2007 GMC YUKON air condition

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

Off-Road Driving
If your vehicle has 20-inch tire/wheel assemblies,
you should not drive off-road unless you are
on a level, solid surface. SeeTires on page 480.
Many of the same design features that help
make your vehicle responsive on paved roads
during poor weather conditions — features
like all-wheel drive — help make it much better
suited for off-road use than a conventional
passenger car. Its higher ground clearance also
helps your vehicle step over some off-road
obstacles. But your vehicle does not have features
like special underbody shielding and a transfer
case low gear range, things that are usually
thought necessary for extended or severe off-road
service. This guide is for operating your vehicle
off paved roads.
Also, seeBraking on page 346.
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.
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.
359

If you put things inside your vehicle – like
suitcases, tools, packages, or anything else – they
go as fast as the vehicle goes. If you have to
stop or turn quickly, or if there is a crash, they’ll
keep going.
{CAUTION:
Things you put inside your vehicle can
strike and injure people in a sudden stop
or turn, or in a crash.
Put things in the cargo area of your
vehicle. Try to spread the weight
evenly.
Never stack heavier things, like
suitcases, inside the vehicle so that
some of them are above the tops of
the seats.
Do not leave an unsecured child
restraint in your vehicle.
When you carry something inside the
vehicle, secure it whenever you can.
Do not leave a seat folded down
unless you need to.There’s also important loading information for
off-road driving in this manual. See “Loading Your
Vehicle for Off-Road Driving” underOff-Road
Driving on page 359.
Automatic Level Control
The automatic level control rear suspension
comes as a part of the Autoride®suspension. See
Autoride®on page 399.
This type of level control is fully automatic and will
provide a better leveled riding position as well
as better handling under a variety of passenger
and loading conditions. An air compressor
connected to the rear shocks will raise or lower
the rear of the vehicle to maintain proper vehicle
height. The system is activated when the
ignition key is turned to RUN and will automatically
adjust vehicle height thereafter. The system
may exhaust (lower vehicle height) for up to
10 minutes after the ignition key has been turned
to OFF. You may hear the air compressor
operating when the height is being adjusted.
If a weight-distributing hitch is being used, it is
recommended to allow the shocks to inate,
thereby leveling the vehicle prior to adjusting the
height.
397

Level Control
Automatic Level Control
The automatic level control rear suspension is
available on light-duty vehicles and comes
as a part of the Autoride
®suspension, if equipped.
This type of level control is fully automatic and
will provide a better leveled riding position as well
as better handling under a variety of passenger
and loading conditions. An air compressor
connected to the rear shocks will raise or lower
the rear of the vehicle to maintain proper vehicle
height. The system is activated when the
ignition key is turned to RUN and will automatically
adjust vehicle height thereafter. The system
may exhaust (lower vehicle height) for up to
ten minutes after the ignition key has been turned
off. You may hear the air compressor operating
when the height is being adjusted.
If a weight-distributing hitch is being used, it is
recommended to allow the shocks to inate,
thereby leveling the vehicle prior to adjusting the
hitch.
Autoride®
The Autoride®feature provides improved vehicle
ride and handling under a variety of passenger and
loading conditions.
The system is fully automatic and uses a computer
controller to continuously monitor vehicle speed,
wheel to body position, lift/dive and steering
position of the vehicle. The controller then sends
signals to each shock absorber to independently
adjust the damping level to provide the optimum
vehicle ride.
Autoride
®also interacts with the tow/haul mode
that, when activated, will provide additional control
of the shock absorbers. This additional control
results in better ride and handling characteristics
when the vehicle is loaded or towing a trailer. See
“Tow/Haul Mode” underTowing a Trailer on
page 400for more information.
399

Gasoline Specications
At a minimum, gasoline should meet ASTM
specication D 4814 in the United States or
CAN/CGSB-3.5 in Canada. Some gasolines may
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl
(MMT). General Motors recommends against the
use of gasolines containing MMT. SeeAdditives
on page 424for additional information.
California Fuel
If your vehicle is certied to meet California
Emissions Standards, it is designed to operate
on fuels that meet California specications.
See the underhood emission control label.
If this fuel is not available in states adopting
California emissions standards, your vehicle will
operate satisfactorily on fuels meeting federal
specications, but emission control system
performance may be affected. The malfunction
indicator lamp may turn on and your vehicle
may fail a smog-check test.SeeMalfunction Indicator Lamp on page 237.
If this occurs, return to your authorized GM dealer
for diagnosis. If it is determined that the condition
is caused by the type of fuel used, repairs
may not be covered by your warranty.
Additives
To provide cleaner air, all gasolines in the
United States are now required to contain additives
that will help prevent engine and fuel system
deposits from forming, allowing your emission
control system to work properly. In most cases,
you should not have to add anything to your fuel.
However, some gasolines contain only the
minimum amount of additive required to meet U.S.
Environmental Protection Agency regulations.
To help keep fuel injectors and intake valves clean,
or if your vehicle experiences problems due to
dirty injectors or valves, look for gasoline that is
advertised as TOP TIER Detergent Gasoline.
Also, your GM dealer has additives that will help
correct and prevent most deposit-related problems.
424

