parking brake GMC YUKON 2012 User Guide

Black plate (31,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-31
{WARNING
It can be dangerous to get out of
the vehicle if the automatic
transmission shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll. Do
not leave the vehicle when the
engine is running unless you
have to. If you have left the
engine running, the vehicle can
move suddenly. You or others
could be injured. To be sure the
vehicle will not move, even when
you are on fairly level ground,
always set the parking brake and
move the shift lever to P (Park).
{WARNING
If the vehicle has a four-wheel
drive transfer case with a
N (Neutral) position, and the
transfer case is in N (Neutral), the
vehicle may roll, even if the
automatic transmission shift lever
is in P (Park). So, be sure the
transfer case is in a drive
gear—not in N (Neutral). Always
set the parking brake.
Follow the proper steps to be sure
the vehicle will not move. See
Shifting Into Park on page 9‑27.
If parking on a hill and pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑68.
Automatic
Transmission
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
If the 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.
Heavy Duty 6-Speed Automatic
Transmission Shown (Light Duty Similar)
See “Range Selection Mode” under
Manual Mode on page 9‑35.

Black plate (32,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-32 Driving and Operating
P (Park):This position locks the
rear wheels. It is the best position to
use when starting the engine
because the vehicle cannot move
easily. When parked on a hill,
especially when the vehicle has a
heavy load, you might notice an
increase in the effort to shift out of
P (Park). See “Torque Lock” under
Shifting Into Park on page 9‑27 for
more information.
{WARNING
It is dangerous to get out of the
vehicle if the shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the vehicle when the
engine is running unless you
have to. If you have left the
engine running, the vehicle can
move suddenly. You or others
could be injured. To be sure the
vehicle will not move, even when
you are on fairly level ground,
(Continued)
WARNING (Continued)
always set the parking brake and
move the shift lever to P (Park).
SeeShifting Into Park on
page 9‑27. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑68.
{WARNING
If the vehicle has a four-wheel
drive transfer case with a
N (Neutral) position, and the
transfer case is in N (Neutral), the
vehicle will be free to roll —even
if the shift lever is in P (Park). Be
sure the transfer case is in a drive
gear, Two-Wheel Drive High or
Four-Wheel Drive High or
Four-Wheel Drive Low —not in
N (Neutral). See Shifting Into Park
on page 9‑27. Always set the
parking brake. R (Reverse):
Use this gear to
back up.
Notice: Shifting to R (Reverse)
while the vehicle is moving
forward could damage the
transmission. The repairs would
not be covered by the vehicle
warranty. Shift to R (Reverse) only
after the vehicle is stopped.
To rock the vehicle back and forth to
get out of snow, ice, or sand without
damaging the transmission, see If
the Vehicle Is Stuck on page 9‑15.
N (Neutral): In this position, the
engine does not connect with the
wheels. To restart the engine when
the vehicle is already moving, use
N (Neutral) only. Also, use
N (Neutral) when the vehicle is
being towed.

Black plate (38,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-38 Driving and Operating
If the lights do not come on, you
should take the vehicle to your
dealer for service. An indicator light
will flash while shifting. It will stay on
when the shift is completed. If for
some reason the transfer case
cannot make a requested shift, it will
return to the last chosen setting.
2
m(Two-Wheel Drive High):This
setting is used for driving in most
street and highway situations. The
front axle is not engaged in
two-wheel drive. This setting also
provides the best fuel economy.
AUTO (Automatic Four-Wheel
Drive): This setting is ideal for use
when road surface traction
conditions are variable. When
driving the vehicle in AUTO, the
front axle is engaged, and the
vehicle's power is sent to the front
and rear wheels automatically
based on driving conditions. Driving
in this mode results in slightly lower
fuel economy than Two-Wheel
Drive High. 4
m(Four-Wheel Drive High):
Use
the Four-Wheel Drive High position
when you need extra traction, such
as on snowy or icy roads or in most
off-road situations. This setting also
engages your front axle to help
drive the vehicle. This is the best
setting to use when plowing snow.
4
n(Four-Wheel Drive Low): This
setting also engages the front axle
and delivers extra torque. You may
never need this setting. It sends
maximum power to all four wheels.
You might choose Four-Wheel Drive
Low if you are driving off-road in
deep sand, deep mud, deep snow,
and while climbing or descending
steep hills.
The vehicle has StabiliTrak. Shifting
into Four-Wheel Drive Low will turn
Traction Control and StabiliTrak off.
See StabiliTrak
®System on
page 9‑46.
{WARNING
Shifting the transfer case to
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). You or someone else
could be seriously injured. Be
sure to set the parking brake
before placing the transfer case in
N (Neutral). See Parking Brake on
page 9‑45.
N (Neutral): Shift the vehicle's
transfer case to N (Neutral) only
when towing the vehicle. See
Recreational Vehicle Towing on
page 10‑93 orTowing the Vehicle
on page 10‑93 for more information.
If the SERVICE 4 WHEEL DRIVE
message stays on, you should take
the vehicle to your dealer for
service. See “SERVICE 4 WHEEL
DRIVE” message under
Transmission Messages on
page 5‑45.

