display GMC SIERRA 2020 Owners Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
304 Driving and Operating
Trailer Lamps
Always check that all trailer lamps
are working at the beginning of each
trip, and periodically on longer trips.
If equipped, the Trailering App will
monitor the RH turn/brake lamp
circuit, LH turn/brake lamp circuit,
running lamp circuit, and reverse
lamp circuits on the trailer. DIC
messages and Trailering App alerts
may be displayed if lighting circuit
issues are detected on the trailer.
Pressing START LIGHT TEST in the
Trailering App automatically
activates the trailer lamps. The
Trailering App is not a substitute for
manually inspecting your trailer
lamps. SeeTrailering App 0310.
Turn Signals When Towing a
Trailer
When properly connected, the trailer
turn signals will illuminate to indicate
the vehicle is turning, changing
lanes, or stopping. When towing a
trailer, the arrows on the instrument cluster will illuminate even if the
trailer is not properly connected or
the bulbs are burned out.
Tow/Haul Mode
For instructions on how to enter
Tow/Haul Mode, see
Driver Mode
Control 0238.
Tow/Haul assists when pulling a
heavy trailer or a large or heavy
load. See Tow/Haul Mode 0226.
Tow/Haul Mode is designed to be
most effective when the vehicle and
trailer combined weight is at least
75% of the vehicle's Gross
Combined Weight Rating (GCWR).
See “Trailer Weight ”under Trailer
Towing 0292.
Tow/Haul Mode is most useful when
towing a heavy trailer or carrying a
large or heavy load:
. Through rolling terrain.
. In stop-and-go traffic.
. In busy parking lots.
Operating the vehicle in Tow/Haul
Mode when lightly loaded or not
towing will not cause damage; however, it is not recommended and
may result in unpleasant engine and
transmission driving characteristics,
heavy or light steering efforts, and
reduced fuel economy.Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for use with electric trailer brakes or
most electric over hydraulic trailer
brake systems. These instructions
apply to both types of electric trailer
brakes.
This symbol is on the Trailer Brake
Control Panel on vehicles with an
ITBC system. The power output to
the trailer brakes is proportional to
the amount of vehicle braking. This

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 305
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/Electronic Stability
Control (ESC) systems. In trailering
conditions that cause the vehicle’s
antilock brake or StabiliTrak/ESC
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/ESC.
If the vehicle’s brake, antilock brake,
or StabiliTrak/ESC systems are not
functioning properly, the ITBC
system may not function fully or at
all. Make sure all of these systems
are fully operational to allow the
ITBC system to function properly.
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.{Warning
Connecting a trailer that has an
air brake system may result in
reduced or complete loss of trailer
braking, including increased
stopping distance or trailer
instability which could result in
serious injury, death, or property
damage. Only use the ITBC
system with electric or electric
over hydraulic trailer brake
systems.
Trailer Brake Control Panel
1. Manual Trailer Brake Apply
Lever
2. Trailer Symbol
3. Trailer Gain Adjustment Buttons
The trailer symbol on the control
panel will light amber when a trailer
with electric brakes is connected.
The ITBC control panel is on the
center stack. See Instrument Panel
Overview 05. The control panel
allows adjustment to the amount of
output, referred to as Trailer Gain,
available to the trailer brakes and
allows manual application of the
trailer brakes. Use the ITBC control
panel and the DIC trailer brake
display page to adjust and display
power output to the trailer brakes.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
306 Driving and Operating
Trailer Brake DIC Display Page
The ITBC display page indicates:
.Trailer Gain setting
. Output to the trailer brakes
. Trailer connection
. System operational status
To display:
. Scroll through the DIC menu
pages
. Press a Trailer Gain (+) or (−)
button
. Activate the Manual Trailer
Brake Apply Lever
TRAILER GAIN: Press a Trailer
Gain button to recall the current
Trailer Gain setting. Each press and
release of the gain buttons will then
change the Trailer Gain setting.
Press the Trailer Gain (+) or (-) to
adjust. Press and hold to
continuously adjust the Trailer Gain.
To turn the output to the trailer off,
adjust the Trailer Gain setting to 0.0.
This setting can be adjusted from
0.0 to 10.0 with a trailer connected
or disconnected. TRAILER OUTPUT: This displays
anytime a trailer with electric brakes
is connected. Output to the trailer
brakes is based on the amount of
vehicle braking present and relative
to the Trailer Gain setting. Output is
displayed from 0 to 100% 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
displays.
. A trailer with electric brakes has
become disconnected.
