GMC SIERRA 2011 Owner's Manual

Black plate (117,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-117
If the vehicle is equipped with an
Integrated Trailer Brake Control
(ITBC) System, the blunt cuts
exist, but are not connected further
in the harness. If an aftermarket
trailer 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. SeeTow/Haul
Mode on page 9‑51 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” under
Trailer Towing on page 9‑95.
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.

Black plate (118,1)GMC Sierra Owner Manual - 2011
9-118 Driving and Operating
Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for electric trailer brakes.
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, antilock
brake, and StabiliTrak (if equipped)
systems. In trailering conditions thatcause the vehicle’s antilock 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 StabiliTrak.
2500 and 3500 series vehicles
with StabiliTrak have a Trailer Sway
Control (TSC) feature. See
Trailer
Sway Control (TSC) on page 9‑124.
2500 and 3500 series vehicles
with StabiliTrak have a Hill Start
Assist (HSA) feature. See Hill Start
Assist (HSA) on page 9‑70.
If the vehicle’s brake, antilock
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 (119,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-119
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. See Instrument Panel
(Base/Uplevel Version) on page 1‑2
or Instrument Panel (Premium
Version) on page 1‑6 for moreinformation. 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 of 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 on the vehicle’s
Driver Information Center (DIC).
See
Driver Information Center (DIC)
on page 5‑33 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 (120,1)GMC Sierra Owner Manual - 2011
9-120 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 any time 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
“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.
On vehicles with Trailer Sway
Control (TSC) or Hill Start Assist
(HSA), output to the electric trailer
brakes may be displayed when the
systems are active. See Trailer
Sway Control (TSC) on page 9‑124
and Hill Start Assist (HSA) on
page 9‑70.

Black plate (121,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-121
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)
.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 on 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's 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.

Black plate (122,1)GMC Sierra Owner Manual - 2011
9-122 Driving and Operating
Use the following procedure to
correctly adjust Trailer Gain for
each towing condition:
1. Make sure the trailer brakes arein 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 9‑25 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.
.The Trailer Brake Display
Page will appear on the
DIC showing TRAILER
GAIN and TRAILER
OUTPUT.
.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.

Black plate (123,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-123
Other ITBC-Related DIC Messages
In addition to displaying TRAILER
GAIN and TRAILER OUTPUT
through the DIC, trailer connection
and ITBC system status are
displayed on 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 10 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 firstdetermines 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 30 seconds.
This message will also turn off
if the driver acknowledges this
message or if the trailer harness
is re-connected.
If the disconnect occurs
while the vehicle is moving,
this message will continue
until the ignition is turned off.
This message will also turn off
if the driver acknowledges this
message or if the trailer harness
is re-connected.
2. There is an electrical fault in the wiring to the electric trailer
brakes. This message will
continue as long as there is
an electrical fault in the trailer
wiring. This message will
also turn off if the driver
acknowledges this message. To determine if the electrical
fault is on the vehicle side or trailer
side of the trailer wiring harness
connection, do the following:
1. Disconnect the trailer wiring
harness from the vehicle.
2. Turn the ignition off.
3. Wait 10 seconds, then turn the ignition back to RUN.
4. If the CHECK TRAILER WIRING message re-appears, the
electrical fault is on the
vehicle side.
If the CHECK TRAILER WIRING
message only re-appears when
connecting the trailer wiring
harness to the vehicle, the
electrical fault is on the
trailer side.

Black plate (124,1)GMC Sierra Owner Manual - 2011
9-124 Driving and Operating
SERVICE TRAILER BRAKE
SYSTEM: This message will be
displayed when there is a problem
with the ITBC system. If this
message persists over multiple
ignition cycles, there is a problem
with the ITBC system. Take the
vehicle to an authorized GM dealer
to have the ITBC system diagnosed
and repaired.
If either the CHECK TRAILER
WIRING or SERVICE TRAILER
BRAKE SYSTEM message is
displayed while driving the vehicle,
power is no longer available
to the trailer brakes. When traffic
conditions allow, carefully pull the
vehicle over to the side of the road
and turn the ignition off. Check the
wiring connection to the trailer and
turn the ignition back on. If either of
these messages continues, either
the vehicle or trailer needs service.An authorized GM dealer may
be able to diagnose and repair
problems with the trailer. However,
any diagnosis and repair of the
trailer is not covered under the
vehicle warranty. Please contact
your trailer dealer for assistance
with trailer repairs and trailer
warranty information.
Trailer Sway
Control (TSC)
Trailer Sway Control (TSC)
2500 and 3500 series vehicles with
StabiliTrak have a Trailer Sway
Control (TSC) feature. If the vehicle
is towing a trailer and the system
detects that the trailer is swaying,
the vehicle's brakes are applied
without the driver pressing the brake
pedal. If the vehicle is equipped with
the Integrated Trailer Brake Control
(ITBC) system, StabiliTrak may also
apply the trailer brakes. The TCS/
StabiliTrak warning light will flash on
the instrument panel cluster to notify
the driver to reduce speed. If the
trailer continues to sway, StabiliTrak
will reduce engine torque to help
slow the vehicle.
Adding non‐dealer accessories can
affect the vehicle's performance.
See
Accessories and Modifications
on page 10‑3 for more information.

