2021 GMC SIERRA manual shifting

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 31
To extend the steps:
.Pressjto extend both steps. A DIC
message displays.
.Pressjagain to extend to the tire.
A DIC message displays.
.Pressjagain to return to normal
operation.
Enable/Disable
To enable or disable the power assist steps,
press and hold
jfor four seconds. A DIC
message displays.
Cleaning
Clean the power assist steps regularly. For
an automatic car wash, extend the steps
while in N (Neutral) using the center stack
switch. The steps will stow when shifting
into D (Drive).
Vehicle Security
This vehicle has theft-deterrent features;
however, they do not make the vehicle
impossible to steal.
Vehicle Alarm System
The indicator light, on the instrument panel
near the windshield, indicates the status of
the system.
Off : Alarm system is disarmed.
On Solid : Vehicle is secured during the
delay to arm the system.
Fast Flash : Vehicle is unsecured. A door or
the hood is open.
Slow Flash : Alarm system is armed.
Arming the Alarm System
1. Turn off the vehicle. 2. Lock the vehicle in one of two ways:
.Use the RKE transmitter.
.With a door open, pressQon the
interior of the door.
3. After 30 seconds, the alarm system will arm and the indicator light will begin to
slowly flash. Pressing
Qon the RKE
transmitter a second time will bypass
the 30-second delay and immediately
arm the alarm system.
The vehicle alarm system will not arm if the
doors are locked with the key.
If the driver door is opened without first
unlocking with the RKE transmitter, the horn
will chirp and the lights will flash to indicate
pre-alarm. If the vehicle is not started,
or the door is not unlocked by pressing
K
on the RKE transmitter during the 10-second
pre-alarm, the alarm will be activated.
The alarm will also be activated if a
passenger door or the hood is opened
without first disarming the system. When
the alarm is activated, the turn signals flash
and the horn sounds for about 30 seconds.
The alarm system will then re-arm to
monitor for the next unauthorized event.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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194 Infotainment System
Manage Settings
Audio Volume Limit :Allows the audio
volume limit to be turned on or off. Touch
Set Audio Volume Limit to choose the
maximum allowable audio volume level.
Set Audio Volume Limit : Allows a
maximum radio volume to be set. Use the
arrows to choose the maximum allowable
level for the audio volume.
Teen Driver Speed Limiter : Limits the
maximum speed of the vehicle. When the
speed limiter is turned on and the vehicle is
started with a Teen Driver key, the DIC
displays a message that the top speed is
limited.
On certain vehicles, when the Speed Limiter
is turned ON, the vehicle’s maximum
acceleration will be limited. The DIC will
display a message that the acceleration is
limited.
Teen Driver Speed Warning : Allows the
speed warning to be turned on or off. Touch
Set Teen Driver Speed Warning to set the
warning speed. Set Teen Driver Speed Warning :
Displays a
warning in the DIC when exceeding a
selectable speed. Choose the desired speed
warning level. The speed warning does not
limit the speed of the vehicle.
SiriusXM Explicit Content Filter (if
equipped) : Allows the SiriusXM Explicit
Content Filter to be turned ON or OFF.
When ON, the teen driver will not be able
to listen to SiriusXM stations that contain
explicit content, and the Explicit Content
Filter selection in the Audio Settings will be
unavailable for change.
When Teen Driver is Active:
.If equipped with Buckle to Drive, shifting
out of P (Park) will be prevented if the
driver seat belt, and in some vehicles the
front passenger seat belt, is not buckled.
.The radio will mute when the driver seat
belt, and in some vehicles the front
passenger seat belt, is not buckled. The
audio from any device paired to the
vehicle will also be muted.
.An object placed on the front passenger
seat, such as a briefcase, handbag,
grocery bag, laptop, or other electronic
device, could cause the passenger sensing
system to falsely sense an unbuckled
front passenger and mute the radio. If this happens, remove the object from
the seat. See
Passenger Sensing System
0 66.
.Some safety systems, such as Forward
Collision Alert, if equipped, cannot be
turned off.
.The gap setting for the Forward Collision
Alert and Adaptive Cruise Control,
if equipped, cannot be changed.