A CHECK TRAILER WIRING
message displays on the DIC.
. There is a fault present in the
wiring to the trailer brakes.
A CHECK TRAILER WIRING
message displays on the DIC.
. The ITBC system is not working
due to a fault. A SERVICE
TRAILER BRAKE SYSTEM
message displays in the DIC.
Manual Trailer Brake Apply
Lever
Slide this lever right to apply the
trailer ’s electric brakes independent
of the vehicle’s brakes. Use this
lever to adjust the Trailer Gain to
achieve proper power output to the
trailer brakes. Under certain
circumstances, this lever can also
be used to apply additional trailer
braking. The trailer and vehicle
brake lamps will come on when
either the vehicle brakes or trailer
brakes are applied and properly
connected.
Trailer Gain Adjustment
Procedure
Trailer Gain should be set for a
specific trailering condition and it
must be readjusted anytime vehicle
loading, trailer loading, or road
surface conditions change.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 307
{Warning
Trailer brakes that are
over-gained or under-gained may
not stop the vehicle and the trailer
as intended and can result in a
crash. Always follow the
instructions to set the Trailer Gain
for the proper trailer stopping
performance.
To adjust Trailer Gain for each
towing condition: 1. Drive the vehicle with the trailer attached on a level road
surface representative of the
towing condition and free of
traffic at about 32–40 km/h
(20–25 mph) and fully apply
the Manual Trailer Brake Apply
Lever.
Adjusting Trailer Gain at
speeds lower than 32–40 km/h
(20–25 mph) may result in an
incorrect gain setting. 2. Adjust the Trailer Gain, using
the Trailer Gain (+) or (−)
adjustment buttons, 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. Adjust the Trailer Gain
to the highest allowable setting
for the towing condition.
3. Readjust Trailer Gain anytime 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
TRAILER CONNECTED: This
message will briefly display when a
trailer with electric brakes is first
connected to the vehicle. This
message will automatically turn off
in about 10 seconds. This message
can be acknowledged before it
automatically turns off. CHECK TRAILER WIRING: This
message will display if:
.
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 30 seconds. This
message will also turn off if it is
acknowledged or if the trailer
harness is reconnected.
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 it is
acknowledged or if the trailer
harness is reconnected.
. There is an electrical fault in the
wiring to the 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 it is
acknowledged.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
308 Driving and Operating
To determine whether the electrical
fault is on the vehicle side or trailer
side of the trailer wiring harness
connection: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 reappears,
the electrical fault is on the
vehicle side.
If the CHECK TRAILER WIRING
message only reappears when
connecting the trailer wiring harness
to the vehicle, the electrical fault is
on the trailer side.
SERVICE TRAILER BRAKE
SYSTEM: This message will display
when there is a problem with the
ITBC system. If this message
continues over multiple ignition
cycles, have the vehicle serviced.
If either the CHECK TRAILER
WIRING or SERVICE TRAILER
BRAKE SYSTEM message displays while driving, the ITBC system may
not be fully functional or may not
function at all. 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.
A 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.
Contact your trailer dealer for
assistance with trailer repairs and
trailer warranty information.
Trailer Sway
Control (TSC)
Vehicles with StabiliTrak/Electronic
Stability Control (ESC) have a
Trailer Sway Control (TSC) feature.
Trailer sway is unintended
side-to-side motion of a trailer while
towing. If the vehicle is towing a
trailer and the TSC detects that
sway is increasing, the vehiclebrakes are selectively applied at
each wheel, to help reduce
excessive trailer sway. If equipped
with the Integrated Trailer Brake
Control (ITBC) system, and the
trailer has an electric brake system,
StabiliTrak/ESC may also apply the
trailer brakes.If TSC is enabled, the Traction
Control System (TCS)/StabiliTrak/
ESC warning light will flash on the
instrument cluster. Reduce vehicle
speed by gradually removing your
foot from the accelerator. If trailer
sway continues, StabiliTrak/ESC
can reduce engine torque to help

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
310 Driving and Operating
Warning (Continued)
.If the trailer brakes are not
operating properly at any
time, or if a DIC message
indicates problems with the
trailer connections or trailer
brakes, carefully pull the
vehicle over to the side of
the road when traffic
conditions allow.
Trailer Tires
Special Trailer (ST) tires differ from
vehicle tires. Trailer tires are
designed with stiff sidewalls to help
prevent sway and to support heavy
loads. These features can make it
difficult to determine if the trailer tire
pressures are low only based on a
visual inspection.
