service GMC YUKON 2012 Workshop Manual

Black plate (47,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-47
StabiliTrak is on automatically
whenever the vehicle is started. To
assist with directional control of the
vehicle, the system should always
be left on. Trailer Sway Control
(TSC) is also on automatically when
the vehicle is started. SeeTrailer
Sway Control (TSC) on page 9‑86
for more information.
When the vehicle is started and
begins to move, the system
performs several diagnostic checks
to insure there are no problems.
The system may be heard or felt
while it is working. This is normal
and does not mean there is a
problem with the vehicle. The
system should initialize before the
vehicle reaches 32 km/h (20 mph).
In some cases, it may take
approximately 3.2 km (2 mi) of
driving before the system initializes. If cruise control is being used when
StabiliTrak activates, the cruise
control automatically disengages.
The cruise control can be
re-engaged when road conditions
allow. See
Cruise Control on
page 9‑51.
If the system fails to turn on or
activate, the StabiliTrak light along
with a message will be displayed on
the Driver Information Center (DIC).
If a DIC message appears, make
sure the StabiliTrak system has not
been turned off using the Traction
Control System (TCS)/StabiliTrak
button. Then turn the vehicle off,
wait 15 seconds, and then turn it
back on again to reset the system.
If any of the messages still appear
on the DIC, the vehicle should be
taken in for service. For more
information on the DIC messages,
see Ride Control System Messages
on page 5‑43.
The StabiliTrak light will flash on the
instrument panel cluster when the
system or the TSC feature is both
on and activated.
The system may be heard or felt
while it is working; this is normal.
The TCS/StabiliTrak button is
located on the instrument panel.
The traction control part of
StabiliTrak can be turned off by
pressing and releasing the TCS/
StabiliTrak button if both systems
(traction control and StabiliTrak)
were previously on.

Black plate (49,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-49
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 the wheel(s) of one axle
is allowed to spin excessively
while the StabiliTrak
®, ABS, brake
warning lights, and any relevant
DIC messages are displayed, the
transfer case could be damaged.
The repairs would not be covered
by the vehicle warranty. Reduce
engine power and do not spin the
wheel(s) excessively while these
lights and messages are
displayed.
The TCS 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, a reduction in
acceleration may be noticed, or a
noise or vibration may be heard.
This is normal.
If cruise control is being used when
the system activates, the StabiliTrak
light will flash and cruise control will
automatically disengage. Cruise
control may be reengaged when
road conditions allow. See
Cruise
Control on page 9‑51.
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, see your
dealer for service.
Non-hybrid vehicles with StabiliTrak
have a Trailer Sway Control (TSC)
feature. See Trailer Sway Control
(TSC) on page 9‑86. Non-hybrid vehicles with StabiliTrak
have a Hill Start Assist (HSA)
feature. See
Hill Start Assist (HSA)
on page 9‑46.
Adding non‐dealer accessories can
affect the vehicle's performance.
See Accessories and Modifications
on page 10‑3.
Locking Rear Axle
Vehicles with a locking rear axle can
give more traction on snow, mud,
ice, sand, or gravel. It works like a
standard axle most of the time, but
when traction is low, this feature will
allow the rear wheel with the most
traction to move the vehicle.

Black plate (54,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-54 Driving and Operating
Turning the System On and Off
Press this button, located next to
the radio, to disable URPA.
The indicator light comes on and
PARK ASSIST OFF displays on the
Driver Information Center (DIC).
SeeObject Detection System
Messages on page 5‑42.
When the System Does Not
Seem to Work Properly
The following messages may be
displayed on the DIC:
SERVICE PARK ASSIST: this
message occurs, take the vehicle to
your dealer for repair. PARK ASSIST OFF:
This message
occurs if the driver disables the
system or if the vehicle is driven
above 8 km/h (5 mph) in
R (Reverse).
PARK ASST BLOCKED SEE
OWNERS MANUAL: This
message can occur under the
following conditions:
.The ultrasonic sensors are not
clean. Keep the rear bumper
free of mud, dirt, snow, ice,
slush, and frost. The message
may not clear until frost or ice
has melted all around and inside
the sensor.
.A trailer is attached to the
vehicle, or a bicycle or an object
hanging out of the liftgate during
the current or last drive cycle.
URPA will return to normal
operation after it is determined
the object is removed. This
could take a few drive cycles.
.A tow bar is attached to the
vehicle. Other conditions may affect system
performance, such as vibrations
from a jackhammer or the
compression of air brakes on a
very large truck.
Side Blind Zone
Alert (SBZA)
If available, the Side Blind Zone
Alert system is a lane changing aid
that assists drivers with avoiding
crashes that occur with vehicles in
the side blind zones.
{WARNING
SBZA does not detect vehicles
rapidly approaching outside of the
side blind zones, pedestrians,
bicyclists, or animals. Failure to
use proper care when changing
lanes may result in injury, death,
or vehicle damage. Always check
for other vehicles and use the
turn signals when changing lanes.

