2021 GMC SIERRA torque

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 237
pedal down. Then, see if you can move the
shift lever away from P (Park) without first
pulling it toward you. If you can, it means
that the shift lever was not fully locked into
P (Park).
Torque Lock
If you are parking on a hill and you do not
shift the transmission into P (Park) properly,
the weight of the vehicle may put too much
force on the parking pawl in the
transmission. You may find it difficult to pull
the shift lever out of P (Park). This is called
torque lock. To prevent torque lock, set the
parking brake and then shift into P (Park)
properly before you leave the driver seat.
When you are ready to drive, move the
shift lever out of P (Park) before you release
the parking brake.
If torque lock does occur, you may need to
have another vehicle push yours a little
uphill to take some of the pressure from the
parking pawl in the transmission. You will
then be able to pull the shift lever out of
P (Park).
Shifting out of Park
This vehicle is equipped with an electronic
shift lock release system. The system is
designed to prevent movement of the shift
lever out of P (Park), unless the brake pedal
is applied and the ignition is on or in
Service Mode.
The shift lock release is always functional
except in the case of an uncharged or low
voltage–less than 9 volt –battery.
If the vehicle has an uncharged or low
voltage battery, try charging or jump
starting the battery. See Jump Starting -
North America 0391.
To shift out of P (Park): 1. Apply the brake pedal.
2. Release the parking brake if it is applied. See Electric Parking Brake 0247.
3. Pull the shift lever toward you, then move it to the desired position, and
release.
If the vehicle still cannot be shifted out of
P (Park): 1. Ease the pressure on, or release the shift lever. 2. While holding the brake pedal, push the
shift lever all the way into P (Park).
3. Pull the shift lever toward you, then move it to the desired position, and
release.
If there is still a problem shifting, have the
vehicle serviced soon.
Parking over Things That Burn
{Warning
Things that can burn could touch hot
exhaust parts under the vehicle and
ignite. Do not park over papers, leaves,
dry grass, or other things that can burn.
Active Fuel Management
If equipped, Active Fuel Management allows
a V8, V6, or L4 gasoline engine to operate
on either all of its cylinders, or a reduced
number of cylinders, depending on the
driving conditions. When less power is
required, such as cruising at a constant
vehicle speed, the system will enable
reduced cylinder operation, allowing the
vehicle to achieve better fuel economy.
When greater power is required, such as

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 239
If parking on a hill and pulling a trailer, see
Driving Characteristics and Towing Tips
0288.
Automatic Transmission
If equipped, there is an electronic shift lever
position indicator within the instrument
cluster. This display comes on when the
ignition is in ACC/ACCESSORY, on or
service mode.
There are several different positions for the
shift lever.
See Driver Mode Control 0251 and “Range
Selection Mode” underManual Mode 0241.
P : This position locks the rear wheels. Use
P (Park) when starting the engine because
the vehicle cannot move easily. When parked on a hill, especially when the
vehicle has a heavy load, you might notice
an increase in the effort to shift out of
P (Park). See
“Torque Lock” underShifting
Into Park 0236.
{Warning
It is dangerous to get out of the vehicle
if the shift lever is not fully in P (Park)
with the parking brake firmly set. The
vehicle can roll.
Do not leave the vehicle when the engine
is running. If you have left the engine
running, the vehicle can move suddenly.
You or others could be injured. To be
sure the vehicle will not move, even
when you are on fairly level ground,
always set the parking brake and move
the shift lever to P (Park). See Shifting
Into Park 0236 and
Driving Characteristics and Towing Tips
0 288.
{Warning
If equipped with four-wheel drive, the
vehicle will be free to roll if the transfer
case is in N (Neutral), even when the shift
lever is in P (Park). You or someone else
could be seriously injured. Be sure the
transfer case is in a drive gear —2
m, 4m,
or 4
n— or set the parking brake before
placing the transfer case in N (Neutral).
See Four-Wheel Drive 0242.
R : Use this gear to back up.
Caution
Shifting to R (Reverse) while the vehicle is
moving forward could damage the
transmission. The repairs would not be
covered by the vehicle warranty. Shift to
R (Reverse) only after the vehicle is
stopped.
To rock the vehicle back and forth to get
out of snow, ice, or sand without damaging
the transmission, see If the Vehicle Is Stuck
0 221.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 243
Caution
Extended high-speed operation in 4n
may damage or shorten the life of the
drivetrain.
An engagement noise and bump is normal
when shifting between 4
nand 4mor
N (Neutral), with the engine running.
