check engine CHEVROLET SILVERADO 2500HD 2021 Workshop Manual

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Service and Maintenance 391
.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 0393 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.
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.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Technical Data 399
ApplicationCapacities
Metric English
I3500 Series Chassis Cab –Front Tank 89.0 L
23.5 gal
I3500 Series Chassis Cab –Rear Tank 151.4 L
40.0 gal
Transfer Case Fluid 2.3 L2.4 qt
Hydraulic Power Steering Fluid 2.0 L2.1 qt
Wheel Nut Torque 190Y 140 lb ft
All capacities are approximate. When adding, be sure to fill to the approximate level, as recommended in this manual. Recheck fluid level
after filling.
*Engine cooling system capacity values are based on the entire cooling system and its components.
Engine Specifications
Engine VIN CodeSpark Plug Gap
6.6L V8 (L8T) 70.95–1.10 mm (0.037–0.043 in)
Spark plug gaps are preset by the manufacturer. Re-gapping the spark plug is not recommended and can damage the spark plug.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
OnStar 413
.Receive a Diagnostic check of the vehicle's
key operating systems.
.Receive Roadside Assistance.
.Manage Wi-Fi Settings, if equipped.
Press
>to get a priority connection to an
OnStar Advisor available 24/7 to:
.Get help for an emergency.
.Be a Good Samaritan or respond to an
AMBER Alert.
.Get assistance in severe weather or other
crisis situations and find evacuation
routes.
OnStar Services
Emergency
Emergency Services require an active safety
and security plan. With Automatic Crash
Response, built-in sensors can automatically
alert a specially trained OnStar Advisor who
is immediately connected in to the vehicle
to help.
Press
>for a priority connection to an
OnStar Advisor who can contact emergency
service providers, direct them to your exact
location, and relay important information. With OnStar Crisis Assist, specially trained
Advisors are available 24 hours a day, 7 days
a week, to provide a central point of
contact, assistance, and information during a
crisis.
With Roadside Assistance, Advisors can
locate a nearby service provider to help with
a flat tire, a battery jump, or an empty
gas tank.
Security
If equipped, OnStar provides these services:
.With Stolen Vehicle Assistance, OnStar
Advisors can use GPS to pinpoint the
vehicle and help authorities quickly
recover it.
.With Remote Ignition Block, if equipped,
OnStar can block the engine from being
restarted.
.With Stolen Vehicle Slowdown,
if equipped, OnStar can work with law
enforcement to gradually slow the
vehicle down.
Theft Alarm Notification
If equipped, if the doors are locked and the
vehicle alarm sounds, a notification by text,
e-mail, or phone call will be sent. If the
vehicle is stolen, an OnStar Advisor can work
with authorities to recover the vehicle.
OnStar Additional
Information
In-Vehicle Audio Messages
Audio messages may play important
information at the following times:
.Prior to vehicle purchase. PressQto
set up an account.
.After change in ownership and at
90 days.
Transferring Service
PressQto request account transfer
eligibility information. The Advisor can
cancel or change account information.
