fuel GMC SIERRA 2021 Repair Manual

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Service and Maintenance 411
missing boots, loose or missing boot
clamps, center bearing excessive
looseness, missing or loose fasteners.
.Check restraint system components. See
Safety System Check060.
.Visually inspect fuel system for damage
or leaks.
.Visually inspect exhaust system and
nearby heat shields for loose or damaged
parts.
.Lubricate body components. See Exterior
Care 0398.
.Check starter switch. See Starter Switch
Check 0347.
.Check automatic transmission shift lock
control function. See Automatic
Transmission Shift Lock Control Function
Check 0347.
.Check ignition transmission lock. See
Ignition Transmission Lock Check 0347.
.Check parking brake and automatic
transmission park mechanism. See Park
Brake and P (Park) Mechanism Check
0 347.
.Check accelerator pedal for damage, high
effort, or binding. Replace if needed.
.Visually inspect gas strut for signs of
wear, cracks, or other damage. Check the
hold open ability of the strut. If the hold
open is low, service the gas strut. See Gas
Strut(s) 0349.
.Inspect sunroof track and seal,
if equipped. See Sunroof043.
.Verify spare tire key lock operation and
lubricate as needed. See Tire Changing
0 381.
.Visually inspect the spare tire to ensure
that it is tightly stowed under the vehicle.
Push, pull, and try to turn the tire. If the
spare tire moves, tighten as necessary.
See Tire Changing 0381.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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Service and Maintenance 413
Footnotes—Maintenance Schedule
Additional Required Services - Normal
(1) Or every four years, whichever comes
first. If driving in dusty conditions, inspect
the filter at each oil change or more often
as needed. See Engine Air Cleaner/Filter
0 334.
(2) Or every two years, whichever comes
first. More frequent replacement may be
needed if the vehicle is driven in areas with
heavy traffic, poor air quality, areas with
high dust levels or are sensitive to
environmental allergens. Filter replacement
may also be needed if you notice reduced
airflow, windows fogging up, or odors. Your
local GM Service location can help you
determine when it is the right time to
replace your filter.
(3) Visually check all fuel and vapor lines
and hoses for proper attachment,
connection, routing, and condition.
(4) Do not directly power wash the transfer
case and/or front/rear axle output seals.
High pressure water can overcome the seals
and contaminate the fluid. Contaminated
fluid will decrease the life of the transfer
case and/or drive axles and should be
replaced. (5)
Or every five years, whichever comes
first. See Cooling System 0335.
(6) Or every 10 years, whichever comes first.
Inspect for fraying, excessive cracking,
or damage; replace, if needed.
(7) Replace brake fluid every five years. See
Brake Fluid 0343.
(8) Or every 12 months, whichever comes
first. See Wiper Blade Replacement 0348.
(9) Or every 10 years, whichever comes first.
See Gas Strut(s) 0349.
(10) Replace air conditioning desiccant every
seven years.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Service and Maintenance 415
Footnotes—Maintenance Schedule
Additional Required Services - Severe
(1) Or every four years, whichever comes
first. If driving in dusty conditions, inspect
the filter at each oil change or more often
as needed. See Engine Air Cleaner/Filter
0 334.
(2) Or every two years, whichever comes
first. More frequent replacement may be
needed if the vehicle is driven in areas with
heavy traffic, poor air quality, areas with
high dust levels or are sensitive to
environmental allergens. Filter replacement
may also be needed if you notice reduced
airflow, windows fogging up, or odors. Your
local GM Service location can help you
determine when it is the right time to
replace your filter.
(3) Visually check all fuel and vapor lines
and hoses for proper attachment,
connection, routing, and condition.
(4) Do not directly power wash the transfer
case and/or front/rear axle output seals.
High pressure water can overcome the seals
and contaminate the fluid. Contaminated
fluid will decrease the life of the transfer
case and/or drive axles and should be
replaced. (5)
Or every five years, whichever comes
first. See Cooling System 0335.
(6) Or every 10 years, whichever comes first.
Inspect for fraying, excessive cracking,
or damage; replace, if needed.
(7) Replace brake fluid every five years. See
Brake Fluid 0343.
(8) Or every 12 months, whichever comes
first. See Wiper Blade Replacement 0348.
(9) Or every 10 years, whichever comes first.
See Gas Strut(s) 0349.
(10) Replace air conditioning desiccant every
seven years.
Special Application Services
.Severe Commercial Use Vehicles Only:
Lubricate chassis components every oil
change.
.Have underbody flushing service
performed. See "Underbody Maintenance"
in Exterior Care 0398.
Additional Maintenance
and Care
Your vehicle is an important investment and
caring for it properly may help to avoid
future costly repairs. To maintain vehicle
performance, additional maintenance
services may be required.
