page 5 GMC ENVOY 2008 Owner's Manual

StabiliTrak®System
Your vehicle is equipped with StabiliTrak®, Electronic
Stability Control (ESC) which combines antilock brake,
traction and stability control systems and helps the driver
maintain directional control of the vehicle in most driving
conditions.
Traction control activates when the controller senses
wheel spin. StabiliTrak
®will selectively apply the brakes
and reduce engine torque to help regain traction.
Stability control activates when the controller senses
a discrepancy between your intended path and the
direction the vehicle is travelling. StabiliTrak
®selectively
applies braking pressure at any one of the vehicle’s
brakes to help guide the vehicle in the direction which
you are steering.
When you rst start your vehicle and begin to drive
away, the system performs several diagnostic checks to
insure there are no problems. You may hear or feel the
system working. This is normal and does not mean there
is a problem with your vehicle. If driving conditions delay
system initialization, the STABILITRAK NOT READY
message may be displayed. If this is the case, your
vehicle does not need servicing.
For more information on the stability messages,
seeDIC Warnings and Messages on page 3-53.When the StabiliTrak
®
system is both on and
actively controlling the
stability of the vehicle,
the StabiliTrak
®light will
blink for the duration of
the event.
You may also feel or hear the system working.
This is normal.
The StabiliTrak
®disable
button is located on the
transmission shift handle.
The StabiliTrak
®system is automatically disabled in
4LO mode and cannot be turned on until the vehicle
is switched to 2HI, 4HI, or 4AWD.
The StabiliTrak
®system has three modes of operation:
STABILITRAK ON, TRACTION CONTROL OFF,
and STABILITRAK OFF.
STABILITRAK ON -The vehicle will default to
STABILITRAK ON every time the driver starts the
vehicle. The StabiliTrak
®light will be off and no DIC
messages will be displayed.
4-6

TRACTION CONTROL OFF - The driver can modify
the engine speed management system by momentarily
pressing the StabiliTrak
®button on the transmission
shift handle. The StabiliTrak®light will come on and
TRACTION CONTROL OFF will be displayed. For
vehicles without a DIC, the StabiliTrak
®indicator light
will come on. Momentarily pressing the StabiliTrak®
button again will return the system to the STABILITRAK
ON mode.
STABILITRAK OFF - The driver can turn off StabiliTrak
®
by pressing the StabiliTrak®button for more than
ve seconds. The StabiliTrak®light will come on and
STABILITRAK OFF will be displayed. For vehicles
without a DIC, the StabiliTrak
®indicator light will come
on. Momentarily pressing the StabiliTrak®button again
will return the system to the STABILITRAK ON mode.
See StabiliTrak
®Off below for more information.
Traction Control Off
In this mode, stability control and brake-traction control
are functional. Engine speed management will be
modied and the driven wheels can spin more freely.
This can cause the brake-traction control to activate more
frequently. If the controller detects excessive wheel spin
in this mode, the StabiliTrak
®indicator light may blink and
the STABILITRAK ACTIVE message may be displayed
to warn the driver that damage may occur to the
transfer case.
StabiliTrak®Off
In this mode, both stability control and part of the
traction control system are disabled. Your vehicle will
still have brake-traction control, but will not be able
to use the engine speed management system. You may
still hear system noises as a result of the brake-traction
control coming on. If the controller detects excessive
wheel spin in this mode, the StabiliTrak
®indicator light
may blink and the STABILITRAK ACTIVE message
may be displayed to warn the driver that damage may
occur to the transfer case.
It is recommended to leave the system on for normal
driving conditions, but it may be necessary to turn the
system off if your vehicle is stuck in sand, mud, ice or
snow, and you may want to “rock” your vehicle in an
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 4-33for more
information.
When the transfer case is in 4LO, the stability system is
automatically disabled. The StabiliTrak
®light will come
on and the STABILITRAK OFF message will appear on
the DIC. The StabiliTrak
®system cannot be turned on
until the vehicle is switched to 2HI, 4HI, or 4AWD.
4-7

