take appropriate action.
SeeOff-Road Driving on page 4-15for information
about driving off-road.
4-36