GMC SIERRA 2020 Owner's Manual

2020 Sierra/Sierra Denali
Sierra/Sierra DenaliOwner’s Manual
84186890 Agmc.com (U.S.)
gmccanada.ca (Canada)
C
M
Y
CM
MY
CY
CMY
K
20_GMC_Sierra_SierraDenali_COV_en_US_84186890A_2019APR11.ai 1 3/21/2\
019 10:51:47 AM 20_GMC_Sierra_SierraDenali_COV_en_US_84186890A_2019APR11.ai 1 3/21/2\
019 10:51:47 AM

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
ContentsIntroduction . . . . . . . . . . . . . . . . . . . . . . 2
Keys, Doors, and Windows . . . . . . 9
Seats and Restraints . . . . . . . . . . . 53
Storage . . . . . . . . . . . . . . . . . . . . . . . 113
Instruments and Controls . . . . . . 118
Lighting . . . . . . . . . . . . . . . . . . . . . . . 165
Infotainment System . . . . . . . . . . 176
Climate Controls . . . . . . . . . . . . . . 177
Driving and Operating . . . . . . . . . 185
Vehicle Care . . . . . . . . . . . . . . . . . . 327
Service and Maintenance . . . . . 440
Technical Data . . . . . . . . . . . . . . . . 458
Customer Information . . . . . . . . . 463
Reporting Safety Defects . . . . . . 473
OnStar . . . . . . . . . . . . . . . . . . . . . . . . 477
Connected Services . . . . . . . . . . . 485
Index . . . . . . . . . . . . . . . . . . . . 488

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
2 Introduction
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.
Canadian Vehicle Owners
A French language manual can be
obtained from your dealer, at
www.helminc.com, or from:
Propriétaires Canadiens
On peut obtenir un exemplaire de
ce guide en français auprès du
concessionnaire ou à l'adresse
suivante:
Helm, Incorporated
Attention: Customer Service
47911 Halyard Drive
Plymouth, MI 48170
USA
Using this Manual
To quickly locate information about
the vehicle, use the Index in the
back of the manual. It is an
alphabetical list of what is in the
manual and the page number where
it can be found.
Litho in U.S.A.
Part No. 84186890 A First Printing©2019 General Motors LLC. All Rights Reserved.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Introduction 3
Danger, Warning, and
Caution
Warning messages found on vehicle
labels and in this manual describe
hazards and what to do to avoid or
reduce them.
{Danger
Danger indicates a hazard with a
high level of risk which will result
in serious injury or death.
{Warning
Warning indicates a hazard that
could result in injury or death.
Caution
Caution indicates a hazard that
could result in property or vehicle
damage.
A circle with a slash through it is a
safety symbol which means“Do
Not,” “Do not do this,” or“Do not let
this happen.”
Symbols
The vehicle has components and
labels that use symbols instead of
text. Symbols are shown along with
the text describing the operation or
information relating to a specific
component, control, message,
gauge, or indicator.
M: Shown when the owner ’s
manual has additional instructions
or information.
*: Shown when the service
manual has additional instructions
or information.
0: Shown when there is more
information on another page —
“see page.” Vehicle Symbol Chart
Here are some additional symbols
that may be found on the vehicle
and what they mean. See the
features in this manual for
information.
u:
Air Conditioning System
G:Air Conditioning Refrigerant Oil
9:Airbag Readiness Light
!:Antilock Brake System (ABS)
$:Brake System Warning Light
9:Dispose of Used Components
Properly
P: Do Not Apply High Pressure
Water
B: Engine Coolant Temperature
_: Flame/Fire Prohibited
H:Flammable
[:Forward Collision Alert
R: Fuse Block Cover Lock
Location
+: Fuses
j:ISOFIX/LATCH System Child
Restraints

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
4 Introduction
Q:Keep Fuse Block Covers
Properly Installed
|: Lane Change Alert
@:Lane Departure Warning
A:Lane Keep Assist
*:Malfunction Indicator Lamp
::Oil Pressure
X:Park Assist
~:Pedestrian Ahead Indicator
O:Power
7: Rear Cross Traffic Alert
I:Registered Technician
/:Remote Vehicle Start
>:Seat Belt Reminders
I: Side Blind Zone Alert
h:Stop/Start
7: Tire Pressure Monitor
d:Traction Control/StabiliTrak/
Electronic Stability Control (ESC)
a: Under Pressure
V:Vehicle Ahead Indicator

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Introduction 5
Instrument Panel Overview

