traction control HUMMER H2 2009 User Guide

The StabiliTrak disable
button is located on the
instrument panel below the
climate controls.
The traction control part of StabiliTrak can be turned off
by pressing and releasing the StabiliTrak button if both
systems (traction control and StabiliTrak) were previously
on. To disable both traction control and StabiliTrak, press
and hold the button until STABILITRAK OFF is displayed
on the DIC and the StabiliTrak light comes on the
instrument panel.
Traction control and StabiliTrak can be turned on by
pressing and releasing the StabiliTrak button if not
automatically shut off for any other reason.
When the traction control or StabiliTrak system is turned
off, the StabiliTrak light and the appropriate traction
control off or StabiliTrak off message will be displayed on
the DIC to warn the driver. The vehicle will still havebrake-traction control when traction control is off, but will
not be able to use the engine speed management
system. See “Traction Control Operation” next for more
information.
When the traction control system has been turned off,
there may be system noises as a result of the
brake-traction control coming on.
It is recommended to leave the system on for normal
driving conditions, but 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. It may also be necessary to turn off the
system when driving in extreme off-road conditions
where high wheel spin is required. SeeIf Your Vehicle
is Stuck in Sand, Mud, Ice, or Snow on page 4-39.
When the transfer case is in Four-Wheel-Low Lock, the
stability system is automatically disabled, the StabiliTrak
light will come on and the STABILITRAK OFF message
will appear on the DIC. Both traction control and
StabiliTrak are automatically disabled in this condition.
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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.
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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.
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To turn the system off,
press and release the
TCS button.
This light will come on
steady when the traction
control system has been
turned off. This light ashes
when TCS is active.
If the TCS button is pressed, the traction control system
will turn off and a TRACTION CONTROL OFF message
will appear on the DIC. Press the TCS button again to
turn the system back on. The TRACTION CONTROL
OFF message will then go off. The Traction Control
System will reset itself at each ignition cycle.
Adding non-dealer/non-retailer accessories can affect
the vehicle’s performance. SeeAccessories and
Modifications on page 5-3.Locking Rear Axle
The locking rear axle can give the vehicle additional
traction from the rear wheels when traveling in off-road
situations such as mud, snow, sand, steep hills and
uneven terrain.
The button used to turn
this feature on or off is
located below the transfer
case dial to the right of
the steering wheel.
To lock the rear axle:
1. Place the transfer case in the Four-Wheel-Low Lock
mode. This is the only mode which will allow the rear
axle to lock. SeeFull-Time Four-Wheel Drive on
page 2-37for more information regarding the transfer
case and Four-Wheel-Low-Lock mode.
2. Press the button with the vehicle stopped or moving
less than 2 mph (3 km/h).
4-10

The light in the button must stop ashing and remain
illuminated before the rear axle is locked.
Notice:If you try to lock the axle while the vehicle
is stuck and the tires are spinning, the vehicle’s
drivetrain could be damaged. The repairs would not
be covered by the vehicle warranty. Always lock
the axle before attempting situations and/or
navigating terrain which could possibly cause the
vehicle to become stuck.
The locking rear axle will be disengaged when the
vehicle’s speed is greater than 40 mph (64 km/h), if the
vehicle’s battery is low and/or the transfer case is
shifted out of Four-Wheel-Low-Lock mode.
Notice:If the vehicle’s axle is locked while driving
on pavement, the drivetrain could be damaged.
Repairs would not be covered by the vehicle
warranty. Do not use the locking axle on pavement.
If four-wheel drive is needed when traveling on
pavement, use only 4HI.Steering
Power Steering
If power steering assist is lost because the engine stops
or the system is not functioning, the vehicle can be
steered but it will take more effort.
Steering Tips
It is important to take curves at a reasonable speed.
Traction in a curve depends on the condition of the tires
and the road surface, the angle at which the curve is
banked, and vehicle speed. While in a curve, speed is
the one factor that can be controlled.
If there is a need to reduce speed, do it before entering
the curve, while the front wheels are straight.
Try to adjust the speed so you can drive through the
curve. Maintain a reasonable, steady speed. Wait
to accelerate until out of the curve, and then accelerate
gently into the straightaway.
4-11

