2003 GMC YUKON DENALI Owners Manual

As you brake, your computer keeps receiving updates
on wheel speed and controls braking pressure
accordingly.
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Stabilitrak@ System
Your vehicle is equipped with Stabilitrak@, which
combines antilock brake, traction and stability control
systems and helps the driver maintain directional control
of the vehicle in most driving conditions.
When you first 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. The system
should initialize before the vehicle reaches
20 m.p.h.
(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 STABILITY
SYS DISABLED or SERVICE STABILITY message
will be displayed.
If the vehicle has gone through heavy
acceleration or braking or multiple turns during the
first two miles of driving after starting your vehicle, the
STABILITY
SYS DISABLED message may appear.
If this is the case, your vehicle does not need servicing.
You will need
to turn the vehicle off and then restart
it
to initialize Stabilitrak@.
If either message appears on the Driver Information
Center (DIC), and your vehicle hasn’t gone through hard
acceleration, braking
or multiple turns in the first two
miles of driving, your vehicle should be taken in
for service. The STABILITY SYS ACTIVE message will appear
on
the Driver Information Center (DIC) only when the
system is both on and activated. You may also feel or
hear the system working; this is normal. For more
information on
the stability messages, see Driver
Information Center (DIC) on page 3-43.
Stabilitrak@and part of the
traction control system can
be turned
off or back on
by pressing the
Stabilitrak@button located
on the instrument
When the system is turned
off, the traction off light will
illuminate, and the STABILITY SYS DISABLED
message will appear on the DIC to warn the driver that
both the stability system and part of the traction
control system are disabled. Your vehicle will still have
brake-traction control when Stabilitrak@is
off, but will
not be able
to use the engine speed management
system. See “Traction Control Operation” next for more
information.
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When the Stabilitrak@system has been turned off you
may still hear 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 your vehicle is stuck in sand, mud, ice
or snow, and you want
to “rock” your 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. See If
You Are
Stuck: In Sand, Mud, Ice or Snow on page
4-4 1.
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 you start your vehicle, and it will activate
and display the TRACTION ACTIVE message in the
Driver Information Center (DIC)
if it senses that any of
the wheels are spinning or beginning to lose traction
while driving. If you turn
off Stabilitrak@, only the
brake-traction control portion
of traction control will
work. The engine speed management will be disabled.
In this state, engine power is not reduced automatically
and the driven wheels can spin more freely. This
can cause the brake-traction control
to activate
constantly. For more information on the traction active
message, see Driver Information Center (DIC) on
page
3-43.
Notice: If the traction off light comes on due to
heavy braking and/or because the traction control
system has been continuously active, do not allow
the wheel@) of one axle to spin excessively.
If you
do, you may be causing damage to your transfer
case. This could lead to costly repairs not covered by
your warranty.
If the brake-traction control system activates constantly
or
if the brakes have heated up due to high speed
braking, the brake-traction control will be automatically
disabled. The system will come back on after the
brakes have cooled. This can take up
to two minutes ot
longer depending on brake usage.
Notice: Don’t allow the wheel(s) of one axle to spin
excessively when the traction
off, ABS and brake
lights are on and the
SERVICE STABILITY MESSAGE
is displayed. In this situation, damage to the transfer
case
is possible. This could lead to costly repairs not
covered by your warranty. You should immediately
reduce engine power until the lights and messages
are no longer displayed.
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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 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 STABILITY SYS ACTIVE message will
appear on the Driver Information Center and the cruise
control will automatically disengage. When road
conditions allow you
to use cruise again, you may
re-engage the cruise control. See “Cruise Control” under
Turn SignaVMultifunction
Lever on page 3-7
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, you should see your dealer for service.
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
Driving on Curves
It’s important to take curves at a reasonable speed.
A
lot of the “driver lost control” accidents mentioned on
the news happen on curves. Here’s 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’s no traction, inertia
will keep the vehicle going in the same direction.
If
you’ve ever tried to steer a vehicle on wet ice, you’ll
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’re
in a curve, speed is the one factor you can control.
Suppose you’re 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.
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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’ll 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.
Steering in Emergencies
There are times when steering can be more effective
than braking. For example, you come over a hill and find
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 can’t; there isn’t room.
That’s the time for evasive action
- steering around the
problem.
Your vehicle can perform very well in emergencies like
these. First apply your brakes.
See
Braking on page 4-6. 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.
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2
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.

