
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 247
Without Head-Up Display
If ACC is engaged, driver action may be
required when ACC cannot apply sufficient
braking because of approaching a vehicle
too rapidly.
When this condition occurs, the collision
alert symbol will flash on the windshield.
Either eight beeps will sound from the front,
or both sides of the Safety Alert Seat,
if equipped, will pulse five times. To view
available settings from the infotainment
screen, touch Settings > Vehicle >
Collision/Detection Systems.
See Defensive Driving 0200.
Approaching and Following a Vehicle
The vehicle ahead indicator is in the
instrument cluster and HUD (if equipped).
It only displays when a vehicle is detected
in your vehicle’s path moving in the same
direction. If this symbol is not displaying,
ACC will not respond to or brake for vehicles
ahead.
ACC automatically slows the vehicle down
and adjusts vehicle speed to follow a
detected vehicle ahead at the selected
following gap. The vehicle speed increases or
decreases to follow a detected vehicle in
front of your vehicle when that vehicle is
traveling slower than your vehicle set speed.
It may apply limited braking, if necessary.
When braking is active, the brake lamps will
come on. The automatic braking may feel or
sound different than if the brakes were
applied manually. This is normal.
Passing a Vehicle While Using ACC
If the set speed is high enough, and the left
turn signal is used to pass a vehicle ahead
in the selected following gap, ACC may
assist by gradually accelerating the vehicle
prior to the lane change.{Warning
When using ACC to pass a vehicle or
perform a lane change, the following
distance to the vehicle being passed may
be reduced. ACC may not apply sufficient
acceleration or braking when passing a
vehicle or performing a lane change.
Always be ready to manually accelerate
or brake to complete the pass or lane
change.
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
248 Driving and Operating
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.
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 (if equipped) will pulse
three times, or three beeps will sound. To
view available settings from the
infotainment screen, touch Settings >
Vehicle > Collision/Detection Systems > Alert
Type > Adaptive Cruise Go Notifier.
When the vehicle ahead drives away, ACC
resumes automatically if the stop was brief.
If necessary, 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 0234. To release
the EPB, press the accelerator pedal.
A DIC warning message may display
indicating to shift to P (Park) before exiting
the vehicle. See Vehicle Messages 0139.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
252 Driving and Operating
Cleaning the Sensing System
The camera sensor on the windshield behind
the rearview mirror can become blocked by
snow, ice, dirt, mud, or debris. This area
needs to be cleaned for ACC to operate
properly.
The vehicle headlamps may need to be
cleaned due to dirt, snow, or ice. Objects
that are not illuminated correctly may be
difficult to detect.
If ACC will not operate, regular cruise control
may be available. See“Switching Between
ACC and Regular Cruise Control” previously
in this section. Always consider driving
conditions before using either cruise control
system.
For cleaning instructions, see “Washing the
Vehicle” underExterior Care 0383.
Advanced Driver Assistance
Systems
This vehicle may have features that work
together to help avoid crashes or reduce
crash damage while driving, backing, and
parking. Read this entire section before
using these systems.
{Warning
Do not rely on the Driver Assistance
Systems. These systems do not replace
the need for paying attention and driving
safely. You may not hear or feel alerts or
warnings provided by these systems.
Failure to use proper care when driving
may result in injury, death, or vehicle
damage. See Defensive Driving 0200.
Under many conditions, these systems
will not:
.Detect children, pedestrians, bicyclists,
or animals.
.Detect vehicles or objects outside the
area monitored by the system.
.Work at all driving speeds.
.Warn you or provide you with enough
time to avoid a crash.
.Work under poor visibility or bad
weather conditions.
.Work if the detection sensor is not
cleaned or is covered by ice, snow,
mud, or dirt. (Continued)
Warning (Continued)
.Work if the detection sensor is
covered up, such as with a sticker,
magnet, or metal plate.
.Work if the area surrounding the
detection sensor is damaged or not
properly repaired.
Complete attention is always required
while driving, and you should be ready to
take action and apply the brakes and/or
steer the vehicle to avoid crashes.
Audible or Safety Alert Seat
Some driver assistance features alert the
driver of obstacles by beeping. To view
available settings from the infotainment
screen, touch Settings > Vehicle > Comfort
and Convenience.
If equipped with the Safety Alert Seat, the
driver seat cushion may provide a vibrating
pulse alert instead of beeping. To view
available settings from the infotainment
screen, touch Settings > Vehicle >
Collision/Detection Systems.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 259
when the Camera App is active. To
access this view when in a forward
gear above 12 km/h (8 mph), select
CAMERA on the infotainment
display and select Picture-in-Picture
Side View. The view can be closed
by selecting X, Home or Back.
Additional Views and Alerts
.Turn Signal Activated Views
Displays a rearward view of the left or
right side of the vehicle and trailer when
a trailer is connected. Views are provided
based on turn signal activation with the
right-side view being shown when the
right turn signal is active and the left side
view being shown when the left turn
signal is active. The feature can be
enabled or disabled.To view available
settings from the infotainment screen,
touch Settings > Vehicle > Collision/
Detection Systems. The view can be
closed early by selecting X, Home or Back.
