2011 GMC YUKON XL brakes

Black plate (79,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-79
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 isclear 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 this
manual's Maintenance Schedule or
Index for more information. 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.
Trailer Towing
If the vehicle has a hybrid engine,
see the Hybrid supplement for more
information.
Do not tow a trailer during break‐in.
See
New Vehicle Break-In on
page 9‑28 for more information.
{WARNING
The driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly.
For example, if the trailer is
too heavy, the brakes may not
work well—or even at all. The
driver and passengers could be
seriously injured. The vehicle may
also be damaged; the resulting
repairs would not be covered by
the vehicle warranty. Pull a trailer
(Continued)
WARNING (Continued)
only if all the steps in this section
have been followed. Ask your
dealer for advice and information
about towing a trailer with the
vehicle.
Notice: Pulling a trailer
improperly can damage the
vehicle and result in costly
repairs not covered by the
vehicle warranty. To pull a trailer
correctly, follow the advice in this
section and see your dealer for
important information about
towing a trailer with the vehicle.
To identify the trailering capacity of
the vehicle, read the information in
“Weight of the Trailer” that appears
later in this section.

Black plate (85,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-85
Safety Chains
Always attach chains between the
vehicle and the trailer. Cross the
safety chains under the tongue
of the trailer to help prevent the
tongue from contacting the road if it
becomes separated from the hitch.
Instructions about safety chains
may be provided by the hitch
manufacturer or by the trailer
manufacturer. If the trailer being
towed weighs up to 2 271 kg
(5,000 lbs) with a factory-installed
step bumper, safety chains may
be attached to the attaching points
on the bumper, otherwise, safety
chains should be attached to holes
on the trailer hitch platform. Always
leave just enough slack so the
combination can turn. Never allow
safety chains to drag on the ground.
Trailer Brakes
A loaded trailer that weighs more
than 900 kg (2,000 lbs) needs to
have its own brake system that is
adequate for the weight of the
trailer. Be sure to read and follow
the instructions for the trailer brakes
so they are installed, adjusted and
maintained properly.
Since the vehicle is equipped with
StabiliTrak
®, the trailer brakes
cannot tap into the vehicle's
hydraulic system.
Trailer Wiring Harness
The vehicle is equipped with the
following wiring harnesses for
towing a trailer.
Basic Trailer Wiring
The trailer wiring harness, with a
seven-pin connector, is located at
the rear of the vehicle and is tied to
the vehicle's frame. The harness
connector can be plugged into a
seven-pin universal heavy-duty
trailer connector available through
your dealer. 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.

Black plate (87,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-87
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 9‑42 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.

Black plate (88,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-88 Driving and Operating
This symbol is located on the Trailer
Brake Control Panel on vehicles
with an Integrated Trailer Brake
Control System. The power output
to the trailer brakes is based on the
amount of brake pressure being
applied by the vehicle’s brake
system. This available power output
to the trailer brakes can be adjusted
to a wide range of trailering
situations.
The ITBC system is integrated
with the vehicle’s brake, anti‐lock
brake and StabiliTrak systems.
In trailering conditions that cause
the vehicle’s anti‐lock brake or
StabiliTrak systems to activate,
power sent to the trailer's brakes
will be automatically adjusted to
minimize trailer wheel lock-up. This
does not imply that the trailer has
the StabiliTrak system. If the vehicle’s brake, anti‐lock
brake or StabiliTrak systems are
not functioning properly, the ITBC
system may not be fully functional
or may not function at all. Make
sure all of these systems are
fully operational to ensure full
functionality of the ITBC system.
The ITBC system is powered
through the vehicle's electrical
system. Turning the ignition off
will also turn off the ITBC system.
The ITBC system is fully functional
only when the ignition is in ON or
in RUN.
The ITBC system can only be used
with trailers with electric brakes.{WARNING
Connecting a trailer that is not
compatible with the ITBC system
may result in reduced or complete
loss of trailer braking. There
may be an increase in stopping
distance or trailer instability which
could result in personal injury or
damage to the vehicle, trailer,
or other property. An aftermarket
controller may be available for
use with trailers with surge,
air, or electric‐over‐hydraulic
trailer brake systems. To
determine the type of brakes
on the trailer and the availability
of controllers, check with your
trailer manufacturer or dealer.