It is recommended that your dealer perform
these services —their trained dealer
technicians know your vehicle best. Your
dealer can also perform a thorough
assessment with a multi-point inspection to
recommend when your vehicle may need
attention.
The following list is intended to explain the
services and conditions to look for that may
indicate services are required.
Battery
The 12-volt battery supplies power to start
the engine and operate any additional
electrical accessories.
.To avoid break-down or failure to start
the vehicle, maintain a battery with full
cranking power.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
416 Service and Maintenance
.Trained dealer technicians have the
diagnostic equipment to test the battery
and ensure that the connections and
cables are corrosion-free.
Belts
.Belts may need replacing if they squeak
or show signs of cracking or splitting.
.Trained dealer technicians have access to
tools and equipment to inspect the belts
and recommend adjustment or
replacement when necessary.
Brakes
Brakes stop the vehicle and are crucial to
safe driving.
.Signs of brake wear may include chirping,
grinding, or squealing noises, or difficulty
stopping.
.Trained dealer technicians have access to
tools and equipment to inspect the brakes
and recommend quality parts engineered
for the vehicle.
Fluids
Proper fluid levels and approved fluids
protect the vehicle’s systems and
components. See Recommended Fluids and
Lubricants 0418 for GM approved fluids.
.Engine oil and windshield washer fluid
levels should be checked at every fuel fill.
.Instrument cluster lights may come on to
indicate that fluids may be low and need
to be filled.
Hoses
Hoses transport fluids and should be
regularly inspected to ensure that there are
no cracks or leaks. With a multi-point
inspection, your dealer can inspect the hoses
and advise if replacement is needed.
Lamps
Properly working headlamps, taillamps, and
brake lamps are important to see and be
seen on the road.
.Signs that the headlamps need attention
include dimming, failure to light, cracking,
or damage. The brake lamps need to be
checked periodically to ensure that they
light when braking.
.With a multi-point inspection, your dealer
can check the lamps and note any
concerns.
Shocks and Struts
Shocks and struts help aid in control for a
smoother ride.
.Signs of wear may include steering wheel
vibration, bounce/sway while braking,
longer stopping distance, or uneven
tire wear.
.As part of the multi-point inspection,
trained dealer technicians can visually
inspect the shocks and struts for signs of
leaking, blown seals, or damage, and can
advise when service is needed.
Tires
Tires need to be properly inflated, rotated,
and balanced. Maintaining the tires can save
money and fuel, and can reduce the risk of
tire failure.
.Signs that the tires need to be replaced
include three or more visible treadwear
indicators; cord or fabric showing through
the rubber; cracks or cuts in the tread or
sidewall; or a bulge or split in the tire.
.Trained dealer technicians can inspect and
recommend the right tires. Your dealer
can also provide tire/wheel balancing
services to ensure smooth vehicle
operation at all speeds. Your dealer sells
and services name brand tires.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Service and Maintenance 419
UsageFluid/Lubricant
Key Lock Cylinders, Hood Hinges, Body Door Hinge Pins, Tailgate Hinge and Linkage, Fuel Door Hinge, Tailgate Handle Pivot Points, Hinges, Latch Bolt, and Linkage Multi-Purpose Lubricant, Superlube. See your dealer.
Transfer Case (Four-Wheel Drive) DEXRON-VI Automatic Transmission Fluid. Windshield Washer Automotive windshield washer fluid that meets regional freeze protection requirements.
Maintenance Replacement Parts
Replacement parts identified below by name, part number, or specification can be obtained from your dealer.
If the vehicle has a diesel engine, see the Duramax diesel supplement.
Part GM Part Number ACDelco Part Number
Engine Air Cleaner/Filter
IWith high capacity air cleaner 84121219 A3244C
IWithout high capacity air cleaner 84121217 A3246C

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Technical Data 425
ApplicationCapacities
Metric English
Engine Oil with Filter
I2.7L L4 Engine 5.7 L
6.0 qt
I4.3L V6 Engine 5.7 L
6.0 qt
I5.3L V8 Engine 7.6 L
8.0 qt
I6.2L V8 Engine 7.6 L
8.0 qt
Fuel Tank IStandard and Short Box (except 2WD Diesel) 90.8 L
24.0 gal
IStandard and Short Box (2WD Diesel) 83.3 L
22.0 gal
ILong Box 107.1 L
28.3 gal

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
432 Customer Information
In the U.S., anyone driving the vehicle is
covered. In Canada, a person driving the
vehicle without permission from the owner
is not covered.
