2007 GMC ACADIA engine

But you will use it when you brake. Once the
power assist is used up, it can take longer to stop
and the brake pedal will be harder to push.
Adding non-dealer/non-retailer accessories can
affect your vehicle’s performance. SeeAccessories
and Modifications on page 385.
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 the engine and begin to drive
away, ABS will check itself. You might hear
a momentary motor or clicking noise while this test
is going on, and you might even notice that the
brake pedal moves a little. This is normal.
If there is a problem
with ABS, this warning
light will stay on.
SeeAnti-Lock Brake
System Warning
Light on page 223.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
wheel.
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Traction control can be turned on by pressing and
releasing the traction control disable button if
not automatically shut off for any other reason.
When the traction control system is turned
off, the StabiliTrak
®light and the appropriate
traction control 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 360.
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.
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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 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.
SeeCruise Control on page 180.
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/retailer
for service.
All-Wheel Drive (AWD) System
If your vehicle has this feature, engine power is
sent to all four wheels when extra traction is
needed. This is like four-wheel drive, but there
is no separate lever or switch to engage or
disengage the front axle. It is fully automatic, and
adjusts itself as needed for road conditions.
When using a compact spare tire on your AWD
equipped vehicle, the AWD system automatically
detects the presence of the compact spare
and the AWD is disabled. To restore the AWD
operation and prevent excessive wear on
the clutch in your AWD system, replace the
compact spare with a full-size tire as soon as
possible. SeeCompact Spare Tire on page 477
for more information.
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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 337.
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.
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Hydroplaning
Hydroplaning is dangerous. So much water can
build up under the tires that they can actually ride
on the water. This can happen if the road is
wet enough and you are going fast enough.
When your vehicle is hydroplaning, it has little or
no contact with the road.
Hydroplaning does not happen often. But it can
if the tires do not have much tread or if the
pressure in one or more is low. It can happen if a
lot of water is standing on the road. If you can
see reections from trees, telephone poles,
or other vehicles, and raindrops dimple the water’s
surface, there could be hydroplaning.
Hydroplaning usually happens at higher speeds.
There just is not a hard and fast rule about
hydroplaning. The best advice is to slow down
when it is raining.
Driving Through Deep Standing Water
Notice:If you drive too quickly through deep
puddles or standing water, water can come in
through the engine’s air intake and badly
damage the engine. Never drive through water
that is slightly lower than the underbody of your
vehicle. If you cannot avoid deep puddles or
standing water, drive through them very slowly.
Driving Through Flowing Water
{CAUTION:
Flowing or rushing water creates strong
forces. If you try to drive through owing
water, as you might at a low water
crossing, your vehicle can be carried away.
As little as six inches of owing water
can carry away a smaller vehicle. If this
happens, you and other vehicle occupants
could drown. Do not ignore police warning
signs, and otherwise be very cautious
about trying to drive through owing water.
349

Before Leaving on a Long Trip
Make sure you are ready. Try to be well rested.
If you must start when you are not fresh — such as
after a day’s work — do not plan to make too
many miles that rst part of the journey. Wear
comfortable clothing and shoes you can easily
drive in.
Is your vehicle ready for a long trip? If you keep it
serviced and maintained, it is ready to go. If it
needs service, have it done before starting out.
Of course, you will nd experienced and able
service experts at dealers/retailers all across
North America. They are ready and willing to help
you if needed.Here are some things you can check before a trip:Windshield Washer Fluid:Is the reservoir
full? Are all windows clean inside and outside?
Wiper Blades:Are they in good shape?
Fuel, Engine Oil, Other Fluids:Have you
checked all levels?
Lamps:Are they all working? Are the lenses
clean?
Tires:They are vitally important to a safe,
trouble-free trip. Is the tread good enough
for long-distance driving? Are the tires
all inated to the recommended pressure?
Weather Forecasts:What is the weather
outlook along your route? Should you
delay your trip a short time to avoid a major
storm system?
Maps:Do you have up-to-date maps?
352

Highway Hypnosis
Is there actually such a condition as highway
hypnosis? Or is it just plain falling asleep at
the wheel? Call it highway hypnosis, lack of
awareness, or whatever.
There is something about an easy stretch of road
with the same scenery, along with the hum of
the tires on the road, the drone of the engine,
and the rush of the wind against the vehicle that
can make you sleepy. Do not let it happen to you!
If it does, your vehicle can leave the road in
less than a second, and you could crash and
be injured.
What can you do about highway hypnosis?
First, be aware that it can happen.Then here are some tips:Make sure your vehicle is well ventilated,
with a comfortably cool interior.
Keep your eyes moving. Scan the road ahead
and to the sides. Check your vehicle’s mirrors
and instruments frequently.
If you get sleepy, pull off the road into a rest,
service, or parking area and take a nap, get
some exercise, or both. For safety, treat
drowsiness on the highway as an emergency.
353

Hill and Mountain Roads
Driving on steep hills or mountains is different
from driving in at or rolling terrain.If you drive regularly in steep country, or if you are
planning to visit there, here are some tips that
can make your trips safer and more enjoyable.
Keep your vehicle in good shape. Check
all uid levels and also the brakes, tires,
cooling system, and transmission. These parts
can work hard on mountain roads.
{CAUTION:
If you do not shift down, the brakes could
get so hot that they would not work well.
You would then have poor braking or
even none going down a hill. You could
crash. Shift down to let the engine assist
the brakes on a steep downhill slope.
354