2008 GMC YUKON XL manual transmission

Keys...............................................................2-3
Remote Keyless Entry (RKE) System................2-4
Remote Keyless Entry (RKE) System
Operation...................................................2-5
Remote Vehicle Start......................................2-8
Doors and Locks............................................2-10
Door Locks..................................................2-10
Power Door Locks........................................2-11
Delayed Locking...........................................2-11
Programmable Automatic Door Locks..............2-11
Rear Door Security Locks..............................2-12
Lockout Protection........................................2-12
Liftgate/Liftglass............................................2-13
Power Liftgate..............................................2-15
Power Running Boards..................................2-18
Windows........................................................2-19
Power Windows............................................2-20
Sun Visors...................................................2-21
Theft-Deterrent Systems..................................2-22
Content Theft-Deterrent.................................2-22
PASS-Key
®III+............................................2-24
PASS-Key®III+ Operation..............................2-24
Starting and Operating Your Vehicle................2-26
New Vehicle Break-In....................................2-26
Ignition Positions..........................................2-26
Retained Accessory Power (RAP)...................2-27Starting the Engine.......................................2-28
Adjustable Throttle and Brake Pedal................2-29
Engine Coolant Heater..................................2-30
Active Fuel Management™.............................2-31
Automatic Transmission Operation...................2-31
Tow/Haul Mode............................................2-37
Four-Wheel Drive..........................................2-38
Parking Brake..............................................2-43
Shifting Into PARK (P)...................................2-44
Shifting Out of PARK (P)...............................2-46
Parking Over Things That Burn.......................2-46
Engine Exhaust............................................2-47
Running the Engine While Parked...................2-48
Mirrors...........................................................2-49
Automatic Dimming Rearview Mirror with
OnStar
®, Compass and Temperature
Display....................................................2-49
Automatic Dimming Rearview Mirror with
Compass and Temperature Display..............2-52
Outside Manual Mirrors..................................2-54
Outside Trailer-Tow Mirrors............................2-54
Outside Power Mirrors...................................2-55
Outside Power Foldaway Mirrors.....................2-56
Outside Automatic Dimming Mirror..................2-57
Park Tilt Mirrors............................................2-57
Outside Convex Mirror...................................2-57
Outside Heated Mirrors..................................2-57
Section 2 Features and Controls
2-1

The power liftgate may be temporarily disabled under
extreme temperatures, or under low battery conditions.
If this occurs, the liftgate can still be operated
manually.
If you shift the transmission out of PARK (P) while the
power function is in progress, the liftgate power function
will continue to completion. If you shift the transmission
out of PARK (P) and accelerate before the power
liftgate latches closed, the liftgate may reverse to the
open position. Cargo could fall out of the vehicle. Always
make sure the power liftgate is closed and latched
before you drive away.
If you power open the liftgate and the liftgate support
struts have lost pressure, the lights will ash and a
chime will sound. The liftgate will stay open temporarily,
then slowly close. See your dealer/retailer for service
before using the liftgate.Obstacle Detection Features
If the liftgate encounters an obstacle during a power
open or close cycle, a warning chime will sound and the
liftgate will automatically reverse direction to the full
closed or open position. After removing the obstruction,
the power liftgate operation can be used again. If the
liftgate encounters multiple obstacles on the same power
cycle, the power function will deactivate, and you
must manually open or close the liftgate. The REAR
ACCESS OPEN warning message in the Driver
Information Center (DIC) will indicate that the liftgate is
open. After removing the obstructions, manually
open the liftgate to the full open position or close the
liftgate to the fully closed and latched position. The
liftgate will now resume normal power operation.
Your vehicle has pinch sensors located on the side
edges of the liftgate. If an object is caught between the
liftgate and the body and presses against this sensor,
the liftgate will reverse direction and open fully.
The liftgate will remain open until it is activated again or
closed manually. Do not force the liftgate open or
closed during a power cycle.
2-17