Black plate (40,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-40 Driving and Operating
Shifting Out of Four-Wheel
Drive Low
To shift from Four-Wheel Drive Low
to Four-Wheel Drive High, AUTO,
or Two-Wheel Drive High, the
vehicle must be stopped or moving
less than 5 km/h (3 mph) with the
transmission in N (Neutral) and the
ignition in ON/RUN. The preferred
method for shifting out of
Four-Wheel Drive Low is to have
your vehicle moving 1.6 to 3.2 km/h
(1 to 2 mph). Turn the knob to the
Four-Wheel Drive High, AUTO,
or Two-Wheel Drive High position.
You must wait for the Four-Wheel
Drive High, AUTO, or Two-Wheel
Drive High indicator light to stop
flashing and remain on before
shifting the transmission into gear.
Notice:Shifting the transmission
into gear before the requested
mode indicator light has stopped
flashing could damage the transfer case. To help avoid
damaging the vehicle, always wait
for the mode indicator lights to
stop flashing before shifting the
transmission into gear.
The vehicle may have significant
engagement noise and bump when
shifting between Four-Wheel Drive
Low and Four-Wheel Drive High
ranges or from N (Neutral) while the
engine is running.
If the knob is turned to the
Four-Wheel Drive High, AUTO,
or Two-Wheel Drive High switch
position when the vehicle is in gear
and/or moving more than 5 km/h
(3 mph), the Four-Wheel Drive High,
AUTO, or Two-Wheel Drive High
indicator light will flash for
30 seconds but will not complete the
shift. With the vehicle moving less
than 5 km/h (3 mph) and the
transmission is in N (Neutral),
attempt the shift again.Shifting into Neutral
To shift the transfer case to
N (Neutral) do the following:
1. Make sure the vehicle is parked
so that it will not roll.
2. Set the parking brake and apply the regular brake pedal. See
Parking Brake on page 9‑45 for
more information.
3. Start the vehicle or turn the ignition to ON/RUN.
4. Put the transmission in N (Neutral).
5. Shift the transfer case to Two-Wheel Drive High.

Black plate (41,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-41
6. Turn the transfer case dialclockwise to N (Neutral) until it
stops and hold it there until the
N (Neutral) light starts blinking.
This will take at least
10 seconds. Then slowly release
the dial to the Four‐Wheel Drive
Low position. The N (Neutral)
light will come on when the
transfer case shift to N (Neutral)
is complete.
7. If the engine is running, verify that the transfer case is in
N (Neutral) by shifting the
transmission to R (Reverse) for
one second, then shift the
transmission to D (Drive) for
one second.
8. Turn the ignition to ACC/ ACCESSORY, which will turn the
engine off. 9. Place the transmission shift
lever in P (Park).
10. Release the parking brake prior to moving the vehicle.
11. Turn the ignition to LOCK/OFF.
Shifting Out of Neutral
To shift out of N Neutral do the
following:
1. Set the parking brake and apply the regular brake pedal.
2. Turn the ignition to ON/RUN with the engine off, and shift the
transmission to N (Neutral).
3. Turn the transfer case dial to the desired transfer case shift
position (Two-Wheel Drive High,
Four-Wheel Drive High,
or AUTO).
After the transfer case has
shifted out of N (Neutral), the
N (Neutral) light will go out. 4. Release the parking brake prior
to moving the vehicle.
Notice: Shifting the transmission
into gear before the Four-Wheel
Drive Low indicator light has
stopped flashing could damage
the transfer case. To help avoid
damaging the vehicle, always wait
for the Four-Wheel Drive Low
indicator light to stop flashing
before shifting the transmission
into gear.
5. Start the engine and shift the transmission to the desired
position.
Excessively shifting the transfer
case into or out of the different
modes may cause the transfer case
to enter the shift protection mode.
This will protect the transfer case
from possible damage and will only
allow the transfer case to respond to
one shift per 10 seconds. The
transfer case may stay in this mode
for up to three minutes.

