2012 GMC YUKON automatic transmission

Black plate (4,1)GMC Yukon/Yukon XL Owner Manual - 2012
6-4 Lighting
When it begins to get dark, the
automatic headlamp system
switches from DRL to the
headlamps.
To turn off the DRL lamps, turn the
exterior lamps control to the OFF
position and then release. For
vehicles first sold in Canada, the
transmission must be in the P (Park)
position before the DRL lamps can
be turned off.
Automatic Headlamp
System
When it is dark enough outside, the
automatic headlamp system turns
on the headlamps at the normal
brightness, along with the taillamps,
sidemarker, parking lamps, and the
instrument panel lights. The radio
lights will also be dim.To turn off the automatic headlamp
system, turn the exterior lamps
switch to the off position and then
release it. For vehicles first sold in
Canada, the transmission must be
in the P (Park) position before the
automatic headlamp system can be
turned off.
The vehicle has a light sensor
located on the top of the instrument
panel which regulates when the
automatic headlamps turn on. Do
not cover the sensor, otherwise the
headlamps will come on whenever
the ignition is on.The system may also turn on the
headlamps when driving through a
parking garage or heavy overcast
weather. This is normal.
There is a delay in the transition
between the daytime and nighttime
operation of the Daytime Running
Lamps (DRL) and the automatic
headlamp systems so that driving
under bridges or bright overhead
street lights does not affect the
system. The DRL and automatic
headlamp system are only affected
when the light sensor detects a
change in lighting lasting longer
than the delay.

Black plate (1,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-1
Driving and
Operating
Driving Information
Distracted Driving . . . . . . . . . . . . . 9-2
Defensive Driving . . . . . . . . . . . . . 9-3
Drunk Driving . . . . . . . . . . . . . . . . . 9-3
Control of a Vehicle . . . . . . . . . . . 9-3
Braking . . . . . . . . . . . . . . . . . . . . . . . 9-4
Steering . . . . . . . . . . . . . . . . . . . . . . . 9-4
Off-Road Recovery . . . . . . . . . . . . 9-5
Loss of Control . . . . . . . . . . . . . . . . 9-5
Off-Road Driving . . . . . . . . . . . . . . 9-6
Driving on Wet Roads . . . . . . . . 9-11
Highway Hypnosis . . . . . . . . . . . 9-12
Hill and Mountain Roads . . . . . 9-13
Winter Driving . . . . . . . . . . . . . . . 9-13
If the Vehicle Is Stuck . . . . . . . . 9-15
Vehicle Load Limits . . . . . . . . . . 9-16
Starting and Operating
New Vehicle Break-In . . . . . . . . 9-21
Adjustable Throttle and BrakePedal . . . . . . . . . . . . . . . . . . . . . . . 9-22
Ignition Positions . . . . . . . . . . . . 9-22 Starting the Engine . . . . . . . . . . 9-24
Engine Heater . . . . . . . . . . . . . . . 9-26
Retained Accessory
Power (RAP) . . . . . . . . . . . . . . . 9-27
Shifting Into Park . . . . . . . . . . . . 9-27
Shifting out of Park . . . . . . . . . . 9-28
Parking over Things
That Burn . . . . . . . . . . . . . . . . . . 9-29
Active Fuel Management
®. . . 9-29
Engine Exhaust
Engine Exhaust . . . . . . . . . . . . . . 9-30
Running the Vehicle While Parked . . . . . . . . . . . . . . . . . . . . . 9-30
Automatic Transmission
Automatic Transmission . . . . . 9-31
Manual Mode . . . . . . . . . . . . . . . . 9-35
Tow/Haul Mode . . . . . . . . . . . . . . 9-36
Drive Systems
Four-Wheel Drive (Two SpeedAutomatic
Transfer Case) . . . . . . . . . . . . . 9-37
Four-Wheel Drive (Single Speed Automatic
Transfer Case) . . . . . . . . . . . . . 9-42
Brakes
Antilock BrakeSystem (ABS) . . . . . . . . . . . . . . 9-44
Parking Brake . . . . . . . . . . . . . . . 9-45
Brake Assist . . . . . . . . . . . . . . . . . 9-45
Hill Start Assist (HSA) . . . . . . . 9-46
Ride Control Systems
StabiliTrak®System . . . . . . . . . 9-46
Locking Rear Axle . . . . . . . . . . . 9-49
Continuous Damping Control (CDC) . . . . . . . . . . . . . . 9-50
Automatic Level Control . . . . . 9-50
Cruise Control
Cruise Control . . . . . . . . . . . . . . . 9-51
Object Detection Systems
Ultrasonic Parking Assist . . . . 9-53
Side Blind Zone Alert (SBZA) . . . . . . . . . . . . . . . 9-54
Rear Vision Camera (RVC) . . . . . . . . . . . . . 9-57
Fuel
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . 9-61
Recommended Fuel . . . . . . . . . 9-62
Gasoline Specifications (U.S.and Canada Only) . . . . . . . . . . 9-62

