Brakes GMC SIERRA 2020 Owner's Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 237
The button for TCS and StabiliTrak/
ESC is on the center stack.
Caution
Do not repeatedly brake or
accelerate heavily when TCS is
off. The vehicle driveline could be
damaged.
To turn off only TCS, press and
release
g. The traction off lighti
displays in the instrument cluster.
The appropriate message will
display in the DIC. To turn TCS on
again, press and release
g. The
traction off light
idisplayed in the
instrument cluster will turn off.
If TCS is limiting wheel spin when
g
is pressed, the system will not turn
off until the wheels stop spinning.
To turn off both TCS and StabiliTrak/
ESC, press and hold
guntil the
traction off light
iand the
StabiliTrak/ESC OFF light
gcome
on and stay on in the instrument cluster, then release. The
appropriate message will display in
the DIC.
To turn TCS and StabiliTrak/ESC on
again, press and release
g. The
traction off light
iand the
StabiliTrak/ESC OFF light
gin the
instrument cluster turn off.
StabiliTrak/ESC will automatically
turn on if the vehicle exceeds
56 km/h (35 mph). Traction control
will remain off.
The vehicle has a Trailer Sway
Control (TSC) feature and a Hill
Start Assist (HSA) feature. See
Trailer Sway Control (TSC) 0308 or
Hill Start Assist (HSA) 0235.
Adding accessories can affect the
vehicle performance. See
Accessories and Modifications
0 329.
Hill Descent
Control (HDC)
If equipped, Hill Descent Control
(HDC) sets and maintains vehicle
speed while driving down steep
grades in a forward or reverse gear.
The HDC switch is on the center
stack, below the climate controls.
Press
5to enable or disable HDC.
Vehicle speed must be below
50 km/h (31 mph).
When enabled, the HDC light
displays on the instrument cluster.
A blinking HDC light indicates the
system is actively applying the
brakes to maintain vehicle speed.
HDC can maintain vehicle speeds
between 1 and 22 km/h (1 and
14 mph) on grades greater than or
equal to 10%.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
242 Driving and Operating
Terrain ModeDrive Select Expected Vehicle Behavior Ideal Terrain
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.
Terrain Mode is only available on
vehicles equipped with the single
speed transfer case.
Terrain Mode can only be
active when:
. Vehicle speed is less than
80 km/h (50 mph).
. The transfer case is in 4
m. Frequent use of this mode may
cause brake wear due to the light
braking.
The vehicle will automatically exit
the mode if the brakes get too hot.
Terrain Mode can be turned back on
after the brakes have cooled.
When Terrain Mode is selected:
.
Auto Engine Start/Stop will be
disabled.
. The Terrain Mode indicator
displays on the instrument
cluster.
Limited-Slip Differential
If equipped, the limited-slip
differential can give more traction on
snow, mud, ice, sand, or gravel.
It works like a standard axle most of
the time, but when traction is low,
this feature allows the drive wheel
with the most traction to move the
vehicle. For vehicles with the
limited-slip differential, driven under
severe conditions, the rear axle fluid
should be changed. See
Maintenance Schedule 0442.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 243
Locking Rear Axle
Vehicles with a locking rear axle can
give more traction on snow, mud,
ice, sand, or gravel. It works like a
standard axle most of the time, but
when traction is low, this feature will
allow the rear wheel with the most
traction to move the vehicle.
Cruise Control
{Warning
Cruise control can be dangerous
where you cannot drive safely at
a steady speed. Do not use
cruise control on winding roads or
in heavy traffic.
Cruise control can be dangerous
on slippery roads. On such roads,
fast changes in tire traction can
cause excessive wheel slip, and
you could lose control. Do not use
cruise control on slippery roads.
If equipped with cruise control, a
speed of about 40 km/h (25 mph) or
more can be maintained without
keeping your foot on the
accelerator. Cruise control does not
work at speeds below about
40 km/h (25 mph).
If the cruise control is being used
and the Traction Control System
(TCS) or StabiliTrak/Electronic
Stability Control (ESC) begins to
limit wheel spin, the cruise control will automatically disengage. See
Traction Control/Electronic Stability
Control
0235. If a collision alert
occurs when cruise control is
activated, cruise control is
disengaged. See Forward Collision
Alert (FCA) System 0268. When
road conditions allow you to safely
use it again, cruise control can be
turned back on.
