
GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 399
.Spray nozzle with a 40 degree wide angle
spray pattern or wider must be used.
.Nozzle must be kept at least 30 cm (1 ft)
away from all surfaces.
Automatic Car Wash
Caution
Some automatic car washes can cause
damage to the vehicle, wheels and
ground effects. Automatic car washes are
not recommended, due to lack of
clearance for the undercarriage and/or
wide rear tires and wheels.
Caution
Automatic car washes can cause damage
to the vehicle, wheels, ground effects,
and convertible top (if equipped).
Do not use automatic car washes due to
lack of clearance for the undercarriage,
wide rear tires, and wheels.
If using an automatic car wash, follow with
the car wash instructions. The windshield
wiper and rear window wiper, if equipped, must be turned off. Remove any accessories
that may be damaged or interfere with the
car wash equipment.
See
Power Assist Steps 030 for cleaning
information.
Rinse the vehicle well, before washing and
after, to remove all cleaning agents
completely. If they are allowed to dry on
the surface, they could stain.
Dry the finish with a soft, clean chamois or
an all-cotton towel to avoid surface
scratches and water spotting.
Finish Care
Application of aftermarket clearcoat sealant/
wax materials is not recommended.
If painted surfaces are damaged, see your
dealer to have the damage assessed and
repaired. Foreign materials such as calcium
chloride and other salts, ice melting agents,
road oil and tar, tree sap, bird droppings,
chemicals from industrial chimneys, etc., can
damage the vehicle's finish if they remain
on painted surfaces. Wash the vehicle as
soon as possible. If necessary, use
non-abrasive cleaners that are marked safe
for painted surfaces to remove foreign
matter. Occasional hand waxing or mild polishing
should be done to remove residue from the
paint finish. See your dealer for approved
cleaning products.
Do not apply waxes or polishes to uncoated
plastic, vinyl, rubber, decals, simulated
wood, or flat paint as damage can occur.
Caution
Machine compounding or aggressive
polishing on a basecoat/clearcoat paint
finish may damage it. Use only
non-abrasive waxes and polishes that are
made for a basecoat/clearcoat paint finish
on the vehicle.
To keep the paint finish looking new, keep
the vehicle garaged or covered whenever
possible.
Protecting Exterior Bright Metal Moldings
Caution
Failure to clean and protect the bright
metal moldings can result in a hazy
white finish or pitting. This damage
would not be covered by the vehicle
warranty.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Customer Information 431
I:View service records from your
dealership and add your own.
D: Select a dealer and view locations,
maps, phone numbers, and hours.
r: Track your vehicle’s warranty
information.
J: View active recalls by Vehicle
Identification Number (VIN). See Vehicle
Identification Number (VIN) 0423.
H:Manage your profile and payment
information. View your GM Rewards Card
earnings and My GMC Rewards points.
F: Chat live with online help
representatives.
Visit my.gmc.com and create an account
today.
GMC Owner Centre (Canada)
mygmccanada.ca
Visit the GMC Owner Centre at
mygmccanada.ca (English) or
my.gmccanada.ca (French) to access similar
benefits to the U.S. site.
GM Mobility Reimbursement
Program
This program is available to qualified
applicants for cost reimbursement, up to
certain limits, of eligible aftermarket
adaptive equipment required for the vehicle,
such as hand controls or a wheelchair/
scooter lift for the vehicle.
To learn about the GM Mobility program,
see www.gmmobility.com or call the GM
Mobility Assistance Center at 1-800-323-9935.
Text Telephone (TTY) users, call
1-800-833-9935.
General Motors of Canada also has a
Mobility program. See www.gm.ca, or call
1-800-GM-DRIVE (800-463-7483) for details.
TTY users call 1-800-263-3830.
Roadside Assistance Program
For U.S.-purchased vehicles, call
1-888-881-3302; (Text Telephone (TTY):
1-888-889-2438).
For Canadian-purchased vehicles, call
1-800-268-6800.
Service is available 24 hours a day, 365 days
a year.
Calling for Assistance
When calling Roadside Assistance, have the
following information ready:
.Your name, home address, and home
telephone number
.Telephone number of your location
.Location of the vehicle
.Model, year, color, and license plate
number of the vehicle
.Odometer reading, Vehicle Identification
Number (VIN), and delivery date of the
vehicle
.Description of the problem
Coverage
Services are provided for the duration of the
vehicle's powertrain warranty.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
436 Customer Information
Customer Literature
Owner’s manuals are written specifically for
owners and are intended to provide basic
operational information about the vehicle.
The owner’s manual includes the
Maintenance Schedule for all models.
Customer literature publications available for
purchase include owner’s manuals, warranty
manuals, and portfolios. Portfolios include an
owner’s manual, warranty manual,
if applicable, and zip lock bag or pouch.
Current and Past Models
Service manuals and customer literature are
available for many current and past model
year GM vehicles.
