2020 GMC SIERRA warning

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
234 Driving and Operating
is only partially applied or there is a
problem with the EPB. A DIC
message will display. Release the
EPB and try to apply it again. If the
light does not come on, or keeps
flashing, have the vehicle serviced.
Do not drive the vehicle if the
Yor
PARK light is flashing. See your
dealer. See Electric Parking Brake
Light 0141.
If the
8light is on, press the EPB
switch and hold it. Continue to hold
the switch until the
Yor PARK
light remains on. If the
8light
remains on, see your dealer.
If the EPB is applied while the
vehicle is moving, the vehicle will
decelerate as long as the switch is
pressed. If the switch is pressed
until the vehicle comes to a stop,
the EPB will remain applied.
The vehicle may automatically apply
the EPB in some situations when
the vehicle is not moving. This is
normal, and is done to periodically
check the correct operation of the
EPB system. If the EPB fails to apply, block the
rear wheels to prevent vehicle
movement.
EPB Release
To release the EPB:
1. Turn the ignition on or to ACC/ ACCESSORY.
2. Apply and hold the brake pedal.
3. Press the EPB switch momentarily.
The EPB is released when the
Y
or PARK light is off.
If the
8light is on, release the EPB
by pressing and holding the EPB
switch. Continue to hold the switch
until the
Yor PARK light is off.
If either light stays on after release
is attempted, see your dealer.
Caution
Driving with the parking brake on
can overheat the brake system
and cause premature wear or
damage to brake system parts.
Make sure that the parking brake
is fully released and the brake
warning light is off before driving.
Automatic EPB Release
The EPB will automatically release if
the vehicle is running, placed into
gear, and an attempt is made to
drive away. Avoid rapid acceleration
when the EPB is applied, to
preserve parking brake lining life.
Brake Assist
Brake Assist detects rapid brake
pedal applications due to
emergency braking situations and
provides additional braking to
activate the Antilock Brake System
(ABS) if the brake pedal is not
pushed hard enough to activate
ABS normally. Minor noise, brake

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

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
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
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.