Notice:If the StabiliTrak®light comes on due to
heavy braking and/or because the traction control
system has been continuously active, do not allow
the wheel(s) of one axle to spin excessively. If you
do, you may be causing damage to the transfer case.
This could lead to costly repairs not covered by your
warranty.
Notice:If you allow the wheel(s) of one axle to spin
excessively while the StabiliTrak
®, ABS and brake
warning lights and the SERVICE STABILITRAK
message are displayed, you could damage the
transfer case. The repairs would not be covered by
your warranty. Reduce engine power and do not spin
the wheel(s) excessively while these lights and this
message are displayed.
StabiliTrak
®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, you may notice a reduction in
acceleration, or may hear a noise or vibration.
This is normal.If your vehicle is in cruise control when the system
activates, the StabiliTrak
®light will blink, and the
cruise control will automatically disengage. When
road conditions allow, you may re-engage the cruise
control. SeeCruise Control on page 3-11.
StabiliTrak
®will turn off automatically if a problem is
detected in the system. The StabiliTrak®light will come
on and SERVICE STABILITRAK will be displayed on
the DIC. For vehicles without a DIC, the StabiliTrak
®
light and the StabiliTrak®service light will both come on.
If the SERVICE STABILITRAK message (or StabiliTrak®
service light) does not clear itself after restarting the
vehicle, you should see your dealer for service.
Adding non-GM accessories can affect your vehicle’s
performance. SeeAccessories and Modifications
on page 5-3for more information.
4-9

Steering
Power Steering
If you lose power steering assist because the engine
stops or the system is not functioning, you can steer
but it will take much more effort.
Steering Tips
It is important to take curves at a reasonable speed.
A lot of the “driver lost control” accidents mentioned on
the news happen on curves. Here is why:
Experienced driver or beginner, each of us is subject
to the same laws of physics when driving on curves.
The traction of the tires against the road surface makes
it possible for the vehicle to change its path when you
turn the front wheels. If there is no traction, inertia will
keep the vehicle going in the same direction. If you
have ever tried to steer a vehicle on wet ice, you will
understand this.
The traction you can get in a curve depends on the
condition of the tires and the road surface, the angle
at which the curve is banked, and your speed. While you
are in a curve, speed is the one factor you can control.Suppose you are steering through a sharp curve.
Then you suddenly accelerate. Both control
systems — steering and acceleration — have to
do their work where the tires meet the road. Adding
the sudden acceleration can demand too much of
those places. You can lose control.
What should you do if this ever happens? Ease up on
the accelerator pedal, steer the vehicle the way you
want it to go, and slow down.
Speed limit signs near curves warn that you should
adjust your speed. Of course, the posted speeds
are based on good weather and road conditions. Under
less favorable conditions you will want to go slower.
If you need to reduce your speed as you approach
a curve, do it before you enter the curve, while the
front wheels are straight ahead.
Try to adjust your speed so you can drive through
the curve. Maintain a reasonable, steady speed.
Wait to accelerate until you are out of the curve,
and then accelerate gently into the straightaway.
Adding non-dealer/non-retailer accessories can affect
your vehicle’s performance. SeeAccessories and
Modifications on page 5-3.
4-10

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. You can avoid these
problems by braking — if you can stop in time. But
sometimes you cannot; there is not room. That is the
time for evasive action — steering around the problem.
Your vehicle can perform very well in emergencies like
these. First apply the brakes. SeeBraking on page 4-3.
It is better to remove as much speed as you can
from a possible 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 you are holding the steering wheel
at the recommended 9 and 3 o’clock positions, you can
turn it 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.
4-11

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 your 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.
A cornering skid is best handled by easing your foot off
the accelerator pedal.
If your 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,
your 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,
you want to 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
your 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.
Off-Road Driving
This off-road guide is for vehicles that have four-wheel
drive. Also, seeBraking on page 4-3. If your vehicle does
not have four-wheel drive, you should not drive off-road
unless you are on a level, solid surface.
The airbag system is designed to work properly under
a wide range of conditions, including off-road usage.
Observe safe driving speeds, especially on rough
terrain. As always, wear your safety belt.
Off-road driving can be great fun. But it does have
some denite hazards. The greatest of these is
the terrain itself.
4-13

