
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
442 Service and Maintenance
Air Conditioning Desiccant
(Replace Every Seven Years)
The air conditioning system requires
maintenance every seven years.
This service requires replacement of
the desiccant to help the longevity
and efficient operation of the air
conditioning system. This service
can be complex. See your dealer.
Tire Rotation and Required
Services Every 12 000 km/
7,500 mi
Rotate the tires, if recommended for
the vehicle, and perform the
following services. SeeTire
Rotation 0396.
. Check engine oil level and oil
life percentage. If needed,
change engine oil and filter, and
reset oil life system. See Engine
Oil 0339 and
Engine Oil Life System 0341.
. If equipped with the engine air
filter life system, check the air
filter life percentage.
If necessary, replace the engine
air filter and reset the engine air filter life system. See
Engine Air
Filter Life System 0343. If the
vehicle is not equipped with the
engine air filter life system,
inspect the engine air cleaner
filter. See Engine Air Cleaner/
Filter 0344.
. Check engine coolant level. See
Cooling System 0346.
. Check windshield washer fluid
level. See Washer Fluid 0354.
. Check tire inflation pressures,
including the spare. See Tire
Pressure 0387.
. Inspect tire wear. See Tire
Inspection 0396.
. Visually check for fluid leaks.
. Inspect brake system. See
Exterior Care 0429.
. Visually inspect steering,
suspension, and chassis
components for damage,
including cracks or tears in the
rubber boots, loose or missing
parts, or signs of wear at least
once a year. See Exterior Care
0 429. If equipped with grease fittings, lubricate the suspension
and steering components every
other oil change for normal
usage and every oil change for
severe usage.
. Inspect power steering for
proper attachment, connections,
binding, leaks, cracks,
chafing, etc.
. Visually inspect drive shafts for
excessive wear, lubricant leaks
or damage including: tube dents,
cracks, constant velocity joint or
universal joint looseness,
cracked or missing boots, loose
or missing boot clamps, center
bearing excessive looseness,
missing or loose fasteners.
. Check restraint system
components. See Safety System
Check 070.
. Visually inspect fuel system for
damage or leaks.
. Visually inspect exhaust system
and nearby heat shields for
loose or damaged parts.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Service and Maintenance 443
.Lubricate body components. See
Exterior Care 0429.
. Check starter switch. See Starter
Switch Check 0363.
. Check automatic transmission
shift lock control function. See
Automatic Transmission Shift
Lock Control Function Check
0363.
. Check ignition transmission lock.
See Ignition Transmission Lock
Check 0363.
. Check parking brake and
automatic transmission park
mechanism. See Park Brake and
P (Park) Mechanism Check
0 364.
. 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) 0365. .
Inspect sunroof track and seal,
if equipped. See Sunroof050.
. Verify spare tire key lock
operation and lubricate as
needed. See Tire Changing
0 407.
. 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
0 407.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
466 Customer Information
Center at 1-800-323-9935. Text
Telephone (TTY) users, call
1-800-833-9935.
General Motors of Canada also has
a Mobility program. See www.gm.ca
or call 1-800-GM-DRIVE
(800-463-7483) for details. TTY
users call 1-800-263-3830.
Roadside Assistance
Program
For U.S.-purchased vehicles, call
1-888-881-3302; (Text Telephone
(TTY): 1-888-889-2438).
For Canadian-purchased vehicles,
call 1-800-268-6800.
Service is available 24 hours a day,
365 days a year.
Calling for Assistance
When calling Roadside Assistance,
have the following information
ready:
.Your name, home address, and
home telephone number
. Telephone number of your
location .
Location of the vehicle
. Model, year, color, and license
plate number of the vehicle
. Odometer reading, Vehicle
Identification Number (VIN), and
delivery date of the vehicle
. Description of the problem
Coverage
Services are provided for the
duration of the vehicle's powertrain
warranty.
