
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
332 Driving and Operating
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. The
Trailer Brake Control Panel is used
along with the Trailer Brake Display
Page on the Driver Information
Center (DIC) to adjust and display
power output to the trailer brakes.
Trailer Brake DIC Display Page
The ITBC system displays
messages in the DIC.
The display page indicates Trailer
Gain setting, power output to the
trailer brakes, trailer connection, and
system operational status.
To display the Trailer Brake Display
Page, do any of the following:
.Scroll through the DIC menu
pages.
. Press a Trailer Gain button.
If the Trailer Brake Display Page
is not currently displayed, 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.
. Activate the Manual Trailer
Brake Apply Lever.
TRAILER GAIN: 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. Press and hold a gain
button to continuously adjust the
Trailer Gain. To turn the output to
the trailer off, adjust the Trailer Gain
setting to 0.0 (zero).
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
will display).
. A trailer with electric brakes has
become disconnected (a
CHECK TRAILER WIRING
message will also display on
the DIC).
. There is a fault present in the
wiring to the trailer brakes (a
CHECK TRAILER WIRING
message will also display on
the DIC).
. The ITBC system is not working
due to a fault (a SERVICE
TRAILER BRAKE SYSTEM
message will also display in
the DIC).
Manual Trailer Brake Apply
The Manual Trailer Brake Apply
Lever is used to apply the trailer ’s
electric brakes independent of the
vehicle’s brakes. Sliding the lever to
the left will apply only the trailer
brakes. Use this lever to adjust
Trailer Gain to properly adjust the
power output to the trailer brakes.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
334 Driving and Operating
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 if 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, there is a problem with the
ITBC system. 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 have a
Trailer Sway Control (TSC) feature.
Trailer sway is unintended
side-to-side motion of a trailer while
being towed. 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 the vehicle
is equipped with the Integrated
Trailer Brake Control (ITBC) system,
and the trailer has the electric
actuated brake system, StabiliTrak
may also apply the trailer brakes.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 335
If TSC is enabled, the Traction
Control System (TCS)/StabiliTrak
warning light will flash on the
instrument cluster. Vehicle speed
must be reduced. If trailer sway
continues, StabiliTrak can reduce
engine torque to help slow the
vehicle. SeeTraction Control/
Electronic Stability Control 0282.
{Warning
Even if the vehicle is equipped
with TSC, trailer sway could result
in loss of control and the vehicle
could crash. If excessive trailer
sway is detected, slow down to a
safe speed. Check the trailer and
vehicle to help correct possible
causes. These could include an
improperly or overloaded trailer,
unrestrained cargo, improper
trailer hitch configuration,
excessive vehicle-trailer speed,
or improperly inflated or incorrect
vehicle or trailer tires. See Towing
Equipment 0325 for trailer
ratings and hitch setup
recommendations. Adding non-dealer accessories can
affect the vehicle performance. See
Accessories and Modifications
0
343.
Electronic Trailer Sway Control
Devices
Some trailers may come equipped
with an electronic device designed
to reduce or control trailer sway.
Aftermarket equipment
manufacturers also offer similar
devices that connect to the wiring
between the trailer and the vehicle.
These devices may interfere with
the vehicle’ s trailer brake or other
systems, including integrated
anti-sway systems, if equipped.
Messages related to trailer
connections or trailer brakes could
appear on the Driver Information
Center (DIC). The effect that these
devices may have on vehicle
handling or trailer brake
performance is unknown.
{Warning
Use of electronic trailer sway
control devices could result in
reduced trailer brake
performance, loss of trailer
brakes, or other malfunctions, and
could cause a crash. You or
others could be injured or killed.
Before using one of these
devices:
. Ask the device or trailer
manufacturer if the device
has been thoroughly tested
for compatibility with the
make, model, and year of
the vehicle as well as
optional equipment installed
on the vehicle.
. Before driving on the open
roads, check that the trailer
brakes are working properly.