There are some important things to remember about
how to load your vehicle.
The heaviest things should be on the load oor and
forward of the rear axle. Put heavier items as far
forward as you can.
Be sure the load is secured properly, so driving on
the off-road terrain does not toss things around.
You will nd other important information in this manual.
SeeLoading Your Vehicle on page 4-34,Luggage
Carrier on page 2-58, andTires on page 5-57.
Environmental Concerns
Off-road driving can provide wholesome and satisfying
recreation. However, it also raises environmental
concerns. We recognize these concerns and urge every
off-roader to follow these basic rules for protecting the
environment:
Always use established trails, roads, and areas that
have been specially set aside for public off-road
recreational driving; obey all posted regulations.
Avoid any driving practice that could damage the
environment — shrubs, owers, trees, grasses — or
disturb wildlife. This includes wheel-spinning,
breaking down trees, or unnecessary driving
through streams or over soft ground.
Always carry a litter bag — make sure all refuse is
removed from any campsite before leaving.
Take extreme care with open res where permitted,
camp stoves, and lanterns.
Never park your vehicle over dry grass or other
combustible materials that could catch re from
the heat of the vehicle’s exhaust system.
Traveling to Remote Areas
It makes sense to plan your trip, especially when
going to a remote area. Know the terrain and plan your
route. You are much less likely to get bad surprises.
Get accurate maps of trails and terrain. Try to learn of
any blocked or closed roads.
It is also a good idea to travel with at least one other
vehicle. If something happens to one of them, the other
can help quickly.
Does your vehicle have a winch? If so, be sure to read
the winch instructions. In a remote area, a winch can be
handy if you get stuck. But you will want to know how to
use it properly.
4-15

Surface Obstacles:Unseen or hidden obstacles can
be hazardous. A rock, log, hole, rut, or bump can startle
you if you are not prepared for them. Often these
obstacles are hidden by grass, bushes, snow, or even
the rise and fall of the terrain itself. Here are some things
to consider:
Is the path ahead clear?
Will the surface texture change abruptly up ahead?
Does the travel take you uphill or downhill? There is
more discussion of these subjects later.
Will you have to stop suddenly or change direction
quickly?
When you drive over obstacles or rough terrain, keep a
rm grip on the steering wheel. Ruts, troughs, or other
surface features can jerk the wheel out of your hands if
you are not prepared.
When you drive over bumps, rocks, or other obstacles,
the wheels can leave the ground. If this happens,
even with one or two wheels, you cannot control the
vehicle as well or at all.Because you will be on an unpaved surface, it is
especially important to avoid sudden acceleration,
sudden turns, or sudden braking.
In a way, off-road driving requires a different kind of
alertness from driving on paved roads and highways.
There are no road signs, posted speed limits, or signal
lights. You have to use your own good judgment
about what is safe and what is not.
Drinking and driving can be very dangerous on any
road. And this is certainly true for off-road driving.
At the very time you need special alertness and driving
skills, your reexes, perceptions, and judgment can be
affected by even a small amount of alcohol. You could
have a serious — or even fatal — accident if you drink
and drive or ride with a driver who has been drinking.
SeeDrunk Driving on page 4-2.
4-17

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 you drive through
it. If it is deep enough to cover the wheel hubs, axles,
or exhaust pipe, do not try it — you probably will not get
through. Also, water that deep can damage the axle
and other vehicle parts.If the water is not too deep, drive slowly through it.
At faster speeds, water splashes on the ignition system
and your vehicle can stall. Stalling can also occur if you
get the tailpipe under water. And, as long as the tailpipe
is under water, you will never be able to start the engine.
When you go through water, remember that when the
brakes get wet, it may take you longer to stop.
SeeDriving in Rain and on Wet Roads on page 4-27for
more information on driving through water.
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 body structure,
steering, suspension, wheels, tires, and exhaust system
for damage. Also, check the fuel lines and cooling system
for any leakage.
Your vehicle will require more frequent service due
to off-road use. Refer to the Maintenance Schedule
for additional information.
4-25

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.
4-27