2021 GMC SIERRA 436

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 2/18/21
Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Keys, Doors, and Windows . . . . . . . . . . . . . . . 7
Seats and Restraints . . . . . . . . . . . . . . . . . . . . . 45
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Instruments and Controls . . . . . . . . . . . . . . . 99
Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Infotainment System . . . . . . . . . . . . . . . . . . . 148
Climate Controls . . . . . . . . . . . . . . . . . . . . . . . 204
Driving and Operating . . . . . . . . . . . . . . . . . . 211
Vehicle Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
Service and Maintenance . . . . . . . . . . . . . . 408
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . 423
Customer Information . . . . . . . . . . . . . . . . . . 428
Reporting Safety Defects . . . . . . . . . . . . . . . 436
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
Connected Services . . . . . . . . . . . . . . . . . . . . . 445
Index . . . . . . . . . . . . . . . . . . . . . . . . . . 448
Introduction
The names, logos, emblems, slogans, vehicle
model names, and vehicle body designs
appearing in this manual including, but not
limited to, GM, the GM logo, GMC, the GMC
Truck Emblem, SIERRA, and DENALI are
trademarks and/or service marks of General
Motors LLC, its subsidiaries, affiliates,
or licensors.
For vehicles first sold in Canada, substitute
the name“General Motors of Canada
Company” for GMC Division wherever it
appears in this manual. This manual describes features that may or
may not be on the vehicle because of
optional equipment that was not purchased
on the vehicle, model variants, country
specifications, features/applications that may
not be available in your region, or changes
subsequent to the printing of this owner’s
manual.
If the vehicle has the Duramax diesel
engine, see the Duramax diesel supplement
for additional and specific information on
this engine.
Refer to the purchase documentation
relating to your specific vehicle to confirm
the features.
Keep this manual in the vehicle for quick
reference.
Litho in U.S.A.
Part No. 84550392 C Third Printing©2021 General Motors LLC. All Rights Reserved.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
10 Keys, Doors, and Windows
Warning (Continued)
children or others could be seriously
injured or killed. They could operate the
power window or other controls or make
the vehicle move. The windows will
function with the key in the ignition or
with the RKE transmitter in the vehicle,
and children or others could be caught in
the path of a closing window. Do not
leave children in a vehicle with the
ignition key or an RKE transmitter.
If the vehicle has the Keyless Access system,
the transmitter has a button on the side of
the transmitter used to remove the key.This key is used for the driver door and
glove box.
Press the button to remove the key. Never
pull the key out without pressing the
button.
See your dealer if a replacement key or
additional key is needed.
If it becomes difficult to turn a key, inspect
the key blade for debris. Periodically clean
with a brush or pick.
With an active OnStar or connected service
plan, an OnStar Advisor may remotely
unlock the vehicle. See
OnStar Overview
0 440. If locked out of the vehicle, see
Roadside
Assistance Program 0431.
If equipped with memory seats, RKE
transmitters 1 and 2 are linked to seating
positions of memory 1 or 2. See Memory
Seats 049.
Remote Keyless Entry (RKE)
System
See Radio Frequency Statement 0436.
If there is a decrease in the Remote Keyless
Entry (RKE) operating range:
.Check the distance. The transmitter may
be too far from the vehicle.
.Check the location. Other vehicles or
objects may be blocking the signal.
.Check the transmitter's battery. See
“Battery Replacement” later in this
section.
.If the transmitter is still not working
correctly, see your dealer or a qualified
technician for service.
Remote Keyless Entry (RKE)
System Operation (Key Access)
The RKE transmitter functions may work up
to 60 m (197 ft) away from the vehicle.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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32 Keys, Doors, and Windows
Disarming the Alarm System
To disarm the alarm system or turn off the
alarm if it has been activated:
.PressKon the RKE transmitter.
.Start the vehicle.
To avoid setting off the alarm by mistake:
.Lock the vehicle after all occupants have
exited.
.Always unlock a door with the RKE
transmitter.
Unlocking the driver door with the key
will not disarm the system or turn off the
alarm.