Shifting into 4
nwill turn Traction Control
and StabiliTrak/Electronic Stability Control
(ESC) off. See Traction Control/Electronic
Stability Control 0248.
Automatic Transfer Case
Two-Speed Transfer Case
If equipped, the transfer case controls are
used to shift into and out of four-wheel
drive.
To shift the transfer case, press the desired
button. The graphic in the instrument
cluster will flash while a shift is in progress.
The graphic displayed will change to indicate
the setting requested.
When the shift is complete the graphic will
stop flashing. The DIC message turns off
once the shift is complete. If the transfer
case cannot complete a shift request, it will
go back to its last chosen setting.
The settings are:
N (Neutral) : Use only when the vehicle
needs to be towed. See Recreational Vehicle
Towing 0395 or
Towing the Vehicle 0394.
2
m(Two-Wheel Drive High) : Use for driving
on most streets and highways. The front
axle is not engaged. This setting provides
the best fuel economy.
AUTO (Automatic Four-Wheel Drive) : Use
when road surface conditions are variable.
When driving in AUTO, the front axle is
engaged, and the vehicle's power is sent to
the front and rear wheels automatically based on driving conditions. This setting
provides slightly lower fuel economy
than 2
m.
4
m(Four-Wheel Drive High) : Use this
setting when extra traction is needed, such
as when driving on snowy or icy roads,
when off-roading, or when plowing snow.
4
n(Four-Wheel Drive Low) : This setting
engages the front axle and delivers extra
torque. Choose 4
nwhen driving off-road in
deep sand, deep mud, or deep snow, and
while climbing or descending steep hills.
While driving in 4
n, keep vehicle speed
below 72 km/h (45 mph).
Shifting into 4
nwill turn Traction Control
and StabiliTrak/ESC off. See Traction Control/
Electronic Stability Control 0248.
Shifts between 2
m, 4m, and AUTO
Any of these shifts can be made at normal
driving speed.
The actual 4x4 shift request is only made
after the button is released. The 4x4 graphic
will remain flashing until the shift request
has completed. A DIC message displays to
indicate that the 4x4 transfer case has been
requested to shift to the new desired state.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
252 Driving and Operating
When you enter this mode, you will
immediately feel a down shift. In this mode
the vehicle also monitors driving behaviors
and automatically enables Performance Shift
Features when spirited driving is detected.
These features maintain lower transmission
gears to increase available engine braking
and improve acceleration response. The
vehicle will exit these features and return to
normal operation after a short period when
spirited driving is no longer detected. If the
vehicle has Magnetic Ride Control, the
suspension will change to provide better
cornering performance.
6Snow/Ice Mode :Snow/Ice Mode
improves vehicle acceleration on snow and
ice covered roads. When active, Snow/Ice
Mode will adjust acceleration to optimize
traction on slippery surfaces. This can
compromise the acceleration on dry asphalt.
This feature is not intended for use when
the vehicle is stuck in sand, mud, ice, snow,
or gravel. If the vehicle becomes stuck, see If
the Vehicle Is Stuck 0221.
7Off-Road Mode : Use this mode for
off-road recreational driving. Off-Road Mode
should be used to improve driving at
moderate speeds, on grass, gravel, dirt,
unpaved roads, or snow-covered roads. The accelerator pedal is tuned for off-road use.
This mode modifies pedal mapping,
All-Wheel Drive (AWD), ride height, Antilock
Brake System (ABS), StabiliTrak/Electronic
Stability Control (ESC), and Traction Control
System (TCS) performance.
For more information on off-road driving see
Off-Road Driving
0215.
_Tow/Haul Mode : Use this mode
when hauling heavy loads to provide
increased performance and vehicle control.
Tow/Haul Mode adjusts the transmission
shift pattern, AWD, and ESC performance.
If the vehicle is turned off with Tow/Haul
Mode active and then restarted within four
hours or less, Tow/Haul will remain active.
Otherwise, the vehicle will start in
Normal Mode.
If the vehicle has a diesel engine, exhaust
braking is automatically activated when
Tow/Haul Mode is selected. It maintains
vehicle speed by automatically
implementing a shift pattern that uses the
engine and the transmission to slow the
vehicle. The system will command
downshifts and use the turbocharger on the
engine to reduce vehicle speed when the
brake is applied. The normal tow/haul shift pattern will return once the vehicle is on a
low grade or when the accelerator pedal is
pressed.