Selling/Transferring the Vehicle
Call 1-888-4ONSTAR (1-888-466-7827)
immediately to terminate your OnStar or
connected services if the vehicle is disposed
of, sold, transferred, or if the lease ends.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
420 Index
IndexA
Accessories and Modifications . . . . . . . . . . . 302
Accessory Power . . . . . . . . . . . . . . . . . . . . . . . . . 229
Add-On Electrical Equipment . . . . . . . . . . . . . 297
Adding a Snow Plow or SimilarEquipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
Additional Information OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Additional Maintenance and Care . . . . . . . . 390
Adjustments Lumbar, Front Seats . . . . . . . . . . . . . . . . . . . . 45
Agreements Trademarks and License . . . . . . . . . . . . . . . 190
Air Cleaner/Filter, Engine . . . . . . . . . . . . . . . . 309
Air Conditioning . . . . . . . . . . . . . . . . . . . . .199, 201
Air Filter
Life System . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
Air Filter, Passenger Compartment . . . . . . . 204
Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Airbag System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
How Does an Airbag Restrain? . . . . . . . . . . 61
Passenger Sensing System . . . . . . . . . . . . . . 62
What Makes an Airbag Inflate? . . . . . . . . . 61
What Will You See after an AirbagInflates? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
When Should an Airbag Inflate? . . . . . . . . 60
Where Are the Airbags? . . . . . . . . . . . . . . . . 59 Airbags
Adding Equipment to the Vehicle . . . . . . . 66
Passenger Status Indicator . . . . . . . . . . . . . 110
Readiness Light . . . . . . . . . . . . . . . . . . . . . . . . 110
Servicing Airbag-Equipped Vehicles . . . . . . 66
System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Alarm
Vehicle Security . . . . . . . . . . . . . . . . . . . . . . . . 27
Alert Lane Change . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
Side Blind Zone (SBZA) . . . . . . . . . . . . . . . . . 260
All-Season Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 337
All-Terrain Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 337
AM-FM Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Antenna Fixed Mast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Multi-band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Antilock Brake System (ABS) . . . . . . . . . . . . . 240 Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Appearance Care Exterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
Apple CarPlay and Android Auto . . . . . . . . . 180
Assistance Program, Roadside . . . . . . . . . . . . 404
Assistance Systems for Driving . . . . . . . . . . 257
Assistance Systems for Parking and Backing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Index 421
AudioBluetooth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Automatic Dimming Mirrors . . . . . . . . . . . . . . . . . . . . . . . 33
Door Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Emergency Braking (AEB) . . . . . . . . . . . . . . 259
Headlamp System . . . . . . . . . . . . . . . . . . . . . 136
Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
Transmission Fluid . . . . . . . . . . . . . . . . . . . . . 308
Automatic Transmission Manual Mode . . . . . . . . . . . . . . . . . . . . . . . . . 235
Shift Lock Control Function Check . . . . . . 322
Auxiliary Roof Mounted Lamp . . . . . . . . . . . . . . . . . . . 139
Auxiliary Jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Avoiding Untrusted Media Devices . . . . . . . . 153
Axle, Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
Axle, Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
B
Battery Exterior Lighting Battery Saver . . . . . . . . 142
Load Management . . . . . . . . . . . . . . . . . . . . . . 141
Power Protection . . . . . . . . . . . . . . . . . . . . . . 142
Battery - North America . . . . . . . . . . . . .318, 367
Blade Replacement, Wiper . . . . . . . . . . . . . . . 322
Blind Spot Mirrors . . . . . . . . . . . . . . . . . . . . . . . . .33 Bluetooth
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 175, 176
Bluetooth Audio . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Brake Parking, Electric . . . . . . . . . . . . . . . . . . . . . . . . 240
System Warning Light . . . . . . . . . . . . . . . . . . 113
Brake Pad Life System . . . . . . . . . . . . . . . . . . . 316
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316
Antilock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
Assist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
Pad Life System . . . . . . . . . . . . . . . . . . . . . . . 316
Braking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Automatic Emergency (AEB) . . . . . . . . . . . 259
Break-In, New Vehicle . . . . . . . . . . . . . . . . . . . . 223
Bulb Replacement Center High-Mounted Stoplamp(CHMSL) and Cargo Lamp . . . . . . . . . . . . 327
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . 325
Headlamp Aiming . . . . . . . . . . . . . . . . . . . . . . 324
Headlamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
Headlamps, Front Turn Signal, Sidemarker, and Parking Lamps . . . . . . 325
License Plate Lamps . . . . . . . . . . . . . . . . . . . 328