Black plate (89,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-89
When trailering, make sure of the
following:
.The ITBC system is used only
with trailers that are equipped
with electric brakes.
.All applicable local and federal
laws and regulations are
followed.
.All electrical and mechanical
connections to the trailer are
made correctly.
.The trailer’s brakes are in proper
working condition.
.The trailer and vehicle are
properly loaded for the towing
condition.
The ITBC system is a factory
installed item. Out‐of‐factory
installation of this system should not
be attempted. GM is not responsible
for warranty or performance of the
system resulting from out‐of‐factory
installation. Trailer Brake Control PanelA. Manual Trailer Brake Apply
Lever
B. Trailer Gain Adjustment Buttons
The ITBC system has a control
panel located on the instrument
panel to the left of the steering
column. The control panel allows
adjustment to the amount of output, referred to as trailer gain, available
to the electric trailer brakes and
allows manual application the trailer
brakes. The Trailer Brake Control
Panel is used along with the Trailer
Brake Display Page on the DIC to
adjust and display power output to
the trailer brakes.
Trailer Brake DIC Display Page
The ITBC system displays
messages into the vehicle’s Driver
Information Center (DIC). See
Driver Information Center (DIC) on
page 5‑28
for more information.
The display page indicates
Trailer Gain setting, power output
to the electric trailer brakes, trailer
connection and system operational
status.

Black plate (90,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-90 Driving and Operating
The Trailer Brake Display Page can
be displayed by performing any of
the following actions:
.Scrolling through the DIC
menu pages using the odometer
trip stem or the DIC Vehicle
Information button (if equipped).
.Pressing a Trailer Gain
button–If the Trailer Brake
Display Page is not currently
displayed, pressing a Trailer
Gain button will first recall the
current Trailer Gain setting.
After the Trailer Brake Display
Page is displayed, each press
and release of the gain buttons
will then cause the Trailer Gain
setting to change.
.Activating the Manual Trailer
Brake Apply lever
.Connecting a trailer equipped
with electric trailer brakes All DIC warning and service
messages must first be
acknowledged by the driver
by pressing the odometer trip
stem or the DIC Vehicle Information
button (if equipped) before the
Trailer Brake Display Page can be
displayed and Trailer Gain can be
adjusted.
TRAILER GAIN
–This setting is
displayed anytime the Trailer Brake
Display Page is active. This setting
can be adjusted from 0.0 to 10.0
with either a trailer connected or
disconnected. To adjust the Trailer
Gain, press one of the Trailer Gain
adjustment buttons located on the
Trailer Brake Control Panel. Press
and hold a gain button to cause the
Trailer Gain to continuously adjust.
To turn the output to the trailer off,
adjust the Trailer Gain setting to
0.0 (zero).
0.0 (zero) gain is the factory
default setting. To properly adjust
trailer gain, see the Trailer Gain
Adjustment Procedure later in this
section. TRAILER OUTPUT
–This is
displayed any time a trailer with
electric brakes is connected.
Output to the electric brakes is
based on the amount of vehicle
braking present and relative to
the Trailer Gain setting. Output is
displayed from 0 to 10 bars for each
gain setting.
The Trailer Output will
indicate “- - - - - -“ on the
Trailer Brake Display Page
whenever the following occur:
.No trailer is connected.
.A trailer without electric brakes
is connected (no DIC message
is displayed).
.A trailer with electric brakes
has become disconnected
(a CHECK TRAILER WIRING
message will also be displayed
on the DIC).