Black plate (55,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-55
SBZA Detection Zones
The SBZA sensor covers a zone of
approximately one lane over from
both sides of the vehicle, 3.5 m
(11 ft). This zone starts at each side
mirror and goes back approximately
5.0 m (16 ft). The height of the
zone is approximately between
0.5 m (1.5 ft) and 2.0 m (6 ft) off the
ground.
Use caution while changing lanes
when towing a trailer, as the SBZA
detection zones do not change
when a trailer is towed.How the System Works
The SBZA symbol lights up in the
side mirrors when the system
detects a vehicle in the side blind
zone, indicating it may be unsafe to
change lanes. Before making a lane
change, check the SBZA display,
check all mirrors, glance over your
shoulder, and use the turn signals.
Left Side Mirror
DisplayRight Side Mirror Display
When the vehicle is started, both
outside mirror SBZA displays will
briefly come on to indicate the
system is operating. When the
vehicle is moving forward, the left or
right side mirror display will light up
if a vehicle is detected in that blind
zone. If the turn signal is activated
and a vehicle is also detected on the same side, the display will flash
to give you extra warning not to
change lanes.
At speeds greater then 32 km/h
(20 mph), SBZA displays may come
on when approaching or passing
other vehicles. SBZA displays may
come on when a passed vehicle
remains in or drops back into the
detection zone. SBZA can be
disabled through the Driver
Information Center (DIC). See
Driver
Information Center (DIC) on
page 5‑29. If SBZA is disabled by
the driver, the SBZA mirror displays
will not light up.
When the System Does Not Seem
To Work Properly
Missed alerts can occur under
normal circumstances and will
increase in wet conditions. The
system does not need to be
serviced. SBZA is designed to
ignore stationary objects; however,
the system may occasionally light
up due to guard rails, signs, trees,

Black plate (56,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-56 Driving and Operating
shrubs, and other stationary objects.
This is normal system operation, the
vehicle does not need service.
If the SBZA displays do not light up
when the system is on and vehicles
are in the blind zone, the system
may need service. Take the vehicle
to your dealer.
SBZA does not operate when the
SBZA sensors in the left or right
corners of the rear bumper are
covered with mud, dirt, snow, ice,
slush, or in heavy rainstorms. For
cleaning instructions, see“Washing
the Vehicle” underExterior Care on
page 10‑98. If the DIC still displays
the SIDE BLIND ZONE SYS.
UNAVAILABLE message after
cleaning the bumper, see your
dealer.
The SBZA displays may remain on
if a trailer is attached to the vehicle,
or a bicycle or object is extending
out to either side of the vehicle.
When SBZA is disabled for any
reason other than the driver turning
it off, it cannot be turned back on. The SIDE BLIND ZONE ALERT ON
option will not be selectable if the
conditions for normal system
operation are not met.
SBZA Error Messages
The following messages may
appear in the DIC:
SIDE BLIND ZONE ALERT
SYSTEM OFF:
This message
indicates that the driver has turned
the system off.
SIDE BLIND ZONE SYS.
UNAVAILABLE: This message
indicates that the SBZA system is
disabled either because the sensor
is blocked and cannot detect
vehicles in your blind zone, or the
vehicle is passing through an open
field of view area, such as the
desert, where there is insufficient
data for operation. This message
may also activate during heavy rain
or due to road spray. The vehicle
does not need service. For cleaning,
see “Washing the Vehicle” under
Exterior Care on page 10‑98. SERVICE SIDE BLIND ZONE
ALERT SYSTEM:
If this message
appears, both SBZA displays will
remain on indicating there is a
problem with the SBZA system.
If these displays remain on after
continued driving, the system needs
service. Take the vehicle to your
dealer.
FCC Information
See Radio Frequency Statement on
page 13‑16 for information
regarding Part 15 of the Federal
Communications Commission (FCC)
rules and Industry Canada
Standards RSS-GEN/210/220/310.
Frequency of operation:
24.05GHz –24.25GHz
Field Strength: Not greater than
2.5V/m peak (0.25V/m average) at a
distance of 3m
The manufacturer is not responsible
for any radio or TV interference
caused by unauthorized
modifications to this equipment.

