2020 GMC SIERRA DENALI warning light

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 403
specified government test
surfaces of asphalt and
concrete. A tire marked C may
have poor traction performance.
Warning: The traction grade
assigned to this tire is based on
straight-ahead braking traction
tests, and does not include
acceleration, cornering,
hydroplaning, or peak traction
characteristics.
Temperature
The temperature grades are A
(the highest), B, and C,
representing the tire's resistance
to the generation of heat and its
ability to dissipate heat when
tested under controlled
conditions on a specified indoor
laboratory test wheel. Sustained
high temperature can cause the
material of the tire to degenerate
and reduce tire life, and
excessive temperature can lead
to sudden tire failure. The grade
C corresponds to a level ofperformance which all
passenger car tires must meet
under the Federal Motor Safety
Standard No. 109. Grades B and
A represent higher levels of
performance on the laboratory
test wheel than the minimum
required by law. Warning: The
temperature grade for this tire is
established for a tire that is
properly inflated and not
overloaded. Excessive speed,
underinflation, or excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure.
Wheel Alignment and Tire
Balance
The tires and wheels were aligned
and balanced at the factory to
provide the longest tire life and best
overall performance. Adjustments to
wheel alignment and tire balancing
are not necessary on a regular
basis. Consider an alignment check
if there is unusual tire wear or the vehicle is significantly pulling to one
side or the other. Some slight pull to
the left or right, depending on the
crown of the road and/or other road
surface variations such as troughs
or ruts, is normal. If the vehicle is
vibrating when driving on a smooth
road, the tires and wheels may need
to be rebalanced. See your dealer
for proper diagnosis.
Wheel Replacement
Replace any wheel that is bent,
cracked, or badly rusted or
corroded. If wheel nuts keep coming
loose, the wheel, wheel bolts and
wheel nuts should be replaced.
If the wheel leaks air, replace it.
Some aluminum wheels can be
repaired. See your dealer if any of
these conditions exist.
Your dealer will know the kind of
wheel that is needed.
Each new wheel should have the
same load-carrying capacity,
diameter, width, offset and be
mounted the same way as the one it
replaces.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
422 Vehicle Care
vehicle, be sure the transfer
case is in a drive gear, not in
N (Neutral).
Caution
If any accessories are left on or
plugged in during the jump
starting procedure, they could be
damaged. The repairs would not
be covered by the vehicle
warranty. Whenever possible, turn
off or unplug all accessories on
either vehicle when jump starting.
4. Turn the ignition off on both vehicles. Unplug unnecessary
accessories plugged into the
accessory power outlets. Turn
off the radio and all the lamps
that are not needed. This will
avoid sparks and help save
both batteries. And it could
save the radio!
5. Open the hood on the other vehicle and locate the
positive (+) and negative (−)
terminal locations on that
vehicle. The positive (+) terminal is
under a red plastic cover at the
positive battery post. To
uncover the positive (+)
terminal, open the red plastic
cover.
For more information on the
location of the remote
positive (+) and remote
negative (−) terminals, see
Engine Compartment Overview
0
332.
{Warning
An electric fan can start up even
when the engine is not running
and can injure you. Keep hands,
clothing, and tools away from any
underhood electric fan.
{Warning
Using a match near a battery can
cause battery gas to explode.
People have been hurt doing this,
(Continued)
Warning (Continued)
and some have been blinded.
Use a flashlight if you need more
light.
Battery fluid contains acid that
can burn you. Do not get it on
you. If you accidentally get it in
your eyes or on your skin, flush
the place with water and get
medical help immediately.
{Warning
Fans or other moving engine
parts can injure you badly. Keep
your hands away from moving
parts once the engine is running.
6. Check that the jumper cables do not have loose or missing
insulation. If they do, you could
get a shock. The vehicles
could be damaged too.

