engine GMC ENVOY 2006 Workshop Manual

Remember: ABS does not change the time you need to
get your foot up to the brake pedal or always decrease
stopping distance. If you get too close to the vehicle
in front of you, you will not have time to apply your
brakes if that vehicle suddenly slows or stops. Always
leave enough room up ahead to stop, even though
you have ABS.
Using ABS
Do not pump the brakes. Just hold the brake pedal
down rmly and let anti-lock work for you. You may feel
the brakes vibrate, or you may notice some noise,
but this is normal.
Braking in Emergencies
With ABS, you can steer and brake at the same time. In
many emergencies, steering can help you more than
even the very best braking.
Locking Rear Axle
If your vehicle has this feature, your locking rear axle
can give you additional traction on snow, mud, ice, sand
or gravel. It works like a standard axle most of the
time, but when one of the rear wheels has no traction
and the other does, this feature will allow the wheel with
traction to move the vehicle.
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, see
DIC Warnings and Messages on page 3-54.
4-9

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.
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.
4-10

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 4-44for 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.
4-11

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.
4-12

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 Modications
on page 5-3for more information.
4-13

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 your 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 your 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-GM accessories can affect your vehicle’s
performance. SeeAccessories and Modications
on page 5-3.
4-14

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.
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.
4-21

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 you 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.
Q:What should I do if my vehicle stalls, or is about
to stall, and I cannot make it up the hill?
A:If this happens, there are some things you should
do, and there are some things you must not do.
First, here is what youshoulddo:
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).
If the engine has stopped running, you will need to
restart it. With the brake pedal pressed and the
parking brake still applied, shift the transmission to
PARK (P) and restart the engine. Then, shift to
REVERSE (R), release the parking brake, and
slowly back down the hill as straight as possible in
REVERSE (R).
As you are backing down the hill, put your left hand
on the steering wheel at the 12 o’clock position.
This way, you will be able to tell if the wheels are
straight and maneuver as you back down. It is
best that you back down the hill with the wheels
straight rather than in the left or right direction.
Turning the wheel too far to the left or right
will increase the possibility of a rollover.
4-25

Here are some things youmust notdo if you stall, or
are about to stall, when going up a hill.
Never attempt to prevent a stall by shifting into
NEUTRAL (N) to rev-up the engine and regain
forward momentum. This will not work. Your vehicle
will roll backwards very quickly and you could go
out of control.
Instead, apply the regular brake to stop the vehicle.
Then apply the parking brake. Shift to
REVERSE (R), release the parking brake, and
slowly back straight down.
Never attempt to turn around if you are about to
stall when going up a hill. If the hill is steep
enough to stall your vehicle, it is steep enough to
cause you to roll over if you turn around. If you
cannot make it up the hill, you must back straight
down the hill.
Q:Suppose, after stalling, I try to back down the hill
and decide I just cannot do it. What should I do?
A:Set the parking brake, put the transmission in
PARK (P) and turn off the engine. Leave the vehicle
and go get some help. Exit on the uphill side and
stay clear of the path the vehicle would take if
it rolled downhill. Do not shift the transfer case to
NEUTRAL when you leave the vehicle. Leave
it in some gear.
{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). This is because
the NEUTRAL position on the transfer case
overrides the transmission. You or someone
else could be injured. If you are going to leave
your vehicle, set the parking brake and shift
the transmission to PARK (P). But do not shift
the transfer case to NEUTRAL. Leave the
transfer case in the Two-Wheel High,
Four-Wheel High or Four-Wheel Low position.
4-26

Driving Downhill
When off-roading takes you downhill, you will want to
consider a number of things:
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, then try to
keep your vehicle headed straight down, and use a
low gear. This way, engine drag can help the brakes and
they will not have to do all the work. Descend slowly,
keeping your 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.
Q:Are there some things I should not do when
driving down a hill?
A:Yes! These are important because if you ignore
them you could lose control and have a serious
accident.
When driving downhill, avoid turns that take you
across the incline of the hill. A hill that is not too
steep to drive down may be too steep to drive
across. You could roll over if you do not drive
straight down.
Never go downhill with the transmission in
NEUTRAL (N). This is called “free-wheeling.” The
brakes will have to do all the work and could
overheat and fade.
Q:Am I likely to stall when going downhill?
A:It is much more likely to happen going uphill. But if
it happens going downhill, here is what to do.
1. Stop your vehicle by applying the regular brakes.
Apply the parking brake.
2. Shift to PARK (P) and, 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.
4-27