Black plate (62,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-62 Driving and Operating
Vehicles that have a FlexFuel badge
and a yellow fuel cap can use either
unleaded gasoline or ethanol fuel
containing up to 85% ethanol (E85).
SeeFuel E85 (85% Ethanol) on
page 9‑64. For all other vehicles,
use only the unleaded gasoline
described under Recommended
Fuel on page 9‑62.
Recommended Fuel
Use regular unleaded gasoline with
a posted octane rating of 87 or
higher. If the octane rating is less
than 87, an audible knocking noise,
commonly referred to as spark
knock, might be heard when driving.
If this occurs, use a gasoline rated
at 87 octane or higher as soon as
possible. If heavy knocking is heard
when using gasoline rated at
87 octane or higher, the engine
needs service.
Gasoline Specifications
(U.S. and Canada Only)
At a minimum, gasoline should
meet ASTM specification
D 4814 in the United States or
CAN/CGSB‐3.5 or 3.511 in Canada.
Some gasolines contain an
octane-enhancing additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). We recommend
against the use of gasolines
containing MMT. See Fuel Additives
on page 9‑63 for additional
information.
California Fuel
Requirements
If the vehicle is certified to meet
California Emissions Standards, it is
designed to operate on fuels that
meet California specifications. See
the underhood emission control
label. If this fuel is not available in
states adopting California Emissions
Standards, the vehicle will operate satisfactorily on fuels meeting
federal specifications, but emission
control system performance might
be affected. The malfunction
indicator lamp could turn on and the
vehicle might fail a smog‐check test.
See
Malfunction Indicator Lamp on
page 5‑21. If this occurs, return to
your authorized dealer for diagnosis.
If it is determined that the condition
is caused by the type of fuel used,
repairs might not be covered by the
vehicle warranty.
Fuels in Foreign
Countries
Never use leaded gasoline or any
other fuel not recommended in the
previous text on fuel. Costly repairs
caused by use of improper fuel
would not be covered by the vehicle
warranty.
To check the fuel availability, ask an
auto club, or contact a major oil
company that does business in the
country where you will be driving.

Black plate (63,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-63
Fuel Additives
To provide cleaner air, all gasolines
in the United States are now
required to contain additives that
help prevent engine and fuel system
deposits from forming, allowing the
emission control system to work
properly. In most cases, nothing
should have to be added to the 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
and avoid problems due to dirty
injectors or valves, look for gasoline
that is advertised as TOP TIER
Detergent Gasoline. Look for the
TOP TIER label on the fuel pump to
ensure gasoline meets enhanced
detergency standards developed by
the auto companies. A list of
marketers providing TOP TIER
Detergent Gasoline can be found at
www.toptiergas.com.For customers who do not use TOP
TIER Detergent Gasoline regularly,
one bottle of GM Fuel System
Treatment PLUS, added to the fuel
tank at every engine oil change, can
help clean deposits from fuel
injectors and intake valves. GM Fuel
System Treatment PLUS is the only
gasoline additive recommended by
General Motors. It is available at
your dealer.
Gasolines containing oxygenates,
such as ethers and ethanol, and
reformulated gasolines might be
available in your area. We
recommend that you use these
gasolines, if they comply with the
specifications described earlier.
However, E85 (85% ethanol) and
other fuels containing more than
15% ethanol must not be used in
vehicles that were not designed for
those fuels.
Notice:
This vehicle was not
designed for fuel that contains
methanol. Do not use fuel
containing methanol. It can
corrode metal parts in the fuel
system and also damage plastic
and rubber parts. That damage
would not be covered under the
vehicle warranty.
Some gasolines that are not
reformulated for low emissions can
contain an octane-enhancing
additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT); ask the attendant
where you buy gasoline whether the
fuel contains MMT. We recommend
against the use of such gasolines.
Fuels containing MMT can reduce
spark plug life and affect emission
control system performance. The
malfunction indicator lamp might
turn on. If this occurs, return to your
dealer for service.