Starting the Engine
If your vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
Move your shift lever to PARK (P) or NEUTRAL (N).
Your engine will not start in any other position – this is a
safety feature. To restart when you are already
moving, use NEUTRAL (N) only.
Notice:Do not try to shift to PARK (P) if your
vehicle is moving. If you do, you could damage the
transmission. Shift to PARK (P) only when your
vehicle is stopped.
Starting Procedure
1. With your foot off the accelerator pedal, turn the
ignition key to START. When the engine starts,
let go of the key. The idle speed will go down as
your engine gets warm. Do not race the engine
immediately after starting it. Operate the engine and
transmission gently to allow the oil to warm up
and lubricate all moving parts.
Your vehicle has a Computer-Controlled Cranking
System. This feature assists in starting the engine
and protects components. If the ignition key is
turned to the START position, and then released
when the engine begins cranking, the engine
will continue cranking for a few seconds or until
the vehicle starts. If the engine does not startand the key is held in START for many seconds,
cranking will be stopped after 15 seconds to prevent
cranking motor damage. To prevent gear damage,
this system also prevents cranking if the engine is
already running. Engine cranking can be stopped by
turning the ignition switch to the ACC/ACCESSORY
or LOCK/OFF position.
Notice:Cranking the engine for long periods of
time, by returning the key to the START position
immediately after cranking has ended, can overheat
and damage the cranking motor, and drain the
battery. Wait at least 15 seconds between each try,
to let the cranking motor cool down.
2. If the engine does not start after 5-10 seconds,
especially in very cold weather (below 0°F or
−18°C), it could be ooded with too much gasoline.
Try pushing the accelerator pedal all the way to
the oor and holding it there as you hold the key in
START for up to a maximum of 15 seconds.
Wait at least 15 seconds between each try, to allow
the cranking motor to cool down. When the
engine starts, let go of the key and accelerator. If
the vehicle starts briey but then stops again, do the
same thing. This clears the extra gasoline from
the engine. Do not race the engine immediately
after starting it. Operate the engine and
transmission gently until the oil warms up and
lubricates all moving parts.
2-28

Active Fuel Management™
Your vehicle’s V8 engine may have Active Fuel
Management™. This system allows the engine to
operate on either all or half of its cylinders, depending
on the driving conditions.
When less power is required, such as cruising at a
constant vehicle speed, the system will operate in the
half cylinder mode, allowing your vehicle to achieve
better fuel economy. When greater power demands are
required, such as accelerating from a stop, passing,
or merging onto a freeway, the system will maintain
full-cylinder operation.
If your vehicle has an Active Fuel Management™
indicator, seeDIC Operation and Displays (With DIC
Buttons) on page 3-56orDIC Operation and Displays
(Without DIC Buttons) on page 3-61for more information
on using this display.
Automatic Transmission Operation
If your vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
If your vehicle is has an automatic transmission, it has
an electronic shift position indicator within the
instrument panel cluster. This display comes on when
the ignition key is turned to the ON/RUN position.
There are several different positions for the shift lever.
Hydra-Matic
®4-Speed
Automatic Transmission
2-31