Taillamps, Turn Signal, Stoplamps, and Back-up Lamps . . . . . . . . . . . . . . . . . . 326
Buying New Tires . . . . . . . . . . . . . . . . . . . . . . . . . 351
C
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
California Perchlorate Materials Requirements . . . 301
California Proposition
65 Warning . . . . . . . . . . . . . . . . . . .301, 318, 367, Back Cover
Camera Truck Bed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Canadian Vehicle Owners . . . . . . . . . . . . . . . . . . . 1
Capacities and Specifications . . . . . . . . . . . . . 398
Carbon Monoxide
Engine Exhaust . . . . . . . . . . . . . . . . . . . . . . . . 232
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Winter Driving . . . . . . . . . . . . . . . . . . . . . . . . . 215
Cargo Tie-Downs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Caution, Danger, and Warning . . . . . . . . . . . . . .2
Center Console Storage . . . . . . . . . . . . . . . . . . . 92
Center High-Mounted Stoplamp (CHMSL) and Cargo Lamp . . . . . . . . . . . . . . 327
Center Seat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Chains, Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354
Charging Wireless . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Charging System Light . . . . . . . . . . . . . . . . . . . . 111
Check Engine Light (Malfunction Indicator) . . . . 111

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
422 Index
Check (cont'd)Ignition Transmission Lock . . . . . . . . . . . . . 322
Child Restraints Infants and Young Children . . . . . . . . . . . . . 69
Lower Anchors and Tethers forChildren . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Older Children . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Securing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84, 87
Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Circuit Breakers . . . . . . . . . . . . . . . . . . . . . . . . . . 329
Cleaning Exterior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
Interior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
Climate Control Systems . . . . . . . . . . . . . . . . . 199 Air Conditioning . . . . . . . . . . . . . . . . . . . . . . . 199
Dual Automatic . . . . . . . . . . . . . . . . . . . . . . . . 201
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Cluster, Instrument . . . . . . . . . . . . . . . . . . . . . . 102
Collision Damage Repair . . . . . . . . . . . . . . . . . 407
Compartments Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Compass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Connected Services Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417 Connections
Connected Services . . . . . . . . . . . . . . . . . . . . 418
Control Hill Descent . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Traction and Electronic Stability . . . . . . . 242
Control Light Hill Descent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Control of a Vehicle . . . . . . . . . . . . . . . . . . . . . 208
Controls Steering Wheel . . . . . . . . . . . . . . . . . . . . . . . . 146
Convex Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Coolant
Engine Temperature Gauge . . . . . . . . . . . . 108
Engine Temperature Warning Light . . . . . 116
Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .199, 201
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . 310
Courtesy Transportation Program . . . . . . . . 406
Coverage Explanations . . . . . . . . . . . . . . . . . . . 170
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 246 Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Cupholders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91
Customer Assistance . . . . . . . . . . . . . . . . . . . . . 403
Offices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
Text Telephone (TTY) Users . . . . . . . . . . . . 403
Customer Information
Publications Ordering Information . . . . . 408
Customer Satisfaction Procedure . . . . . . . . . 401
Cybersecurity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410D
Damage Repair, Collision . . . . . . . . . . . . . . . . . 407
Danger, Warning, and Caution . . . . . . . . . . . . . .2
Data Collection Infotainment System . . . . . . . . . . . . . . . . . . . 411
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
Data Recorders, Event . . . . . . . . . . . . . . . . . . . . 411
Database Coverage Explanations . . . . . . . . . 170
Daytime Running Lamps (DRL) . . . . . . . . . . . 136
Defensive Driving . . . . . . . . . . . . . . . . . . . . . . . . 208
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Destination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Diagnostics Connected Services . . . . . . . . . . . . . . . . . . . . 419
Differential, Limited-Slip . . . . . . . . . . . . . . . . . 245
Distracted Driving . . . . . . . . . . . . . . . . . . . . . . . . 207
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Door Ajar Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . 22
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Power Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Drive Belt Routing, Engine . . . . . . . . . . . . . . .400
Driver Teen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Driver Assistance Systems . . . . . . . . . . . . . . . 247
