Brakes GMC SIERRA 2020 User Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 197
wet enough and you are going fast
enough. When the vehicle is
hydroplaning, it has little or no
contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.Allow extra following distance.
. Pass with caution.
. Keep windshield wiping
equipment in good shape.
. Keep the windshield washer fluid
reservoir filled.
. Have good tires with proper
tread depth. See Tires0379.
. Turn off cruise control.
Hill and Mountain Roads
Driving on steep hills or through
mountains is different than driving
on flat or rolling terrain. Tips include: .
Keep the vehicle serviced and in
good shape.
. Check all fluid levels and brakes,
tires, cooling system, and
transmission.
. Shift to a lower gear when going
down steep or long hills.
{Warning
Using the brakes to slow the
vehicle on a long downhill slope
can cause brake overheating, can
reduce brake performance, and
could result in a loss of braking.
Shift the transmission to a lower
gear to let the engine assist the
brakes on a steep downhill slope.
{Warning
Coasting downhill in N (Neutral)
or with the ignition off is
dangerous. This can cause
overheating of the brakes and
(Continued)
Warning (Continued)
loss of steering assist. Always
have the engine running and the
vehicle in gear.
. Drive at speeds that keep the
vehicle in its own lane. Do not
swing wide or cross the
center line.
. Be alert on top of hills;
something could be in your lane
(e.g., stalled car, crash).
. Pay attention to special road
signs (e.g., falling rocks area,
winding roads, long grades,
passing or no-passing zones)
and take appropriate action.
Winter Driving
Driving on Snow or Ice
Snow or ice between the tires and
the road creates less traction or
grip, so drive carefully. Wet ice can
occur at about 0 °C (32 °F) when

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
198 Driving and Operating
freezing rain begins to fall. Avoid
driving on wet ice or in freezing rain
until roads can be treated.
For Slippery Road Driving:
.Accelerate gently. Accelerating
too quickly causes the wheels to
spin and makes the surface
under the tires slick.
. Turn on Traction Control. See
Traction Control/Electronic
Stability Control 0235.
. The Antilock Brake System
(ABS) improves vehicle stability
during hard stops, but the
brakes should be applied sooner
than when on dry pavement.
See Antilock Brake System
(ABS) 0232.
. Allow greater following distance
and watch for slippery spots. Icy
patches can occur on otherwise
clear roads in shaded areas.
The surface of a curve or an
overpass can remain icy when
the surrounding roads are clear.
Avoid sudden steering
maneuvers and braking while
on ice. .
Turn off cruise control.
Blizzard Conditions
Stop the vehicle in a safe place and
signal for help. Stay with the vehicle
unless there is help nearby.
If possible, use Roadside
Assistance. See Roadside
Assistance Program 0467. To get
help and keep everyone in the
vehicle safe:
. Turn on the hazard warning
flashers.
. Tie a red cloth to an outside
mirror.
{Warning
Snow can trap engine exhaust
under the vehicle. This may
cause exhaust gases to get
inside. Engine exhaust contains
carbon monoxide (CO), which
cannot be seen or smelled. It can
cause unconsciousness and even
death.
(Continued)
Warning (Continued)
If the vehicle is stuck in snow:
. Clear snow from the base of
the vehicle, especially any
blocking the exhaust pipe.
. Open a window about 5 cm
(2 in) on the vehicle side
that is away from the wind,
to bring in fresh air.
. 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 0220.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 209
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
015.
To shift out of P (Park), the ignition
must be on or in Service Mode, and
the brake pedal must be applied.
{Warning
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering
systems and disable the airbags.
While driving, only shut the
vehicle off in an emergency.
Stopping the Engine/LOCK/
OFF (No Indicator Lights) : When
the vehicle is stopped, press
ENGINE START/STOP once to turn
the engine off.
If the vehicle is in P (Park), the
ignition will turn off, and Retained
Accessory Power (RAP) will remain
active. See Retained Accessory
Power (RAP) 0217. If the vehicle is not in P (Park), the
ignition will return to ACC/
ACCESSORY and display the
message SHIFT TO PARK in the
Driver Information Center (DIC).