Turning off the TCS or StabiliTrak/
ESC system will disengage the
cruise control.
If the brakes are applied, cruise
control disengages.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
244 Driving and Operating
5:Press to turn cruise control on
or off. A white indicator comes on or
off in the instrument cluster.
+RES : If there is a set speed in
memory, press the control up briefly
to resume to that speed or press
and hold to accelerate. If cruise
control is already engaged, use to
increase vehicle speed.
SET− :Press the control down
briefly to set the speed and activate
cruise control. If cruise control is
already engaged, use to decrease
vehicle speed.
*: Press to disengage cruise
control without erasing the set
speed from memory.
Setting Cruise Control
If
5is on when not in use, SET− or
+RES could get pressed and go into
cruise when not desired. Keep
5
off when cruise is not being used.
1. Press
5to turn the cruise
system on.
2. Get up to the desired speed. 3. Press and release SET−.
4. Remove your foot from the
accelerator.
The cruise control indicator on the
instrument cluster turns green after
cruise control has been set to the
desired speed. See Instrument
Cluster 0127.
Resuming a Set Speed
If the cruise control is set at a
desired speed and then the brakes
are applied or
*is pressed, the
cruise control is disengaged without
erasing the set speed from memory.
Once the vehicle reaches about
40 km/h (25 mph) or more, press
RES+ up briefly. The vehicle returns
to the previously set speed.
Increasing Speed While Using
Cruise Control
Do one of the following:
. Press and hold +RES up until
the desired speed is reached,
then release it. .
To increase vehicle speed in
small increments, press +RES
up briefly. For each press, the
vehicle goes about 1 km/h
(1 mph) faster.
The speedometer reading can be
displayed in either English or metric
units. See Instrument Cluster 0127.
The increment value used depends
on the units displayed.
Reducing Speed While Using
Cruise Control
Do one of the following:
. Press and hold SET– down until
the desired lower speed is
reached, then release it.
. To slow down in small
increments, press SET– down
briefly. For each press, the
vehicle goes about 1 km/h
(1 mph) slower.
The speedometer reading can be
displayed in either English or metric
units. See Instrument Cluster 0127.
The increment value used depends
on the units displayed.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
246 Driving and Operating
used, ACC can be turned back on.
Disabling the TCS or StabiliTrak/
ESC system will disengage and
prevent engagement of ACC.
ACC can reduce the need for you to
frequently brake and accelerate,
especially when used on
expressways, freeways, and
interstate highways. When used on
other roads, you may need to take
over the control of braking or
acceleration more often.
{Warning
ACC has limited braking ability
and may not have time to slow
the vehicle down enough to avoid
a collision with another vehicle
you are following. This can occur
when vehicles suddenly slow or
stop ahead, or enter your lane.
Also see“Alerting the Driver” later
in this section. Complete attention
is always required while driving
and you should be ready to take
action and apply the brakes. See
Defensive Driving 0187.
{Warning
ACC will not detect or brake for
children, pedestrians, animals,
or other objects.
Do not use ACC when:
. On winding and hilly roads
or when the camera sensor
is blocked by snow, ice,
or dirt. The system may not
detect a vehicle ahead.
Keep the windshield and
headlamps clean.
. When visibility is poor due
to rain, snow, fog, dirt,
insect residue, or dust;
when other foreign objects
obscure the camera’s view;
or when the vehicle in front
or oncoming traffic causes
additional environmental
obstructions, such as road
spray. ACC performance is
limited under these
conditions.
(Continued)
Warning (Continued)
.On slippery roads where
fast changes in tire traction
can cause excessive
wheel slip
. With extremely heavy cargo
loaded in the cargo area or
rear seat
. When towing a trailer

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 247
J:Press to turn the system on or
off. The indicator turns white on the
instrument cluster when ACC is
turned on.
RES+ : Press briefly to resume the
previous set speed or to increase
vehicle speed if ACC is already
activated. To increase speed by
about 1 km/h (1 mph), press RES+
briefly. To increase speed to the
next 5 km/h (5 mph) mark on the
speedometer, hold RES+.