Roadside Assistance is not a part of the New
Vehicle Limited Warranty. General Motors
North America and GMC reserve the right to
make any changes or discontinue the
Roadside Assistance program at any time
without notification.
General Motors North America and GMC
reserve the right to limit services or
payment to an owner or driver if they
decide the claims are made too often, or the
same type of claim is made many times.
Services Provided
.Emergency Fuel Delivery:Delivery of
enough fuel for the vehicle to get to the
nearest service station.
.Lock-Out Service: Service to unlock the
vehicle if you are locked out. A remote
unlock may be available if you have
OnStar. For security reasons, the driver
must present identification before this
service is given.
.Emergency Tow from a Public Road or
Highway: Tow to the nearest GMC dealer
for warranty service, or if the vehicle was in a crash and cannot be driven.
Assistance is not given when the vehicle
is stuck in the sand, mud, or snow.
.Flat Tire Change:
Service to change a flat
tire with the spare tire. The spare tire,
if equipped, must be in good condition
and properly inflated. It is the owner's
responsibility for the repair or
replacement of the tire if it is not covered
by the warranty.
.Battery Jump Start: Service to jump start
a dead battery.
.Trip Interruption Benefits and Assistance:
If your trip is interrupted due to a
warranty event, incidental expenses may
be reimbursed within the Powertrain
warranty period. Items considered are
reasonable and customary hotel, meals,
rental car, or a vehicle being delivered
back to the customer, up to 500 miles.
Services Not Included in Roadside
Assistance
.Impound towing caused by violation of
any laws
.Legal fines
.Mounting, dismounting, or changing of
snow tires, chains, or other traction
devices Service is not provided if a vehicle is in an
area that is not accessible to the service
vehicle or is not a regularly traveled or
maintained public road, which includes ice
and winter roads. Off-road use is not
covered.
Services Specific to Canadian-Purchased
Vehicles
.Fuel Delivery:
Reimbursement is up to 7 L.
Diesel fuel delivery may be restricted.
Propane and other fuels are not provided
through this service.
.Lock-Out Service: Vehicle registration is
required.
.Trip Interruption Benefits and Assistance:
Must be over 150 km from where your
trip was started to qualify.
Pre-authorization, original detailed
receipts, and a copy of the repair orders
are required. Once authorization has been
received, the Roadside Assistance advisor
will help to make arrangements and
explain how to receive payment.
.Alternative Service: If assistance cannot
be provided right away, the Roadside
Assistance advisor may give permission to
get local emergency road service. You will
receive payment, up to $100, after
sending the original receipt to Roadside

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Customer Information 433
Assistance. Mechanical failures may be
covered, however any cost for parts and
labor for repairs not covered by the
warranty are the owner’s responsibility.
Scheduling Service Appointments
When the vehicle requires warranty service,
contact your dealer and request an
appointment. By scheduling a service
appointment and advising the service
consultant of your transportation needs,
your dealer can help minimize your
inconvenience.
If the vehicle cannot be scheduled into the
service department immediately, keep
driving it until it can be scheduled for
service, unless, of course, the problem is
safety related. If it is, please call your
dealership, let them know this, and ask for
instructions.
If your dealer requests you to bring the
vehicle for service, you are urged to do so
as early in the work day as possible to
allow for same-day repair.
Courtesy Transportation Program
To enhance your ownership experience, we
and our participating dealers are proud to
offer Courtesy Transportation, a customer
support program for vehicles with the
Bumper-to-Bumper (Base Warranty Coverage
period in Canada), extended powertrain,
and/or hybrid-specific warranties in both the
U.S. and Canada.
Several Courtesy Transportation options are
available to assist in reducing inconvenience
when warranty repairs are required.
Courtesy Transportation is not a part of the
New Vehicle Limited Warranty. A separate
manual entitled“Limited Warranty and
Owner Assistance Information” furnished
with each new vehicle provides detailed
warranty coverage information.
Transportation Options
Warranty service can generally be
completed while you wait. However, if you
are unable to do so, your dealer may offer
the following transportation options:
Shuttle Service
This includes one-way or round-trip shuttle
service within reasonable time and distance
parameters of your dealer's area. Public Transportation or Fuel Reimbursement
If overnight warranty repairs are needed,
and public transportation is used, the
expense must be supported by original
receipts and within the maximum amount
allowed by GM. If U.S. customers arrange
their own transportation, limited
reimbursement for reasonable fuel expenses
may be available. Claim amounts should
reflect actual costs and be supported by
original receipts. See your dealer for
information.
Courtesy Rental Vehicle
For an overnight warranty repair, the dealer
may provide an available courtesy rental
vehicle or provide for reimbursement of a
rental vehicle. Reimbursement is limited and
must be supported by original receipts as
well as a signed and completed rental
agreement and meet state/provincial, local,
and rental vehicle provider requirements.