When the vehicle is shifted into
P (Park), the ignition system will
turn off.
The vehicle may have an electric
steering column lock. The lock is
activated when the ignition is turned
off and driver door is opened.
A sound may be heard as the lock
actuates or releases. The steering
column lock may not release with
the wheels turned off center. If this
happens, the vehicle may not start.
Move the steering wheel from left to
right while attempting to start the
vehicle. If this does not work, the
vehicle needs service.
Unless an emergency exists, do not
turn the engine off when the vehicle
is moving. This will cause a loss of
power assist in the brake and
steering systems and disable the
airbags.
If the vehicle must be shut off in an
emergency: 1. If the vehicle cannot be pulled
over, and must be shut off
while driving, press and hold
ENGINE START/STOP button
for longer than two seconds,
or press twice in five seconds.
2. Brake using a firm and steady pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
3. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. After shifting
to N (Neutral), firmly apply the
brakes and steer the vehicle to
a safe location.
4. Come to a complete stop, shift to P (Park) with an automatic
transmission, or Neutral with a
manual transmission, and
make sure engine is off. On
vehicles with an automatic
transmission, the shift lever
must be in P (Park) to turn the
ignition off.
5. Set the parking brake. See Electric Parking Brake 0233.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 211
0 (Stopping the Engine/LOCK/
OFF) :This position turns off the
vehicle. It also locks the ignition, the
transmission, and the steering
column, if equipped with a locking
steering column.
To turn off the vehicle:
1. Make sure that the vehicle is stopped.
2. Shift to P (Park).
3. Continue to hold the brake pedal, then set the parking
brake. See Electric Parking
Brake 0233. 4. Push the key all the way in
toward the steering column,
then turn the key to
LOCK/OFF.
5. Remove the key.
6. Release the brake pedal.
See your dealer if the key can be
removed in any other position.
Retained Accessory Power (RAP)
will remain active. See Retained
Accessory Power (RAP) 0217.
A warning chime will sound when
the driver door is opened and the
key is in the ignition.
If equipped with a locking steering
column, the steering can bind with
the front wheels turned off center,
which may prevent key rotation out
of LOCK/OFF. If this happens, move
the steering wheel from right to left
while turning the key to ACC/
ACCESSORY. If this does not work,
then the vehicle needs service.
{Warning
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering
systems and disable the airbags.
While driving, turn off the vehicle
only in an emergency.
In an emergency, if the vehicle
cannot be pulled over and must be
turned off while driving: 1. Push the key all the way in toward the steering column,
then turn the key to ACC/
ACCESSORY.
2. Brake using firm and steady pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
3. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. Continue
braking and steer the vehicle to
a safe location.
4. Come to a complete stop.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
214 Driving and Operating
{Warning
The automatic engine Stop/Start
feature causes the engine to shut
off while the vehicle is still on. Do
not exit the vehicle before shifting
to P (Park). The vehicle may
restart and move unexpectedly.
Always shift to P (Park), and then
turn the ignition off before exiting
the vehicle.
Auto Engine Stop/Start
When the brakes are applied and
the vehicle is at a complete stop,
the engine may turn off. When
stopped, the tachometer displays
AUTO STOP. See Tachometer
0 132. When the brake pedal is
released or the accelerator pedal is
pressed, the engine will restart.
To maintain vehicle performance,
other conditions may cause the
engine to automatically restart
before the brake pedal is released.
Auto Stops may not occur and/or
Auto Starts may occur because: .
The climate control settings
require the engine to be running
to cool or heat the vehicle
interior.
. The vehicle battery charge
is low.
. The vehicle battery has recently
been disconnected.
. Minimum vehicle speed has not
been reached since the last
Auto Stop.
. The accelerator pedal is
pressed.
. The engine or transmission is
not at the required operating
temperature.
. The outside temperature is not
in the required operating range.
. The vehicle is in any gear other
than D (Drive).
. Tow/Haul Mode or other driver
modes have been selected.
. The vehicle is on a steep hill or
grade. .
The driver door has been
opened or the driver seat belt
has been unbuckled.