Black plate (8,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-8 Driving and Operating
When driving on hills:
.Use a low gear and keep a firm
grip on the steering wheel.
.Maintain a slow speed.
.When possible, drive straight up
or down the hill.
.Slow down when approaching
the top of the hill.
.Use headlamps even during the
day to make the vehicle more
visible.
{WARNING
Driving to the top of a hill at high
speed can cause an accident.
There could be a drop-off,
embankment, cliff, or even
another vehicle. You could be
seriously injured or killed. As you
near the top of a hill, slow down
and stay alert.
.Never go downhill forward or
backward with either the
transmission or transfer case in
N (Neutral). The brakes could
overheat and you could lose
control.
{WARNING
If the vehicle has the two‐speed
automatic transfer case, shifting
the transfer case to N (Neutral)
can cause your vehicle to roll
even if the transmission is in
P (Park). This is because the
N (Neutral) position on the
transfer case overrides the
transmission. You or someone
else could be injured. If leaving
the vehicle, set the parking brake
and shift the transmission to
P (Park). Shift the transfer case to
any position but N (Neutral).
.When driving down a hill, keep
the vehicle headed straight
down. Use a low gear because
the engine will work with the
brakes to slow the vehicle and
help keep the vehicle under
control.
{WARNING
Heavy braking when going down
a hill can cause your brakes to
overheat and fade. This could
cause loss of control and you or
others could be injured or killed.
Apply the brakes lightly when
descending a hill and use a low
gear to keep vehicle speed under
control.
If the vehicle stalls on a hill:
1. Apply the brakes to stop the vehicle, and then apply the
parking brake.

Black plate (9,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-9
2. Shift into P (Park) and thenrestart the engine.
.If driving uphill when the
vehicle stalls, shift to
R (Reverse), release the
parking brake, and back
straight down.
.Never try to turn the vehicle
around. If the hill is steep
enough to stall the vehicle,
it is steep enough to cause
it to roll over.
.If you cannot make it up the
hill, back straight down
the hill.
.Never back down a hill in
N (Neutral) using only the
brake.
.The vehicle can roll
backward quickly and you
could lose control.
.If driving downhill when the
vehicle stalls, shift to a
lower gear, release the
parking brake, and drive
straight down the hill. 3. If the vehicle cannot be restarted
after stalling, set the parking
brake, shift an automatic
transmission into P (Park), and
turn the vehicle off.
3.1. Leave the vehicle and
seek help.
3.2. Stay clear of the path the vehicle would take if it
rolled downhill.
.Avoid turns that take the vehicle
across the incline of the hill.
A hill that can be driven straight
up or down might be too steep to
drive across. Driving across an
incline puts more weight on the
downhill wheels which could
cause a downhill slide or a
rollover.
.Surface conditions can be a
problem. Loose gravel, muddy
spots, or even wet grass can
cause the tires to slip sideways, downhill. If the vehicle slips
sideways, it can hit something
that will trip it
–a rock, a
rut, etc. –and roll over.
.Hidden obstacles can make the
steepness of the incline more
severe. If a rock is driven across
with the uphill wheels, or if the
downhill wheels drop into a rut
or depression, the vehicle can tilt
even more.
.If an incline must be driven
across, and the vehicle starts to
slide, turn downhill. This should
help straighten out the vehicle
and prevent the side slipping.
{WARNING
Getting out of the vehicle on the
downhill side when stopped
across an incline is dangerous.
If the vehicle rolls over, you could
be crushed or killed. Always get
out on the uphill side of the
vehicle and stay well clear of
the rollover path.

Black plate (15,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-15
WARNING (Continued)
For more information about
carbon monoxide, seeEngine
Exhaust on page 9‑30.
Run the engine for short periods
only as needed to keep warm, but
be careful.
To save fuel, run the engine for only
short periods as needed to warm
the vehicle and then shut the engine
off and close the window most of
the way to save heat. Repeat this
until help arrives but only when you
feel really uncomfortable from the
cold. Moving about to keep warm
also helps.
If it takes some time for help to
arrive, now and then when you run
the engine, push the accelerator
pedal slightly so the engine runs
faster than the idle speed. This
keeps the battery charged to restart
the vehicle and to signal for help
with the headlamps. Do this as little
as possible to save fuel.
If the Vehicle Is Stuck
Slowly and cautiously spin the
wheels to free the vehicle when
stuck in sand, mud, ice, or snow.
If the vehicle has a traction system,
it can often help to free a stuck
vehicle. Refer to the vehicle's
traction system in the Index. If stuck
too severely for the traction system
to free the vehicle, turn the traction
system off and use the rocking
method.
{WARNING
If the vehicle's tires spin at high
speed, they can explode, and you
or others could be injured. The
vehicle can overheat, causing an
engine compartment fire or other
damage. Spin the wheels as little
as possible and avoid going
above 55 km/h (35 mph). For information about using tire
chains on the vehicle, see
Tire
Chains on page 10‑70.
Rocking the Vehicle to Get
it Out
Turn the steering wheel left and
right to clear the area around the
front wheels. For four-wheel-drive
vehicles, shift into Four‐Wheel High
or, if the vehicle has a two‐speed
automatic transfer case, Four‐Wheel
Low. For vehicles with StabiliTrak
®,
turn the traction control part of the
system off. Shift back and forth
between R (Reverse) and a forward
gear, spinning the wheels as little as
possible. To prevent transmission
wear, wait until the wheels stop
spinning before shifting gears.