Driver Information Center (DIC) . . . . . . 119, 120
Driver Mode Control . . . . . . . . . . . . . . . . . . . . . 244

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Index 423
Driver Mode Control Light . . . . . . . . . . . . . . . . 117
DrivingAssistance Systems . . . . . . . . . . . . . . . . . . . . 257
Better Fuel Economy . . . . . . . . . . . . . . . . . . . 207
Characteristics and Towing Tips . . . . . . . . 268
Defensive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
Hill and Mountain Roads . . . . . . . . . . . . . . 215
If the Vehicle is Stuck . . . . . . . . . . . . . . . . . 216
Impaired . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
Loss of Control . . . . . . . . . . . . . . . . . . . . . . . . 210
Off-Road . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
Off-Road Recovery . . . . . . . . . . . . . . . . . . . . . 210
Vehicle Load Limits . . . . . . . . . . . . . . . . . . . . . 217
Wet Roads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Dual Automatic Climate Control
System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
E
E85 or FlexFuel . . . . . . . . . . . . . . . . . . . . . . . . . . 264
Electric Parking Brake . . . . . . . . . . . . . . . . . . . . 240
Electric Parking Brake Light . . . . . . . . . . . . . . . 113
Electrical Equipment, Add-On . . . . . . . . . . . . 297
Electrical SystemEngine Compartment Fuse Block . . . . . . . 329
Fuses and Circuit Breakers . . . . . . . . . . . . . 329
Instrument Panel Fuse Block . . . . . . 332, 334
Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328 Electronic Stability Control (ESC) Off
Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Emergency OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . 309
Check Light (Malfunction Indicator) . . . . . 111
Compartment Overview . . . . . . . . . . . . . . . . 304
Coolant Temperature Gauge . . . . . . . . . . . 108
Coolant Temperature Warning Light . . . . 116
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 310
Drive Belt Routing . . . . . . . . . . . . . . . . . . . . 400
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 307
Oil Pressure Gauge . . . . . . . . . . . . . . . . . . . . 107
Oil Pressure Light . . . . . . . . . . . . . . . . . . . . . . . 117
Overheated ProtectionOperating Mode . . . . . . . . . . . . . . . . . . . . . 314
Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
Power Messages . . . . . . . . . . . . . . . . . . . . . . . 126
Running While Parked . . . . . . . . . . . . . . . . . 232
Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Engine Air Filter Life System . . . . . . . . . . . . . 308
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Equipment, Towing . . . . . . . . . . . . . . . . . . . . . . 276
Event Data Recorders . . . . . . . . . . . . . . . . . . . . . 411 Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Extended Parking . . . . . . . . . . . . . . . . . . . . . . . . . 231
Extender, Seat Belt . . . . . . . . . . . . . . . . . . . . . . . 56
Exterior Cargo Lamps . . . . . . . . . . . . . . . . . . . . 139
Exterior Lamp Controls . . . . . . . . . . . . . . . . . . . .134
Exterior Lamps Off Reminder . . . . . . . . . . . . 136
Exterior Lighting Battery Saver . . . . . . . . . . .142
F
Fan
Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
Filter,
Engine Air Cleaner . . . . . . . . . . . . . . . . . . . . . 309
Fixed Mast Antenna . . . . . . . . . . . . . . . . . . . . . . 153
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Flashers, Hazard Warning . . . . . . . . . . . . . . . . . 137
Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355 Changing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
FlexFuel E85 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
Floor Console Storage . . . . . . . . . . . . . . . . . . . . . 93
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .381
Fluid
Automatic Transmission . . . . . . . . . . . . . . . 308
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
Four-Wheel Drive Transfer Case . . . . . . . . 236
Power Steering . . . . . . . . . . . . . . . . . . . . . . . . 314
Washer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Index 425
Hill Descent Control Light . . . . . . . . . . . . . . . . . 114
Hill Start Assist (HSA) . . . . . . . . . . . . . . . . . . . . 242
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
How to Wear Seat Belts Properly . . . . . . . . . .52
HVAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .199, 201
I
If the System Needs Service . . . . . . . . . . . . . 170
Ignition Positions . . . . . . . . . . . . . . . . . . . 224, 226
Ignition Transmission Lock Check . . . . . . . . 322
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
IndicatorVehicle Ahead . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Infants and Young Children, Restraints . . . . 69
Information Publication Ordering . . . . . . . . . . . . . . . . . . . 408
Infotainment System . . . . . . . . . . . . . . . . . . . . . 411
Instrument Cluster . . . . . . . . . . . . . . . . . . . . . . . 102
Instrument Panel Overview . . . . . . . . . . . . . . . . 4
Interior Rearview Mirrors . . . . . . . . . . . . . . . . . 34
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 143