Black plate (64,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-64 Driving and Operating
Fuel E85 (85% Ethanol)
Vehicles that have a FlexFuel badge
and a yellow fuel cap can use either
unleaded gasoline or ethanol fuel
containing up to 85% ethanol (E85).
For all other vehicles, use only the
unleaded gasoline described under
Recommended Fuel on page 9‑62.
We encourage the use of E85 in
vehicles that are designed to use it.
The ethanol in E85 is a“renewable”
fuel, meaning it is made from
renewable sources such as corn
and other crops.
Many service stations will not have
an 85% ethanol fuel (E85) pump
available. The U.S. Department of
Energy has an alternative fuels
website (www.afdc.energy.gov/afdc/
locator/stations/) that can help you find E85 fuel. Those stations that do
have E85 should have a label
indicating ethanol content. Do not
use the fuel if the ethanol content is
greater than 85%.
At a minimum, E85 should meet
ASTM Specification D 5798 or
CGSB Specification 3.512. Filling
the tank with fuel mixtures that
do not meet ASTM or CGSB
specifications can affect driveability
and could cause the malfunction
indicator lamp to come on. As the
outside temperature approaches
freezing, ethanol fuel distributors
should supply winter grade ethanol,
the same as with unleaded
gasoline.
It is best not to alternate repeatedly
between gasoline and E85. If you
do switch fuels, it is recommended
that you add as much fuel as
possible
—do not add less than
11 L (3 gal) when refueling. You
should drive the vehicle immediately
after refueling for at least 11 km
(7 mi) to allow the vehicle to adapt
to the change in ethanol
concentration.
E85 has less energy per liter
(gallon) than gasoline, so you will
need to refill the fuel tank more
often when using E85 than when
you are using gasoline. See Filling
the Tank on page 9‑65.
Notice: Some additives are not
compatible with E85 fuel and can
harm the vehicle's fuel system.
Do not add anything to E85.
Damage caused by additives
would not be covered by the
vehicle warranty.

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 (78,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-78 Driving and Operating
*The fuses for these two circuits are
installed in the underhood electrical
center, but the wires are not
connected. They should be
connected by your dealer or a
qualified service center.
Heavy-Duty Trailer Wiring Harness
Package
The vehicle is equipped with the
seven-wire trailer towing harness.
This harness with a seven-pin
universal trailer connector is
attached to a bracket on the hitch
platform.The seven-wire harness contains
the following trailer circuits:
.Yellow: Left Stop/Turn Signal
.Dark Green: Right Stop/Turn
Signal
.Brown: Taillamps
.White: Ground
.Light Green: Back-up Lamps
.Red: Battery Feed*
.Dark Blue: Trailer Brake*
*The fuses for these two circuits are
installed in the underhood electrical
center, but the wires are not
connected. They should be
connected by your dealer or a
qualified service center.
If charging a remote (non-vehicle)
battery, press the tow/haul mode
button located at the end of the shift
lever. This will boost the vehicle
system voltage and properly charge
the battery. If the trailer is too light
for tow/haul mode, turn on the headlamps as a second way to
boost the vehicle system and
charge the battery.
Electric Brake Control Wiring
Provisions
These wiring provisions are
included with the vehicle as part of
the trailer wiring package. These
provisions are for an electric brake
controller. The instrument panel
contains blunt cut wires near the
data link connector for the trailer
brake controller. The harness
contains the following wires:
.Dark Blue: Brake Signal to
Trailer Connector
.Red/Black: Battery
.Light Blue/White: Brake Switch
.White: Ground
It should be installed by your dealer
or a qualified service center.
If the vehicle is equipped with an
ITBC, the blunt cuts exist, but are
not connected further in the
harness. If an aftermarket trailer