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
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

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 8/27/19
Index 489
Caution, Danger, and Warning . . . . 3
Center Console Storage . . . . . . . . 113
Center High-MountedStoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . . . 369
Center Seat . . . . . . . . . . . . . . . . . . . . . 55
Chains, Tire . . . . . . . . . . . . . . . . . . . . 404
Charging Wireless . . . . . . . . . . . . . . . . . . . . . . 122
Charging System Light . . . . . . . . . 137
Check Engine Light (MalfunctionIndicator) . . . . . . . . . . . . . . . . . . . . 137
Ignition Transmission Lock . . . 363
Child Restraints Infants and Young Children . . . . . 86
Lower Anchors and Tethers
for Children . . . . . . . . . . . . . . . . . . . 91
Older Children . . . . . . . . . . . . . . . . . . 84
Securing . . . . . . . . . . . . 104, 107, 108
Systems . . . . . . . . . . . . . . . . . . . . . . . . 88
Circuit Breakers . . . . . . . . . . . . . . . . 370
Cleaning Exterior Care . . . . . . . . . . . . . . . . . 429
Interior Care . . . . . . . . . . . . . . . . . . 435
Climate Control Systems . . . . . . . 177 Air Conditioning . . . . . . . . . . . . . . 177
Dual Automatic . . . . . . . . . . . . . . . 179 Climate Control Systems (cont'd)
Heating . . . . . . . . . . . . . . . . . . . . . . . 177
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Cluster, Instrument . . . . . . . . . . . . . 126
Collision Damage Repair . . . . . . . 469
Compartments Storage . . . . . . . . . . . . . . . . . . . . . . . .112
Compass . . . . . . . . . . . . . . . . . . . . . . . 120
Connected Services Connections . . . . . . . . . . . . . . . . . . 485
Diagnostics . . . . . . . . . . . . . . . . . . . 486
Navigation . . . . . . . . . . . . . . . . . . . . 484
Connections Connected Services . . . . . . . . . . 485
Control Hill Descent . . . . . . . . . . . . . . . . . . 237
Traction and ElectronicStability . . . . . . . . . . . . . . . . . . . . . 235
Control Light Hill Descent . . . . . . . . . . . . . . . . . . 141
Control of a Vehicle . . . . . . . . . . . . . 188
Convex Mirrors . . . . . . . . . . . . . . . . . . 39
Coolant Engine Temperature Gauge . . 133
Engine TemperatureWarning Light . . . . . . . . . . . . . . . 144
Cooling . . . . . . . . . . . . . . . . . . . . 177, 179
Cooling System . . . . . . . . . . . . . . . . . 346 Courtesy Transportation
Program . . . . . . . . . . . . . . . . . . . . . . . 468
Cruise Control . . . . . . . . . . . . . . . . . . 243 Light . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Cruise Control, Adaptive . . . . . . . . 245
Cupholders . . . . . . . . . . . . . . . . . . . . . 112
Customer Assistance . . . . . . . . . . . 465 Offices . . . . . . . . . . . . . . . . . . . . . . . . 464
Text Telephone (TTY)Users . . . . . . . . . . . . . . . . . . . . . . . 465
Customer Information
Publications OrderingInformation . . . . . . . . . . . . . . . . . . 471
Customer Satisfaction Procedure . . . . . . . . . . . . . . . . . . . . . 462
Cybersecurity . . . . . . . . . . . . . . . . . . . 474
D
Damage Repair, Collision . . . . . . . 469
Danger, Warning, and Caution . . . . 3
Data Collection
Infotainment System . . . . . . . . . . 475
OnStar . . . . . . . . . . . . . . . . . . . . . . . 475
Data Recorders, Event . . . . . . . . . 474
Daytime Running Lamps (DRL) . . . . . . . . . . . . . . . . . . 168
Defensive Driving . . . . . . . . . . . . . . . 187