J
Jack Auxiliary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Jump Starting - North America . . . . . . . . . . . 367
K
Keyless Entry
Remote (RKE) System . . . . . . . . . . . . . . . . 10, 13
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 9
L
Labeling, Tire Sidewall . . . . . . . . . . . . . . . . . . . 338
Lamps Auxiliary Roof Mounted Lamp . . . . . . . . . 139
Daytime Running (DRL) . . . . . . . . . . . . . . . . 136
Dome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Exterior Cargo . . . . . . . . . . . . . . . . . . . . . . . . . 139
Exterior Controls . . . . . . . . . . . . . . . . . . . . . . . 134
Exterior Lamps Off Reminder . . . . . . . . . . 136
Exterior Lighting Battery Saver . . . . . . . . 142
License Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
Malfunction Indicator (CheckEngine) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
On Reminder . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Lane Change Alert (LCA) . . . . . . . . . . . . . . . . . 261
Lane Departure Warning (LDW) . . . . . . . . . . 262
Lane Departure Warning Light . . . . . . . . . . . . 115
Lap-Shoulder Belt . . . . . . . . . . . . . . . . . . . . . . . . . 54
LATCH System Replacing Parts after a Crash . . . . . . . . . . . 84
LATCH, Lower Anchors and Tethers for Children . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 LED Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Lighting
Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Exit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Illumination Control . . . . . . . . . . . . . . . . . . . 140
LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Task . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Lights Airbag Readiness . . . . . . . . . . . . . . . . . . . . . . 110
Antilock Brake System (ABS)Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Brake System Warning . . . . . . . . . . . . . . . . . 113
Charging System . . . . . . . . . . . . . . . . . . . . . . . 111
Check Engine (Malfunction Indicator) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Door Ajar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Driver Mode Control . . . . . . . . . . . . . . . . . . . . 117
Electric Parking Brake . . . . . . . . . . . . . . . . . . . 113
Electronic Stability Control (ESC), Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Engine Coolant Temperature Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Engine Oil Pressure . . . . . . . . . . . . . . . . . . . . . 117
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Four-Wheel-Drive . . . . . . . . . . . . . . . . . . . . . . . 114
Front Fog Lamp . . . . . . . . . . . . . . . . . . . . . . . . . 118
High-Beam On . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Index 427
Off-Road (cont'd)Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
Oil Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
Engine Oil Life System . . . . . . . . . . . . . . . . . 307
Engine Oil Pressure Gauge . . . . . . . . . . . . . 107
Pressure Light . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Older Children, Restraints . . . . . . . . . . . . . . . . . 68
Online Owner Center . . . . . . . . . . . . . . . . . . . . 403
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
OnStar Additional Information . . . . . . . . . . . .413
OnStar Emergency . . . . . . . . . . . . . . . . . . . . . . . .413
OnStar Overview . . . . . . . . . . . . . . . . . . . . . . . . . .412
OnStar Security . . . . . . . . . . . . . . . . . . . . . . . . . . .413
OnStar System . . . . . . . . . . . . . . . . . . . . . . 157, 168
Operating Mode Overheated Engine Protection . . . . . . . . . 314
Operation Fog Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Outlets Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Overheated Engine Protection Operating Mode . . . . . . . . . . . . . . . . . . . . . . . .314
Overheating, Engine . . . . . . . . . . . . . . . . . . . . . . 312
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 Instrument Panel . . . . . . . . . . . . . . . . . . . . . . . . 4P
Park
Shifting Into . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
Shifting Out of . . . . . . . . . . . . . . . . . . . . . . . . 231
Park Assist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
Parking
Brake and P (Park) MechanismCheck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
Extended . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Over Things That Burn . . . . . . . . . . . . . . . . . 231
Parking or Backing Assistance Systems . . . . . . . . . . . . . . . . . . . . 249
Passenger Airbag Status Indicator . . . . . . . . .110
Passenger Compartment Air Filter . . . . . . . 204
Passenger Sensing System . . . . . . . . . . . . . . . . 62
Perchlorate Materials Requirements, California . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
Personalization Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Phone Apple CarPlay and Android Auto . . . . . . . 180
Bluetooth . . . . . . . . . . . . . . . . . . . . . . . . . . 175, 176
Pickup Conversion to Chassis Cab . . . . . . . . 299
Port USB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Positioning Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Power