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

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 8/27/19
Index 491
Extender, Seat Belt . . . . . . . . . . . . . . 70
Exterior Cargo Lamps . . . . . . . . . . 171
Exterior Lamp Controls . . . . . . . . . 165
Exterior Lamps Off Reminder . . . 167
Exterior Lighting BatterySaver . . . . . . . . . . . . . . . . . . . . . . . . . 174
F
FanEngine . . . . . . . . . . . . . . . . . . . . . . . . 353
Filter, Engine Air Cleaner . . . . . . . . . . . 344
Flash-to-Pass . . . . . . . . . . . . . . . . . . . 168
Flashers, Hazard Warning . . . . . . 169
Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . 405 Changing . . . . . . . . . . . . . . . . . . . . . 407
FlexFuel
E85 . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
Floor Console Storage . . . . . . . . . . 114
Floor Mats . . . . . . . . . . . . . . . . . . . . . . 438
Fluid Automatic Transmission . . . . . . 343
Brakes . . . . . . . . . . . . . . . . . . . . . . . . 357
Four-Wheel DriveTransfer Case . . . . . . . . . . . . . . . 227
Power Steering . . . . . . . . . . . . . . . 354
Washer . . . . . . . . . . . . . . . . . . . . . . . 354
Fog Lamps . . . . . . . . . . . . . . . . . . . . . 170 Folding Mirrors . . . . . . . . . . . . . . . . . . 42
Forward Collision Alert
(FCA) System . . . . . . . . . . . . . . . . . 268
Four-Wheel Drive . . . . . . . . . . 227, 361
Four-Wheel-Drive Light . . . . . . . . . 141
Frequency Statement Radio . . . . . . . . . . . . . . . . . . . . . . . . . 472
Front Axle . . . . . . . . . . . . . . . . . . . . . . 361
Front Fog Lamp Light . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Front Pedestrian Braking
(FPB) System . . . . . . . . . . . . . . . . . 272
Front Seats Adjustment . . . . . . . . . . . . . . . . . . . . . 54
Heated and Ventilated . . . . . . . . . . 60
Fuel
Additives . . . . . . . . . . . . . . . . . . . . . 282
Economy, Driving for Better . . . 186
Filling a Portable FuelContainer . . . . . . . . . . . . . . . . . . . 286
Filling the Tank . . . . . . . . . . 283, 285
Foreign Countries . . . . . . . . . . . . 281
Gauge . . . . . . . . . . . . . . . . . . . . . . . . 131
Low Fuel Warning Light . . . . . . . 145
Management, Active . . . . . . . . . . 219
Prohibited Fuels . . . . . . . . . . . . . . 281
Recommended . . . . . . . . . . 280, 281
Top Tier . . . . . . . . . . . . . . . . . . . . . . 280 Full-Size Spare Tire . . . . . . . . . . . . 418
Fuses
Engine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . . . . 371
Fuses and Circuit Breakers . . . 370
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . 374, 376G
Garage Door Opener . . . . . . . . . . . 161
Programming . . . . . . . . . . . . . . . . . 161
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . 365
Gauges
Engine CoolantTemperature . . . . . . . . . . . . . . . . 133
Engine Oil Pressure . . . . . . . . . . 132
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Odometer . . . . . . . . . . . . . . . . . . . . . 131
Speedometer . . . . . . . . . . . . . . . . . 130
Tachometer . . . . . . . . . . . . . . . . . . . 131
Trip Odometer . . . . . . . . . . . . . . . . 131
Voltmeter . . . . . . . . . . . . . . . . . . . . . 134
Warning Lights and Indicators . . . . . . . . . . . . . . . . . . . 125
General Information Service and Maintenance . . . . . 439
Towing . . . . . . . . . . . . . . . . . . . . . . . . 287
Vehicle Care . . . . . . . . . . . . . . . . . . 328