Black plate (22,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-22 Driving and Operating
Adjustable Throttle and
Brake Pedal
On vehicles with this feature, you
can change the position of the
throttle and brake pedals.
No adjustment to the pedals can
be made when the vehicle is in
R (Reverse) or while using cruise
control.
The control used to adjust the
pedals is located on the instrument
panel below the climate control
system.
Press the bottom of the control to
move the pedals closer. Press the
top of the control to move the
pedals away.Before you start driving, fully press
the brake pedal to confirm the
adjustment is right for you. While
driving, make only small
adjustments.
The vehicle may have a memory
function which lets pedal settings be
saved and recalled. See
Memory
Seats on page 3‑7.
Ignition Positions
The ignition switch has four different
positions. To shift out of P (Park), the ignition
must be in ON/RUN or ACC/
ACCESSORY and the regular brake
pedal must be applied.
A (STOPPING THE ENGINE/
LOCK/OFF):
When the vehicle is
stopped, turn the ignition switch to
LOCK/OFF to turn the engine off.
Retained Accessory Power (RAP)
will remain active. See Retained
Accessory Power (RAP) on
page 9‑27.
This position locks the ignition.
It also locks the transmission on
automatic transmission vehicles.
The key can be removed in
LOCK/OFF.
Do not turn the engine off when the
vehicle is moving. This will cause a
loss of power assist in the brake
and steering systems and disable
the airbags.

Black plate (23,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-23
If the vehicle must be shut off in an
emergency:
1. Brake using a firm and steadypressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. After shifting
to N (Neutral), firmly apply the
brakes and steer the vehicle to a
safe location.
3. Come to a complete stop, shift to P (Park), and turn the ignition
to LOCK/OFF. On vehicles with
an automatic transmission, the
shift lever must be in P (Park) to
turn the ignition switch to the
LOCK/OFF position.
4. Set the parking brake. See Parking Brake on page 9‑45.{WARNING
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering
systems and disable the airbags.
While driving, only shut the
vehicle off in an emergency.
If the vehicle cannot be pulled over,
and must be shut off while driving,
turn the ignition to ACC/
ACCESSORY.
The steering can bind with the
wheels turned off center. If this
happens, move the steering wheel
from right to left while turning the
key to ACC/ACCESSORY. If this
doesn't work, then the vehicle needs
service. Notice:
Using a tool to force the
key to turn in the ignition could
cause damage to the switch or
break the key. Use the correct
key, make sure it is all the way in,
and turn it only with your hand.
If the key cannot be turned by
hand, see your dealer.
B (ACC/ACCESSORY): This
position lets things like the radio
and the windshield wipers operate
while the engine is off. Use this
position if the vehicle must be
pushed or towed.
C (ON/RUN): This position can be
used to operate the electrical
accessories and to display some
instrument panel cluster warning
and indicator lights. This position
can also be used for service and
diagnostics, and to verify the proper
operation of the malfunction
indicator lamp as may be required
for emission inspection purposes.

Black plate (24,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-24 Driving and Operating
The switch stays in this position
when the engine is running. The
transmission is also unlocked in this
position on automatic transmission
vehicles.
If you leave the key in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. You may not be able to
start the vehicle if the battery is
allowed to drain for an extended
period of time.
D (START):This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.
A warning tone will sound when the
driver door is opened and the
ignition is in ACC/ACCESSORY or
LOCK/OFF, and the key is in the
ignition.Starting the Engine
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Move the shift lever to P (Park) or
N (Neutral). The engine will not start
in any other position. To restart the
engine when the vehicle is already
moving, use N (Neutral) only.
Notice: Do not try to shift to
P (Park) if the vehicle is moving.
If you do, you could damage the
transmission. Shift to P (Park)
only when the vehicle is stopped.
Starting Procedure
1. With your foot off the accelerator pedal, turn the ignition to START.
When the engine starts, let go of
the key. The idle speed will go
down as the engine warms. 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. The 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 start and the key is held in
START, 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.