Door Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Outlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Protection, Battery . . . . . . . . . . . . . . . . . . . . . 142
Retained Accessory (RAP) . . . . . . . . . . . . . . 229
Seat Adjustment . . . . . . . . . . . . . . . . . . . . . . . . 44
Steering Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 314
Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Power Assist Steps . . . . . . . . . . . . . . . . . . . . . . . . 26
Pregnancy, Using Seat Belts . . . . . . . . . . . . . . 56
Privacy Vehicle Data Recording . . . . . . . . . . . . . . . . 410
Problems with Route Guidance . . . . . . . . . . 169
Program Courtesy Transportation . . . . . . . . . . . . . . . 406
Prohibited Fuels . . . . . . . . . . . . . . . . . . . . . . . . . 264
Proposition 65 Warning, California . . . . . . . . . . . . . . . . . . . . .301, 318, 367, Back Cover
Publication Ordering Information . . . . . . . . 408
R
Radio
HD Radio Technology . . . . . . . . . . . . . . . . . . . 151
Radio Data System (RDS) . . . . . . . . . . . . . . . . . 152
Radio Frequency Statement . . . . . . . . . . . . . . 409
Radio Reception . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
428 Index
RadiosAM-FM Radio . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Satellite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Reading Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320 Locking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
Rear Camera Mirror . . . . . . . . . . . . . . . . . . . . . . . 34
Rear Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Heated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Rear Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Rear Vision Camera (RVC) . . . . . . . . . . . . . . . . 249
Rear Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Rearview Mirror Truck Bed Camera . . . . . . . . . . . . . . . . . . . . . . 37
Rearview Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 34 Automatic Dimming . . . . . . . . . . . . . . . . . . . . 34
Reclining Seatbacks . . . . . . . . . . . . . . . . . . . . . . . 45
Recognition Voice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
Recommended Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Recommended Fluids and Lubricants . . . . . 393
Records Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
Recreational Vehicle Towing . . . . . . . . . . . . . 370
Reimbursement Program, GM
Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404
Remote Keyless Entry (RKE) System . . . 10, 13 Remote Vehicle Start . . . . . . . . . . . . . . . . . . . . . 20
Replacement
Glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Replacement Parts Airbags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 394
Replacing Airbag System . . . . . . . . . . . . . . . . . . 67
Replacing LATCH System Parts after a
Crash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Replacing Seat Belt System Parts after a Crash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Reporting Safety Defects Canadian Government . . . . . . . . . . . . . . . . . 409
General Motors . . . . . . . . . . . . . . . . . . . . . . . . 410
U.S. Government . . . . . . . . . . . . . . . . . . . . . . . 409
Restraints
Where to Put . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Retained Accessory Power (RAP) . . . . . . . . . 229
Reverse Tilt Mirrors . . . . . . . . . . . . . . . . . . . . . . . 34
Ride Control Systems Enhanced Traction System (ETS) . . . . . . . 245
Roads Driving, Wet . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
Roadside Assistance Program . . . . . . . . . . . . 404
Roof Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Rotation, Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
Routing, Engine Drive Belt . . . . . . . . . . . . . . .400 Running the Vehicle While Parked . . . . . . . 232
S
Safety Defects Reporting
Canadian Government . . . . . . . . . . . . . . . . . 409
General Motors . . . . . . . . . . . . . . . . . . . . . . . . 410
U.S. Government . . . . . . . . . . . . . . . . . . . . . . . 409
Safety Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Safety System Check . . . . . . . . . . . . . . . . . . . . . 56
Satellite Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Scheduling Appointments . . . . . . . . . . . . . . . . 405
Seat Belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Extender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
How to Wear Seat Belts Properly . . . . . . . 52
Lap-Shoulder Belt . . . . . . . . . . . . . . . . . . . . . . . 54
Reminders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Replacing after a Crash . . . . . . . . . . . . . . . . . 57
Use During Pregnancy . . . . . . . . . . . . . . . . . . 56
Seats Adjustment, Front . . . . . . . . . . . . . . . . . . . . . . 43
Center Seat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Head Restraints . . . . . . . . . . . . . . . . . . . . . . . . . 42
Heated and Ventilated Front . . . . . . . . . . . . 49
Heated, Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Lumbar Adjustment, Front . . . . . . . . . . . . . . 45
Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Power Adjustment, Front . . . . . . . . . . . . . . . 44