While in the Electronic Range Select (ERS)
Mode (see
“manual mode”), grade breaking
is deactivated, allowing the driver to select a
range and limiting the highest gear
available.
For more information on trailer weight
specifications, see Towing Equipment 0296.
gTerrain Mode : Use for finer control
during low speed, off-road driving. When
using this mode it will mimic the
characteristics of four-wheel-drive low (4
n)
without the torque capabilities.
Use when:
.Traveling on very rough roads at very low
speeds, such as a two-track or heavily
rutted road.
.Traveling slowly in grassy fields.
.Pulling a boat out of the water on a
trailer.
.Using the vehicle for public off-road
recreational driving. See Off-Road Driving
0 215 and
Hill and Mountain Roads 0219.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 253
When in Terrain Mode, the vehicle will shift
automatically but may hold a lower gear
longer to maximize engine torque. The
steering will change to provide more precise
control. A unique pedal map, transmission
shift pattern, and rpm control are utilized to
give better control at lower speeds and over
rough terrain. When the vehicle comes to a
stop, Vehicle Hold is engaged. TCS will be
optimized for maximum torque transfer
across axles, and Active Braking During Lift
Throttle will be engaged.
Active Braking During Lift Throttle:
.Automatically applies light braking,
similar to heavy engine braking of
four-wheel-drive low.
.Applies light braking in D (Drive) until the
vehicle is at idle speeds. In Manual L1 and
Manual L2, moderate braking may stop
the vehicle.
.Reduces trailer braking.Terrain Mode Drive
Select Expected Vehicle Behavior Ideal Terrain
Drive (L3-Lx) Minor deceleration when off
throttle and mild ability to
modulate throttle; mimics
performance of 4
nwithout torque
multiplication. Grassy fields,
mild two tracks,
rutted roads,
large rolling hills,
L2 Moderate deceleration when off
throttle and moderate ability to
modulate throttle; will bring vehicle
to a stop in most cases. Mild rock crawling,
heavy ruts,
short, steeper grades,
L1 Significant deceleration when off
throttle and significant ability to
modulate throttle; will bring vehicle
to a stop in most cases. Rock crawling downhill
Active Braking During Lift Throttle will
reduce the back and forth between the
accelerator and brake pedals.
Vehicle Hold Features:
.When the vehicle comes to a stop on an
incline grade in forward gear or on a
decline grade in reverse gear, Vehicle
Hold is engaged until the accelerator
pedal is pressed.
.When the vehicle is in forward gear on a
decline, the vehicle is allowed to creep
down the hill when the brake pedal is
released without pressing the accelerator
pedal. The vehicle will also creep forward
on flat ground.
.If the driver seat belt is removed and the
driver door is opened while the vehicle is
being held, EPB will be engaged.
.EPB will engage if the vehicle is held for
an extended period.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
306 Driving and Operating
If either the CHECK TRAILER WIRING or
SERVICE TRAILER BRAKE SYSTEM message
displays while driving, the ITBC system may
not be fully functional or may not function
at all. When traffic conditions allow,
carefully pull the vehicle over to the side of
the road and turn the ignition off. Check the
wiring connection to the trailer and turn the
ignition back on. If either of these messages
continues, either the vehicle or trailer needs
service.
A GM dealer may be able to diagnose and
repair problems with the trailer. However,
any diagnosis and repair of the trailer is not
covered under the vehicle warranty. Contact
your trailer dealer for assistance with trailer
repairs and trailer warranty information.
Trailer Sway Control (TSC)
Vehicles with StabiliTrak/Electronic Stability
Control (ESC) have a Trailer Sway Control
(TSC) feature. Trailer sway is unintended
side-to-side motion of a trailer while towing.
If the vehicle is towing a trailer and the TSC
detects that sway is increasing, the vehicle
brakes are selectively applied at each wheel,
to help reduce excessive trailer sway.
If equipped with the Integrated Trailer BrakeControl (ITBC) system, and the trailer has an
electric brake system, StabiliTrak/ESC may
also apply the trailer brakes.
If TSC is enabled, the Traction Control
System (TCS)/StabiliTrak/ESC warning light
will flash on the instrument cluster. Reduce
vehicle speed by gradually removing your
foot from the accelerator. If trailer sway
continues, StabiliTrak/ESC can reduce engine
torque to help slow the vehicle. TSC will not
function if StabiliTrak/ESC is turned off. See
Traction Control/Electronic Stability Control
0
248.
