2007 GMC SIERRA CLASSIC traction control

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.
Traction Assist System (TAS)
Your vehicle may have a Traction Assist
System (TAS) that limits wheel spin. This is
especially useful in slippery road conditions.
The system operates only if it senses that one or
both of the rear wheels are spinning or beginning
to lose traction. When this happens, the system
reduces engine power to limit wheel spin.
The traction control system is enabled every time
your vehicle is started. The system will activate
if it senses that any of the wheels are spinning or
beginning to lose traction.
You may hear or feel the system working or notice a
lack of accelerator response, but this is normal.
The Traction Assist System may operate on dry
roads under some conditions. When this happens,
you may notice a reduction in acceleration.
This is normal and doesn’t mean there’s a problem
with your vehicle. Examples of these conditions
include a hard acceleration in a turn, an abrupt
upshift or downshift of the transmission or driving
on rough roads.
363

If your vehicle is in cruise control when the TAS
begins to limit wheel spin, the cruise control will
automatically disengage. When road conditions
allow you to safely use it again, you may re-engage
the cruise control. SeeCruise Control on page 217.
When the traction off
light is on, the TAS is
off and will not limit
wheel spin. Adjust your
driving accordingly.
The traction off light will come on under the
following conditions:
The Traction Assist System is turned off,
either by pressing the TAS on/off button,
located on the instrument panel, or by turning
off the automatic engagement feature of
the TAS.
The transmission is in FIRST (1); TAS will not
operate in this gear. This is normal.
The vehicle is driven on an extremely rough
road. When the vehicle leaves the rough
surface, slows down or stops, the light will go
off and TAS will turn on again. This is normal.
A Traction Assist System, Anti-Lock Brake
System or engine-related problem has been
detected and the vehicle needs service.
If the vehicle has been driven with the TAS
system on for long periods of time, or if the
vehicle has gone through many several high
speed braking maneuvers the system may be
automatically disabled. The system will
automatically re-enable after approximately
two minutes of not using the brakes.
SeeTraction Off Light on page 256.
The Traction Assist System, as delivered from the
factory, will automatically come on whenever
you start your vehicle. To limit wheel spin,
especially in slippery road conditions, you should
always leave the system on. But you can turn
the TAS off if you ever need to. You should turn
the TAS off if your vehicle ever gets stuck in sand,
mud or snow and rocking the vehicle is required.
364

It is recommended to use this system as follows:
For superior ride comfort in an unloaded vehicle
the button should be out. The indicator light will
not be lit. This button position indicates
NORMAL levels of ride control or damping.
For superior ride comfort when trailering, fully
loaded, driving off-road, or when personal
preferences demand more control, the button
should be pressed in with the indicator light lit.
This switch position indicates FIRM levels of
ride control or damping.
The following guide can also be used to help
determine the best setting.
NORMAL:The indicator light will not be lit when
the system is in this setting. Use for normal
city and highway driving. This setting provides a
smooth, soft ride when the vehicle is unloaded.
FIRM (Unloaded):Press the button to activate
this setting, the indicator light will be lit. Use
this setting when road conditions or personal
preference demand more control. This setting
provides more “feel” or response to the road
conditions.FIRM (Loaded):Press the button to activate
this setting, the indicator light will be lit. Use this
setting to minimize trailer inputs to the vehicle
or when the vehicle is fully loaded. This setting is
also appropriate for off-road driving.
You can select a setting at any time based on
road and trailering conditions to provide the best
ride and handling. Select a new setting whenever
driving conditions change.
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.
366

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.
SeeTraction Assist System (TAS) on page 363.
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 468.
367

Try not to pass more than one vehicle at a time
on two-lane roads. Reconsider before passing
the next vehicle.
Do not overtake a slowly moving vehicle too
rapidly. Even though the brake lamps are not
ashing, it may be slowing down or starting
to turn.
If you are being passed, make it easy for the
following driver to get ahead of you. Perhaps
you can ease a little to the right.
Loss of Control
Let us review what driving experts say
about what happens when the three control
systems — brakes, steering, and
acceleration — do not have enough friction
where the tires meet the road to do what the
driver has asked.
In any emergency, do not give up. Keep trying to
steer and constantly seek an escape route or
area of less danger.
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,
your 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 you have the Traction Assist System (TAS),
remember: It helps avoid only the acceleration
skid. SeeTraction Assist System (TAS) on
page 363. If you do not have this system, or if the
system is off, then an acceleration skid is also
best handled by easing your foot off the
accelerator pedal.
371

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 will 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 reducing vehicle speed 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.Off-Road Driving
This off-road guide is for vehicles that have
four-wheel drive. Also, seeBraking on page 360.
If your vehicle does not have four-wheel drive
or is equipped with 20-inch tire/wheel assemblies,
you should not drive off-road unless you are on
a level, solid surface.
Off-road driving can be great fun. But it does have
some denite hazards. The greatest of these is
the terrain itself.
“Off-roading” means you have left the great
North American road system behind. Traffic lanes
are not marked. Curves are not banked. There
are no road signs. Surfaces can be slippery, rough,
uphill, or downhill. In short, you have gone right
back to nature.
Off-road driving involves some new skills. And
that is why it is very important that you read this
guide. You will nd many driving tips and
suggestions. These will help make your off-road
driving safer and more enjoyable.
372

Driving in Mud, Sand, Snow, or Ice
When you drive in mud, snow, or sand, your wheels
will not get good traction. You cannot accelerate as
quickly, turning is more difficult, and you will need
longer braking distances. If your vehicle has
four-wheel drive, seeFour-Wheel Drive on
page 153for transfer case mode selection.
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,
your 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.
389

And, if your tires do not have much tread left,
you will get even less traction. It is always wise to
go slower and be cautious if rain starts to fall
while you are driving. The surface may get wet
suddenly when your reexes are tuned for driving
on dry pavement. If your vehicle has four-wheel
drive, seeFour-Wheel Drive on page 153for
transfer case mode selection.
The heavier the rain, the harder it is to see.
Even if your windshield wiper blades are in good
shape, a heavy rain can make it harder to see
road signs and traffic signals, pavement markings,
the edge of the road, and even people walking.
It is wise to keep your wiping equipment in
good shape and keep your windshield washer
uid reservoir lled with washer uid. Replace your
windshield wiper inserts when they show signs
of streaking or missing areas on the windshield,
or when strips of rubber start to separate from
the inserts.
{CAUTION:
Wet brakes can cause accidents. They
may not work as well in a quick stop and
may cause pulling to one side. You could
lose control of the vehicle.
After driving through a large puddle of
water or a car wash, apply your brake pedal
lightly until your brakes work normally.
Driving too fast through large water puddles or
even going through some car washes can cause
problems, too. The water may affect your brakes.
Try to avoid puddles. But if you cannot, try to slow
down before you hit them.
393