SET– :Press briefly to set the
speed and activate ACC or to
decrease vehicle speed if ACC is
already activated. To decrease
speed by about 1 km/h (1 mph),
press SET– briefly. To decrease
speed to the next 5 km/h (5 mph)
mark on the speedometer,
hold SET–.
*: Press to disengage ACC
without erasing the selected set
speed.
[: Press to select a following gap
setting for ACC of Far, Medium,
or Near. The speedometer reading can be
displayed in either English or metric
units. See
Instrument Cluster 0127.
The increment value used depends
on the units displayed.
Switching Between ACC and
Regular Cruise Control
To switch between ACC and regular
cruise control, press and hold
*.
A Driver Information Display (DIC)
message displays. See Vehicle
Messages 0156.
ACC IndicatorRegular Cruise
Control Indicator
When ACC is engaged, a green
o
indicator will be lit on the instrument
cluster and the following gap will be
displayed. When the regular cruise
control is engaged, a green
J
indicator will be lit on the instrument
cluster; the following gap will not
display.
When the vehicle is turned on, the
cruise control mode will be set to
the last mode used before the
vehicle was turned off.
{Warning
Always check the cruise control
indicator on the instrument cluster
to determine which mode cruise
control is in before using the
feature. If ACC is not active, the
vehicle will not automatically
brake for other vehicles, which
could cause a crash if the brakes
are not applied manually. You and
others could be seriously injured
or killed.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
248 Driving and Operating
Setting Adaptive Cruise Control
If
Jis on when not in use, SET–/
RES+ could be pressed by mistake
and engage ACC when not desired.
Keep
Joff when cruise is not
being used.
Select the set speed desired for
ACC. This is the vehicle speed
when no vehicle is detected in
your path.
While the vehicle is moving, ACC
will not set at a speed less than 25
km/h (15 mph), although it can be
resumed when driving at lower
speeds.
To set ACC while moving:
1. Press
J.
2. Get up to the desired speed.
3. Press and release SET–.
4. Remove foot from the accelerator.
After ACC is set, it may immediately
apply the brakes if a vehicle ahead
is detected closer than the selected
following gap. ACC can also be set while the
vehicle is stopped if ACC is on and
the brake pedal is applied.
The ACC indicator displays on the
instrument cluster. When ACC is
turned on, the indicator will be lit
white.
Be mindful of speed limits,
surrounding traffic speeds, and
weather conditions when selecting
the set speed.
Resuming a Set Speed
If the ACC is set at a desired speed
and then the brakes are applied,
ACC is disengaged without erasing
the set speed from memory.
To begin using ACC again, press
RES+ briefly while moving more
than 5 km/h (3 mph). The vehicle
returns to the previous set speed.
A green ACC indicator and the set
speed display on the instrument
cluster. The vehicle ahead indicator
may be flashing if a vehicle ahead
was present and moved. See
“Approaching and Following a
Vehicle”
later in this section.
Once ACC has resumed, if there is
no vehicle ahead, if the vehicle
ahead is beyond the selected
following gap, or if the vehicle has
exited a sharp curve, then the
vehicle speed will increase to the
set speed.
Increasing Speed While ACC Is at
a Set Speed
If ACC is already activated, do one
of the following:
. Use the accelerator to get to the
higher speed. Press SET–.
Release SET– and the
accelerator pedal. The vehicle
will now cruise at the higher
speed.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 251
may feel or sound different than if
the brakes were applied manually.
This is normal.
Stationary or Very Slow-Moving
Objects
{Warning
ACC may not detect and react to
stopped or slow-moving vehicles
ahead of you. For example, the
system may not brake for a
vehicle it has never detected
moving. This can occur in
stop-and-go traffic or when a
vehicle suddenly appears due to
a vehicle ahead changing lanes.
Your vehicle may not stop and
could cause a crash. Use caution
when using ACC. Your complete
attention is always required while
driving and you should be ready
to take action and apply the
brakes.Irregular Objects Affecting ACC
ACC may have difficulty detecting
the following objects:
.
