2021 GMC SIERRA key battery

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
344 Vehicle Care
Stop/Start System
Vehicles equipped with a 2.7L L3B, 3.0L LM2,
5.3L L84 or 6.2L L87 are equipped with a
Stop/Start system to shut off the engine to
help conserve fuel. SeeStop/Start System
0 233.
Vehicles with the Stop/Start system have an
Absorbed Glass Mat (AGM) 12-volt battery.
Installation of a standard 12-volt battery will
result in reduced 12-volt battery life. When
using a 12-volt battery charger on the 12-volt
AGM battery, some chargers have an AGM
battery setting on the charger. If available,
use the AGM setting on the charger to limit
charge voltage to 14.8 volts. Follow the
charger manufacturer’s instructions.
{Warning
WARNING: Battery posts, terminals, and
related accessories contain lead and lead
compounds, chemicals known to the
State of California to cause cancer and
birth defects or other reproductive harm.
Batteries also contain other chemicals
known to the State of California to cause
cancer. WASH HANDS AFTER HANDLING.
(Continued)
Warning (Continued)
For more information go to
www.P65Warnings.ca.gov/
passenger-vehicle.
See California Proposition 65 Warning 0322
and the back cover.
Vehicle Storage
{Warning
Batteries have acid that can burn you and
gas that can explode. You can be badly
hurt if you are not careful. See Jump
Starting - North America 0391 for tips on
working around a battery without
getting hurt.
Infrequent Usage: Remove the black,
negative (−) cable from the battery to keep
the battery from running down.
Extended Storage: Remove the black,
negative (−) cable from the battery or use a
battery trickle charger.
Negative Battery Cable Disconnection
{Warning
Before disconnecting the negative battery
cable, turn off all features, turn the
ignition off, and remove the key,
if equipped, from the vehicle. If this is
not done, you or others could be injured,
and the vehicle could be damaged.
Caution
If the battery is disconnected with the
ignition on or the vehicle in Retained
Accessory Power (RAP), the OnStar
back-up battery will be permanently
discharged and will need to be replaced.
1. Make sure the lamps, features, and accessories are turned off.
2. Turn the ignition off and remove the key, if equipped.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
396 Vehicle Care
Dinghy Towing (Vehicles with a
Two-Speed Transfer Case)
Only dinghy tow four-wheel-drive vehicles
with a two-speed transfer case that have an
N (Neutral) and a 4
n(Four-Wheel Drive
Low) setting.
{Warning
Shifting a four-wheel-drive vehicle's
transfer case into N (Neutral) can allow
the vehicle to move even if the
transmission is in P (Park). You or others
could be injured. Set the parking brake
and use wheel blocks before shifting the
transfer case to N (Neutral). To dinghy tow:
1. Position the vehicle being towed behind the tow vehicle, facing forward and on a
level surface.
2. Securely attach the vehicle being towed to the tow vehicle.
3. Apply the parking brake and start the engine.
4. Shift the transfer case to N (Neutral). See “Shifting into N (Neutral)” under
Four-Wheel Drive 0242.
5. With the engine running, release the parking brake and verify that the
transfer case is in N (Neutral) by shifting
the transmission to D (Drive) and then to
R (Reverse). There should be no
movement while shifting the
transmission.
6. Shift the transmission to D (Drive).
7. If equipped with an ignition key, turn the ignition to ACC/ACCESSORY.
If equipped with Keyless Access, turn the
engine off. Disregard the Shift to P (Park)
DIC message. See Ignition Positions
(Keyless Access) 0230 or
Ignition Positions (Key Access) 0229.
{Warning
To avoid death, serious injury,
or property damage, before dinghy
towing the vehicle, always disconnect and
secure the 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” inBattery - North
America 0343.
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

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 397
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. SeeDoor Locks
0 21.
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 0343.
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) 0230 or
Ignition Positions (Key Access) 0229.
4. Set the parking brake. See Electric
Parking Brake 0247.
5. Disconnect from the tow vehicle.
6. Shift the transmission to N (Neutral). 7. Shift the transfer case to 2m(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 0118.
8. Start the engine. Check that the vehicle is in 2
m(Two-Wheel Drive High) by
starting the engine and shifting the
transmission to D (Drive) and then to
R (Reverse). There should be movement
of the vehicle while shifting.
9. Shift the transmission to P (Park) and turn off the ignition.
10. Release the parking brake and remove the wheel blocks.
11. Reset any lost presets. The outside temperature display will
default to 0 °C (32 °F) but will reset with
normal usage.
Dolly Towing