{Warning
Trailer sway can result in a crash and in
serious injury or death, even if the
vehicle is equipped with TSC.
If the trailer begins to sway, reduce
vehicle speed by gradually removing your
foot from the accelerator. Then pull over
to check the trailer and vehicle to help
correct possible causes, including an
improperly or overloaded trailer,
unrestrained cargo, improper trailer hitch
configuration, or improperly inflated or
incorrect vehicle or trailer tires. See
Towing Equipment 0296 for trailer
ratings and hitch setup recommendations.
Aftermarket Electronic Trailer Sway
Control Devices
Some trailers may come equipped with an
electronic device designed to reduce or
control trailer sway. Aftermarket equipment
manufacturers also offer similar devices that
connect to the wiring between the trailer
and the vehicle. These devices may interfere
with the vehicle’s trailer brake or other
systems, including integrated anti-sway
systems, if equipped. Messages related to

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 341
message displays, washer fluid will need to
be added to the windshield washer fluid
reservoir.
Open the cap with the washer symbol on it.
Add washer fluid until the tank is full. See
Engine Compartment Overview0325 for
reservoir location.
Caution
.Do not use washer fluid that contains
any type of water repellent coating.
This can cause the wiper blades to
chatter or skip.
.Do not use engine coolant (antifreeze)
in the windshield washer. It can
damage the windshield washer system
and paint.
(Continued)
Caution (Continued)
.Do not mix water with ready-to-use
washer fluid. Water can cause the
solution to freeze and damage the
washer fluid tank and other parts of
the washer system.
.When using concentrated washer fluid,
follow the manufacturer instructions
for adding water.
.Fill the washer fluid tank only
three-quarters full when it is very cold.
This allows for fluid expansion if
freezing occurs, which could damage
the tank if it is completely full.
Brakes
Disc brake linings have built-in wear
indicators that make a high-pitched warning
sound when the brake linings are worn and
new linings are needed. The sound can come
and go or can be heard all the time when
the vehicle is moving, except when applying
the brake pedal firmly.
{Warning
The brake wear warning sound means
that soon the brakes will not work well.
That could lead to a crash. When the
brake wear warning sound is heard, have
the vehicle serviced.
Caution
Continuing to drive with worn-out brake
linings could result in costly brake
repairs.
Some driving conditions or climates can
cause a brake squeal when the brakes are
first applied, clearing up following several
applications. This does not mean something
is wrong with the brakes.
Properly torqued wheel nuts are necessary
to help prevent brake pulsation. When tires
are rotated, inspect brake linings for wear
and evenly tighten wheel nuts in the proper
sequence to torque specifications. See
Capacities and Specifications 0424.
Brake pads should be replaced as complete
axle sets.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
374 Vehicle Care
Replace the tire if:
.The indicators at three or more
places around the tire can be seen.
.There is cord or fabric showing
through the tire's rubber.
.The tread or sidewall is cracked, cut,
or snagged deep enough to show
cord or fabric.
.The tire has a bump, bulge, or split.
.The tire has a puncture, cut, or other
damage that cannot be repaired well
because of the size or location of the
damage.
Tire Rotation
Tires should be rotated every 12 000 km
(7,500 mi). SeeMaintenance Schedule
0 409.
Tires are rotated to achieve a more
uniform wear for all tires. The first
rotation is the most important.
Anytime unusual wear is noticed, rotate
the tires as soon as possible, check for
proper tire inflation pressure, and check
for damaged tires or wheels. If the unusual wear continues after the
rotation, check the wheel alignment.
See
When It Is Time for New Tires 0375
and
Wheel Replacement 0378.Use this rotation pattern when rotating
the tires.
Do not include the spare tire in the tire
rotation.
Adjust the front and rear tires to the
recommended inflation pressure on the
Tire and Loading Information label after the tires have been rotated. See
Tire
Pressure 0367 and
Vehicle Load Limits 0222.
Reset the Tire Pressure Monitor System.
See Tire Pressure Monitor Operation
0 369.
Check that all wheel nuts are properly
tightened. See “Wheel Nut Torque”
under Capacities and Specifications
0 424.
{Warning
Rust or dirt on a wheel, or on the
parts to which it is fastened, can
cause wheel nuts to become loose
over time. The wheel could come off
and cause a crash. When changing a
wheel, remove any rust or dirt from
places where the wheel attaches to
the vehicle. In an emergency, a cloth
or paper towel can be used; however,
use a scraper or wire brush later to
remove all rust or dirt.