How to Detect a Tamper Condition
IfKis pressed on the RKE transmitter and
the horn chirps three times, an alarm
occurred previously while the alarm system
was armed.
If the alarm has been activated, a message
will appear on the DIC.
Steering Column Lock
If equipped, the steering column lock is a
theft-deterrent device. This feature locks the
steering column when the vehicle is turned
off and the driver door is opened, or when the driver door is opened and then the
vehicle is turned off. The steering column
unlocks when the vehicle is turned on.
The Driver Information Center (DIC) may
display one of these messages:
.A message to service the steering column
lock indicates that an issue has been
detected with the column lock feature
and the vehicle should be serviced.
.A message that the steering column is
locked indicates that the engine is
running, but the steering column is still
locked. It is normal for the column to be
locked during a remote start, but the
column should unlock after the brake
pedal is pressed and the vehicle is started.
No message will display during a remote
start.
.A message that the steering wheel must
be turned and the vehicle must be started
again indicates that the column lock
mechanism is bound, the column locking
device was unable to unlock the steering
column, and the vehicle did not start.
If this happens, immediately turn the
steering wheel from side to side to
unbind the column lock. If this does not
unlock the steering column, turn the
vehicle off and open the driver door to
reset the system. Then turn the vehicle
on and immediately turn the steering
wheel side to side for about 15 seconds.
In some cases, it may take significant
force to unbind the column.
To keep the steering column from binding,
straighten the front wheels before turning
off the vehicle.
Immobilizer
See Radio Frequency Statement 0436.
Immobilizer Operation
This vehicle has a passive theft-deterrent
system.
The system does not have to be manually
armed or disarmed.
The vehicle is automatically immobilized
when the vehicle is turned off.
The system is automatically disarmed when
the ignition is turned from off to on.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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104 Instruments and Controls
and wirelessly charges one Qi compatible
smartphone. The power output of the
system is capable of charging at a rate up
to 3 amp (19.5 W) as requested by the
compatible smartphone. SeeRadio
Frequency Statement 0436.
{Warning
Wireless charging can affect the
operation of an implanted pacemaker or
other medical devices. If you have one, it
is recommended to consult with your
doctor before using the wireless charging
system.
The vehicle must be on, in ACC/ACCESSORY,
or Retained Accessory Power (RAP) must be
active. The wireless charging feature may
not correctly indicate charging when the
vehicle is in RAP, or during Bluetooth phone
calls. See Retained Accessory Power (RAP)
0 236.
The operating temperature is −20 °C (−4 °F)
to 60 °C (140 °F) for the charging system
and 0 °C (32 °F) to 35 °C (95 °F) for the
smartphone.
{Warning
Remove all objects from the charging pad
before charging your compatible
smartphone. Objects, such as coins, keys,
rings, paper clips, or cards, between the
smartphone and charging pad will
become very hot. On the rare occasion
that the charging system does not detect
an object, and the object gets wedged
between the smartphone and charger,
remove the smartphone and allow the
object to cool before removing it from
the charging pad, to prevent burns.
To charge a compatible smartphone:
1. Remove all objects from the charging pad. The system may not charge if there
are any objects between the smartphone
and charging pad.
2. Place the smartphone face up on the
@
symbol on the charging pad.
To maximize the charge rate, ensure the
smartphone is fully seated and centered
in the holder with nothing under it.
A thick smartphone case may prevent
the wireless charger from working,
or may reduce the charging performance.
See your dealer for additional
information.
3. A green
}will appear on theVon
the infotainment display. This indicates
that the smartphone is properly
positioned and charging. If a smartphone
is placed on the charging pad and
}
does not display, remove the
smartphone from the pad, turn it
180 degrees, and wait three seconds
before placing/aligning the smartphone
on the pad again.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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136 Instruments and Controls
Bed View Camera Lighting
This feature specifies if the truck bed rail
lights are turned on when the Bed View
Camera is active. SeeAssistance Systems for
Parking or Backing 0266.
Touch Off or On.