. The hood has been opened.
. The Auto Stop has reached the
maximum allowed time.
Auto Stop Disable Switch
If equipped, the automatic engine
Stop/Start feature can be disabled
and enabled by pressing the switch
with the
hsymbol. Auto Stop is
enabled each time you start the
vehicle.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
224 Driving and Operating
L :This position allows selection of
a range of gears appropriate for
current driving conditions.
If equipped, see “Range Selection
Mode” underManual Mode 0224.
Caution
Spinning the tires or holding the
vehicle in one place on a hill
using only the accelerator pedal
may damage the transmission.
The repair will not be covered by
the vehicle warranty. If the vehicle
is stuck, do not spin the tires.
When stopping on a hill, use the
brakes to hold the vehicle in
place.
Manual Mode
Range Selection Mode
Range Selection Mode helps control
the vehicle's transmission and
vehicle speed while driving downhill
or towing a trailer by letting you
select a desired range of gears.
To use this feature:
1. Move the shift lever to L (Manual Mode).
2. Press the plus/minus buttons on the shift lever to select the
desired range of gears for
current driving conditions.
When the shift lever is moved from
D (Drive) to L (Manual Mode), a
number displays next to the L,
indicating the current transmission
range. This number is the highest gear that
the transmission will command while
operating in L (Manual Mode). All
gears below that number are
available. As driving conditions
change, the transmission can
automatically shift to lower gears.
For example, when L5 is selected,
1 (First) through 5 (Fifth) gears are
automatically shifted by the
transmission, but 6 (Sixth) cannot be
used until the plus/minus button on
the shift lever is used to change to
the range.
When the shift lever is moved from
D (Drive) to L (Manual Mode), a
downshift may occur. The gear that
the transmission is operating in
when the shift lever is moved from
D (Drive) to L (Manual Mode)
determines if a downshift occurs.
See the following charts.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
226 Driving and Operating
10-Speed Automatic TransmissionGear before shifting from D (Drive) to
L (Manual Mode) 10th 9th 8th 7th 6th 5th 4th 3rd 2nd 1st
Range after shifting from D (Drive) to
L (Manual Mode) - Tow/Haul not engaged L7 L7 L7 L6 L5 L4 L3 L3 L2 L1
Range after shifting from D (Drive) to
L (Manual Mode) - Tow/Haul engaged L7 L7 L6 L5 L4 L3 L3 L3 L2 L1
Grade Braking is not available when
Range Selection Mode is active.
See Tow/Haul Mode 0226.
While using Range Selection Mode,
cruise control and the Tow/Haul
Mode can be used.
If the vehicle has an exhaust brake,
it can also be used, but will not
automatically downshift the
transmission. See “Exhaust Brake”
in the Duramax diesel supplement.
Caution
Spinning the tires or holding the
vehicle in one place on a hill
using only the accelerator pedal
may damage the transmission.
The repair will not be covered by
the vehicle warranty. If the vehicle
is stuck, do not spin the tires.
When stopping on a hill, use the
brakes to hold the vehicle in
place.
Low Traction Mode
If equipped, Low Traction Mode
assists in vehicle acceleration when
road conditions are slippery, such as with ice or snow. While the
vehicle is at a stop, select L2 using
Range Selection Mode. This will
limit torque to the wheels and help
prevent the tires from spinning.
Tow/Haul Mode
The Tow/Haul Mode adjusts the
transmission shift pattern to reduce
shift cycling. This provides
increased performance, vehicle
control, and enhanced transmission
and engine cooling when driving
down steep hills or mountain
grades, when towing, or when
hauling heavy loads. See
Driver
Mode Control 0238 to activate Tow/
Haul Mode.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
232 Driving and Operating
cannot complete a shift request, it
will go back to its last chosen
setting.
The settings are:
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.
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.
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. 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.
Once the 4x4 shift has completed,
the DIC message disappears, the
4x4 graphic stops flashing, and the
current setting is indicated.