.When trying to change a safety feature
that is not configurable in Teen Driver,
the DIC displays a message indicating
that Teen Driver is active and the action
is not available.
.Super Cruise, if equipped, is not available.
.Enhanced Low Fuel Warning (if equipped)
–When the vehicle is low on fuel, the
low fuel light on the instrument cluster
flashes and the DIC low fuel warning
cannot be dismissed.
.Do not tow a trailer.
Report Card
The vehicle owner must secure the driver’s
consent to record certain vehicle data when
the vehicle is driven with a registered Teen
Driver key. There is one Report Card per

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Driving and Operating 211
Driving and Operating
Driving Information
Driving for Better Fuel Economy . . . . . . . 212
Distracted Driving . . . . . . . . . . . . . . . . . . . . . . 212
Defensive Driving . . . . . . . . . . . . . . . . . . . . . . 213
Impaired Driving . . . . . . . . . . . . . . . . . . . . . . . 213
Control of a Vehicle . . . . . . . . . . . . . . . . . . . . 213
Braking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
Steering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
Off-Road Recovery . . . . . . . . . . . . . . . . . . . . . 214
Loss of Control . . . . . . . . . . . . . . . . . . . . . . . . . 215
Off-Road Driving . . . . . . . . . . . . . . . . . . . . . . . 215
Driving on Wet Roads . . . . . . . . . . . . . . . . . 219
Hill and Mountain Roads . . . . . . . . . . . . . . 219
Winter Driving . . . . . . . . . . . . . . . . . . . . . . . . 220
If the Vehicle Is Stuck . . . . . . . . . . . . . . . . . . 221
Vehicle Load Limits . . . . . . . . . . . . . . . . . . . . 222
Truck-Camper Loading Information . . . . 226
Starting and Operating
New Vehicle Break-In . . . . . . . . . . . . . . . . . . 228
Ignition Positions (Key Access) . . . . . . . . 229
Ignition Positions (Keyless Access) . . . . . 230
Starting the Engine . . . . . . . . . . . . . . . . . . . . 232
Stop/Start System . . . . . . . . . . . . . . . . . . . . . 233
Engine Heater . . . . . . . . . . . . . . . . . . . . . . . . . 234
Retained Accessory Power (RAP) . . . . . . . 236
Shifting Into Park . . . . . . . . . . . . . . . . . . . . . 236
Shifting out of Park . . . . . . . . . . . . . . . . . . . 237Parking over Things That Burn . . . . . . . . . 237
Active Fuel Management . . . . . . . . . . . . . . 237
Extended Parking . . . . . . . . . . . . . . . . . . . . . . 238
Engine Exhaust
Engine Exhaust . . . . . . . . . . . . . . . . . . . . . . . . 238
Running the Vehicle While Parked . . . . . 238
Automatic Transmission
Automatic Transmission . . . . . . . . . . . . . . . 239
Manual Mode . . . . . . . . . . . . . . . . . . . . . . . . . 241
Tow/Haul Mode . . . . . . . . . . . . . . . . . . . . . . . 242
Drive Systems
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . 242
Brakes
Electric Brake Boost . . . . . . . . . . . . . . . . . . . 246
Antilock Brake System (ABS) . . . . . . . . . . 246
Electric Parking Brake . . . . . . . . . . . . . . . . . . 247
Brake Assist . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
Hill Start Assist (HSA) . . . . . . . . . . . . . . . . . 248
Ride Control Systems
Traction Control/Electronic Stability
Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
Hill Descent Control (HDC) . . . . . . . . . . . . 250
Driver Mode Control . . . . . . . . . . . . . . . . . . . 251
Limited-Slip Differential . . . . . . . . . . . . . . . . 254
Locking Rear Axle . . . . . . . . . . . . . . . . . . . . . 254
Cruise Control
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . . 254
Adaptive Cruise Control (Camera) . . . . . . 256
Driver Assistance Systems
Driver Assistance Systems . . . . . . . . . . . . . 265
Assistance Systems for Parking or Backing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
Assistance Systems for Driving . . . . . . . . 274
Forward Collision Alert (FCA) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
Automatic Emergency Braking (AEB) . . . 277
Front Pedestrian Braking (FPB) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Side Blind Zone Alert (SBZA) . . . . . . . . . . 280
Lane Change Alert (LCA) . . . . . . . . . . . . . . . 280
Lane Keep Assist (LKA) . . . . . . . . . . . . . . . . . 281
Fuel
Top Tier Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . 283
Recommended Fuel (Except 6.2L V8 Engine) . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
Recommended Fuel (6.2L V8 Engine) . . . . . . . . . . . . . . . . . . . . . . . . . . 284
Prohibited Fuels . . . . . . . . . . . . . . . . . . . . . . . 284
Fuels in Foreign Countries . . . . . . . . . . . . . 284
Fuel Additives . . . . . . . . . . . . . . . . . . . . . . . . . 284
E85 or FlexFuel . . . . . . . . . . . . . . . . . . . . . . . . 284
Filling the Tank (Pickup Model) . . . . . . . . 285
Filling the Tank (Chassis Cab Model) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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Driving and Operating 215
2. Turn the steering wheel aboutone-eighth of a turn, until the right front
tire contacts the pavement edge.