MANUAL MODE (M):This position, is available on
vehicles with the Allison Transmission®or Hydra-Matic®
6-Speed transmission. It lets drivers select the range
of gears appropriate for current driving conditions. If your
vehicle has this feature, see Range Select Mode
(Allison Transmission
®or Hydra-Matic®6-Speed
transmission) later in this section.
THIRD (3):This position is also used for normal driving.
It reduces vehicle speed more than DRIVE (D) without
using the brakes. You might choose THIRD (3)
instead of DRIVE (D) when driving on hilly, winding
roads, when towing a trailer, so there is less shifting
between gears and when going down a steep hill.
SECOND (2):This position reduces vehicle speed even
more than THIRD (3) without using your brakes. You can
use SECOND (2) on hills. It can help control your speed
as you go down steep mountain roads, but then you
would also want to use the brakes off and on.
If you manually select SECOND (2) in an automatic
transmission, the transmission will start in second gear.
You can use this feature for reducing the speed of the
rear wheels when you are trying to start your vehicle from
a stop on slippery road surfaces.FIRST (1):For the Hydra-Matic
®4-Speed transmission
this position reduces vehicle speed even more than
SECOND (2) without using the brakes. You can use it
on very steep hills, or in deep snow or mud. If the
shift lever is put in FIRST (1) while the vehicle is moving
forward, the transmission does not shift into rst gear
until the vehicle is going slowly enough.
For an Allison Transmission
®or Hydra-Matic®6-Speed
transmission, this position reduces vehicle speed
without using your brakes. You can use it for
major/severe downgrades and off-road driving where
the vehicle would otherwise accelerate due to steepness
of grade. When you shift to FIRST (1) it provides the
lowest gear appropriate to your current road speed and
continues to downshift as the vehicle slows, eventually
downshifting to FIRST (1) gear.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by your warranty. If you are stuck,
do not spin the tires. When stopping on a hill,
use the brakes to hold the vehicle in place.
2-35

Range Selection Mode (Allison®or
Hydra-Matic®6-Speed Transmission)
Your vehicle may have a Range Selection Mode.
The Range Selection Mode helps control the vehicle’s
transmission and vehicle speed while driving down hill
or towing a trailer by letting you select a desired range
of gears.
To use this feature, do the following:
1. Move the shift lever to the MANUAL MODE (M).
2. Press the plus/minus buttons, located on the
steering column shift lever, to select the desired
range of gears for your current driving conditions.When MANUAL MODE (M) is selected a number
displays next to the M, indicating the current gear.
This number is the highest gear that can be used.
However, your vehicle can automatically shift to lower
gears as it adjusts to driving conditions. This means that
all gears below that number are available. When
FIFTH (5) is selected, FIRST (1) through FIFTH (5)
gears are automatically shifted by the vehicle, but
SIXTH (6) cannot be used until the plus/minus button
located on the steering column lever is used to change
to the gear.
Grade Braking is not available when the Range
Selection Mode is active. SeeTow/Haul Mode on
page 2-37.
While using the Range Selection mode feature, cruise
control and the Tow/Haul mode can be used.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by your warranty. If you are stuck,
do not spin the tires. When stopping on a hill,
use the brakes to hold the vehicle in place.
2-36

;(Parking Lamps):Turn the control to this position
to turn on the parking lamps together with the
following:
Instrument Panel Lights
Taillamps
License Plate Lamps
2(Headlamps):Turn the control to this position to
turn on the headlamps together with the following lamps
listed below.
Parking Lamps
Instrument Panel Lights
Taillamps
License Plate Lamps
When the headlamps are turned on while the vehicle is
on, the headlamps turn off automatically 10 minutes
after the ignition is turned off. When the headlamps are
turned on while the vehicle is off, the headlamps will
stay on for 10 minutes before automatically turning off to
prevent the battery from being drained.
Headlamps on Reminder
A reminder chime will sound when the headlamps or
parking lamps are manually turned on and your ignition
is off and a door is open. To disable the chime, turn
the light off.
Daytime Running Lamps (DRL)
Daytime Running Lamps (DRL) can make it easier for
others to see the front of your vehicle during the
day. DRL can be helpful in many different driving
conditions, but they can be especially helpful in the short
periods after dawn and before sunset. Fully functional
daytime running lamps are required on all vehicles
rst sold in Canada.
The DRL system will come on when the following
conditions are met:
The ignition is on.
The exterior lamps control is in AUTO.
The transmission is not in PARK (P).
The light sensor determines it is daytime.
When the DRL are on, only the DRL lamps will be on.
The taillamps, sidemarker, and other lamps will not
be on. The instrument panel will not be lit up either.
3-17

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