2020 GMC SIERRA DENALI light

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 427
Warning (Continued)
negative battery cable and cover
the negative battery post and
cable with a non-conductive
material. If the battery is left
connected or the battery cable
contacts the post, the Electric
Parking Brake may activate
during towing, which could cause
a crash.
8. Disconnect the negative (–) battery cable. See “Negative
Battery Cable Disconnection”
in Battery - North America
0 358.
9. Shift the transmission to P (Park).
Caution
If the steering column is locked,
vehicle damage may occur. 10. Move the steering wheel to
make sure the steering column
is unlocked.
11. If the vehicle has an ignition key, keep it in the towed
vehicle in ACC/ACCESSORY
to prevent the steering column
from locking. If the vehicle is
equipped with Keyless Access,
keep the RKE transmitter
outside of the vehicle and
manually lock the doors.
Access the vehicle by using
the key in the door lock. See
Door Locks 026.
Disconnecting the Towed Vehicle
Before disconnecting from the tow
vehicle: 1. Park on a level surface. Secure the vehicle with wheel blocks.
2. Re-connect the negative (–) battery. See Battery - North
America 0358. 3. Turn on the ignition with the
engine off. For vehicles with a
key, turn the ignition to ON/
RUN with the engine off. If the
vehicle is equipped with
Keyless Access, with your foot
off the brake pedal, press and
hold ENGINE START/STOP for
five seconds until the green
light comes on in the button.
See Ignition Positions (Keyless
Access) 0208 or
Ignition Positions (Key Access)
0 210.
4. Set the parking brake. See Electric Parking Brake 0233.
5. Disconnect from the tow vehicle.
6. Shift the transmission to N (Neutral).
7. Shift the transfer case to 2
m
(Two-Wheel Drive High). When
the shift to 2
m(Two-Wheel
Drive High) is complete, the
light in the instrument cluster
will stop flashing and stay lit.
See Four-Wheel-Drive Light
0 141.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 429
Appearance Care
Exterior Care
Locks
Locks are lubricated at the factory.
Use a de-icing agent only when
absolutely necessary, and have the
locks greased after using. See
Recommended Fluids and
Lubricants0452.
Washing the Vehicle
To preserve the vehicle's finish,
wash it often and out of direct
sunlight.
{Warning
Do not power wash any part of
the vehicle’s interior, including the
vinyl floor covering. This could
damage safety and other systems
in the vehicle, which would not be
covered by the vehicle warranty.
Caution
Do not use petroleum-based,
acidic, or abrasive cleaning
agents as they can damage the
vehicle's paint, metal, or plastic
parts. If damage occurs, it would
not be covered by the vehicle
warranty. Approved cleaning
products can be obtained from
your dealer. Follow all
manufacturer directions regarding
correct product usage, necessary
safety precautions, and
appropriate disposal of any
vehicle care product.
Caution
Avoid using high-pressure
washes closer than 30 cm (12 in)
to the surface of the vehicle. Use
of power washers exceeding
8 274 kPa (1,200 psi) can result
in damage or removal of paint
and decals.
Caution
Do not power wash any
component under the hood that
has this
esymbol.
This could cause damage that
would not be covered by the
vehicle warranty.
Underhood Component Power
Washing
If power washing underhood
components, do not exceed these
limits:
. Fluid pressures of 110 bar
(1600 psi)
. Fluid temperatures of 25°C
(77°F)
. Nozzle must remain 30 cm
(12 in) or farther from
components.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
436 Vehicle Care
Speaker Covers
Vacuum around a speaker cover
gently, so that the speaker will not
be damaged. Clean spots with water
and mild soap.
Coated Moldings
Coated moldings should be cleaned.
.When lightly soiled, wipe with a
sponge or soft, lint-free cloth
dampened with water.
. When heavily soiled, use warm
soapy water.
Fabric/Carpet/Suede
Start by vacuuming the surface
using a soft brush attachment. If a
rotating vacuum brush attachment is
being used, only use it on the floor
carpet. Before cleaning, gently
remove as much of the soil as
possible:
.Gently blot liquids with a paper
towel. Continue blotting until no
more soil can be removed.
. For solid soils, remove as much
as possible prior to vacuuming. To clean:
1. Saturate a clean, lint-free colorfast cloth with water.
Microfiber cloth is
recommended to prevent lint
transfer to the fabric or carpet.
2. Remove excess moisture by gently wringing until water does
not drip from the cleaning cloth.
3. Start on the outside edge of the soil and gently rub toward the
center. Fold the cleaning cloth
to a clean area frequently to
prevent forcing the soil in to the
fabric.
