2008 GMC YUKON XL maintenance

Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-2
Rear Seats
..............................................1-11
Safety Belts
.............................................1-30
Child Restraints
.......................................1-51
Airbag System
.........................................1-76
Restraint System Check
............................1-92
Features and Controls..................................... 2-1
Keys
........................................................ 2-3
Doors and Locks
......................................2-10
Windows
.................................................2-19
Theft-Deterrent Systems
............................2-22
Starting and Operating Your Vehicle
...........2-26
Mirrors
....................................................2-49
Object Detection Systems
..........................2-58
OnStar
®System
......................................2-60
Universal Home Remote System
................2-64
Storage Areas
.........................................2-71
Sunroof
..................................................2-74
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-4
Climate Controls
......................................3-23
Warning Lights, Gages, and Indicators
........3-37
Driver Information Center (DIC)
..................3-55
Audio System(s)
.......................................3-81Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-45
Service and Appearance Care.......................... 5-1
Service
..................................................... 5-3
Fuel
......................................................... 5-5
Checking Things Under the Hood
...............5-12
Rear Axle
...............................................5-52
Four-Wheel Drive
.....................................5-54
Front Axle
...............................................5-55
Headlamp Aiming
.....................................5-56
Bulb Replacement
....................................5-59
Windshield Wiper Blade Replacement
.........5-62
Tires
......................................................5-64
Appearance Care
...................................5-108
Vehicle Identication
...............................5-116
Electrical System
....................................5-117
Capacities and Specications
...................5-124
Maintenance Schedule..................................... 6-1
Maintenance Schedule
................................ 6-2
Customer Assistance Information.................... 7-1
Customer Assistance and Information
........... 7-2
Reporting Safety Defects
...........................7-14
Vehicle Data Recording and Privacy
...........7-16
Index................................................................ 1
2008 GMC Yukon, Yukon XL Owner ManualM

Restraint System Check
Checking the Restraint Systems
Safety Belts
Now and then, make sure the safety belt reminder light
and all your belts, buckles, latch plates, retractors
and anchorages are working properly.
Look for any other loose or damaged safety belt system
parts. If you see anything that might keep a safety
belt system from doing its job, have it repaired. Torn or
frayed safety belts may not protect you in a crash.
They can rip apart under impact forces. If a belt is torn
or frayed, get a new one right away.
Make sure the safety belt reminder light is working. See
Safety Belt Reminders on page 3-39for more
information.
Keep safety belts clean and dry. SeeCare of Safety
Belts on page 5-111.
Airbags
The airbag system does not need regularly scheduled
maintenance or replacement. Make sure the airbag
readiness light is working. SeeAirbag Readiness Light
on page 3-40for more information.
Notice:If an airbag covering is damaged, opened,
or broken, the airbag may not work properly. Do
not open or break the airbag coverings. If there are
any opened or broken airbag covers, have the
airbag covering and/or airbag module replaced. For
the location of the airbag modules, seeWhat
Makes an Airbag Inflate? on page 1-83. See your
dealer/retailer for service.
1-92

Malfunction Indicator Lamp
Check Engine Light
A computer system called OBD II (On-Board
Diagnostics-Second Generation) monitors operation of
the fuel, ignition, and emission control systems. It makes
sure that emissions are at acceptable levels for the life of
the vehicle, helping to produce a cleaner environment.
The check engine light
comes on to indicate that
there is an OBD II
problem and service is
required.
Malfunctions often are indicated by the system before
any problem is apparent. This can prevent more serious
damage to your vehicle. This system is also designed
to assist your service technician in correctly diagnosing
any malfunction.Notice:If you keep driving your vehicle with this
light on, after a while, the emission controls
might not work as well, your vehicle’s fuel economy
might not be as good, and the engine might not
run as smoothly. This could lead to costly repairs
that might not be covered by your warranty.
Notice:Modications made to the engine,
transmission, exhaust, intake, or fuel system of
your vehicle or the replacement of the original tires
with other than those of the same Tire Performance
Criteria (TPC) can affect your vehicle’s emission
controls and can cause this light to come on.
Modications to these systems could lead to costly
repairs not covered by your warranty. This could
also result in a failure to pass a required Emission
Inspection/Maintenance test. SeeAccessories
and Modifications on page 5-3.
3-48

Did you just drive through a deep puddle of water?
If so, your vehicle’s electrical system might be wet. The
condition is usually corrected when the electrical system
dries out. A few driving trips should turn the light off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane on page 5-5. Poor fuel quality causes
the engine not to run as efficiently as designed. You
might notice this as stalling after start-up, stalling when
you put the vehicle into gear, misring, hesitation on
acceleration, or stumbling on acceleration — these
conditions might go away once the engine is warmed up.
This will be detected by the system and cause the light to
turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at least
one full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn off,
your dealer/retailer can check the vehicle. Your
dealer/retailer has the proper test equipment and
diagnostic tools to x any mechanical or electrical
problems that might have developed.Emissions Inspection and Maintenance
Programs
Some state/provincial and local governments have or
might begin programs to inspect the emission control
equipment on your vehicle. Failure to pass this
inspection could prevent you from getting a vehicle
registration.
Here are some things you need to know to help your
vehicle pass an inspection:
Your vehicle will not pass this inspection if the check
engine light is on or not working properly.
Your vehicle will not pass this inspection if the OBD
(on-board diagnostic) system determines that critical
emission control systems have not been completely
diagnosed by the system. The vehicle would be
considered not ready for inspection. This can happen if
you have recently replaced the battery or if the
battery has run down. The diagnostic system is
designed to evaluate critical emission control systems
during normal driving. This can take several days
of routine driving. If you have done this and your vehicle
still does not pass the inspection for lack of OBD
system readiness, your dealer/retailer can prepare the
vehicle for inspection.
3-50

