2007 GMC YUKON Owner's Manual

But the ability to drive is affected well below a
BAC of 0.10 percent. Research shows that
the driving skills of many people are impaired at a
BAC approaching 0.05 percent, and that the
effects are worse at night. All drivers are impaired
at BAC levels above 0.05 percent. Statistics
show that the chance of being in a collision
increases sharply for drivers who have a BAC of
0.05 percent or above. A driver with a BAC level of
0.06 percent has doubled his or her chance of
having a collision. At a BAC level of 0.10 percent,
the chance of this driver having a collision is
12 times greater; at a level of 0.15 percent, the
chance is 25 times greater!
The body takes about an hour to rid itself of the
alcohol in one drink. No amount of coffee or
number of cold showers will speed that up. “I will
be careful” is not the right answer. What if
there is an emergency, a need to take sudden
action, as when a child darts into the street?
A person with even a moderate BAC might not be
able to react quickly enough to avoid the
collision.There is something else about drinking and driving
that many people do not know. Medical research
shows that alcohol in a person’s system can make
crash injuries worse, especially injuries to the
brain, spinal cord, or heart. This means that when
anyone who has been drinking — driver or
passenger — is in a crash, that person’s chance
of being killed or permanently disabled is
higher than if the person had not been drinking.
{CAUTION:
Drinking and then driving is very
dangerous. Your reexes, perceptions,
attentiveness, and judgment can be
affected by even a small amount of
alcohol. You can have a serious — or
even fatal — collision if you drive after
drinking. Please do not drink and drive or
ride with a driver who has been drinking.
Ride home in a cab; or if you are with a
group, designate a driver who will not
drink.
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Control of a Vehicle
You have three systems that make your vehicle
go where you want it to go. They are the
brakes, the steering, and the accelerator. All
three systems have to do their work at the places
where the tires meet the road.
Sometimes, as when you are driving on snow or
ice, it is easy to ask more of those control systems
than the tires and road can provide. That means
you can lose control of your vehicle.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 421.
Braking
SeeBrake System Warning Light on page 233.
Braking action involves perception time and
reaction time.
First, you have to decide to push on the brake
pedal. That is perception time. Then you
have to bring up your foot and do it. That is
reaction time.Average reaction time is about three-fourths of a
second. But that is only an average. It might
be less with one driver and as long as two or
three seconds or more with another. Age, physical
condition, alertness, coordination, and eyesight
all play a part. So do alcohol, drugs, and
frustration. But even in three-fourths of a second,
a vehicle moving at 60 mph (100 km/h) travels
66 feet (20 m). That could be a lot of distance in an
emergency, so keeping enough space between
your vehicle and others is important.
And, of course, actual stopping distances vary
greatly with the surface of the road, whether it is
pavement or gravel; the condition of the road,
whether it is wet, dry, or icy; tire tread; the
condition of your brakes; the weight of the vehicle;
and the amount of brake force applied.
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Avoid needless heavy braking. Some people drive
in spurts — heavy acceleration followed by
heavy braking — rather than keeping pace with
traffic. This is a mistake. Your brakes may
not have time to cool between hard stops. Your
brakes will wear out much faster if you do a lot of
heavy braking. If you keep pace with the traffic
and allow realistic following distances, you
will eliminate a lot of unnecessary braking. That
means better braking and longer brake life.
If your engine ever stops while you are driving,
brake normally but do not pump your brakes. If you
do, the pedal may get harder to push down. If
your engine stops, you will still have some power
brake assist. But you will use it when you
brake. Once the power assist is used up, it may
take longer to stop and the brake pedal will
be harder to push.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 421.Anti-Lock Brake System (ABS)
Your vehicle has the Anti-Lock Brake System
(ABS), an advanced electronic braking system that
will help prevent a braking skid.
When you start your engine and begin to drive
away, ABS will check itself. You may hear a
momentary motor or clicking noise while this test
is going on. This is normal.
If there is a problem
with ABS, this warning
light will stay on.
SeeAnti-Lock Brake
System Warning
Light on page 234.
Along with ABS, your vehicle has a Dynamic Rear
Proportioning (DRP) system. If there is a DRP
problem, both the brake and ABS warning lights
will come on accompanied by a 10-second
chime. The lights and chime will come on each
time the ignition is turned on until the problem is
repaired. See your dealer for service.
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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.
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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 Differential
If your vehicle has this feature, your locking
differential 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 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.
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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 244.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.
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Traction control and StabiliTrak®can be turned
on by pressing and releasing the StabiliTrak®
button if not automatically shut off for any other
reason.
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 390.
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.
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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 200.
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.
352