Always check all trailer tire
pressures before each trip when the
tires are cool. Low trailer tire
pressure is a leading cause of trailer
tire blow-outs. If the vehicle is equipped with a
trailer tire pressure monitoring
system, see the trailer tire pressure
monitoring system description and
the trailering app.
Trailer tires deteriorate over time.
The trailer tire sidewall will show the
week and year the tire was
manufactured. Many trailer tire
manufacturers recommend
replacing tires more than six
years old.
Overloading is another leading
cause of trailer tire blow-outs. Never
load your trailer with more weight
than the tires are designed to
support. The load rating is located
on the trailer tire sidewall.
Always know the maximum speed
rating for the trailer tires before
driving. This may be significantly
lower than the vehicle tire speed
rating. The speed rating may be on
the trailer tire sidewall. If the speed
rating is not shown, the default
trailer tire speed rating is 105 km/h
(65 mph).
Trailering App
Trailer Light App
If equipped, the Trailer Lights App is
on the Home Page of the
infotainment display.
Touch Start to cycle the trailer lamps
on and off to determine if they are
working. The test follows this
sequence:
1. The running lights turn on first and remain on throughout the
sequence.
2. The brake lights turn on for about two seconds.
3. The left turn signal light flashes three times.
4. The right turn signal light flashes three times.
5. The reverse lights turn on for about two seconds.
6. Steps 2–5 repeat for approximately one minute and
45 seconds, or until the test
deactivates.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 311
Touch Stop to stop the test. The test
will automatically end after
one minute and 45 seconds.
The sequence also deactivates
when any of the following occur:
.The ignition is turned off.
. The transmission is shifted out
of P (Park).
. The brake pedal is pressed.
. The turn signal is activated.
. The hazard warning lights are
activated.
Trailering App
If equipped, the Trailering App is on
the Home Page of the infotainment
display.
If equipped this feature allows
profiles for connected trailers to be
created to view status, to store and
track trailer usage information, and
to set up towing assistance
features.
The Trailering App Preview will
appear when the Trailering App is
opened for the first time from the Home Page. Touch GET STARTED
in the Trailering App to go into
the app.
When a trailer is electrically
connected, there will be an option to
create a profile, use a guest profile,
or cancel. After Cancel is selected a
third time, Don’t Remind Me will
display and touching that will turn off
the trailer detection pop-up. To turn
the Trailer Detection Alert on, select
ON in the Settings tab.
When a trailer is electrically
connected and after a Trailer Profile
has been created, the trailer
detection pop-up will appear with a
list of all of the custom Trailer
Profiles made on the vehicle. To
load an existing Trailer Profile,
select one of the Trailer Profiles
listed, or load the Guest Trailer
Profile by selecting GUEST
TRAILER. Touching Cancel,
Accessory/No trailer, or shifting the
vehicle from P (Park), will select
Accessory/No trailer as the active
Trailer Profile and will dismiss the
pop- up.
Create a Trailer Profile
1. Touch Create Profile on the pop-up or touch + Add Trailer
in the Trailering App.
2. Create a name for the trailer.
3. Select the hitch type. A checklist profile will be
created based on the type
selected.
4. Select the trailer type.
A pop-up will indicate the setup is
complete. Touch DONE to complete
the process or touch TRAILER
FEATURE SETUP to set up the
Tow/Haul Mode reminder, Trailer
Tire Pressure Monitoring System,
if equipped, maintenance reminders,
or towing assistance, if equipped.
Import a Trailer Profile
A trailer profile saved to an OnStar
account can be imported to the
vehicle. 1. Touch Import Profile on the pop-up.
2. Select a trailer profile from the list.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
312 Driving and Operating
3. Touch IMPORT.
A pop-up will indicate the import
was successful. Touch OK to return
to the trailer list and select the trailer
profile. The Tow/Haul Mode
reminder, Brake Gain Setting and
Trailer Tire Pressure sensor
learning, if equipped, do not import.
Trailer Feature Setup
Tow/Haul Mode Reminder
To turn the Tow/Haul Mode
Reminder setting on, touch Yes. To
turn it off, touch No.
Trailer Tire Pressure Setup
If the Trailer Tire Pressure
Monitoring System (TTPMS) is
detected, touch the Tire Pressure
Monitoring icon to set up tire
pressure monitoring.Touch Yes to
set up the sensors or touch No to
return to the previous screen.
A trailer must be electrically
connected to the vehicle before
starting the sensor-to-vehicle learn
process. After selecting Start from the Learn
Sensors screen, use the Tool
Method or the Manual Method
(described below) to learn each tire
sensor, during which the current tire
number will be highlighted.