Vehicles in front of your vehicle
that have a rear aspect that is
low, small, or irregular
. An empty truck or trailer that has
no cargo in the cargo bed
. Vehicles with cargo extending
from the back end
. Non-standard shaped vehicles,
such as vehicle transport,
vehicles with a side car fitted,
or horse carriages
. Vehicles that are low to the road
surface
. Objects that are close to the
front of your vehicle
. Vehicles on which extremely
heavy cargo is loaded in the
cargo area or rear seat
ACC Automatically Disengages
ACC may automatically disengage
and the driver will need to manually
apply the brakes to slow the
vehicle if:
.
The front camera is blocked or
visibility is reduced.
. The Traction Control System
(TCS) or StabiliTrak/ESC system
has activated or been disabled.
. There is a fault in the system.
. A DIC message displays to
indicate that ACC is temporarily
unavailable.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
252 Driving and Operating
The ACC indicator will turn white
when ACC is no longer active.
In some cases, when ACC is
temporarily unavailable, regular
cruise control may be used. See
“Switching Between ACC and
Regular Cruise Control”previously
in this section. Always consider
driving conditions before using
either cruise control system.
Notification to Resume ACC
ACC will maintain a follow gap
behind a detected vehicle and slow
your vehicle to a stop behind that
vehicle.
If the stopped vehicle ahead has
driven away and ACC has not
resumed, the vehicle ahead
indicator will flash as a reminder to
check traffic ahead before
proceeding. In addition, the left and
right sides of the Safety Alert Seat
will pulse three times, or three
beeps will sound. See ”Alert Type”
and “Adaptive Cruise Go Notifier” in
“Collision/Detection Systems” under
Vehicle Personalization 0157. When the vehicle ahead drives
away, press RES+ or the
accelerator pedal to resume ACC.
If stopped for more than
two minutes or if the driver door is
opened and the driver seat belt is
unbuckled, the ACC automatically
applies the Electric Parking Brake
(EPB) to hold the vehicle. The EPB
status light will turn on. See
Electric
Parking Brake 0233.
A DIC warning message may
display indicating to shift to P (Park)
before exiting the vehicle. See
Vehicle Messages 0156.
{Warning
If ACC has stopped the vehicle,
and if ACC is disengaged, turned
off, or canceled, the vehicle will
no longer be held at a stop. The
vehicle can move. When ACC is
holding the vehicle at a stop,
always be prepared to manually
apply the brakes.
{Warning
Leaving the vehicle without
placing it in P (Park) can be
dangerous. Do not leave the
vehicle while it is being held at a
stop by ACC. Always place the
vehicle in P (Park) and turn off
the ignition before leaving the
vehicle.
ACC Override
If using the accelerator pedal while
ACC is active, the ACC indicator
turns blue on the instrument cluster
indicating ACC braking will not
occur. ACC will resume operation
when the accelerator pedal is not
being pressed.
{Warning
The ACC will not automatically
apply the brakes if your foot is
resting on the accelerator pedal.
You could crash into a vehicle
ahead of you.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 253
Curves in the Road
{Warning
On curves, ACC may not detect a
vehicle ahead in your lane. You
could be startled if the vehicle
accelerates up to the set speed,
especially when following a
vehicle exiting or entering exit
ramps. You could lose control of
the vehicle or crash. Do not use
ACC while driving on an entrance
or exit ramp. Always be ready to
use the brakes if necessary.
{Warning
On curves, ACC may respond to
a vehicle in another lane, or may
not have time to react to a vehicle
in your lane. You could crash into
a vehicle ahead of you, or lose
control of your vehicle. Give extra
attention in curves and be ready(Continued)
Warning (Continued)
to use the brakes if necessary.
Select an appropriate speed while
driving in curves.
ACC may operate differently in a
sharp curve. It may reduce the
vehicle speed if the curve is too
sharp.
When following a vehicle and
entering a curve, ACC may not
detect the vehicle ahead and
accelerate to the set speed. When
this happens, the vehicle ahead
indicator will not appear.
ACC may detect a vehicle that is
not in your lane and apply the
brakes.
ACC may occasionally provide an
alert and/or braking that is
considered unnecessary. It could
respond to vehicles in different
lanes or stationary objects when
entering or exiting a curve. This is
normal operation. The vehicle does
not need service.