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Driving and Operating 199
Trailer Towing
General Towing Information . . . . . . . . . . . 276
Driving Characteristics andTowing Tips . . . . . . . . . . . . . . . . . . . . . . . . . 276
Trailer Towing . . . . . . . . . . . . . . . . . . . . . . . . 280
Towing Equipment . . . . . . . . . . . . . . . . . . . . 284
Trailer Sway Control (TSC) . . . . . . . . . . . . . 294
Trailering App . . . . . . . . . . . . . . . . . . . . . . . . . 296
Conversions and Add-Ons
Add-On Electrical Equipment . . . . . . . . . . 306
Adding a Snow Plow or Similar Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . 306
Pickup Conversion to Chassis Cab . . . . . 308
Driving Information
Driving for Better Fuel Economy
Driving habits can affect fuel mileage. Here
are some driving tips to get the best fuel
economy possible:
.Set the climate controls to the desired
temperature after the engine is started,
or turn them off when not required.
.Avoid fast starts and accelerate smoothly.
.Brake gradually and avoid abrupt stops.
.Avoid idling the engine for long periods
of time.
.When road and weather conditions are
appropriate, use cruise control.
.Always follow posted speed limits or
drive more slowly when conditions
require.
.Keep vehicle tires properly inflated.
.Combine several trips into a single trip.
.Replace the vehicle's tires with the same
TPC Spec number molded into the tire's
sidewall near the size.
.Follow recommended scheduled
maintenance.
Distracted Driving
Distraction comes in many forms and can
take your focus from the task of driving.
Exercise good judgment and do not let other
activities divert your attention away from
the road. Many local governments have
enacted laws regarding driver distraction.
Become familiar with the local laws in
your area.
To avoid distracted driving, keep your eyes
on the road, keep your hands on the
steering wheel, and focus your attention on
driving.
.Do not use a phone in demanding driving
situations. Use a hands-free method to
place or receive necessary phone calls.
.Watch the road. Do not read, take notes,
or look up information on phones or
other electronic devices.
.Designate a front seat passenger to
handle potential distractions.
.Become familiar with vehicle features
before driving, such as programming
favorite radio stations and adjusting
climate control and seat settings. Program
all trip information into any navigation
device prior to driving.

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Driving and Operating 217
near a strong radio antenna signal causing
interference to the Keyless Access system.
SeeRemote Key Operation 015.
To shift out of P (Park), the vehicle must be
on and the brake pedal must be applied.
{Warning
Turning off the vehicle while moving may
cause loss of power assist in the brake
and steering systems and disable the
airbags. While driving, only shut the
vehicle off in an emergency.
Stopping the Engine/LOCK/OFF (No Indicator
Lights) : When the vehicle is stopped, press
ENGINE START/STOP once to turn the
engine off.
If the vehicle is in P (Park), the vehicle will
turn off, and Retained Accessory Power (RAP)
will remain active. See Retained Accessory
Power (RAP) 0220.
If the vehicle is not in P (Park), the vehicle
will return to accessory mode and display
the message SHIFT TO PARK in the Driver
Information Center (DIC). When the vehicle is
shifted into P (Park), the vehicle will turn off. The vehicle may have an electric steering
column lock. The lock is activated when the
ignition is turned off and driver door is
opened. A sound may be heard as the lock
actuates or releases. The steering column
lock may not release with the wheels turned
off center. If this happens, the vehicle may
not start. Move the steering wheel from left
to right while attempting to start the
vehicle. If this does not work, the vehicle
needs service.
Unless an emergency exists, do not turn the
engine off when the vehicle is moving. This
will cause a loss of power assist in the brake
and steering systems and disable the
airbags.
If the vehicle must be shut off in an
emergency:
1. If the vehicle cannot be pulled over, and must be shut off while driving, press and
hold ENGINE START/STOP button for
longer than two seconds, or press twice
in five seconds.
2. Brake using a firm and steady pressure. Do not pump the brakes repeatedly. This
may deplete power assist, requiring
increased brake pedal force. 3. Shift the vehicle to N (Neutral). This can
be done while the vehicle is moving.