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
6 Introduction
1. Tow/Haul Mode (On SomeModels). See Driver Mode
Control 0238
Automatic Transfer Case
Control (If Equipped).
See Four-Wheel Drive 0227
Driver Mode Control 0238 (If
Equipped).
2. Air Vents 0182.
3. Head-Up Display (HUD) 0152
(If Equipped).
4. Turn Signal Lever. See Turn
and Lane-Change Signals
0 170.
Windshield Wiper/Washer
0 120.
5. Instrument Cluster 0127.
6. Shift Lever. See Automatic
Transmission 0221.
Range Selection Mode. See
Manual Mode 0224.
7. Light Sensor. See Automatic
Headlamp System 0168.
8. Infotainment 0176.
9. Climate Control Systems 0177
(If Equipped). Dual Automatic Climate Control
System
0179 (If Equipped).
10. Heated and Ventilated Front
Seats 061 (If Equipped).
11.
XPark Assist Switch (If
Equipped). See Assistance
Systems for Parking or Backing
0 257.
gTraction Control/Electronic
Stability Control 0235.
|Hazard Warning Flashers
0 169.
ALane Keep Assist (LKA)
(1500 Series) 0278 (If
Equipped).
@Lane Departure Warning
(LDW) (2500/3500 Series)
0 276 (If Equipped).
5Hill Descent Control Switch
(If Equipped). See Hill Descent
Control (HDC) 0237.
jPower Assist Steps 036 (If
Equipped).
5Power Release Tailgate
(If Equipped). See Tailgate
0 28.
DC/AC Switch. See Power
Outlets 0122.
hAuto Stop Disable Switch
(If Equipped). See Stop/Start
System 0213.
LExpress Window Down
Button (If Equipped). See
Power Windows 049.
Tow/Haul Mode 0226 (On
Some Models).
12. Power Outlet (Alternating Current) (If Equipped). See
Power Outlets 0122.
13. Power Outlets 0122.
14. USB Port. See the infotainment manual.
15. Wireless Charging 0124 (If
Equipped).

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Introduction 7
16. Trailer Brake Control Panel (IfEquipped). See “Integrated
Trailer Brake Control System”
under Towing Equipment
0 296.
17. ENGINE START/STOP. See Ignition Positions (Keyless
Access) 0208 or
Ignition Positions (Key Access)
0 210.
18. Steering Wheel Controls (If Equipped). See the
infotainment manual.
Driver Information Center (DIC)
Controls. See Driver
Information Center (DIC) (Base
Level) 0148 or
Driver Information Center (DIC)
(Midlevel and Uplevel) 0149.
19. Horn 0120.
20. Hood Release. See Hood
0 330.
21. Steering Wheel Adjustment
0119 (Out of View).
22. Cruise Control 0243.
Adaptive Cruise Control (1500
Series) 0245 (If Equipped). Forward Collision Alert (FCA)
System
0268 (If Equipped).
23. Data Link Connector (DLC) (Out of View). See Malfunction
Indicator Lamp (Check Engine
Light) 0138.
24. Electric Parking Brake 0233.
25. Fog Lamps 0170 (If
Equipped).
Instrument Panel Illumination
Control 0172.
Exterior Cargo Lamps 0171.
Exterior Lamp Controls 0165.
Task Lighting 0171 (If
Equipped).

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
8 Introduction
2NOTES

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Keys, Doors, and Windows 9
Keys, Doors, and
Windows
Keys and Locks
Keys (Key Access) . . . . . . . . . . . . . . 9
Keys (Keyless Access) . . . . . . . . 12
Remote Keyless Entry (RKE)System . . . . . . . . . . . . . . . . . . . . . . . 13
Remote Keyless Entry (RKE) System Operation (Key
Access) . . . . . . . . . . . . . . . . . . . . . . 13
Remote Keyless Entry (RKE) System Operation (Keyless
Access) . . . . . . . . . . . . . . . . . . . . . . 15
Remote Vehicle Start . . . . . . . . . . 24
Door Locks . . . . . . . . . . . . . . . . . . . . 25
Power Door Locks . . . . . . . . . . . . . 26
Delayed Locking . . . . . . . . . . . . . . . 26
Automatic Door Locks . . . . . . . . . 26
Lockout Protection . . . . . . . . . . . . . 27
Safety Locks . . . . . . . . . . . . . . . . . . . 27
Doors
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . 28
Power Assist Steps . . . . . . . . . . . . 36
Vehicle Security
Vehicle Security . . . . . . . . . . . . . . . . 37
Vehicle Alarm System . . . . . . . . . 37 Steering Column Lock . . . . . . . . . 38
Immobilizer . . . . . . . . . . . . . . . . . . . . 39
Immobilizer Operation . . . . . . . . . 39
Exterior Mirrors
Convex Mirrors . . . . . . . . . . . . . . . . 40
Manual Mirrors . . . . . . . . . . . . . . . . . 41
Trailer-Tow Mirrors . . . . . . . . . . . . . 41
Power Mirrors . . . . . . . . . . . . . . . . . . 43
Folding Mirrors . . . . . . . . . . . . . . . . . 43
Heated Mirrors . . . . . . . . . . . . . . . . . 44
Automatic Dimming Mirror . . . . . 44
Blind Spot Mirrors . . . . . . . . . . . . . . 44
Reverse Tilt Mirrors . . . . . . . . . . . . 45
Interior Mirrors
Interior Rearview Mirrors . . . . . . . 46
Manual Rearview Mirror . . . . . . . . 46
Automatic Dimming Rearview
Mirror . . . . . . . . . . . . . . . . . . . . . . . . . 46
Rear Camera Mirror . . . . . . . . . . . . 46
Windows
Windows . . . . . . . . . . . . . . . . . . . . . . . 48
Manual Windows . . . . . . . . . . . . . . 49
Power Windows . . . . . . . . . . . . . . . 49
Rear Windows . . . . . . . . . . . . . . . . . 51
Sun Visors . . . . . . . . . . . . . . . . . . . . . 51
Roof
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . 51
Keys and Locks
Keys (Key Access)
{Warning
Leaving children in a vehicle with
the ignition key is dangerous and
children or others could be
seriously injured or killed. They
could operate the power windows
or other controls or make the
vehicle move. The windows will
function with the keys in the
ignition, 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.