4. Continue gently rubbing the soiled area until there is no
longer any color transfer from
the soil to the cleaning cloth.
5. If the soil is not completely removed, use a mild soap
solution followed only by plain
water. If the soil is not completely
removed, it may be necessary to
use a commercial upholstery
cleaner or spot lifter. Test a small
hidden area for colorfastness before
using a commercial upholstery
cleaner or spot lifter. If ring
formation occurs, clean the entire
fabric or carpet.
After cleaning use a paper towel to
blot excess moisture.
Cleaning High Gloss Surfaces
and Vehicle Information and
Radio Displays
Use a microfiber cloth on high gloss
surfaces or vehicle displays. First,
use a soft bristle brush to remove
dirt that can scratch the surface.
Then gently clean by rubbing with a
microfiber cloth. Never use window
cleaners or solvents. Periodically
hand wash the microfiber cloth
separately, using mild soap. Do not
use bleach or fabric softener. Rinse
thoroughly and air dry before
next use.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Service and Maintenance 449
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.
. 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 0452 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
450 Service and Maintenance
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. Vehicle Care
To help keep the vehicle looking like
new, vehicle care products are
available from your dealer. For
information on how to clean and
protect the vehicle’s interior and
exterior, see
Interior Care 0435 and
Exterior Care 0429.
Wheel Alignment
Wheel alignment is critical for
ensuring that the tires deliver
optimal wear and performance.
. Signs that the alignment may
need to be adjusted include
pulling, improper vehicle
handling, or unusual tire wear.
. Your dealer has the required
equipment to ensure proper
wheel alignment.
Windshield
For safety, appearance, and the
best viewing, keep the windshield
clean and clear.
. Signs of damage include
scratches, cracks, and chips.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
476 OnStar
OnStar
OnStar Overview
OnStar Overview . . . . . . . . . . . . . 476
OnStar Services
Emergency . . . . . . . . . . . . . . . . . . . 477
Security . . . . . . . . . . . . . . . . . . . . . . 478
OnStar Additional Information
OnStar AdditionalInformation . . . . . . . . . . . . . . . . . . 478
OnStar Overview
=Voice Command Button
QBlue OnStar Button
>Red Emergency Button
This vehicle may be equipped with a
comprehensive, in-vehicle system
that can connect to an OnStar
Advisor for Emergency, Security,
Navigation, Connections, and
Diagnostics Services. OnStar
services may require a paid service
plan and data plan. OnStar requires
the vehicle battery and electrical
system, cellular service, and GPS
satellite signals to be available and
operating. OnStar acts as a link to
existing emergency service
providers. OnStar may collect
information about you and your
vehicle, including location
information. See OnStar User Terms, Privacy Statement, and
Software Terms for more details
including system limitations at
www.onstar.com (U.S.) or
www.onstar.ca (Canada).
The OnStar system status light is
next to the OnStar buttons. If the
status light is:
.
Solid Green: System is ready.
. Flashing Green: On a call.
. Red: Indicates a problem.
. Off: System is off. Press
Q
twice to speak with an OnStar
Advisor.
Press
Qor call 1-888-4ONSTAR
(1-888-466-7827) to speak to an
Advisor.
Functionality of the Voice Command
button may vary by vehicle and
region.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 8/27/19
Index 487
IndexA
Accessories andModifications . . . . . . . . . . . . . . . . . . 329
Accessory Power . . . . . . . . . . . . . . . 216
Active Fuel Management . . . . . . . 219
Adaptive Cruise Control . . . . . . . . 245
Add-On Electrical Equipment . . . 322
Adding a Snow Plow or Similar Equipment . . . . . . . . . . . . . 323
Additional Information
OnStar . . . . . . . . . . . . . . . . . . . . . . . 478
Additional Maintenance and Care . . . . . . . . . . . . . . . . . . . . . . 449
Adjustments
Lumbar, Front Seats . . . . . . . . . . . . 56
Air Cleaner/Filter, Engine . . . . . . . 344
Air Conditioning . . . . . . . . . . . 177, 179
Air Filter Life System . . . . . . . . . . . . . . . . . . . 343
Air Filter, Passenger Compartment . . . . . . . . . . . . . . . . . 183