Black plate (45,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-45
Braking in Emergencies
ABS allows the driver to steer and
brake at the same time. In many
emergencies, steering can help
more than even the very best
braking.
Parking Brake
Set the parking brake by holding the
regular brake pedal down, then
pushing down the parking brake
pedal.If the ignition is on, the brake
system warning light will come on.
See
Brake System Warning Light on
page 5‑23.
Notice: Driving with the parking
brake on can overheat the brake
system and cause premature
wear or damage to brake system
parts. Make sure that the parking
brake is fully released and the
brake warning light is off before
driving.
To release the parking brake, hold
the regular brake pedal down, then
push down momentarily on the
parking brake pedal until you feel
the pedal release. Slowly pull your
foot up off the parking brake pedal.
If the parking brake is not released
when you begin to drive, the brake
system warning light will flash and a
chime will sound warning you that
the parking brake is still on.
If you are towing a trailer and are
parking on a hill, see Driving
Characteristics and Towing Tips on
page 9‑68.
Brake Assist
This vehicle has a brake assist
feature designed to assist the driver
in stopping or decreasing vehicle
speed in emergency driving
conditions. This feature uses the
stability system hydraulic brake
control module to supplement the
power brake system under
conditions where the driver has
quickly and forcefully applied the
brake pedal in an attempt to quickly
stop or slow down the vehicle. The
stability system hydraulic brake
control module increases brake
pressure at each corner of the
vehicle until the ABS activates.
Minor brake pedal pulsation or
pedal movement during this time is
normal and the driver should
continue to apply the brake pedal as
the driving situation dictates. The
brake assist feature will
automatically disengage when the
brake pedal is released or brake
pedal pressure is quickly
decreased.

Black plate (53,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-53
Ending Cruise Control
There are three ways to end cruise
control:
.To disengage cruise control,
step lightly on the brake pedal.
.Press the[on the steering
wheel.
.To turn off the cruise control,
press
Ion the steering wheel.
Erasing Speed Memory
The cruise control set speed is
erased from memory by pressing
the
Ibutton or if the ignition is
turned off.
Object Detection
Systems
Ultrasonic Parking Assist
If available, the Ultrasonic Rear
Parking Assist (URPA) system uses
sensors on the rear bumper to
assist with parking and avoiding
objects while in R (Reverse).
{WARNING
The URPA system does not
detect pedestrians, bicyclists,
animals, or any other objects
located below the bumper or that
are too close or too far from the
vehicle. To prevent injury, death,
or vehicle damage, even with
URPA, always check behind the
vehicle and check all mirrors
before backing.
How the System Works
URPA comes on automatically
when the shift lever is moved into
R (Reverse). A single tone sounds
to indicate the system is working.
URPA operates only at speeds less
than 8 km/h (5 mph).
An obstacle is indicated by
audible beeps. The time between
the beeps gets shorter as the
vehicle approaches the obstacle.
A continuous tone is heard when
the distance is less than
30 cm (12 in).
To be detected, objects must be at
least 25 cm (10 in) off the ground
and below liftgate level. Objects
must also be within 2.5 m (8 ft) from
the rear bumper. This distance may
be less during warmer or humid
weather.

