engine GMC YUKON XL 2007 Repair Manual

REMOTE START
If your vehicle has this feature, it allows you to
turn the remote start off or on. The remote
start feature allows you to start the engine from
outside of the vehicle using your remote keyless
entry transmitter. See″Remote Vehicle Start″
underRemote Keyless Entry System Operation on
page 113for more information.
Press the customization button until REMOTE
START appears on the DIC display. Press
the set/reset button once to access the settings for
this feature. Then press the customization
button to scroll through the following settings:
OFF:The remote start feature will be disabled.
ON (default):The remote start feature will
be enabled.
NO CHANGE:No change will be made to this
feature. The current setting will remain.
Choose one of the available settings and press
the set/reset button while it is displayed on the DIC
to select it.
FACTORY SETTINGS
This feature allows you to set all of the
customization features back to their factory default
settings.
Press the customization button until FACTORY
SETTINGS appears on the DIC display. Press the
set/reset button once to access the settings for
this feature. Then press the customization button
to scroll through the following settings:
RESTORE ALL (default):The customization
features will be set to their factory default settings.
DO NOT RESTORE:The customization features
will not be set to their factory default settings.
Choose one of the available settings and press the
set/reset button while it is displayed on the DIC
to select it.
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{CAUTION:
This system provides you with a far
greater access to audio stations and song
listings. Giving extended attention to
entertainment tasks while driving can
cause a crash and you or others can be
injured or killed. Always keep your eyes
on the road and your mind on the
drive — avoid engaging in extended
searching while driving.
Keeping your mind on the drive is important for
safe driving. For more information, seeDefensive
Driving on page 340.Here are some ways in which you can help avoid
distraction while driving.
While your vehicle is parked:Familiarize yourself with all of its controls.
Familiarize yourself with its operation.
Set up your audio system by presetting your
favorite radio stations, setting the tone, and
adjusting the speakers. Then, when driving
conditions permit, you can tune to your favorite
radio stations using the presets and steering
wheel controls if the vehicle has them.
Notice:Before adding any sound equipment
to your vehicle, such as an audio system,
CD player, CB radio, mobile telephone,
or two-way radio, make sure that it can be
added by checking with your dealer. Also,
check federal rules covering mobile radio and
telephone units. If sound equipment can be
added, it is very important to do it properly.
Added sound equipment may interfere with the
operation of your vehicle’s engine, radio, or
other systems, and even damage them.
Your vehicle’s systems may interfere with the
operation of sound equipment that has
been added.
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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 426.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 233.
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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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 both systems were previously off, if not
automatically shut off for any other reason.
When the system is turned off, the TRACTION
CONTROL OFF message and the StabiliTrak
®
light will appear to warn the driver that both
the traction control and part of StabiliTrak®are
disabled. 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 388.
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.
SeeCruise Control on page 196.
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.
350

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.
SeeStabiliTrak
®System on page 348.
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.
351

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.
If you think you will need some more ground
clearance at the front of your vehicle, you
can remove the front fascia lower air dam.
The front fascia lower air dam is held in place by
two bolts and 10 snap features. The bolts and
snap features are accessible from underneath the
front fascia.
The following steps must be performed on the
bolts and snap features to remove the air dam:
1. Remove the 2 outboard air dam bolts.
2. With a at-blade screwdriver, push down on
the snap features and disengage the snaps.
3. After the bolts are removed and the snaps are
disengaged, push forward on the air dam until
it is free.
When you are back on roads, though, be sure to
replace the air dam.Notice:Operating your vehicle for extended
periods without the front fascia lower air dam
installed can cause improper air ow to the
engine. Always be sure to replace the front
fascia air dam when you are nished off-road
driving.
To reinstall the lower air dam do the following:
1. Line up the snap features and push the
air dam rearward to engage the snaps.
2. Install the 2 outboard bolts.
Before You Go Off-Roading
There are some things to do before you go out.
For example, be sure to have all necessary
maintenance and service work done. Check to
make sure all underbody shields, if the vehicle has
them, are properly attached. Be sure you read
all the information about your four-wheel-drive or
all-wheel-drive vehicle in this manual. Is there
enough fuel? Is the spare tire fully inated? Are the
uid levels up where they should be? What are
the local laws that apply to off-roading where you
will be driving? If you do not know, you should
check with law enforcement people in the
area. Will you be on someone’s private land?
If so, be sure to get the necessary permission.
357