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. Once the
4x4 shift has completed, the DIC
message disappears, the 4x4
graphic stops flashing, and the
current setting is indicated.Brakes
Electric Brake Boost
Vehicles equipped with electric
brake boost have hydraulic brake
circuits that are electronically
controlled when the brake pedal is
applied during normal operation.
The system performs routine tests
and turns off within a few minutes
after the vehicle is shutdown. Noise
may be heard during this time. If the
brake pedal is pressed during the
tests or when the electric brake
boost system is off, a noticeable
change in pedal force and travel
may be felt. This is normal.
Antilock Brake
System (ABS)
The Antilock Brake System (ABS)
helps prevent a braking skid and
maintain steering while
braking hard.
ABS performs a system check when
the vehicle is first driven.
A momentary motor or clicking noise

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 233
may be heard while this test is going
on, and the brake pedal may move
slightly. This is normal.
If there is a problem with ABS, this
warning light stays on. SeeAntilock
Brake System (ABS) Warning Light
0 141.
ABS does not change the time
needed to get a foot on the brake
pedal and does not always
decrease stopping distance. If you
get too close to the vehicle ahead,
there will not be enough time to
apply the brakes if that vehicle
suddenly slows or stops. Always
leave enough room ahead to stop,
even with ABS.
Using ABS
Do not pump the brakes. Just hold
the brake pedal down firmly.
Hearing or feeling ABS operate is
normal.
Braking in Emergencies
ABS allows steering and braking at
the same time. In many
emergencies, steering can help
even more than braking.
Electric Parking Brake
The vehicle has an Electric Parking
Brake (EPB). The EPB can always
be activated, even if the ignition is off. To prevent draining the battery,
avoid repeated cycles of the EPB
when the engine is not running.
The system has a
Yor PARK
Electric Parking Brake light, and a
8
Service Parking Brake light. See
Electric Parking Brake Light 0141
and
Service Electric Parking Brake Light
0 141. There are also parking
brake-related Driver Information
Center (DIC) messages.
Before leaving the vehicle, check for
the
Yor PARK light to ensure that
the parking brake is applied.
EPB Apply
To apply the EPB:
1. Be sure the vehicle is at a complete stop.
2. Press the EPB switch momentarily.
The
Yor PARK light will flash and
then stay on once the EPB is fully
applied. If the
Yor PARK light
flashes continuously, then the EPB

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 235
pedal pulsation, and/or pedal
movement during this time may
occur. Continue to apply the brake
pedal as the driving situation
dictates. Brake Assist disengages
when the brake pedal is released.
Hill Start Assist (HSA)
{Warning
Do not rely on the HSA feature.
HSA does not replace the need to
pay attention and drive safely.
You may not hear or feel alerts or
warnings provided by this system.
Failure to use proper care when
driving may result in injury, death,
or vehicle damage. See
Defensive Driving0187.
When the vehicle is stopped on a
grade, Hill Start Assist (HSA)
prevents the vehicle from rolling in
an unintended direction during the
transition from brake pedal release
to accelerator pedal apply. The
brakes release when the accelerator
pedal is applied. If the accelerator pedal is not applied within a few
minutes, the Electric Parking Brake
will apply. The brakes may also
release under other conditions. Do
not rely on HSA to hold the vehicle.
HSA is available when the vehicle is
facing uphill in a forward gear,
or when facing downhill in
R (Reverse). The vehicle must
come to a complete stop on a grade
for HSA to activate.
Ride Control Systems
Traction Control/
Electronic Stability
Control
System Operation
The vehicle has a Traction Control
System (TCS) and StabiliTrak/
Electronic Stability Control (ESC)
system. These systems help limit
wheel spin and assist the driver in
maintaining control, especially on
slippery road conditions.
TCS activates if it senses any of the
drive wheels are spinning or
beginning to lose traction. When this
happens, TCS applies the brakes to
the spinning wheels and reduces
engine power to limit wheel spin.
StabiliTrak/ESC activates when the
vehicle senses a difference between
the intended path and the direction
the vehicle is actually traveling.
StabiliTrak/ESC selectively applies
braking pressure to any one of the
vehicle wheel brakes to assist the
driver in keeping the vehicle on the