Teen Driver
See “Teen Driver” underSettings 0186.
Valet Mode
This will lock the infotainment system and
steering wheel controls. It may also limit
access to vehicle storage locations,
if equipped.
To enable valet mode:
1. Enter a four-digit code on the keypad.
2. Select Enter to go to the confirmation screen.
3. Re-enter the four-digit code.
Touch Lock or Unlock to lock or unlock the
system. Touch Back to go back to the
previous menu.
Universal Remote System
See Radio Frequency Statement 0436.
Universal Remote System
Programming
If equipped, these buttons are in the
overhead console.
This system can replace up to three remote
control transmitters used to activate devices
such as garage door openers, security
systems, and home automation devices.
These instructions refer to a garage door
opener, but can be used for other devices. Do not use the Universal Remote system
with any garage door opener that does not
have the stop and reverse feature. This
includes any garage door opener model
manufactured before April 1, 1982.
Read the instructions completely before
programming the Universal Remote system.
It may help to have another person assist
with the programming process.
Keep the original hand-held transmitter for
use in other vehicles as well as for future
programming. Erase the programming when
vehicle ownership is terminated. See
“Erasing Universal Remote System Buttons”
later in this section.
To program a garage door opener, park
outside directly in line with and facing the
garage door opener receiver. Clear all people
and objects near the garage door.
Make sure the hand-held transmitter has a
new battery for quick and accurate
transmission of the radio-frequency signal.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Infotainment System 195
vehicle. Data is only recorded when a
registered Teen Driver key is used to
operate the vehicle.
The Report Card data is collected from the
time Teen Driver is activated or the last
time the Report Card was reset. The
following items may be recorded:
.Distance Driven–the total distance
driven.
.Maximum Speed –the maximum vehicle
speed detected.
.Overspeed Warnings –the number of
times the speed warning setting was
exceeded.
.Wide Open Throttle –the number of
times the accelerator pedal was pressed
nearly all the way down.
.Forward Collision Alerts –the number of
times the driver was notified when
approaching a vehicle ahead too quickly
and at potential risk for a crash.
.Forward Automatic Braking, also called
Automatic Emergency Braking (if
equipped) –the number of times the
vehicle detected that a forward collision
was imminent and applied the brakes.
.Reverse Automatic Braking (if equipped) –
the number of times the vehicle detected
that a rearward collision was imminent
and applied the brakes.
.Traction Control –the number of times
the Traction Control System activated to
reduce wheel spin or loss of traction.
.Stability Control –the number of events
which required the use of electronic
stability control.
.Antilock Braking System Active –The
number of Antilock Brake System
activations.
.Tailgating Alerts –the number of times
the driver was alerted for following a
vehicle ahead too closely.
Report Card Data
Cumulative Data is saved for all trips until
the Report Card is reset or until the
maximum count is exceeded. If the
maximum count is exceeded for a Report
Card line item, that item will no longer be
updated in the Report Card until it is reset.
Each item will report a maximum of
1,000 counts. The distance driven will report
a maximum of 64 374 km (40,000 mi). To delete Report Card data, do one of the
following:
.From the Report Card display, touch
Reset.
.Touch Clear All Teen Keys and PIN from
the Teen Driver menu. This will also
unregister any Teen Driver keys and
delete the PIN.
Forgotten PIN
See your dealer to reset the PIN.
Trademarks and License
Agreements
FCC Information
See Radio Frequency Statement 0436.
"Made for iPod," and "Made for iPhone,"
mean that an electronic accessory has been
designed to connect specifically to iPod or
iPhone, respectively, and has been certified
by the developer to meet Apple

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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266 Driving and Operating
.Front and rear bumpers and the area
below the bumpers
.Front grille and headlamps
.Front camera lens in the front grille or
near the front emblem
.Front side and rear side panels
.Outside of the windshield in front of the
rearview mirror
.Side camera lens on the bottom of the
outside mirrors
.Rear side corner bumpers
.Rear Vision Camera in the tailgate handle
.Rear Camera Mirror and Cargo View
Camera in the Center High-Mounted
StoplampRadio Frequency
This vehicle may be equipped with driver
assistance systems that operate using radio
frequency. See
Radio Frequency Statement
0 436.