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 8/27/19
Index 497
Steering (cont'd)Wheel Adjustment . . . . . . . . . . . . .118
Wheel Controls . . . . . . . . . . . . . . . .119
Steering Column Lock . . . . . . . . . . . 37
Steps
Power Assist . . . . . . . . . . . . . . . . . . . 34
Stop/Start System . . . . . . . . . . . . . . 213
Stoplamps and Back-up Lamps Bulb Replacement . . . . . . . . . . . . 368
Storage Rear . . . . . . . . . . . . . . . . . . . . . . . . . . .113
Storage Areas Center Console . . . . . . . . . . . . . . . .113
Floor Console . . . . . . . . . . . . . . . . .114
Glove Box . . . . . . . . . . . . . . . . . . . . .112
Underseat . . . . . . . . . . . . . . . . . . . . .113
Storage Compartments . . . . . . . . . 112
Struts Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
Stuck Vehicle . . . . . . . . . . . . . . . . . . . 199
Sun Visors . . . . . . . . . . . . . . . . . . . . . . . 50
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . 3
System Brake Pad Life . . . . . . . . . . . . . . . . 356
Engine Air Filter Life . . . . . . . . . . 343
Forward CollisionAlert (FCA) . . . . . . . . . . . . . . . . . . 268 System (cont'd)
Infotainment . . . . . . . . . . . . . 176, 475
Noise Control . . . . . . . . . . . . . . . . . 362
Systems
Driver Assistance . . . . . . . . . . . . . 255
T
Tachometer . . . . . . . . . . . . . . . . . . . . . 131
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . . 29
TaillampsBulb Replacement . . . . . . . . . . . . 368
Task Lighting . . . . . . . . . . . . . . . . . . . 171
Text Telephone (TTY) Users . . . . 465
Theft-Deterrent Systems . . . . . . . . . 37 Immobilizer . . . . . . . . . . . . . . . . . . . . . 37
Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 All-Season . . . . . . . . . . . . . . . . . . . . 379
All-Terrain . . . . . . . . . . . . . . . . . . . . 381
Buying New Tires . . . . . . . . . . . . . 399
Chains . . . . . . . . . . . . . . . . . . . . . . . . 404
Changing . . . . . . . . . . . . . . . . . . . . . 407
Designations . . . . . . . . . . . . . . . . . 383
Different Size . . . . . . . . . . . . . . . . . 401
Full-Size Spare . . . . . . . . . . . . . . . 418
If a Tire Goes Flat . . . . . . . . . . . . 405
Inspection . . . . . . . . . . . . . . . . . . . . 396
Low Profile . . . . . . . . . . . . . . . . . . . 380 Tires (cont'd)
Pressure . . . . . . . . . . . . . . . . . 387, 389
Pressure Light . . . . . . . . . . . . . . . . 144
Pressure Monitor Operation . . 390
Pressure Monitor System . . . . . 389
Rotation . . . . . . . . . . . . . . . . . . . . . . 396
Sidewall Labeling . . . . . . . . . . . . . 381
Terminology and Definitions . . 385
Uniform Tire Quality
Grading . . . . . . . . . . . . . . . . . . . . . 402
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . . . 403
Wheel Replacement . . . . . . . . . . 403
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . 399
Winter . . . . . . . . . . . . . . . . . . . . . . . . 380
Top Tier Fuel . . . . . . . . . . . . . . . . . . . 280
Tow/Haul Mode . . . . . . . . . . . . . . . . . 227
Tow/Haul Mode Light . . . . . . . . . . . 141
Towing Driving Characteristics . . . . . . . . 287
Equipment . . . . . . . . . . . . . . . . . . . . 296
General Information . . . . . . . . . . 287
Recreational Vehicle . . . . . . . . . . 424
Trailer . . . . . . . . . . . . . . . . . . . . . . . . 292
Trailer Sway Control (TSC) . . . 308
Vehicle . . . . . . . . . . . . . . . . . . . . . . . 424