Oil Pressure Gage
The oil pressure gage shows the engine oil pressure in
psi (pounds per square inch) when the engine is
running. Canadian vehicles indicate pressure in kPa
(kilopascals).
Oil pressure may vary with engine speed, outside
temperature and oil viscosity, but readings above the
low pressure zone indicate the normal operating range.
When the oil pressure reaches the low pressure
zone, the OIL PRESSURE LOW STOP ENGINE
message will appear in the Driver Information Center
(DIC). SeeDIC Warnings and Messages on page 3-64
andEngine Oil on page 5-15for more information.A reading in the low pressure zone may be caused by a
dangerously low oil level or some other problem
causing low oil pressure. Check your oil as soon as
possible.
{CAUTION:
Do not keep driving if the oil pressure is low. If
you do, your engine can become so hot that it
catches re. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice:Lack of proper engine oil maintenance may
damage the engine. The repairs would not be
covered by your warranty. Always follow the
maintenance schedule in this manual for changing
engine oil.
If your vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information. United States
Canada
3-51

Oil Pressure Light
{CAUTION:
Do not keep driving if the oil pressure is low. If
you do, your engine can become so hot that it
catches re. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice:Lack of proper engine oil maintenance may
damage the engine. The repairs would not be covered
by your warranty. Always follow the maintenance
schedule in this manual for changing engine oil.
This light will come on
briey when you start your
engine. If it does not,
have your vehicle serviced.When the light comes on and stays on, it means that oil
is not owing through your engine properly. You
could be low on oil and you might have some other
system problem.
Security Light
For information regarding
this light and the vehicle’s
security system, see
Content Theft-Deterrent on
page 2-22.
3-52

Transmission Temperature
Press the trip/fuel button until TRANS TEMP displays.
This display shows the temperature of the automatic
transmission uid in either degrees Fahrenheit (°F) or
degrees Celsius (°C).
Instantaneous Economy and Active Fuel
Management™ Indicator
If your vehicle has this display, press the trip/fuel button
until INST ECONOMY V8 MODE displays. This
display shows the current fuel economy at a particular
moment and will change frequently as driving conditions
change. This display shows the instantaneous fuel
economy in miles per gallon (mpg) or liters per
100 kilometers (L/100 km). Unlike average economy,
this screen cannot be reset.
An Active Fuel Management™ indicator will display on
the right side of the DIC, while INST ECONOMY
displays on the left side. Active Fuel Management™
allows the engine to operate on either four or eight
cylinders, depending on your driving demands. When
Active Fuel Management™ is active, V4 MODE will
display on the DIC. When Active Fuel Management™ is
inactive, V8 MODE will display. SeeActive Fuel
Management™ on page 2-31for more information.
Blank Display
This display shows no information.
Vehicle Information Menu Items
T
(Vehicle Information):Press this button to scroll
through the following menu items:
Oil Life
Press the vehicle information button until OIL LIFE
REMAINING displays. This display shows an estimate
of the oil’s remaining useful life. If you see 99% OIL LIFE
REMAINING on the display, that means 99% of the
current oil life remains. The engine oil life system
will alert you to change the oil on a schedule consistent
with your driving conditions.
When the remaining oil life is low, the CHANGE
ENGINE OIL SOON message will appear on the display.
See “CHANGE ENGINE OIL SOON” underDIC
Warnings and Messages on page 3-64. You should
change the oil as soon as you can. SeeEngine Oil on
page 5-15. In addition to the engine oil life system
monitoring the oil life, additional maintenance is
recommended in the Maintenance Schedule in this
manual. SeeScheduled Maintenance on page 6-4for
more information.
3-59

When the remaining oil life is low, the CHANGE ENGINE
OIL SOON message will appear on the display. See
“CHANGE ENGINE OIL SOON” underDIC Warnings and
Messages on page 3-64. You should change the oil as
soon as you can. SeeEngine Oil on page 5-15.In
addition to the engine oil life system monitoring the oil life,
additional maintenance is recommended in the
Maintenance Schedule in this manual. SeeScheduled
Maintenance on page 6-4for more information.
Remember, you must reset the OIL LIFE display
yourself after each oil change. It will not reset itself.
Also, be careful not to reset the OIL LIFE display
accidentally at any time other than when the oil has just
been changed. It cannot be reset accurately until the
next oil change. To reset the engine oil life system, see
Engine Oil Life System on page 5-18.
Relearn Remote Key
To access this display, the vehicle must be in PARK (P).
This display allows you to match Remote Keyless
Entry (RKE) transmitters to your vehicle. To match an
RKE transmitter to your vehicle:
1. Press the trip odometer reset stem until RELEARN
REMOTE KEY displays.
2. Press and hold the trip odometer reset stem for
three seconds.
The message REMOTE KEY LEARNING ACTIVE
will display.3. Press and hold the lock and unlock buttons on the
rst transmitter at the same time for about
15 seconds.
On vehicles with memory recall seats, the rst
transmitter learned will match driver 1 and
the second will match driver 2.
A chime will sound indicating that the transmitter is
matched.
4. To match additional transmitters at this time, repeat
Step 3.
Each vehicle can have a maximum of eight
transmitters matched to it.
5. To exit the programming mode, you must cycle the
key to LOCK/OFF.
Language
This display allows you to select the language in which
the DIC messages will appear. To select a language:
1. Press the trip odometer reset stem until
ODOMETER displays.
2. While in the ODOMETER display, press and hold
the trip odometer reset stem for three seconds until
the currently set language displays.
3-63