2007 GMC SIERRA wheel

Let us say the road is wet and you are driving
safely. Suddenly, an animal jumps out in front of
you. You slam on the brakes and continue braking.
Here is what happens with ABS:
A computer senses that wheels are slowing down.
If one of the wheels is about to stop rolling, the
computer will separately work the brakes at each
front wheel and at both rear wheels.ABS can change the brake pressure faster than
any driver could. The computer is programmed to
make the most of available tire and road
conditions. This can help you steer around the
obstacle while braking hard.
As you brake, your computer keeps receiving
updates on wheel speed and controls braking
pressure accordingly.
380

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 may be equipped with the
StabiliTrak®system 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 rst start your vehicle and begin to
drive away, the system performs several diagnostic
checks to ensure 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 mph (32 km/h). In
some cases, it may take approximately two
miles of driving before the system initializes.
381

If the system fails to turn on or activate, the
StabiliTrak®light along with one of the following
messages will be displayed on the Driver
Information Center (DIC): TRACTION CONTROL
OFF, SERVICE TRACTION CONTROL,
STABILITRAK OFF, SERVICE STABILITRAK. If
these DIC messages appear, make sure the
StabiliTrak
®system has not been turned off using
the StabiliTrak®on/off button. Then turn the
steering wheel clockwise from the nine o’clock
position to the three o’clock position. If this clears
the message(s), your vehicle does not need
servicing. If this does not clear the message(s),
then turn the vehicle off, wait 15 seconds, and then
turn it back on again to reset the system. If any
of these messages still appear on the Driver
Information Center (DIC), your vehicle should be
taken in for service. For more information on
the DIC messages, seeDriver Information Center
(DIC) on page 267.The StabiliTrak
®light
will ash on the
instrument panel cluster
when the system is
both on and activated.
You may also feel or hear the system working;
this is normal.
The traction control
disable button is located
on the instrument
panel below the climate
controls.
The traction control part of StabiliTrak
®can be
turned off by pressing and releasing the
StabiliTrak
®button if both systems (traction control
and StabiliTrak®) were previously on. To disable
both traction control and StabiliTrak®, press
and hold the button for ve seconds.
Traction control and StabiliTrak
®can be turned on
by pressing and releasing the StabiliTrak®button if
not automatically shut off for any other reason.
382

When the TCS or StabiliTrak®system is turned
off, the StabiliTrak®light and the appropriate TCS
off or StabiliTrak®off message will be displayed
on the DIC to warn the driver. Your vehicle will still
have brake-traction control when traction control
is off, but will not be able to use the engine speed
management system. See “Traction Control
Operation” next for more information.
When the traction control 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. SeeIf Your Vehicle is
Stuck in Sand, Mud, Ice, or Snow on page 422.
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. Both traction
control and StabiliTrak
®are automatically disabled
in this condition.
383

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. It will
activate and the StabiliTrak
®light will ash if
it senses that any of the wheels are spinning or
beginning to lose traction while driving. If you turn
off traction control, only the brake-traction
control portion of traction control will work. The
engine speed management will be disabled. In this
mode, engine power is not reduced automatically
and the driven wheels can spin more freely.
This can cause the brake-traction control to
activate constantly.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.
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 StabiliTrak
®light will ash 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 on page 218.
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.
384

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.
SeeStabiliTrak
®System on page 381.
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.
385

Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 486.
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 378. 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.
386

Off-Road Recovery
You may nd that your right wheels have dropped
off the edge of a road onto the shoulder while
you are 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 untilthe right front tire contacts the pavement edge.
Then turn the 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.
387