After shifting to N (Neutral), firmly apply
the brakes and steer the vehicle to a
safe location.
4. Come to a complete stop, shift to P (Park), and make sure engine is off.
The shift lever must be in P (Park) to
turn the vehicle off.
5. Set the parking brake. See Electric
Parking Brake 0234.
{Warning
Turning off the vehicle while moving may
cause loss of power assist in the brake
and steering systems and disable the
airbags. While driving, only shut the
vehicle off in an emergency.
Accessory Mode (Amber Indicator Light) :
This mode allows some electrical accessories
to be used when the engine is off.
With the vehicle off, pressing the ENGINE
START/STOP button one time without the
brake pedal applied will place the vehicle in
accessory mode.

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Driving and Operating 241
The speedometer reading can be displayed
in either English or metric units. See
Instrument Cluster (Base Level)0112 or
Instrument Cluster (Uplevel) 0113. The
increment value used depends on the units
displayed.
Reducing Speed While Using Cruise Control
If cruise control is already activated:
.Press and hold SET– down until the
desired lower speed is reached, then
release it.
.To decrease vehicle speed in small
increments, briefly press SET– down. For
each press, the vehicle goes about 1 km/h
(1 mph) slower.
The speedometer reading can be displayed
in either English or metric units. See
Instrument Cluster (Base Level) 0112 or
Instrument Cluster (Uplevel) 0113. The
increment value used depends on the units
displayed.
Passing Another Vehicle While Using Cruise
Control
Use the accelerator pedal to increase the
vehicle speed. When you take your foot off
the accelerator pedal, the vehicle will slow
down to the previously set cruise speed.
While pressing the accelerator pedal or shortly following the release to override
cruise control, briefly pressing SET–
will
result in cruise control set to the current
vehicle speed.
Using Cruise Control on Hills
How well cruise control works on a hill
depends on the vehicle speed, the load, and
the steepness of the hill. When going up a
steep hill, you may have to apply the
accelerator pedal to maintain the set speed.
While going downhill, cruise braking helps
maintain driver selected speed.
Cruise Grade Braking is enabled when the
vehicle is started and cruise control is active.
It assists in maintaining driver selected
speed when driving on downhill grades by
using the engine and transmission to slow
the vehicle.
For other forms of descent control, see Hill
Descent Control (HDC) 0237, Automatic
Transmission 0223, and Tow/Haul Mode
0 227.
Ending Cruise Control
There are four ways to end cruise control:
.Lightly apply the brake pedal.
.Press*.
.Shift the transmission to N (Neutral).
.Press5.
Erasing Speed Memory
The cruise control set speed is erased from
memory if
5is pressed or the ignition is
turned off.
Adaptive Cruise Control (Camera)
If equipped, Adaptive Cruise Control (ACC)
allows the cruise control set speed and
following gap to be selected. Read this
entire section before using this system. The
following gap is the following time between
your vehicle and a vehicle detected directly
ahead in your path, moving in the same
direction. If no vehicle is detected in your
path, ACC works like regular cruise control.
ACC uses a windshield mounted front
camera sensor.
See Radio Frequency Statement 0413.
If a vehicle is detected in your path, ACC can
apply acceleration or limited, moderate
braking to maintain the selected following
gap. To disengage ACC, apply the brake.
If ACC is controlling the vehicle speed when
the Traction Control System (TCS) or
StabiliTrak/Electronic Stability Control (ESC)
system activates, ACC may automatically

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Vehicle Care 353
.The TPMS sensor matching process was
not done or not completed successfully
after rotating the tires. The malfunction
light and the DIC message should go off
after successfully completing the sensor
matching process. See "TPMS Sensor
Matching Process" later in this section.
.One or more TPMS sensors are missing or
damaged. The malfunction light and the
DIC message should go off when the
TPMS sensors are installed and the sensor
matching process is performed
successfully. See your dealer for service.
.Replacement tires or wheels do not match
the original equipment tires or wheels.
Tires and wheels other than those
recommended could prevent the TPMS
from functioning properly. SeeBuying
New Tires 0360.
.Operating electronic devices or being near
facilities using radio wave frequencies
similar to the TPMS could cause the TPMS
sensors to malfunction.