Black plate (125,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-125
Conversions and
Add-Ons
Add-On Electrical
Equipment
Notice:Do not add anything
electrical to the vehicle unless
you check with your dealer first.
Some electrical equipment can
damage the vehicle and the
damage would not be covered
by the vehicle's warranty. Some
add-on electrical equipment can
keep other components from
working as they should.
Add-on equipment can drain the
vehicle battery, even if the vehicle
is not operating.
The vehicle has an airbag system.
Before attempting to add anything
electrical to the vehicle, see
Servicing the Airbag-Equipped
Vehicle on page 3‑46 andAdding
Equipment to the Airbag-Equipped
Vehicle on page 3‑46.
Adding a Snow Plow or
Similar Equipment
Before installing a snow plow on the
vehicle, here are some things you
need to know:
Notice: If your vehicle does
not have the snow plow prep
package, adding a plow can
damage your vehicle, and the
repairs would not be covered by
warranty. Unless your vehicle was
built to carry a snow plow, do not
add one to your vehicle. If your
vehicle has the snow plow prep
package, called RPO VYU, then
the payload your vehicle can
carry will be reduced when a
snow plow is installed. Your
vehicle can be damaged if either
the front or rear axle ratings or
the Gross Vehicle Weight (GVW)
are exceeded. Some vehicles are built with a
special snow plow prep package,
called RPO VYU. If your vehicle
has this option, you can add a
plow to it, provided certain weights,
such as the weights on the vehicle's
axles and the Gross Vehicle
Weight (GVW), are not exceeded.
The plow the vehicle can carry
depends on many things, such as:
.The options the vehicle came
with, and the weight of those
options.
.The weight and number of
passengers you intend to carry.
.The weight of items added to
the vehicle, like a tool box or
truck cap.
.The total weight of any
additional cargo you intend
to carry.

Black plate (126,1)GMC Sierra Owner Manual - 2011
9-126 Driving and Operating
Say, for example, you have a 318 kg
(700 lb) snow plow. The total weight
of all occupants and cargo inside
the cab should not exceed 135 kg
(300 lb). This means that you may
only be able to carry one passenger.
But, even this may be too much
if you have got other equipment
already adding to the weight of
the vehicle.
Here are some guidelines for safely
carrying a snow plow on the vehicle:
.Make sure the weight on the
front and rear axles does not
exceed the axle rating for each.
.For the front axle, if more cargo
or passengers must be carried,
appropriate counter ballast must
be installed rear of the rear axle.
Counter ballast must be properly
secured so it will not move
during driving.
.Follow the snow
plow manufacturer's
recommendations regarding
rear ballast. Rear ballast may
be required to ensure a proper
front and rear weight distribution
ratio, even though the actual
weight at the front axle may be
less than the front axle rating.
.The snow plow manufacturer
or installer can assist you in
determining the amount of rear
ballast required, to help make
sure the snowplow/vehicle
combination does not exceed
the GVW rating, the front and
rear axle ratings, and the front
and rear weight distribution ratio.
.The total vehicle must not
exceed the GVW rating.
Front axle reserve capacity is the
difference between the Gross Axle
Weight Rating (GAWR) and the front
axle weight of the vehicle with full fuel and passengers. Basically,
it is the amount of weight that can
be added to the front axle before
reaching the front GAWR.
The front axle reserve capacity
for the vehicle can be found
in the lower right corner of the
Certification/Tire label, as shown.
United States