Drive the vehicle with the
trailer attached on a level
road surface that is free of
traffic at about 32-40 km/h
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Vehicle Care 383
FusesUsage
3 Antilock brake system pump
4 Instrument panel BEC 1
5 Passenger motorized seat belt
6 4WD transfer case electronic control
7 Electric park brake
8 Instrument panel BEC 2
9 Driver motorized seat belt
10 Rear window defogger
11 Starter
12 Cooling fan 1
13 Cooling fan 2
14 Left trailer stop/ Turn signal lamps
15 Trailer parking lamps Fuses
Usage
16 Trailer reverse lamps
17 Right trailer stop/ Turn signal lamps
18 Fuel pump
19 Integrated chassis control module
20 Electronic suspension control
module
21 Fuel pump power module
22 Upfitter 1
23 Upfitter 2
24 Front wiper
25 Antilock brake system valve
26 Upfitter 2
27 Upfitter 3
28 Right parking lamps
29 Left parking lamps Fuses
Usage
30 Upfitter 3
31 Upfitter 4
32 Upfitter 4
33 Reverse lamps
34 Engine control module/Ignition
35 Air conditioning clutch
36 Heated mirrors
37 Upfitter 1
38 Center high-mounted
stoplamp
39 Miscellaneous/ Ignition
40 Transmission/ Ignition
41 Fuel pump 2
42 Cooling fan clutch
43 Engine
44 Fuel injectors A–odd

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
498 Index
Maintenance Schedule (cont'd)Recommended Fluids and
Lubricants . . . . . . . . . . . . . . . . . . . 456
Transfer Case . . . . . . . . . . . . . . . . 272
Malfunction Indicator Lamp . . . . . 150
Manual Mirrors . . . . . . . . . . . . . . . . . . 47
Manual Mode . . . . . . . . . . . . . . . . . . . 268
Manual Windows . . . . . . . . . . . . . . . . 52
Media Avoiding Untrusted Devices . . 195
Memory Features . . . . . . . . . . . . . . . . 13
Memory Seats . . . . . . . . . . . . . . . . . . . 62
Messages Engine Power . . . . . . . . . . . . . . . . 164
Vehicle . . . . . . . . . . . . . . . . . . . . . . . 164
Vehicle Speed . . . . . . . . . . . . . . . . 164
Mirrors Automatic Dimming . . . . . . . . . . . . . 50
Automatic Dimming
Rearview . . . . . . . . . . . . . . . . . . . . . . 52
Blind Spot . . . . . . . . . . . . . . . . . . . . . . 50
Convex . . . . . . . . . . . . . . . . . . . . . . . . . 47
Folding . . . . . . . . . . . . . . . . . . . . . . . . . 49
Heated . . . . . . . . . . . . . . . . . . . . . . . . . 50
Manual . . . . . . . . . . . . . . . . . . . . . . . . . 47
Manual Rearview . . . . . . . . . . . . . . . 52
Power . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Tilt in Reverse . . . . . . . . . . . . . . . . . . 51 Mirrors (cont'd)
Trailer Tow . . . . . . . . . . . . . . . . . . . . . . 48
Mirrors, Interior Rearview . . . . . . . . 51
Monitor System, Tire Pressure . . . . . . . . . . . . . . . . . . . . . . 399
Multi-band Antenna . . . . . . . . . . . . . 194
N
Navigation OnStar . . . . . . . . . . . . . . . . . . . . . . . 481
New Vehicle Break-In . . . . . . . . . . . 255
Noise Control System . . . . . . . . . . 373
O
Odometer . . . . . . . . . . . . . . . . . . . . . . . 142 Trip . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Off-Road . . . . . . . . . . . . . . . . . . . . . . . 239 Driving . . . . . . . . . . . . . . . . . . . . . . . . 239
Recovery . . . . . . . . . . . . . . . . . . . . . 238
Oil
Engine . . . . . . . . . . . . . . . . . . . . . . . . 350
Engine Oil Life System . . . . . . . 353
Engine Oil Pressure Gauge . . . 143
Pressure Light . . . . . . . . . . . . . . . . 156
Older Children, Restraints . . . . . . . 92
Online Owner Center . . . . . . . . . . . 468
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . 478
OnStar Additional Information . . . . . . . . . . . . . . . . . . . . 485 OnStar Connections . . . . . . . . . . . . 482
OnStar Diagnostics . . . . . . . . . . . . . 484
OnStar Emergency . . . . . . . . . . . . . 480
OnStar Navigation . . . . . . . . . . . . . . 481
OnStar Overview . . . . . . . . . . . . . . . 479
OnStar Security . . . . . . . . . . . . . . . . 481
Operating Mode