3. Turn the steering wheel to go straight down the roadway.
Loss of Control
Skidding
There are three types of skids that
correspond to the vehicle's three control
systems:
.Braking Skid —wheels are not rolling.
.Steering or Cornering Skid —too much
speed or steering in a curve causes tires
to slip and lose cornering force.
.Acceleration Skid —too much throttle
causes the driving wheels to spin.
Defensive drivers avoid most skids by taking
reasonable care suited to existing conditions,
and by not overdriving those conditions. But
skids are always possible.
If the vehicle starts to slide, follow these
suggestions:
.Ease your foot off the accelerator pedal
and steer the way you want the vehicle
to go. The vehicle may straighten out. Be
ready for a second skid if it occurs.
.Slow down and adjust your driving
according to weather conditions. Stopping
distance can be longer and vehicle control
can be affected when traction is reduced
by water, snow, ice, gravel, or other
material on the road. Learn to recognize
warning clues —such as enough water,
ice, or packed snow on the road to make
a mirrored surface —and slow down
when you have any doubt.
.Try to avoid sudden steering, acceleration,
or braking, including reducing vehicle
speed by shifting to a lower gear. Any
sudden changes could cause the tires to
slide.
Remember: Antilock brakes help avoid only
the braking skid.
Off-Road Driving
Four-wheel-drive vehicles can be used for
off-road driving. Vehicles without four-wheel
drive and vehicles not equipped with All
Terrain (AT) or On-Off Road (OOR) tires must
not be driven off-road except on a level,
solid surface. For contact information about
the original equipment tires, see the
warranty manual.
One of the best ways for successful off-road
driving is to control the speed.
{Warning
When driving off-road, bouncing and
quick changes in direction can easily
throw you out of position. This could
cause you to lose control and crash. You
and your passengers should always wear
seat belts.
Before Driving Off-Road
.Have all necessary maintenance and
service work completed.
.Fuel the vehicle, fill fluid levels, and check
inflation pressure in all tires, including the
spare, if equipped.
.Read all the information about
four-wheel-drive vehicles in this manual.
.Remove any underbody air deflector,
if equipped. Re-attach the air deflector
after off-road driving.
.Know the local laws that apply to off-road
driving.
To gain more ground clearance if needed, it
may be necessary to remove the front fascia
lower air dam, if equipped. However, driving
without the air dam reduces fuel economy.

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Driving and Operating 217
{Warning
If the vehicle has the two-speed
automatic transfer case, shifting the
transfer case to N (Neutral) can cause
your vehicle to roll even if the
transmission is in P (Park). This is because
the N (Neutral) position on the transfer
case overrides the transmission. You or
someone else could be injured. If leaving
the vehicle, set the parking brake and
shift the transmission to P (Park). Shift
the transfer case to any position but
N (Neutral).
.When driving down a hill, keep the
vehicle headed straight down. Use a low
gear because the engine will work with
the brakes to slow the vehicle and help
keep the vehicle under control.