If the TPMS is not functioning properly, it
cannot detect or signal a low tire pressure
condition. See your dealer for service if the
TPMS malfunction light and DIC message
come on and stay on.
Tire Fill Alert (If Equipped)
This feature provides visual and audible
alerts outside the vehicle to help when
inflating an underinflated tire to the
recommended cold tire pressure.
When the low tire pressure warning light
comes on: 1. Park the vehicle in a safe, level place.
2. Set the parking brake firmly.
3. Place the vehicle in P (Park).
4. Add air to the tire that is underinflated. The turn signal lamp will flash.
When the recommended pressure is
reached, the horn sounds once and the
turn signal lamp will stop flashing and
briefly turn solid.
Repeat these steps for all underinflated tires
that have illuminated the low tire pressure
warning light.
{Warning
Overinflating a tire could cause the tire
to rupture and you or others could be
injured. Do not exceed the maximum (Continued)
Warning (Continued)
pressure listed on the tire sidewall. See
Tire Sidewall Labeling0346 and
Vehicle Load Limits 0210.
If the tire is overinflated by more than
35 kPa (5 psi), the horn will sound multiple
times and the turn signal lamp will continue
to flash for several seconds after filling
stops. To release and correct the pressure,
while the turn signal lamp is still flashing,
briefly press the center of the valve stem.
When the recommended pressure is reached,
the horn sounds once.
If the turn signal lamp does not flash within
15 seconds after starting to inflate the tire,
the tire fill alert has not been activated or is
not working.
If the hazard warning flashers are on, the
tire fill alert visual feedback will not work
properly.
The TPMS will not activate the tire fill alert
properly under the following conditions:
.There is interference from an external
device or transmitter.
.The air pressure from the inflation device
is not sufficient to inflate the tire.

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Customer Information 415
Vehicle Data Recording and
Privacy
The vehicle has a number of computers that
record information about the vehicle’s
performance and how it is driven or used.
For example, the vehicle uses computer
modules to monitor and control engine and
transmission performance, to monitor the
conditions for airbag deployment and
deploy them in a crash, and, if equipped, to
provide antilock braking to help the driver
control the vehicle. These modules may
store data to help the dealer technician
service the vehicle or to help GM improve
safety or features. Some modules may also
store data about how the vehicle is
operated, such as rate of fuel consumption
or average speed. These modules may retain
personal preferences, such as radio presets,
seat positions, and temperature settings.
Cybersecurity
GM collects information about the use of
your vehicle including operational and safety
related information. We collect this
information to provide, evaluate, improve,
and troubleshoot our products and services
and to develop new products and services.
The protection of vehicle electronics systems
and customer data from unauthorized
outside electronic access or control is
important to GM. GM maintains appropriate
security standards, practices, guidelines and
controls aimed at defending the vehicle and
the vehicle service ecosystem against
unauthorized electronic access, detecting
possible malicious activity in related
networks, and responding to suspected
cybersecurity incidents in a timely,
coordinated and effective manner. Security
incidents could impact your safety or
compromise your private data. To minimize
security risks, please do not connect your
vehicle electronic systems to unauthorized
devices or connect your vehicle to any
unknown or untrusted networks (such as
Bluetooth, WIFI or similar technology). In
the event you suspect any security incident
impacting your data or the safe operation of
your vehicle, please stop operating your
vehicle and contact your dealer.
Event Data Recorders
This vehicle is equipped with an Event Data
Recorder (EDR). The main purpose of an EDR
is to record, in certain crash or near
crash-like situations, such as an air bag
deployment or hitting a road obstacle, data
that will assist in understanding how a
vehicle’s systems performed. The EDR is
designed to record data related to vehicle
dynamics and safety systems for a short
period of time, typically 30 seconds or less.
The EDR in this vehicle is designed to record
such data as:
.How various systems in your vehicle were
operating;
.Whether or not the driver and passenger
safety belts were buckled/fastened;
.How far (if at all) the driver was
depressing the accelerator and/or brake
pedal; and,
.How fast the vehicle was traveling.
These data can help provide a better
understanding of the circumstances in which
crashes and injuries occur.