Overheated EngineProtection . . . . . . . . . . . . . . . . . . . 364
Operation Fog Lamps . . . . . . . . . . . . . . . . . . . 181
Ordering Service Publications . . . . . . . . . . 474
Outlets Power . . . . . . . . . . . . . . . . . . . . . . . . 133
Overheated Engine
Protection Operating Mode . . . . 364
Overheating, Engine . . . . . . . . . . . . 363
Overview . . . . . . . . . . . . . . . . . . . . . . . 188
P
Park Shifting Into . . . . . . . . . . . . . . . . . . . 262
Shifting Out of . . . . . . . . . . . . . . . . 263
Parking Brake . . . . . . . . . . . . . . . . . . . . . . . . . 281
Brake and P (Park)
Mechanism Check . . . . . . . . . . 375

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
502 Index
Towing (cont'd)Trailer . . . . . . . . . . . . . . . . . . . . . . . . 307
Trailer Sway Control (TSC) . . . 334
Vehicle . . . . . . . . . . . . . . . . . . . . . . . 430
Traction Control System (TCS)/StabiliTrak Light . . . . . . . . . . . . . 155
Off Light . . . . . . . . . . . . . . . . . . . . . . 154
Traction Control/Electronic
Stability Control . . . . . . . . . . . . . . . 282
Trademarks and License Agreements . . . . . . . . . . . . . . . . . . . 218
Trailer Sway Control (TSC) . . . . . . . . . . 334
Tow Mirrors . . . . . . . . . . . . . . . . . . . . . 48
Towing . . . . . . . . . . . . . . . . . . . . . . . . 307
Transfer Case . . . . . . . . . . . . . . . . . . 272
Transmission Automatic . . . . . . . . . . . . . . . . . . . . . 265
Fluid, Automatic . . . . . . . . . 354, 357
Temperature Gauge . . . . . . . . . . 145
Transportation Program, Courtesy . . . . . . . . . . . . . . . . . . . . . . 471
Trip Odometer . . . . . . . . . . . . . . . . . . 142
Truck-Camper Loading Information . . . . . . . . . . . . . . . . . . . . 253
Turn and Lane-Change Signals . . . . . . . . . . . . . . . . . . . . . . . . 181 Turn Signal
Bulb Replacement . . . . . . . . . . . . 378
U
Uniform Tire Quality Grading . . . 410
Universal Remote System . . . . . . 172Operation . . . . . . . . . . . . . . . . . . . . . 174
Programming . . . . . . . . . . . . . . . . . 172
Updates Software . . . . . . . . . . . . . . . . . . . . . . 189
USB Port . . . . . . . . . . . . . . . . . . . . . . . 197
Using This Manual . . . . . . . . . . . . . . . . 2
V
Vehicle Alarm System . . . . . . . . . . . . . . . . . . 44
Canadian Owners . . . . . . . . . . . . . . . 2
Control . . . . . . . . . . . . . . . . . . . . . . . 236
Identification Number (VIN) . . . 460
Load Limits . . . . . . . . . . . . . . . . . . . 248
Messages . . . . . . . . . . . . . . . . . . . . 164
Personalization . . . . . . . . . . . . . . . 165
Remote Start . . . . . . . . . . . . . . . . . . . 39
Security . . . . . . . . . . . . . . . . . . . . . . . . 44
Speed Messages . . . . . . . . . . . . . 164
Towing . . . . . . . . . . . . . . . . . . . . . . . . 430
Vehicle Ahead Indicator . . . . . . . . 154 Vehicle Care
Tire Pressure . . . . . . . . . . . . . . . . . 397
Vehicle Data Recording and Privacy . . . . . . . . . . . . . . . . . . . . . . . . 477
Ventilation, Air . . . . . . . . . . . . . . . . . . 231
Visors . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Voice Recognition . . . . . . . . . . . . . . 205
Voltage Devices and Wiring . . . . 380
Voltmeter Gauge . . . . . . . . . . . . . . . 145
W
Warning Brake System Light . . . . . . . . . . . 152
Caution and Danger . . . . . . . . . . . . . 3
Lane Departure (LDW) . . . . . . . 295
Warning Lights, Gauges, and Indicators . . . . . . . . . . . . . . . . . . . . . 137
Warnings Hazard Flashers . . . . . . . . . . . . . . 180
Washer Fluid . . . . . . . . . . . . . . . . . . . 366
Wheels Alignment and Tire Balance . . .411
Different Size . . . . . . . . . . . . . . . . . 409
Replacement . . . . . . . . . . . . . . . . . 412
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 407
Where to Put the Restraint . . . . . . 98
Wi-Fi . . . . . . . . . . . . . . . . . . . . . . . . . . . 482