{Warning
Heavy braking when going down a hill
can cause your brakes to overheat and
fade. This could cause loss of control and
you or others could be injured or killed.(Continued)
Warning (Continued)
Apply the brakes lightly when descending
a hill and use a low gear to keep vehicle
speed under control.
If a brake fade condition is detected, a DIC
warning message is displayed. Adjust brake
pedal use and shift to a lower transmission
gear to reduce braking.
If the brakes continue to fade to a severe
condition, additional DIC messages are
displayed. The brake system warning light
will illuminate, and the vehicle speed may
be limited. See Brake System Warning Light
0 117.
If the vehicle stalls on a hill: 1. Apply the brakes to stop the vehicle, and then apply the parking brake.
2. Shift into P (Park) and then restart the engine.
.If driving uphill when the vehicle
stalls, shift to R (Reverse), release the
parking brake, and back
straight down.
.Never try to turn the vehicle around.
If the hill is steep enough to stall the
vehicle, it is steep enough to cause it
to roll over.
.If you cannot make it up the hill,
back straight down the hill.
.Never back down a hill in N (Neutral)
using only the brake. The vehicle can
roll backward quickly and you could
lose control.
.If driving downhill when the vehicle
stalls, shift to a lower gear, release
the parking brake, and drive straight
down the hill.
3. If the vehicle cannot be restarted after stalling, set the parking brake, shift into
P (Park), and turn the vehicle off.
3.1. Leave the vehicle and seek help.
3.2. Stay clear of the path the vehicle would take if it rolled downhill.
.Avoid turns that take the vehicle across
the incline of the hill. A hill that can be
driven straight up or down might be too
steep to drive across. Driving across an
incline puts more weight on the downhill
wheels, which could cause a downhill
slide or a rollover.

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Driving and Operating 221
Warning (Continued)
.Fully open the air outlets on or under
the instrument panel.
.Adjust the climate control system to
circulate the air inside the vehicle and
set the fan speed to the highest
setting. See“Climate Control Systems.”
For more information about CO, see
Engine Exhaust 0238.
To save fuel, run the engine for short
periods to warm the vehicle and then shut
the engine off and partially close the
window. Moving about to keep warm also
helps.
If it takes time for help to arrive, when
running the engine, push the accelerator
pedal slightly so the engine runs faster than
the idle speed. This keeps the battery
charged to restart the vehicle and to signal
for help with the headlamps. Do this as
little as possible, to save fuel.
If the Vehicle Is Stuck
Slowly and cautiously spin the wheels to
free the vehicle when stuck in sand, mud,
ice, or snow. See “Rocking the Vehicle to Get
It Out” later in this section. The Traction Control/Electronic Stability
Control can often help to free a stuck
vehicle. See
Traction Control/Electronic
Stability Control 0248. If TC/ESC cannot free
the vehicle, see “Rocking the Vehicle to Get
it Out” following.
{Warning
If the vehicle's tires spin at high speed,
they can explode, and you or others
could be injured. The vehicle can
overheat, causing an engine compartment
fire or other damage. Spin the wheels as
little as possible and avoid going above
56 km/h (35 mph).
For information about using tire chains on
the vehicle, see Tire Chains0379.
Rocking the Vehicle to Get It Out
Caution
Do not hold the steering wheel at full
rotation for more than 15 seconds and/or
at an elevated RPM. Damage may occur
to the power steering system and there
may be loss of power steering assist. Turn the steering wheel left and right to
clear the area around the front wheels. Then
make sure the wheels are pointed straight
ahead. For four-wheel-drive vehicles, shift
into Four-Wheel Drive High. Turn the TCS
off. Shift back and forth between R (Reverse)
and a forward gear, spinning the wheels as
little as possible. To prevent transmission
wear, wait until the wheels stop spinning
before shifting gears. Slowly spinning the
wheels in the forward and reverse directions
causes a rocking motion that could free the
vehicle. If that does not get the vehicle out
after a few tries, it might need to be towed
out. See
Towing the Vehicle 0394. Recovery
hooks can be used, if the vehicle has them.
Recovery Hooks
{Warning
Never pull on recovery hooks from the
side. The hooks could break and you and
others could be injured. When using
recovery hooks, always pull the vehicle
from the front.