Each sensor has a minimum of
two minutes to learn, shown by a
timer. After a sensor is learned, a
checkmark appears next to the tire,
the vehicle horn will sound, the
vehicle’s brake lamps will flash, and
all working trailer lamps will flash.
It then moves to the next sensor.
To cancel the process touch Stop.
The recommended tire pressure
must be entered for the trailer tires.
This allows the vehicle to alert when
the tire pressure is high or low.
TTPMS must learn the location of
the installed tire sensors to show
correct air pressure and
temperature for each tire. To set up,
use one of the following options or
see a tire or trailer dealer for
service. The learning process must
be repeated when the trailer tires
are rotated or replaced. See
“Editinga Trailer Profile”
later in this section
for tire pressure sensor relearn
information.
Tool Method: A TTPMS activation
tool can be purchased separately to
learn the sensor locations.
Manual Method: Without the tool,
the air pressure can be increased or
decreased in each tire for
10 seconds. Do not exceed the
maximum inflation pressure found
on the tire sidewalls. Make sure to
re-adjust tire pressure to the
recommended level when the
process is complete.
Sensor Learning Steps
To complete the sensor-to-vehicle
learn process:
1. Touch Start on the Learn Sensors screen. The horn
chirps twice and the Learning
Active screen appears on the
infotainment display.
2. Start with the driver side front trailer tire.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 315
Light, Reverse Lights, and Electric
Brakes, if equipped), the view will
display OK.
Connection Problem
If any of the trailer connections are
not detected, a message about the
connection issue will appear on the
Driver Information Center (DIC). The
infotainment display will also show
the connection issue in the
Connection Status view.
Diagnose View
Touch Diagnose to see more
information about the connection
problem.
This view will display the names of
the trailer connector pins, a graphic
of the trailer connector, and a
graphic of the back of the trailer.
Any connector pin that failed will be
amber color, and the location of the
corresponding connection will be
highlighted on the graphic of the
back of the trailer.The Running Lights connection may
not detect partial outages. Activate
the light test to check all trailer
lamps. See
“Light Test”following.
If the trailer is not equipped with
reverse lights or electric brakes and
you are receiving failure messages
in the DIC or on this view, turn off
the Reverse Lights Alert or the
Electric Brakes Alert setting in the
trailer ’s profile page.
Light Test
Touch Start Light Test to cycle the
trailer lights on and off to determine
if they are working. The test follows
this sequence: 1. The running lights turn on first and remain on throughout the
sequence.
2. The brake lights turn on for about two seconds.
3. The left turn signal light flashes three times.
4. The right turn signal light flashes three times. 5. The reverse lights turn on for
about two seconds.
6. Steps 2–5 repeat for approximately one minute and
45 seconds, or until the test
deactivates.
Touch Stop to stop the test. The test
will automatically end after
one minute and 45 seconds.
The sequence also deactivates
when any of the following occur:
. The ignition is turned off.
. The transmission is shifted out
of P (Park).
. The brake pedal is pressed.
. The turn signal is activated.
. The hazard warning lights are
activated.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
316 Driving and Operating
Trailer
1. Trailer Tire Pressure/Temperature
2. Mileage of Trailer
Mileage
The mileage accumulated while this
Trailer Profile is active will display.
Touch mileage to edit.
Tire Pressure and Temperature
If the TTPMS sensor-to-vehicle
learn process was completed, the
status view will display the current
tire pressure and temperature of the
trailer tires related to the active Trailer Profile. If a tire’
s pressure is
low or high, the color of the
pressure value will be amber. If a
sensor malfunctions, the values are
dashed lines. If the screen displays
“Service Tire Pressure Monitoring
System”, the vehicle needs to be
taken to a dealer for service.
Maintenance
1. List of Maintenance
Reminders
2. Add a New Maintenance Reminder
The Maintenance Status view
displays reminders. Touch a
reminder to edit.
Touch + New Maintenance
Reminder to go to the Select New
Reminder view.
The progress bar turns yellow when
the maintenance item reaches 90%
complete.
The progress bar turns red when
the maintenance item reaches
100% complete.
Maintenance Notifications
.Touch Service Complete to reset
the maintenance reminder.
. Touch Remind Me Later to delay
the reminder.
. Touch X next to Upcoming Alerts
(90%) to dismiss the alert. It will
not appear again.
. Touch X next to Maintenance
Due (100%) to delay the alert to
the next ignition cycle.
Always follow all of the maintenance
instructions that came with your
trailer.