Air Vents . . . . . . . . . . . . . . . . . . . . . . . 182
Airbag System Check . . . . . . . . . . . . . . . . . . . . . . . . . . 83
How Does an Airbag
Restrain? . . . . . . . . . . . . . . . . . . . . . 76
Passenger Sensing System . . . . 77 Airbag System (cont'd)
What Makes an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . . . 75
What Will You See after an
Airbag Inflates? . . . . . . . . . . . . . . . 76
When Should an Airbag Inflate? . . . . . . . . . . . . . . . . . . . . . . . . 75
Where Are the Airbags? . . . . . . . . 73
Airbags
Adding Equipment to theVehicle . . . . . . . . . . . . . . . . . . . . . . . . 82
Passenger Status Indicator . . . 136
Readiness Light . . . . . . . . . . . . . . 135
Servicing Airbag-Equipped Vehicles . . . . . . . . . . . . . . . . . . . . . . . 82
System Check . . . . . . . . . . . . . . . . . . 71
Alarm Vehicle Security . . . . . . . . . . . . . . . . 36
Alert Lane Change . . . . . . . . . . . . . . . . . 274
Side Blind Zone (SBZA) . . . . . . 274
All-Season Tires . . . . . . . . . . . . . . . . 379
All-Terrain Tires . . . . . . . . . . . . . . . . . 381
Antilock Brake System (ABS) . . . 232 Warning Light . . . . . . . . . . . . . . . . . 140
Appearance Care Exterior . . . . . . . . . . . . . . . . . . . . . . . 429
Interior . . . . . . . . . . . . . . . . . . . . . . . . 435

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 8/27/19
488 Index
Assistance Program,Roadside . . . . . . . . . . . . . . . . . . . . . . 466
Assistance Systems for Driving . . . . . . . . . . . . . . . . . . . . . . . . 268
Assistance Systems for Parking and Backing . . . . . . . . . . 257
Auto Stop
Stop/Start System . . . . . . . . . . . . 213
Automatic Dimming Mirrors . . . . . . . . . . . . . . . . 43
Door Locks . . . . . . . . . . . . . . . . . . . . . 27
Emergency Braking (AEB) . . . . 270
Headlamp System . . . . . . . . . . . . 168
Transmission . . . . . . . . . . . . . . . . . 221
Transmission Fluid . . . . . . . . . . . 343
Automatic Transmission
Manual Mode . . . . . . . . . . . . . . . . . 224
Shift Lock Control FunctionCheck . . . . . . . . . . . . . . . . . . . . . . . 363
Axle, Front . . . . . . . . . . . . . . . . . . . . . . 361
Axle, Rear . . . . . . . . . . . . . . . . . . . . . . 362
B
Battery Exterior Lighting BatterySaver . . . . . . . . . . . . . . . . . . . . . . . 174
Load Management . . . . . . . . . . . . 174 Battery (cont'd)
Power Protection . . . . . . . . . . . . . 174
Battery - North America . . . . 358, 419
Blade Replacement, Wiper . . . . . 364
Blind Spot Mirrors . . . . . . . . . . . . . . . 43
Brake Electric Boost . . . . . . . . . . . . . . . . . 232
Parking, Electric . . . . . . . . . . . . . . 233
System Warning Light . . . . . . . . 139
Brake Pad Life System . . . . . . . . . 356
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . 355 Antilock . . . . . . . . . . . . . . . . . . . . . . . 232
Assist . . . . . . . . . . . . . . . . . . . . . . . . . 234
Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 357
Pad Life System . . . . . . . . . . . . . . 356
Braking . . . . . . . . . . . . . . . . . . . . . . . . . 188 AutomaticEmergency (AEB) . . . . . . . . . . . 270
Braking System Front Pedestrian (FPB) . . . . . . . 272
Break-In, New Vehicle . . . . . . . . . . 208
Bulb Replacement Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 369
Halogen Bulbs . . . . . . . . . . . . . . . . 367
Headlamp Aiming . . . . . . . . . . . . . 366
Headlamps . . . . . . . . . . . . . . . . . . . 367 Bulb Replacement (cont'd)
Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . . . 367
License Plate Lamps . . . . . . . . . 369
Taillamps, Turn Signal, Stoplamps, and Back-up
Lamps . . . . . . . . . . . . . . . . . . . . . . 368
Buying New Tires . . . . . . . . . . . . . . . 399
C
Calibration . . . . . . . . . . . . . . . . . . . . . . 120
California Perchlorate Materials
Requirements . . . . . . . . . . . . . . . 329
California Proposition
65 Warning . . . . . . . . . .329, 358, 419, Back Cover
Canadian Vehicle Owners . . . . . . . . 2
Capacities and Specifications . . . . . . . . . . . . . . . . . 458
Carbon Monoxide Engine Exhaust . . . . . . . . . . . . . . . 220
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . 29
Winter Driving . . . . . . . . . . . . . . . . 197
Cargo Tie-Downs . . . . . . . . . . . . . . . . . . . . .115