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Driving and Operating 225
the actual loads on the front and rear
axles, weigh the vehicle at a weigh
station. Your dealer can help with this.
Be sure to spread the load equally on
both sides of the centerline.
The Certification/Tire label also contains
important information about the Front
Axle Reserve Capacity. SeeAdding a
Snow Plow or Similar Equipment 0318.
{Warning
In the case of a sudden stop or
collision, things carried in the bed of
your truck could shift forward and
come into the passenger area,
injuring you and others. If you put
things in the bed of your truck, you
should make sure they are properly
secured.
Caution
Overloading the vehicle may cause
damage. Repairs would not be covered by
the vehicle warranty. Do not overload the
vehicle.
Using heavier suspension components
to get added durability might not
change the weight ratings. Ask your
dealer to help load the vehicle the
right way.
{Warning
Things you put inside the vehicle can
strike and injure people in a sudden
stop or turn, or in a crash.
.Put things in the cargo area of the
vehicle. Try to spread the weight
evenly.
.Never stack heavier things, like
suitcases, inside the vehicle so
that some of them are above the
tops of the seats.
.Do not leave an unsecured child
restraint in the vehicle.
.When you carry something inside
the vehicle, secure it whenever
you can.
.Do not leave a seat folded down
unless you need to. There is also important loading
information for off-road driving in this
manual. See
“Loading the Vehicle for
Off-Road Driving“ underOff-Road
Driving 0215.
Two-Tiered Loading
Depending on the model of the pickup,
an upper load platform can be created
by positioning three or four 5 cm (2 in)
by 15 cm (6 in) wooden planks across
the width of the pickup box. The planks
must be inserted in the pickup box
depressions.
When using this upper load platform,
be sure the load is securely tied down
to prevent it from shifting. The load's
center of gravity should be positioned
in a zone over the rear axle. The zone is
located in the area between the front
of each wheel well and the rear of each
wheel well. The center of gravity height
must not extend above the top of the
pickup box flareboard.

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228 Driving and Operating
cargo load should not exceed the truck's
cargo weight rating, and the camper's
center of gravity (1) should fall within
the truck's recommended center of
gravity zone (2) when installed.
Any accessories or other equipment
that are added to the vehicle must be
weighed. Then, subtract this extra
weight from the CWR. This extra weight
may shorten the center of gravity zone
of the vehicle.
If the slide-in camper and its load
weighs less than the CWR, the center of
gravity zone for the vehicle may be
larger.
Secure loose items to prevent weight
shifts that could affect the balance of
the vehicle. When the truck-camper is
loaded, drive to a scale and weigh on
the front and on the rear wheels
separately to determine axle loads.
Individual axle loads should not exceed
either of the gross axle weight ratings
(GAWR). The total axle loads should not
exceed the vehicle's gross vehicle
weight rating (GVWR). These ratings aregiven on the Certification/Tire label
attached to the B-pillar. See
“Certification/Tire Label”
underVehicle
Load Limits 0222. If weight ratings are
exceeded, move or remove items to
bring all weights below the ratings.
See your dealer for more information
on curb weights, cargo weights, Cargo
Weight Rating, and the correct center of
gravity zone.
Starting and Operating
New Vehicle Break-In
Caution
The vehicle does not need an elaborate
break-in. But it will perform better in the
long run if you follow these guidelines:
.Keep the vehicle speed at 88 km/h
(55 mph) or less for the first 805 km
(500 mi).
(Continued)
Caution (Continued)
.Do not drive at any one constant
speed, fast or slow, for the first
805 km (500 mi). Do not make
full-throttle starts. Avoid downshifting
to brake or slow the vehicle.
.Avoid making hard stops for the first
322 km (200 mi) or so. During this
time the new brake linings are not yet
broken in. Hard stops with new linings
can mean premature wear and earlier
replacement. Follow this breaking-in
guideline every time you get new
brake linings.
.Do not tow a trailer during break-in.
See Trailer Towing 0293 for the
trailer towing capabilities of the
vehicle and more information.
Following break-in, engine speed and load
can be gradually increased.