Requirements vary and may include
minimum age requirements, insurance
coverage, credit card, etc. Additional fees
such as fuel, rental vehicle insurance, taxes,
levies, usage fees, excessive mileage,
or rental usage beyond the completion of
the repair are also your responsibility.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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Customer Information 437
Administrator, NHTSA
1200 New Jersey Avenue, S.E.
Washington, D.C. 20590
You can also obtain other information
about motor vehicle safety from
http://www.safercar.gov
.
Reporting Safety Defects to the
Canadian Government
If you live in Canada, and you believe
that the vehicle has a safety defect,
notify Transport Canada immediately,
and notify General Motors of Canada
Company. Call Transport Canada at
1-800-333-0510; go to:
www.tc.gc.ca/recalls (English)
www.tc.gc.ca/rappels (French)
or write to:
Transport Canada
Motor Vehicle Safety Directorate
Defect Investigations and Recalls
Division
80 Noel Street
Gatineau
,QC J8Z 0A1
Reporting Safety Defects to
General Motors
In addition to notifying NHTSA (or Transport
Canada) in a situation like this, notify
General Motors.
In the U.S., call 1-800-462-8782, or write:
GMC Customer Assistance Center
P.O. Box 33172
Detroit, MI 48232-5172
In Canada, call 1-800-263-3777 (English) or
1-800-263-7854 (French), or write:
General Motors of Canada Company
Customer Care Centre, Mail Code:
CA1-163-005
1908 Colonel Sam Drive
Oshawa, Ontario L1H 8P7
In Mexico, call 800-466-0812 or
800-466-0801.
In other Central America and Caribbean
Countries, call 52-555-901-2369.
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.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
446 Connected Services
PressQ, then ask the Advisor to download
directions to the vehicle’s navigation system,
if equipped. After the call ends, the
navigation screen will provide prompts to
begin driving directions. Routes that are sent
to the navigation screen can only be
canceled through the navigation system.
See www.onstar.com (U.S.) or www.onstar.ca
(Canada).
Connections
The following services help with staying
connected.
For coverage maps, see www.onstar.com
(U.S.) or www.onstar.ca (Canada).
Ensuring Security
.Change the default passwords for the
Wi-Fi hotspot and myGMC mobile
application. Make these passwords
different from each other and use a
combination of letters and numbers to
increase the security.
.Change the default name of the SSID
(Service Set Identifier). This is your
network’s name that is visible to other
wireless devices. Choose a unique name
and avoid family names or vehicle
descriptions. Wi-Fi Hotspot (If Equipped)
The vehicle may have a built-in Wi-Fi
hotspot that provides access to the Internet
and web content at 4G LTE speed. Up to
seven mobile devices can be connected.
A data plan is required. Use the in-vehicle
controls only when it is safe to do so.
1. To retrieve Wi-Fi hotspot information, press
=to open the OnStar app on the
infotainment display, then select Wi-Fi
Hotspot. On some vehicles, touch Wi-Fi
or Wi-Fi Settings on the screen.
2. The Wi-Fi settings will display the Wi-Fi hotspot name (SSID), password, and on
some vehicles, the connection type (no
Internet connection, 3G, 4G, 4G LTE), and
signal quality (poor, good, excellent). The
LTE icon shows connection to Wi-Fi. It is
possible that the icon may not illuminate
even though the vehicle has an active
connection.
3. To change the SSID or password, press
Qor call 1-888-4ONSTAR to connect
with an Advisor. On some vehicles, the
SSID and password can be changed in
the Wi-Fi Hotspot menu. After initial set-up, your vehicle’s Wi-Fi
hotspot will connect automatically to your
mobile devices. Manage data usage by
turning Wi-Fi on or off on your mobile
device, using the myGMC mobile app, or by
contacting an OnStar Advisor. On some
vehicles, Wi-Fi can also be managed from
the Wi-Fi Hotspot menu.
MyGMC Mobile App (If Available)
Download the myGMC mobile app to
compatible Apple and Android smartphones.
GMC users can access the following services
from a smartphone:
.Remotely start/stop the vehicle,
if factory-equipped.
.Lock/unlock doors, if equipped with
automatic locks.
.Activate the horn and lamps.
.Check the vehicle’s fuel level, oil life,
or tire pressure, if factory-equipped with
the Tire Pressure Monitor System.
.Send destinations to the vehicle.
.Locate the vehicle on a map (U.S.
market only).
.Turn the vehicle's Wi-Fi hotspot on/off,
manage settings, and monitor data
consumption, if equipped.
.Locate a dealer and schedule service.