Black plate (91,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-91
.There is a fault present in the
wiring to the electric trailer
brakes (a CHECK TRAILER
WIRING message will also be
displayed on the DIC).
.There is a fault in the ITBC
system (a SERVICE TRAILER
BRAKE SYSTEM message will
also be displayed in the DIC).
Manual Trailer Brake Apply
The Manual Trailer Brake Apply
Lever is located on the Trailer
Brake Control Panel and is used to
apply the trailer ’s electric brakes
independent of the vehicle’s brakes.
This lever is used in the Trailer Gain
Adjustment Procedure to properly
adjust the power output to the trailer
brakes. Sliding the lever to the left
will apply only the trailer brakes.
The power output to the trailer is
indicated in the Trailer Brake
Display Page in the DIC. If the
vehicle’s service brakes are applied while using the Manual Trailer Brake
Apply Lever, the trailer output power
will be the greater of the two.
The trailer and the vehicle's brake
lamps will come on when either
vehicle braking or manual trailer
brakes are applied.
Trailer Gain Adjustment Procedure
Trailer Gain should be set for a
specific trailering condition and
must be adjusted any time vehicle
loading, trailer loading or road
surface conditions change.
Setting the Trailer Gain properly
is needed for the best trailer
stopping performance. A trailer
that is over-gained may result in
locked trailer brakes. A trailer that
is under-gained may result in not
enough trailer braking. Both of these
conditions may result in poorer
stopping and stability of the vehicle
and trailer.
Use the following procedure to
correctly adjust Trailer Gain for each
towing condition:
1. Make sure the trailer brakes are
in proper working condition.
2. Connect a properly loaded trailer to the vehicle and make
all necessary mechanical and
electrical connections. See
Vehicle Load Limits on
page 9‑23 for more information.
3. After the electrical connection is made to a trailer equipped with
electric brakes:
.A TRAILER CONNECTED
message will be briefly
displayed on the DIC
display.
.The Trailer Brake Display
Page will appear on the
DIC showing TRAILER
GAIN and TRAILER
OUTPUT.

Black plate (92,1)GMC Yukon/Yukon XL Owner Manual - 2011
9-92 Driving and Operating
.In the Trailer Output display
on the DIC,“- - - - - -“will
disappear if there is no
error present. Connecting
a trailer without electric
brakes will not clear the
six dashed lines.
4. Adjust the Trailer Gain by using the gain adjustment (+ / -)
buttons on the Trailer Brake
Control Panel.
5. Drive the vehicle with the trailer attached on a level road
surface representative of the
towing condition and free of
traffic at about 32 to 40 km/h
(20 to 25 mph) and fully apply
the Manual Trailer Brake Apply
lever.
Adjusting trailer gain at speeds
lower than 32 to 40 km/h
(20 to 25 mph) may result in an
incorrect gain setting. 6. Adjust the Trailer Gain to just
below the point of trailer wheel
lock-up, indicated by trailer
wheel squeal or tire smoke when
a trailer wheel locks.
Trailer wheel lock-up may not
occur if towing a heavily loaded
trailer. In this case, adjust the
Trailer Gain to the highest
allowable setting for the towing
condition.
7. Re-adjust Trailer Gain any time vehicle loading, trailer loading or
road surface conditions change
or if trailer wheel lock-up is
noticed at any time while towing
Other ITBC Related DIC Messages
In addition to displaying TRAILER
GAIN and TRAILER OUTPUT
through the DIC, trailer connection
and ITBC system status is displayed
in the DIC. TRAILER CONNECTED
–This
message will be briefly displayed
when a trailer with electric brakes is
first connected to the vehicle. This
message will automatically turn off
in about ten seconds. The driver
can also acknowledge this message
before it automatically turns off.
CHECK TRAILER WIRING –This
message will be displayed if:
1. The ITBC system first determines connection to a
trailer with electric brakes and
then the trailer harness becomes
disconnected from the vehicle.
If the disconnect occurs while
the vehicle is stationary, this
message will automatically
turn off in about thirty seconds.
This message will also turn off if
the driver acknowledges this
message off or if the trailer
harness is re-connected.