Note
EDR data are recorded by your vehicle only
if a non-trivial crash situation occurs; no
data are recorded by the EDR under normal

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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OnStar 419
OnStar Additional
Information
In-Vehicle Audio Messages
Audio messages may play important
information at the following times:
.Prior to vehicle purchase. PressQto set
up an account.
.After change in ownership and at
90 days.
Transferring Service
PressQto request account transfer
eligibility information. The Advisor can
cancel or change account information.
Selling/Transferring the Vehicle
Call 1-888-4ONSTAR (1-888-466-7827)
immediately to terminate your OnStar or
connected services if the vehicle is disposed
of, sold, transferred, or if the lease ends.
Reactivation for Subsequent Owners
PressQand follow the prompts to speak to
an Advisor as soon as possible. The Advisor
will update vehicle records and explain
OnStar or connected service options.
How OnStar Service Works
Automatic Crash Response, Emergency
Services, Crisis Assist, Stolen Vehicle
Assistance, Remote Services, and Roadside
Assistance are available on most vehicles.
Not all OnStar services are available
everywhere or on all vehicles. For more
information, a full description of OnStar
services, system limitations, and OnStar User
Terms, Privacy Statement, and Software
Terms:
.Call 1-888-4ONSTAR (1-888-466-7827).
.See www.onstar.com (U.S.).
.See www.onstar.ca (Canada).
.Call TTY 1-877-248-2080.
.PressQto speak with an Advisor.
OnStar or connected services cannot work
unless the vehicle is in a place where OnStar
has an agreement with a wireless service
provider for service in that area. The
wireless service provider must also have
coverage, network capacity, reception, and
technology compatible with OnStar or
connected services. Service involving location
information about the vehicle cannot work
unless GPS signals are available,
unobstructed, and compatible with the
OnStar hardware. OnStar or connected services may not work if the OnStar
equipment is not properly installed or it has
not been properly maintained. If equipment
or software is added, connected,
or modified, OnStar or connected services
may not work. Other problems beyond the
control of OnStar
—such as hills, tall
buildings, tunnels, weather, electrical system
design and architecture of the vehicle,
damage to the vehicle in a crash, or wireless
phone network congestion or jamming —
may prevent service.
See Radio Frequency Statement 0413.
Services for People with Disabilities
Advisors provide services to help with
physical disabilities and medical conditions.
Press
Qto help:
.Locate a gas station with an attendant to
pump gas.
.Find a hotel, restaurant, etc., that meets
accessibility needs.
.Provide directions to the closest hospital
or pharmacy in urgent situations.

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OnStar 421
Vehicle and Power Issues
OnStar services require a vehicle electrical
system, wireless service, and GPS satellite
technologies to be available and operating
for features to function properly. These
systems may not operate if the battery is
discharged or disconnected.
Add-on Electrical Equipment
The OnStar system is integrated into the
electrical architecture of the vehicle. Do not
add any electrical equipment. SeeAdd-On
Electrical Equipment 0306. Added electrical
equipment may interfere with the operation
of the OnStar system and cause it to not
operate.
Vehicle Software Updates
OnStar or GM may remotely deliver
software updates or changes to the vehicle
without further notice or consent. These
updates or changes may enhance or
maintain safety, security, or the operation
of the vehicle or the vehicle systems.
Software updates or changes may affect or
erase data or settings that are stored in the
vehicle, such as saved navigation
destinations or pre-set radio stations.
Neither OnStar nor GM is responsible for
any affected or erased data or settings. These updates or changes may also collect
personal information. Such collection is
described in the OnStar privacy statement or
separately disclosed at the time of
installation. These updates or changes may
also cause a system to automatically
communicate with GM servers to collect
information about vehicle system status,
identify whether updates or changes are
available, or deliver updates or changes. An
active OnStar agreement constitutes consent
to these software updates or changes and
agreement that either OnStar or GM may
remotely deliver them to the vehicle.