Off-Road Recovery
You may find that your right wheels have dropped off
the edge of a road onto the shoulder while you’re
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 your vehicle straddles the edge of
the pavement. You can turn the steering wheel up
to
one-quarter turn until the right front tire contacts
the pavement edge. Then turn your steering wheel
to go
straight down the roadway.
Passing
The driver of a vehicle about to pass another on a
two-lane highway waits for just the right moment,
accelerates, moves around the vehicle ahead, then
goes back into the right lane again.
A simple maneuver?
Not necessarily! Passing another vehicle on a two-lane
highway is a potentially dangerous move, since the
passing vehicle occupies the same lane as oncoming
traffic for several seconds.
A miscalculation, an error in
judgment, or a brief surrender
to frustration or anger
can suddenly put the passing driver face
to face with the
worst of all traffic accidents
- the head-on collision.
So here are some tips for passing:
0 “Drive ahead.” Look down the road, to the sides
and
to crossroads for situations that might affect
your passing patterns.
If you have any doubt
whatsoever about making a successful pass, wait
for a better time.
0 Watch for traffic signs, pavement markings and
lines.
If you can see a sign up ahead that might
indicate a turn or an intersection, delay your pass.
A broken center line usually indicates it’s all
right
to pass (providing the road ahead is clear).
Never cross a solid line on your side of the lane or
a double solid line, even if the road seems empty
of approaching traffic.
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0 Do not get too close to the vehicle you want to
pass while you’re awaiting an opportunity. For
one thing, following
too closely reduces your area
of vision, especially if you’re following a larger
vehicle.
Also, you won’t have adequate space if the
vehicle ahead suddenly slows or stops. Keep
back a reasonable distance.
When it looks like a chance to pass is coming up,
start
to accelerate but stay in the right lane and
don’t get
too close. Time your move so you will be
increasing speed as the time comes
to move
into the other lane. If the way is clear
to pass, you
will have a “running start” that more than makes
up for the distance you would lose by dropping
back. And
if something happens to cause you to
cancel your pass, you need only slow down
and drop back again and wait for another
opportunity.
If other vehicles are lined up to pass a slow vehicle.
wait your turn. But take care that someone isn’t
trying
to pass you as you pull out to pass the slow
vehicle. Remember to glance over your shoulder
and check the blind spot.
Check your mirrors, glance over your shoulder and
start your left lane change signal before moving out
of the right lane
to pass. When you are far
enough ahead of the passed vehicle
to see its front
in your inside mirror, activate your right lane
change signal and move back into the right lane.
(Remember that
if your right outside mirror is
convex, the vehicle you just passed may seem
to
be farther away from you than it really is.)
- Try not to pass more than one vehicle at a time on
two-lane roads. Reconsider before passing the
next vehicle.
Don’t overtake a slowly moving vehicle too rapidly.
Even though the brake lamps are not flashing,
it
may be slowing down or starting to turn.
If you’re being passed, make it easy for the
following driver
to get ahead of you. Perhaps you
can ease a little to the right.
4-1 4

Loss of Control
Let’s review what driving experts say about what happens
when the three control systems (brakes, steering and
acceleration) don’t have enough friction where the tires
meet the road
to do what the driver has asked.
In any emergency, don’t give up. Keep trying
to steer
and constantly seek an escape route or area of
less danger.
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, your wheels
aren’t 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’ll
want
to slow down and adjust your driving to these
conditions.
It is important to slow down on slippery
surfaces because stopping distance will be 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 engine braking by shifting
to a
lower gear). Any sudden changes could cause the tires
to slide. You may 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 anti-lock brake system (ABS) helps
avoid only the braking skid.
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