Traction GMC ENVOY 2008 User Guide

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

The following chart describes the StabiliTrak®system events and the corresponding messages and lights that will be
displayed on the instrument panel cluster.
Vehicles with a DIC Vehicles without a DIC Event
StabiliTrak®
Indicator LightDIC MessageStabiliTrak
®
Indicator LightStabiliTrak
®Service
Light—
Off None Off OffStabiliTrak
®On
mode (System is fully
enabled, but is not
actively controlling
vehicle stability).
Solid Traction Control Off Solid OffTraction Control
Off Mode
Solid StabiliTrak
®Off Solid OffStabiliTrak
®Off Mode
(StabiliTrak®indicator
light will ash when
system rst enters
this mode).
Blinking StabiliTrak
®Active Blinking OffStabiliTrak
®system
activates using
engine speed
management, brake
traction control,
and/or stability
control.
Solid Service StabiliTrak
®Solid SolidStabiliTrak
®system is
disabled due to a
system fault.
SolidStabiliTrak
®Not
ReadySolid OffStabiliTrak®system is
disabled due to a
failure to initialize.
4-8

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

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

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-road driving does require some new and different
skills. Here is what we mean.
Tune your senses to different kinds of signals. Your
eyes, for example, need to constantly sweep the terrain
for unexpected obstacles. Your ears need to listen
for unusual tire or engine sounds. With your arms,
hands, feet, and body, you will need to respond to
vibrations and vehicle bounce.
Controlling your vehicle is the key to successful off-road
driving. One of the best ways to control your vehicle
is to control your speed. Here are some things to keep
in mind. At higher speeds:
You approach things faster and you have less time
to scan the terrain for obstacles.
You have less time to react.
You have more vehicle bounce when you drive over
obstacles.
You will need more distance for braking, especially
since you are 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. You need to be familiar with the terrain and its
many different features. Here are some things to
consider.
Surface Conditions:Off-roading can take you over
hard-packed dirt, gravel, rocks, grass, sand, mud, snow,
or ice. Each of these surfaces affects the steering,
acceleration, and braking of your vehicle in different
ways. Depending upon the kind of surface you are on,
you may experience slipping, sliding, wheel spinning,
delayed acceleration, poor traction, and longer braking
distances.
4-16

Driving on Off-Road 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 your 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, you need to decide if it is
one of those hills that is just 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, constantincline 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
may not see this because the crest of the hill is hidden
by bushes, grass, or shrubs.
Here are some other things to consider 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.
4-18

Driving Uphill
Once you decide you can safely drive up the hill, you
need to take some special steps.
Use a low gear and get a rm grip on the steering
wheel.
Get a smooth start up the hill and try to maintain
your speed. Do not use more power than you
need, because you do not want the wheels to
start spinning or sliding.
{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 your speed as you approach the top of
the hill.
Attach a ag to the vehicle to make you 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 your headlamps even during the day. They
make your vehicle more visible to oncoming traffic.
{CAUTION:
Driving to the top (crest) of a hill at full speed
can cause an accident. There could be a
drop-off, embankment, cliff, or even another
vehicle. You could be seriously injured or killed.
As you near the top of a hill, slow down and
stay alert.
There are some things you should do if the vehicle stalls,
or is about to stall, and you cannot make it up the hill:
Push the brake pedal to stop the vehicle and keep it
from rolling backwards. Also, apply the parking
brake.
If the engine is still running, shift the transmission to
REVERSE (R), release the parking brake, and slowly
back down the hill in REVERSE (R).
4-19

Driving in Mud, Sand, Snow, or Ice
When you drive in mud, snow, or sand, the wheels
will not get good traction. You cannot accelerate
as quickly, turning is more difficult, and you will
need longer braking distances.
It is best to use a low gear when you are in mud — the
deeper the mud, the lower the gear. In really deep mud,
the idea is to keep your vehicle moving so you do not get
stuck.
When you drive on sand, you will sense a change in
wheel traction. But it will depend upon how loosely
packed the sand is. On loosely packed sand, such as
on beaches or sand dunes, the tires will tend to sink into
the sand. This has an effect on steering, accelerating,
and braking. Drive at a reduced speed and avoid sharp
turns or abrupt maneuvers.Hard packed snow and ice offer the worst tire traction.
On these surfaces, it is very easy to lose control.
On wet ice, for example, the traction is so poor that
you will have difficulty accelerating. And if you do get
moving, poor steering and difficult braking can cause
you to slide out of control.
{CAUTION:
Driving on frozen lakes, ponds, or rivers can
be dangerous. Underwater springs, currents
under the ice, or sudden thaws can weaken the
ice. Your vehicle could fall through the ice and
you and your passengers could drown. Drive
your vehicle on safe surfaces only.
4-24