Delayed Locking . . . . . . . . . . . . . . . . . 27

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 8/27/19
490 Index
DiagnosticsConnected Services . . . . . . . . . . 486
Differential, Limited-Slip . . . . . . . . 242
Distracted Driving . . . . . . . . . . . . . . . 187
Dome Lamps . . . . . . . . . . . . . . . . . . . 172
Door Ajar Light . . . . . . . . . . . . . . . . . . . . . 147
Delayed Locking . . . . . . . . . . . . . . . . 27
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Power Locks . . . . . . . . . . . . . . . . . . . . 27
Drive Belt Routing, Engine . . . . . . 461
Driver Assistance Systems . . . . . 255
Driver Information
Center (DIC) . . . . . . . . . . . . . 147, 148
Driver Mode Control . . . . . . . . . . . . 238
Driver Mode Control Light . . . . . . 144
Driving Assistance Systems . . . . . . . . . . 268
Better Fuel Economy . . . . . . . . . 186
Characteristics andTowing Tips . . . . . . . . . . . . . . . . . 287
Defensive . . . . . . . . . . . . . . . . . . . . . 187
Drunk . . . . . . . . . . . . . . . . . . . . . . . . . 188
Hill and Mountain Roads . . . . . . 197
If the Vehicle is Stuck . . . . . . . . . 199
Loss of Control . . . . . . . . . . . . . . . 190
Off-Road . . . . . . . . . . . . . . . . . . . . . 191
Off-Road Recovery . . . . . . . . . . . 190 Driving (cont'd)
Vehicle Load Limits . . . . . . . . . . . 200
Wet Roads . . . . . . . . . . . . . . . . . . . 196
Winter . . . . . . . . . . . . . . . . . . . . . . . . 197
Dual Automatic Climate Control System . . . . . . . . . . . . . . . . 179
E
E85 or FlexFuel . . . . . . . . . . . . . . . . 282
Electric Brake Boost . . . . . . . . . . . . 232
Electric Parking Brake . . . . . . . . . . 233
Electric Parking Brake Light . . . . 140
Electrical Equipment,Add-On . . . . . . . . . . . . . . . . . . . . . . . 322
Electrical System Engine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . . . . 371
Fuses and Circuit Breakers . . . 370
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . 374, 376
Overload . . . . . . . . . . . . . . . . . . . . . 370
Electronic Stability Control (ESC) Off Light . . . . . . . . . . . . . . . . 143
Emergency
OnStar . . . . . . . . . . . . . . . . . . . . . . . 477
Engine Air Cleaner/Filter . . . . . . . . . . . . . 344 Engine (cont'd)
Check Light (Malfunction
Indicator) . . . . . . . . . . . . . . . . . . . . 137
Compartment Overview . . . . . . . 332
Coolant Temperature
Gauge . . . . . . . . . . . . . . . . . . . . . . 133
Coolant Temperature Warning Light . . . . . . . . . . . . . . . 144
Cooling System . . . . . . . . . . . . . . . 346
Drive Belt Routing . . . . . . . . . . . . 461
Exhaust . . . . . . . . . . . . . . . . . . . . . . 220
Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
Heater . . . . . . . . . . . . . . . . . . . . . . . . 215
Oil Life System . . . . . . . . . . . . . . . 341
Oil Pressure Gauge . . . . . . . . . . 132
Oil Pressure Light . . . . . . . . . . . . 145
Overheated Protection Operating Mode . . . . . . . . . . . . . 352
Overheating . . . . . . . . . . . . . . . . . . 351
Power Messages . . . . . . . . . . . . . 155
Running While Parked . . . . . . . . 220
Starting . . . . . . . . . . . . . . . . . . . . . . . 212
Engine Air Filter Life System . . . . 343
Entry Lighting . . . . . . . . . . . . . . . . . . . 173
Equipment, Towing . . . . . . . . . . . . . 296
Event Data Recorders . . . . . . . . . . 474
Exit Lighting . . . . . . . . . . . . . . . . . . . . 173
Extended Parking . . . . . . . . . . . . . . . 219