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
OnStar 441
.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.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./Cana-
da/Mexico-14632426) - 2021 - CRC - 11/5/20
Index 453
H
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
Hazard Warning Flashers . . . . . . . . . . . . . . . . .142
HD Radio Technology . . . . . . . . . . . . . . . . . . . . 156
Head Restraints . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Head-up Display . . . . . . . . . . . . . . . . . . . . . . . . . .128
HeadlampsAiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
Automatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . 350
Daytime Running Lamps (DRL) . . . . . . . . . . 141
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Headlamps, Front Turn Signal,Sidemarker, and Parking Lamps . . . . . . 350
High-Beam On Light . . . . . . . . . . . . . . . . . . . 123
High/Low Beam Changer . . . . . . . . . . . . . . . 141
Lamps On Reminder . . . . . . . . . . . . . . . . . . . 123
Heated Rear Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Steering Wheel . . . . . . . . . . . . . . . . . . . . . . . . 100
Heated and Ventilated Front Seats . . . . . . . .52
Heated Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Heater Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204, 206
High-Beam On Light . . . . . . . . . . . . . . . . . . . . . . 123
Hill and Mountain Roads . . . . . . . . . . . . . . . . 219
Hill Descent Control (HDC) . . . . . . . . . . . . . . . 250 Hill Descent Control Light . . . . . . . . . . . . . . . . . 119
Hill Start Assist (HSA) . . . . . . . . . . . . . . . . . . . . 248
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
How to Wear Seat Belts Properly . . . . . . . . . .55
HVAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204, 206
I
If the System Needs Service . . . . . . . . . . . . . . 175
Ignition Positions . . . . . . . . . . . . . . . . . . . 229, 230
Ignition Transmission Lock Check . . . . . . . . 347
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Indicator
Pedestrian Ahead . . . . . . . . . . . . . . . . . . . . . . . 119
Vehicle Ahead . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Infants and Young Children, Restraints . . . . .72
Information Publication Ordering . . . . . . . . . . . . . . . . . . . 435
Infotainment System . . . . . . . . . . . . . . . . . . . . 439
Instrument Cluster . . . . . . . . . . . . . . . . . . . . . . . 106
Instrument Panel Overview . . . . . . . . . . . . . . . . 4
Interior Rearview Mirrors . . . . . . . . . . . . . . . . . 38
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 148
J
Jack Auxiliary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Jump Starting - North America . . . . . . . . . . . 391
K
Keyless Entry Remote (RKE) System . . . . . . . . . . . . . . . . 10, 13
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 9
L
Labeling, Tire Sidewall . . . . . . . . . . . . . . . . . . . 362
Lamps Auxiliary Roof Mounted Lamp . . . . . . . . . 144
Daytime Running (DRL) . . . . . . . . . . . . . . . . . 141
Dome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Exterior Cargo . . . . . . . . . . . . . . . . . . . . . . . . . 144
Exterior Controls . . . . . . . . . . . . . . . . . . . . . . . 139
Exterior Lamps Off Reminder . . . . . . . . . . . 141
Exterior Lighting Battery Saver . . . . . . . . 147
License Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . 352
Malfunction Indicator (CheckEngine) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
On Reminder . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Lane Change Alert (LCA) . . . . . . . . . . . . . . . . . 280
Lane Keep Assist (LKA) . . . . . . . . . . . . . . . . . . . .281
Lane Keep Assist Light . . . . . . . . . . . . . . . . . . . . 119
Lap-Shoulder Belt . . . . . . . . . . . . . . . . . . . . . . . . . .57
LATCH System Replacing Parts after a Crash . . . . . . . . . . . 88
LATCH, Lower Anchors and Tethers for Children . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./Cana-
da/Mexico-14632426) - 2021 - CRC - 11/5/20
456 Index
PowerDoor Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Outlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Protection, Battery . . . . . . . . . . . . . . . . . . . . . 147
Retained Accessory (RAP) . . . . . . . . . . . . . . 236
Seat Adjustment . . . . . . . . . . . . . . . . . . . . . . . . 47
Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Power Assist Steps . . . . . . . . . . . . . . . . . . . . . . . . 30
Pregnancy, Using Seat Belts . . . . . . . . . . . . . . 59
Privacy Vehicle Data Recording . . . . . . . . . . . . . . . . 437
Problems with Route Guidance . . . . . . . . . . .174
Program Courtesy Transportation . . . . . . . . . . . . . . . 433
Prohibited Fuels . . . . . . . . . . . . . . . . . . . . . . . . . 284
Proposition 65 Warning,
California . . . . . . . . . . . . . . . . . . . . .322, 343, 391, Back Cover
Publication Ordering Information . . . . . . . . 435
R
Radio HD Radio Technology . . . . . . . . . . . . . . . . . . 156
Radio Data System (RDS) . . . . . . . . . . . . . . . . . 157
Radio Frequency Statement . . . . . . . . . . . . . . 436
Radio Reception . . . . . . . . . . . . . . . . . . . . . . . . . .158 Radios
AM-FM Radio . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Satellite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Reading Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346 Locking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
Rear Camera Mirror . . . . . . . . . . . . . . . . . . . . . . . 38
Rear Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Heated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Rear Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Rear Vision Camera (RVC) . . . . . . . . . . . . . . . . 266
Rear Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Rearview Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 38 Automatic Dimming . . . . . . . . . . . . . . . . . . . . 38
Reclining Seatbacks . . . . . . . . . . . . . . . . . . . . . . . 48
Recognition Voice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
Recommended Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283, 284
Recommended Fluids and Lubricants . . . . . 418
Records Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
Recreational Vehicle Towing . . . . . . . . . . . . . 395
Reimbursement Program, GM Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .431
Remote Keyless Entry (RKE) System . . . 10, 13
Remote Vehicle Start . . . . . . . . . . . . . . . . . . . . . 20 Replacement
Glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
Replacement Parts Airbags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
Replacing Airbag System . . . . . . . . . . . . . . . . . . . 71
Replacing LATCH System Parts after a Crash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Replacing Seat Belt System Parts after a Crash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Reporting Safety Defects
Canadian Government . . . . . . . . . . . . . . . . . 437
General Motors . . . . . . . . . . . . . . . . . . . . . . . . 437
U.S. Government . . . . . . . . . . . . . . . . . . . . . . . 436
Restraints Where to Put . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Retained Accessory Power (RAP) . . . . . . . . . 236
Reverse Tilt Mirrors . . . . . . . . . . . . . . . . . . . . . . . 38
Ride Control Systems Enhanced Traction System (ETS) . . . . . . . 254
Roads
Driving, Wet . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
Roadside Assistance Program . . . . . . . . . . . . .431
Roof Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Rotation, Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . 374
Routing, Engine Drive Belt . . . . . . . . . . . . . . . 427
Running the Vehicle While Parked . . . . . . . 238