Assistance Systems for Parking or
Backing
If equipped, the Rear Vision Camera (RVC),
Surround Vision, Rear Park Assist (RPA),
Front Park Assist (FPA), and Rear Cross
Traffic Alert (RCTA) may help the driver park
or avoid objects. Always check around the
vehicle when parking or backing.
The RVC, RPA, and Surround Vision will not
work properly if the tailgate is down. If the
tailgate is down, do not use these systems.
Rear Vision Camera (RVC)
When the vehicle is shifted into R (Reverse),
the RVC displays an image of the area
behind the vehicle in the infotainment
display. The previous screen displays when
the vehicle is shifted out of R (Reverse) after
a short delay. To return to the previous
screen sooner, press any button on the
infotainment system, shift into P (Park), or, while in D (Drive), reach a vehicle speed of
approximately 12 km/h (8 mph). The rear
vision camera is in the tailgate handle.
1. View Displayed by the Rear Vision
Camera

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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Driving and Operating 281
When the vehicle is started, both outside
mirror LCA displays will briefly come on to
indicate the system is operating. When the
vehicle is in a forward gear, the left or right
side mirror display will light up if a moving
vehicle is detected in the next lane over in
that blind zone or rapidly approaching that
zone. If the turn signal is activated in the
same direction as a detected vehicle, this
display will flash as an extra warning not to
change lanes.
LCA can be disabled through vehicle
personalization. When you disable LCA, SBZA
is also disabled. SeeVehicle Personalization
0 131. If LCA is disabled by the driver, the
LCA mirror displays will not light up.
When the System Does Not Seem to
Work Properly
The LCA system requires some driving for
the system to calibrate to maximum
performance. This calibration may occur
more quickly if the vehicle is driving on a
straight highway road with traffic and
roadside objects (e.g., guardrails, barriers).
LCA displays may not come on when
passing a vehicle quickly, for a stopped
vehicle, or when towing a trailer. The LCA
detection zones that extend back from the side of the vehicle do not move further back
when a trailer is towed. Use caution while
changing lanes when towing a trailer. LCA
may alert to objects attached to the vehicle,
such as a trailer, bicycle, or object extending
out to either side of the vehicle. Attached
objects may also interfere with the
detection of vehicles. This is normal system
operation; the vehicle does not need service.
LCA may not always alert the driver to
vehicles in the next lane over, especially in
wet conditions or when driving on sharp
curves. The system does not need to be
serviced. The system may light up due to
guardrails, signs, trees, shrubs, and other
non-moving objects. This is normal system
operation; the vehicle does not need service.
LCA may not operate when the LCA sensors
in the left or right corners of the rear
bumper are covered with mud, dirt, snow,
ice, or slush, or in heavy rainstorms. For
cleaning instructions, see "Washing the
Vehicle" under
Exterior Care0398. If the
DIC still displays the system unavailable
message after cleaning both sides of the
vehicle toward the rear corners of the
vehicle, see your dealer. If the LCA displays do not light up when
moving vehicles are in the side blind zone or
are rapidly approaching this zone and the
system is clean, the system may need
service. Take the vehicle to your dealer.
Radio Frequency Information
See
Radio Frequency Statement 0436.
Lane Keep Assist (LKA)
If equipped, LKA may help avoid crashes due
to unintentional lane departures. This
system uses a camera to detect lane
markings between 60 km/h (37 mph) and
180 km/h (112 mph). It may assist by gently
turning the steering wheel if the vehicle
approaches a detected lane marking. It may
also provide a Lane Departure Warning
(LDW) alert if the vehicle crosses a detected
lane marking. LKA can be overridden by
turning the steering wheel. This system is
not intended to keep the vehicle centered in
the lane. LKA will not assist and alert if the
turn signal is active in the direction of lane
departure, or if it detects that you are
accelerating, braking or actively steering.