To order, call 1-800-551-4123 Monday–Friday,
8:00 a.m.–6:00 p.m. eastern time
For credit card orders only (VISA,
MasterCard, or Discover), see Helm, Inc. at:
www.helminc.com.
To order by mail, write to:
Helm, Incorporated
Attention: Customer Service
47911 Halyard Drive
Plymouth, MI 48170
Make checks payable in U.S. funds.
Radio Frequency Statement
This vehicle uses license-exempt transmitters
/ receivers / systems that operate on a
radio frequency that complies with Part 15/
Part 18 of the Federal Communications
Commission (FCC) rules and with Innovation,
Science and Economic Development (ISED)
Canada's license-exempt RSS(s) / RSP-100 /
ICES-GEN.
Operation is subject to the following two
conditions:1. The device may not cause harmful interference.
2. The device must accept any interference received, including interference that may
cause undesired operation of the device.
Changes or modifications to any of these
systems by other than an authorized service
facility could void authorization to use this
equipment.
Reporting Safety Defects
Reporting Safety Defects to the
United States Government
If you believe that your vehicle has a
defect which could cause a crash or
could cause injury or death, you should
immediately inform the National
Highway Traffic Safety Administration
(NHTSA) in addition to notifying General
Motors.
If NHTSA receives similar complaints, it
may open an investigation, and if it
finds that a safety defect exists in a
group of vehicles, it may order a recall
and remedy campaign. However, NHTSA
cannot become involved in individual
problems between you, your dealer,
or General Motors.
To contact NHTSA, you may call the
Vehicle Safety Hotline toll-free at
1-888-327-4236 (TTY: 1-800-424-9153); go
to http://www.safercar.gov; or
write to:

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
438 Customer Information
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 driving conditions and no personal data
(e.g., name, gender, age, and crash location)
are recorded. However, other parties, such
as law enforcement, could combine the EDR
data with the type of personally identifying
data routinely acquired during a crash
investigation.
To read data recorded by an EDR, special
equipment is required, and access to the
vehicle or the EDR is needed. In addition to
the vehicle manufacturer, other parties, such
as law enforcement, that have the special
equipment, can read the information if they
have access to the vehicle or the EDR.
GM will not access these data or share it
with others except: with the consent of the
vehicle owner or, if the vehicle is leased,
with the consent of the lessee; in response
to an official request by police or similar
government office; as part of GM's defense
of litigation through the discovery process;
or, as required by law. Data that GM collects
or receives may also be used for GM
research needs or may be made available to
others for research purposes, where a need
is shown and the data is not tied to a
specific vehicle or vehicle owner.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./Cana-
da/Mexico-14632426) - 2021 - CRC - 11/5/20
448 Index
IndexA
Accessories and Modifications . . . . . . . . . . . 323
Accessory Power . . . . . . . . . . . . . . . . . . . . . . . . . 236
Active Fuel Management . . . . . . . . . . . . . . . . 237
Adaptive Cruise Control . . . . . . . . . . . . . . . . . . 256
Add-On Electrical Equipment . . . . . . . . . . . . . .318
Adding a Snow Plow or SimilarEquipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .318
Additional Information OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
Additional Maintenance and Care . . . . . . . . .415
Adjustments Lumbar, Front Seats . . . . . . . . . . . . . . . . . . . . 48
Agreements
Trademarks and License . . . . . . . . . . . . . . . 195
Air Cleaner/Filter, Engine . . . . . . . . . . . . . . . . 334
Air Conditioning . . . . . . . . . . . . . . . . . . . . 204, 206
Air Filter Life System . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333
Air Filter, Passenger Compartment . . . . . . . 209
Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
Airbag System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
How Does an Airbag Restrain? . . . . . . . . . . 64
Passenger Sensing System . . . . . . . . . . . . . . 66
What Makes an Airbag Inflate? . . . . . . . . . 64
What Will You See after an AirbagInflates? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Airbag System (cont'd)
When Should an Airbag Inflate? . . . . . . . . 63
Where Are the Airbags? . . . . . . . . . . . . . . . . 62
Airbags Adding Equipment to the Vehicle . . . . . . . 69
Passenger Status Indicator . . . . . . . . . . . . . . 114
Readiness Light . . . . . . . . . . . . . . . . . . . . . . . . . 114
Servicing Airbag-Equipped Vehicles . . . . . . 69
System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Alarm Vehicle Security . . . . . . . . . . . . . . . . . . . . . . . . . 31
Alert
Lane Change . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
Side Blind Zone (SBZA) . . . . . . . . . . . . . . . . . 280
All-Season Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 361
All-Terrain Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 362
AM-FM Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Antenna Fixed Mast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
Multi-band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
Antilock Brake System (ABS) . . . . . . . . . . . . . 246
Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Appearance Care Exterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
Apple CarPlay and Android Auto . . . . . . . . . .185