Black plate (70,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-70 Driving and Operating
Making Turns
Notice:Making very sharp turns
while trailering could cause the
trailer to come in contact with the
vehicle. The vehicle could be
damaged. Avoid making very
sharp turns while trailering.
When turning with a trailer, make
wider turns than normal. Do this
so the trailer will not strike soft
shoulders, curbs, road signs, trees
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance.
If the trailer turn signal bulbs burn
out, the arrows on the instrument
panel will still flash for turns. It is
important to check occasionally to
be sure the trailer bulbs are still
working.
Driving on Grades
Reduce speed and shift to a lower
gear before starting down a long or
steep downgrade. If the transmission is not shifted down, the
brakes might get hot and no longer
work well.
Vehicles can tow in D (Drive). Shift
the transmission to a lower gear if
the transmission shifts too often
under heavy loads and/or hilly
conditions.
The tow/haul mode may be used if
the transmission shifts too often.
See
Tow/Haul Mode Light on
page 5‑25.
When towing at high altitude on
steep uphill grades, consider the
following: Engine coolant will boil at
a lower temperature than at normal
altitudes. If the engine is turned off
immediately after towing at high
altitude on steep uphill grades, the
vehicle may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
automatic transmission in P (Park)
for a few minutes before turning the engine off. If the overheat warning
comes on, see
Engine Overheating
on page 10‑21.
Parking on Hills
{WARNING
Parking the vehicle on a hill with
the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface.
If parking the rig on a hill:
1. Press the brake pedal, but do not shift into P (Park) yet. Turn
the wheels into the curb if facing
downhill or into traffic if facing
uphill.
2. Have someone place chocks under the trailer wheels.

Black plate (71,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-71
3. When the wheel chocks are inplace, release the regular brakes
until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parking brake and shift
into P (Park).
5. If the vehicle is four-wheel-drive and has a two-speed transfer
case, be sure the transfer case
is in a drive gear and not in
N (Neutral).
6. Release the brake pedal.
{WARNING
It can be dangerous to get out of
the vehicle if the shift lever is not
fully in P (Park) with the parking
brake firmly set. The vehicle
can roll.
If the engine has been left
running, the vehicle can move
suddenly. You or others could be
injured. To be sure the vehicle will (Continued)
WARNING (Continued)
not move, even when on fairly
level ground, use the steps that
follow.
Always put the shift lever fully in
P (Park) with the parking brake
firmly set.
If the transfer case on a
four-wheel-drive vehicle is in
N (Neutral), the vehicle will be
free to roll, even if the shift lever
is in P (Park). Be sure the transfer
case is in a drive gear —not in
N (Neutral).
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear. 4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is
clear of the chocks.
7. Stop and have someone pick up and store the chocks.
Maintenance When Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule on
page 11‑3. Things that are
especially important in trailer
operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system and
brake system. It is a good idea to
inspect these before and during
the trip.
Check periodically to see that all
hitch nuts and bolts are tight.

Black plate (79,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-79
brake controller is installed, the
ITBC must be disconnected. Do not
power both ITBC and aftermarket
controllers to control the trailer
brakes at the same time.
Tow/Haul Mode
Pressing this button at the end of
the shift lever turns on and off the
tow/haul mode.
This indicator light on the instrument
panel cluster comes on when the
tow/haul mode is on.Tow/Haul is a feature that assists
when pulling a heavy trailer or a
large or heavy load. See
Tow/Haul
Mode on page 9‑36 for more
information.
Tow/Haul is designed to be most
effective when the vehicle and
trailer combined weight is at least
75 percent of the vehicle's Gross
Combined Weight Rating (GCWR).
See “Weight of the Trailer” earlier in
the section. Tow/Haul is most useful
under the following driving
conditions:
.When pulling a heavy trailer or a
large or heavy load through
rolling terrain.
.When pulling a heavy trailer or a
large or heavy load in stop and
go traffic.
.When pulling a heavy trailer or a
large or heavy load in busy
parking lots where improved low
speed control of the vehicle is
desired. Operating the vehicle in Tow/Haul
when lightly loaded or with no trailer
at all will not cause damage.
However, there is no benefit to the
selection of Tow/Haul when the
vehicle is unloaded. Such a
selection when unloaded may
result in unpleasant engine and
transmission driving characteristics
and reduced fuel economy. Tow/
Haul is recommended only when
pulling a heavy trailer or a large or
heavy load.
Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for electric trailer brakes.