Getting Familiar with Off-Road Driving
It is a good idea to practice in an area that is
safe and close to home before you go into
the wilderness. Off-road driving does require some
new and different skills. Here is what we mean.
Tune your senses to different kinds of signals.
Your eyes, for example, need to constantly sweep
the terrain for unexpected obstacles. Your ears
need to listen for unusual tire or engine sounds.
With your arms, hands, feet and body, you
will need to respond to vibrations and vehicle
bounce.
Controlling your vehicle is the key to successful
off-road driving. One of the best ways to
control your vehicle is to control your speed. Here
are some things to keep in mind. At higher
speeds:
You approach things faster and you have less
time to scan the terrain for obstacles.
You have less time to react.
You have more vehicle bounce when you
drive over obstacles.
You will need more distance for braking,
especially since you are on an unpaved
surface.
{CAUTION:
When you are driving off-road, bouncing
and quick changes in direction can easily
throw you out of position. This could
cause you to lose control and crash. So,
whether you are driving on or off the road,
you and your passengers should wear
safety belts.
360

Q:What should I do if my vehicle stalls, or is
about to stall, and I cannot make it up
the hill?
A:If this happens, there are some things you
should do, and there are some things you
must not do. First, here is what youshoulddo:
Push the brake pedal to stop the vehicle
and keep it from rolling backwards. Also, apply
the parking brake.
If your engine is still running, shift the
transmission to REVERSE (R), release the
parking brake, and slowly back down the hill in
REVERSE (R).
If your engine has stopped running, you will
need to restart it. With the brake pedal
pressed and the parking brake still applied,
shift the transmission to PARK (P) and restart
the engine. Then, shift to REVERSE (R),
release the parking brake, and slowly back
down the hill as straight as possible in
REVERSE (R).
As you are backing down the hill, put your left
hand on the steering wheel at the 12 o’clock
position. This way, you will be able to tell if your
wheels are straight and maneuver as you back
down. It is best that you back down the hill with
your wheels straight rather than in the left or
right direction. Turning the wheel too far to the
left or right will increase the possibility of a
rollover.
365

Here are some things youmust notdo if you stall,
or are about to stall, when going up a hill.
Never attempt to prevent a stall by shifting
into NEUTRAL (N) to rev-up the engine
and regain forward momentum. This will not
work. Your vehicle will roll backwards
very quickly and you could go out of control.
Instead, apply the regular brake to stop
the vehicle. Then apply the parking brake.
Shift to REVERSE (R), release the parking
brake, and slowly back straight down.
{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). This is
because the NEUTRAL position on the
transfer case overrides the transmission.
You or someone else could be injured. If
you are going to leave your vehicle, set the
parking brake and shift the transmission to
PARK (P). But do not shift the transfer case
to NEUTRAL.
Never attempt to turn around if you are about to
stall when going up a hill. If the hill is steep
enough to stall your vehicle, it is steep enough
to cause you to roll over if you turn around. If
you cannot make it up the hill, you must back
straight down the hill.
Q:Suppose, after stalling, I try to back down
the hill and decide I just cannot do it. What
should I do?
A:Set the parking brake, put your transmission
in PARK (P) and turn off the engine. Leave
the vehicle and go get some help. Exit on the
uphill side and stay clear of the path the
vehicle would take if it rolled downhill. Do not
shift the transfer case to NEUTRAL when
you leave the vehicle. Leave it in some gear.
366