When to Inspect the Engine
Air Cleaner/Filter
If your vehicle has an air lter restriction indicator,
it lets you know when the engine air cleaner/lter
needs to be replaced. On vehicles with a restriction
indicator, you should inspect the air lter
restriction indicator at every oil change and
replace the engine air cleaner/lter when the
indicator tells you to.
On vehicles without an air lter restriction indicator,
inspect the air cleaner/lter at the MaintenanceII
intervals and replace it at the rst oil change
after each 50,000 mile (83 000 km) interval.
SeeScheduled Maintenance on page 551for
more information. If you are driving in dusty/dirty
conditions, inspect the lter at each engine oil
change.
How to Inspect the Engine
Air Cleaner/Filter
Vehicles With an Air Filter Restriction
Indicator
Locate the air lter restriction indicator on the
engine air cleaner/lter cover. When the indicator
turns black or is in the red/orange “change”
zone, replace the lter and reset the indicator.
See the steps following to replace the engine
air cleaner/lter and to reset the air lter restriction
indicator.
Vehicles Without an Air Filter Restriction
Indicator
To inspect the air cleaner/lter, remove the engine
air cleaner/lter from the vehicle by following
step 1 through 6. When you have the engine air
cleaner/lter removed, lightly shake it to release
loose dust and dirt. If the engine air cleaner/lter
remains caked with dirt, a new lter is required.
438

Notice:If your engine catches re because
you keep driving with no coolant, your vehicle
can be badly damaged. The costly repairs
would not be covered by your warranty.
SeeOverheated Engine Protection Operating
Mode on page 450for information on driving
to a safe place in an emergency.
If No Steam Is Coming From Your
Engine
The ENGINE OVERHEATED STOP ENGINE
or the ENGINE OVERHEATED IDLE ENGINE
message, along with a low coolant condition,
can indicate a serious problem.
If you get an engine overheat warning, but see or
hear no steam, the problem may not be too
serious. Sometimes the engine can get a little too
hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. SeeTowing a Trailer
on page 400.If you get the ENGINE OVERHEATED STOP
ENGINE or the ENGINE OVERHEATED IDLE
ENGINE message with no sign of steam, try this
for a minute or so:
1. If you have an air conditioner and it is on,
turn it off.
2. Turn on your heater to full hot at the highest
fan speed and open the windows as
necessary.
3. In heavy traffic, let the engine idle in
NEUTRAL (N) while stopped. If it is safe to
do so, pull off the road, shift to PARK (P)
or NEUTRAL (N) and let the engine idle.
If you no longer have the overheat warning,
you can drive. Just to be safe, drive slower for
about 10 minutes. If the warning does not
come back on, you can drive normally.
If the warning continues, pull over, stop, and
park your vehicle immediately.
449

If there is still no sign of steam and your vehicle
is equipped with an engine-driven cooling fan,
push down the accelerator until the engine speed
is about twice as fast as normal idle speed for
at least ve minutes while you are parked.
If there is still no sign of steam and your vehicle is
equipped with an electric cooling fan, idle the
engine for ve minutes while you are parked.
If you still have the warning, turn off the engine
and get everyone out of the vehicle until it
cools down. Also, see “Overheated Engine
Protection Operating Mode” later in this section.
You may decide not to lift the hood but to get
service help right away.Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is
displayed, an overheat protection mode which
alternates ring groups of cylinders helps prevent
engine damage. In this mode, you will notice a
loss in power and engine performance. This
operating mode allows your vehicle to be driven to
a safe place in an emergency. Driving extended
miles (km) and/or towing a trailer in the overheat
protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine
damage, allow the engine to cool before
attempting any repair. The engine oil will be
severely degraded. Repair the cause of coolant
loss, change the oil and reset the oil life
system. SeeEngine Oil on page 432.
450