Skidding
In a skid, a driver can lose control of the vehicle.
Defensive drivers avoid most skids by taking reasonable
care suited to existing conditions, and by not overdriving
those conditions. But skids are always possible.
The three types of skids correspond to the vehicle’s
three control systems. In the braking skid, the wheels are
not rolling. In the steering or cornering skid, too much
speed or steering in a curve causes tires to slip and lose
cornering force. And in the acceleration skid, too much
throttle causes the driving wheels to spin.
If the vehicle starts to slide, ease your foot off the
accelerator pedal and quickly steer the way you want
the vehicle to go. If you start steering quickly enough,
the vehicle may straighten out. Always be ready for
a second skid if it occurs.Of course, traction is reduced when water, snow, ice,
gravel, or other material is on the road. For safety, slow
down and adjust your driving to these conditions. It is
important to slow down on slippery surfaces because
stopping distance is longer and vehicle control more
limited.
While driving on a surface with reduced traction, try
your best to avoid sudden steering, acceleration, or
braking, including reducing vehicle speed by shifting to a
lower gear. Any sudden changes could cause the tires to
slide. You might not realize the surface is slippery until
the vehicle is skidding. Learn to recognize warning
clues —such as enough water, ice, or packed snow on
the road to make a mirrored surface — and slow down
when you have any doubt.
Remember: Any Antilock Brake System (ABS) helps
avoid only the braking skid.
4-14

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

Getting Familiar with Off-Road Driving
It is a good idea to practice in an area that is safe
and close to home before you go into the wilderness.
Off-roading requires some new and different skills.
Tune your senses to different kinds of signals. Your eyes
need to constantly sweep the terrain for unexpected
obstacles. Your ears need to listen for unusual tire
or engine sounds. Use your arms, hands, feet, and body
to respond to vibrations and vehicle bounce.
Controlling the vehicle is the key to successful off-road
driving. One of the best ways to control the vehicle
is to control the speed. At higher speeds:
You approach things faster and have less time
to react.
There is less time to scan the terrain for obstacles.
The vehicle has more bounce when driving over
obstacles.
More braking distance is needed, especially on an
unpaved surface.
{CAUTION:
When you are driving off-road, bouncing and quick
changes in direction can easily throw you out of
position. This could cause you to lose control and
crash. So, whether you are driving on or off the
road, you and your passengers should wear
safety belts.
Scanning the Terrain
Off-road driving can take you over many different kinds
of terrain. Be familiar with the terrain and its many
different features.
Surface Conditions:Off-roading surfaces can be
hard-packed dirt, gravel, rocks, grass, sand, mud, snow,
or ice. Each of these surfaces affects the vehicle’s
steering, acceleration, and braking in different ways.
Depending on the surface, slipping, sliding, wheel
spinning, delayed acceleration, poor traction, and longer
braking distances can occur.
4-22

Driving on Hills
Off-road driving often takes you up, down, or across a
hill. Driving safely on hills requires good judgment
and an understanding of what the vehicle can and
cannot do. There are some hills that simply cannot be
driven, no matter how well built the vehicle.
{CAUTION:
Many hills are simply too steep for any vehicle. If
you drive up them, you will stall. If you drive down
them, you cannot control your speed. If you drive
across them, you will roll over. You could be
seriously injured or killed. If you have any doubt
about the steepness, do not drive the hill.
Approaching a Hill
When you approach a hill, decide if it is too steep to
climb, descend, or cross. Steepness can be hard to
judge. On a very small hill, for example, there may be a
smooth, constant incline with only a small change in
elevation where you can easily see all the way to the top.
On a large hill, the incline may get steeper as you near
the top, but you might not see this because the crest of
the hill is hidden by bushes, grass, or shrubs.
Consider this as you approach a hill:
Is there a constant incline, or does the hill get
sharply steeper in places?
Is there good traction on the hillside, or will the
surface cause tire slipping?
Is there a straight path up or down the hill so you
will not have to make turning maneuvers?
Are there obstructions on the hill that can block your
path, such as boulders, trees, logs, or ruts?
What is beyond the hill? Is there a cliff, an
embankment, a drop-off, a fence? Get out and walk
the hill if you do not know. It is the smart way to
nd out.
Is the hill simply too rough? Steep hills often have
ruts, gullies, troughs, and exposed rocks because
they are more susceptible to the effects of erosion.
4-25

Driving Uphill
Once you decide it is safe to drive up the hill:
Use transmission and transfer case low gear and
get a rm grip on the steering wheel.
Get a smooth start up the hill and try to maintain
speed. Not using more power than needed can
avoid spinning the wheels or sliding.
Let the traction system work to control any wheel
slippage. The traction control system allows for
moderate wheel spin with some capability to dig in
and power up the hill.
Do not continue if the vehicle shudders or exhibits
suspension hopping. This can cause damage to
the driveline or suspension components. Improper
driving technique is not covered by the vehicle
warranty.
{CAUTION:
Turning or driving across steep hills can be
dangerous. You could lose traction, slide
sideways, and possibly roll over. You could be
seriously injured or killed. When driving up hills,
always try to go straight up.
Try to drive straight up the hill if at all possible.
If the path twists and turns, you might want to
nd another route.
Ease up on the speed as you approach the top of
the hill.
Attach a ag to the vehicle to be more visible to
approaching traffic on trails or hills.
Sound the horn as you approach the top of the hill
to let opposing traffic know you are there.
Use headlamps even during the day to make the
vehicle more visible to oncoming traffic.
4-26