Privacy
The complete OnStar Privacy Statement may
be found at www.onstar.com (U.S.),
or www.onstar.ca (Canada). We recommend
that you review it. If you have any
questions, call 1-888-4ONSTAR
(1-888-466-7827) or press
Qto speak with
an Advisor. Users of wireless
communications are cautioned that the
privacy of any information sent via wireless
cellular communications cannot be assured.
Third parties may unlawfully intercept or
access transmissions and private
communications without consent.
OnStar - Software Acknowledgements
To obtain the source code under GPL, LGPL,
MPL, and other open source licenses, that is
contained in this product, please visit
https://opensource.lge.com. In addition to
the source code, all referred license terms,
warranty disclaimers, and copyright notices
are available for download. This offer is valid
for a period of three years after our last
shipment of this product. This offer is valid
to anyone in receipt of this information.
*Provided through LG Electronics Inc., who is
solely responsible for provisions of related
OSS compliance.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
434 Index
ReplacementGlass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331
Replacement Parts Airbags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
Replacing Airbag System . . . . . . . . . . . . . . . . . . . . . . . . . . 74
LATCH System Parts After a Crash . . . . . . 91
Seat Belt System Parts after a
Crash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Reporting Safety Defects
Canadian Government . . . . . . . . . . . . . . . . . 414
General Motors . . . . . . . . . . . . . . . . . . . . . . . . 414
U.S. Government . . . . . . . . . . . . . . . . . . . . . . . 414
Restraints Where to Put . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Retained Accessory Power (RAP) . . . . . . . . . 220
Reverse Tilt Mirrors . . . . . . . . . . . . . . . . . . . . . . . 38
Roads Driving, Wet . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Roadside Assistance Program . . . . . . . . . . . . 408
Roof
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Rotation, Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . 357
Routing, Engine Drive Belt . . . . . . . . . . . . . . . 404
Running Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Running the Vehicle While Parked . . . . . . . 223S
Safety Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Safety Defects Reporting Canadian Government . . . . . . . . . . . . . . . . . 414
General Motors . . . . . . . . . . . . . . . . . . . . . . . . 414
U.S. Government . . . . . . . . . . . . . . . . . . . . . . . 414
Safety System Check . . . . . . . . . . . . . . . . . . . . . 63
Satellite Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Scheduling Appointments . . . . . . . . . . . . . . . . 410
Seat Belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57 Buckle To Drive . . . . . . . . . . . . . . . . . . . . . . . . . 58
Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Extender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
How to Wear Seat Belts Properly . . . . . . . 58
Lap-Shoulder Belt . . . . . . . . . . . . . . . . . . . . . . . 60
Reminders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Replacing after a Crash . . . . . . . . . . . . . . . . . 64
Use During Pregnancy . . . . . . . . . . . . . . . . . . 63
Seats Adjustment, Front . . . . . . . . . . . . . . . . . . . . . . 48
Center Seat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Head Restraints . . . . . . . . . . . . . . . . . . . . . . . . . 47
Heated and Ventilated, Front . . . . . . . . . . . 54
Heated, Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Lumbar Adjustment, Front . . . . . . . . . . . . . . 50
Massage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Seats (cont'd)
Power Adjustment, Front . . . . . . . . . . . . . . . 49
Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Reclining Seatbacks . . . . . . . . . . . . . . . . . . . . . 49
Underseat Storage . . . . . . . . . . . . . . . . . . . . . 100
Securing Child Restraints . . . . . . . . . . . . . . 92, 95
Security Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Vehicle Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Accessories and Modifications . . . . . . . . . 310
Climate Control System . . . . . . . . . . . . . . . . . 191
Doing Your Own Work . . . . . . . . . . . . . . . . . . 311
Electric Parking Brake Light . . . . . . . . . . . . 124
Maintenance Records . . . . . . . . . . . . . . . . . 400
Maintenance, General Information . . . . . 393
Parts Identification . . . . . . . . . . . . . . . . . . . . . 401
Scheduling Appointments . . . . . . . . . . . . . . 410
Services
Special Application . . . . . . . . . . . . . . . . . . . . . 397
Servicing the Airbag . . . . . . . . . . . . . . . . . . . . . . .73
Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181, 183
Shift Lock Control Function Check, Automatic Transmission . . . . . . . . . . . . . . . . 330
Shifting Into Park . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220