2020 GMC SIERRA DENALI ignition

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 305
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(Continued)
Warning (Continued)
system with electric or electric
over hydraulic trailer brake
systems.
Trailer Brake Control Panel
1. Manual Trailer Brake ApplyLever
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.
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

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 307
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.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
308 Driving and Operating
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 vehicle
brakes 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
slow the vehicle. TSC will not
function if StabiliTrak/ESC is turned
off. See
Traction Control/Electronic
Stability Control 0235.
{Warning
Trailer sway can result in a crash
and in serious injury or death,
even if the vehicle is equipped
with TSC.
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
310 Driving and Operating
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.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 315
Connections OK
If all of the trailer connections are
detected (Running Lights, Left Turn
Signal Light, Right Turn Signal
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 - 8/27/19
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
318 Driving and Operating
associated with Custom Trailer
Profiles in addition to default
checklists.
Trailers View
Touch the Trailers tab to view,
activate, create, edit, or delete
Trailer Profiles.
If a trailer is connected, touch the
Trailer Profile name to activate a
Trailer Profile.
There can be up to five Custom
Trailer Profiles on the vehicle.
The Custom Trailer Profiles and
Guest Trailer are in order of the
most frequently used.
All personalization features are
based on the settings for each
driver in vehicle personalization.
The list of Trailer Profiles is based
on vehicle personalization settings.
Guest Trailer
If the Guest Trailer Profile is the
active Trailer Profile, trailer
detection, connections status, theft,
and the Tow/Haul reminder alerts
can be sent. The system will nottrack total mileage or fuel economy,
but the system will track trip mileage
and fuel economy if the Guest
Trailer Profile is active. The Trailer
Tire Pressure Monitoring System or
maintenance reminders cannot be
set up for a Guest Trailer Profile.
The Guest Trailer Profile cannot be
edited.
Touch
pto learn more about the
Guest Trailer option.
No Trailer Connected
When there is no trailer connected,
Trailer Profiles cannot be activated
but most options can be edited.
Trailer Brake Gain Memory
The system can memorize the brake
gain setting of a Trailer Profile or a
Guest Trailer Profile. When a Trailer
Profile or Guest Trailer Profile is
selected, and a brake gain setting is
set for that Trailer Profile, a quick
notice will appear to indicate that
the system has recalled that
profile’s brake gain setting. If a Trailer Profile is already active
and the brake gain setting had been
set for that Trailer Profile, the quick
notice will trigger whenever the
ignition is turned on.
If there was an error in setting the
brake gain for a Trailer Profile, there
will be a notification. This pop-up
will not appear if the Guest Trailer
Profile is active or if there is no
trailer connected.
Trailer brake gain should be set for
a specific trailering condition and
must be adjusted anytime vehicle
loading, trailer loading, or road
surface conditions change.
Editing a Trailer Profile
Trailer Profile View
Touch to edit any of the following
options in the Trailer Profile view:
.
Trailer Name
. Towing Assistance Setup
. Tire Pressure Setup
. Trailer Maintenance
. Mileage

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
322 Driving and Operating
If Tow/Haul Mode is off and this
setting is on for a Trailer Profile,
each time the ignition is turned on a
reminder will appear to turn on Tow/
Haul Mode when the Trailer Profile
is active.
If Tow/Haul Mode is on and this
setting is on for a Trailer Profile, the
reminder will not appear when the
Trailer Profile is active.Conversions and
Add-Ons
Add-On Electrical
Equipment
{Warning
The Data Link Connector (DLC) is
used for vehicle service and
Emission Inspection/Maintenance
testing. SeeMalfunction
Indicator Lamp (Check Engine
Light) 0137. A device connected
to the DLC —such as an
aftermarket fleet or
driver-behavior tracking device —
may interfere with vehicle
systems. This could affect vehicle
operation and cause a crash.
Such devices may also access
information stored in the vehicle’s
systems.
Caution
Some electrical equipment can
damage the vehicle or cause
components to not work and
would not be covered by the
vehicle warranty. Always check
with your dealer before adding
electrical equipment.
Add-on equipment can drain the
vehicle's 12-volt 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 082 and
Adding Equipment to the
Airbag-Equipped Vehicle 082.
For information on wiring auxiliary
switches, see www.gmupfitter.com
or contact your dealer.