A Trailer Length Indicator Overlay is
available in the Turn Signal Activated
Views when the trailer is relatively
straight behind the vehicle and a
compatible profile is configured and
selected via the Trailering App. The
overlay will not be visible when the position of the trailer is too far to the left
or right. The overlay can be enabled or
disabled. To view available settings from
the infotainment screen, touch Settings >
Vehicle > Collision/Detection Systems.
.Jack-Knife Detection and Alert
The vehicle may be equipped with
Jack-Knife Detection. The system will track
the position of the trailer relative to the
vehicle. As the front of the trailer
approaches the rear of the vehicle, a
warning or an alert will be displayed.
A warning indicates to the driver to
proceed with caution, an alert indicates
that a collision is imminent. Based on
vehicle equipment and user settings, the
visual warning or alert may be
accompanied by audible or safety alert
seat notifications. To view available
settings from the infotainment screen,
touch Settings > Vehicle > Collision/
Detection Systems.
.Trailer Angle Indicator
The vehicle may be equipped with a
Trailer Angle Indicator. The Trailer Angle
Indicator gives the driver a visual
representation of the trailer’s position
relative to the vehicle. (Available only in
Reverse, Guidelines On, Rear Trailering
Views).
{Warning
Use Hitch Guidance only to help back the
vehicle to a trailer hitch or, when
traveling above 12 km/h (8 mph), to
briefly check the status of your trailer. Do
not use for any other purpose, such as
making lane change decisions. Before
making a lane change, always check the
mirrors and glance over your shoulder.
Improper use could result in serious
injury to you or others.
HD Surround Vision with Trailer Camera
Provisions
If equipped, this feature provides additional
views to aid in trailering/towing. The
system shows multiple views in the
infotainment display using five cameras
mounted around the vehicle and up to two
additional accessory cameras that can be
mounted on or in a trailer. The front camera
is in the grille under the front emblem, the
side cameras are on the bottom of the
outside mirrors, the rear camera is in the
tailgate handle and the bed camera is

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
262 Driving and Operating
.The accessory trailer cameras were
plugged in when the vehicle was running.
The vehicle needs to be off, with all doors
closed, for at least five minutes prior to
plugging in a trailer camera.
A view may switch automatically if:
.The vehicle is shifted to another gear.
Park Assist
The vehicle may be equipped with Rear Park
Assist (RPA) or Front and Rear Park Assist
(FRPA). Under certain conditions, the Park
Assist system can assist the driver as the
vehicle moves at speeds of less than 8 km/h
(5 mph). The sensors on the bumpers may
detect objects up to 1.2 m (4 ft) in front and
1.8 m (6 ft) behind the vehicle within a zone
25 cm (10 in) high off the ground and below
bumper level. These detection distances may
be shorter during warmer or humid weather.
Blocked sensors will not detect objects and
can also cause false detections. Keep the
sensors clean of mud, dirt, snow, ice, and
slush; and clean sensors after a car wash in
freezing temperatures.
{Warning
The Park Assist system does not detect
children, pedestrians, bicyclists, animals,
or objects located below the bumper or
that are too close or too far from the
vehicle. It is not available at speeds
greater than 8 km/h (5 mph). To prevent
injury, death, or vehicle damage, even
with Park Assist, always check the area
around the vehicle and check all mirrors
before moving forward or backing.
The instrument cluster may have a Park
Assist display with bars that show “distance
to object” and object location information
for the Front and Rear Park Assist system.
As the object gets closer, more bars light up
and the bars change color from yellow to
amber to red. When an object is first detected around the
vehicle, one beep will be heard from the
front or rear (depending on the object's
location), or the driver's seat will pulse two
times if equipped with Safety Alert Seat.
When the object is very close to the vehicle,
the beeps will be continuous or the driver's
seat will pulse five times. Beeps in the front
are higher pitched than beeps in the rear.
Turning the Features On or Off
PressXon the center stack to turn on or
off the Front and Rear Park Assist. The
indicator light next to the button comes on
when the features are on and turns off
when the features have been disabled.
Front and Rear Park Assist can be turned
Off, On, or On with Towbar. To view
available settings from the infotainment
screen, touch Settings > Vehicle > Comfort
and Convenience. If Park Assist is turned off
through vehicle personalization, the Park
Assist button will be disabled. To turn Park

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 263
Assist on again, select On in vehicle
personalization. The On with Towbar setting
allows Park Assist to work properly with a
trailer hitch. Some larger trailer hitches may
not be compatible.
Turn off Park Assist when towing a trailer.
To turn the RPA symbols on or off, from the
infotainment screen, touch Settings >
Vehicle > Comfort and Convenience > Rear
Park Assist Symbols.
Rear Cross Traffic Alert (RCTA)
System
If equipped, when the vehicle is shifted into
R (Reverse), RCTA shows a red warning
triangle with a left or right pointing arrow
on the infotainment display to warn of
traffic coming from the left or right. This
system detects objects coming from up to
20 m (65 ft) from the left or right side of
the vehicle. When an object is detected,
either three beeps sound from the left or
right or three Safety Alert Seat pulses occur
on the left or right side, depending on the
direction of the detected vehicle.Use caution while backing up when towing
a trailer, as the RCTA detection zones that
extend out from the back of the vehicle do
not move further back when a trailer is
towed.
RCTA is disabled when the trailer connection
status is displayed.
RCTA can be turned off. To view available
settings from the infotainment screen, touch
Settings > Vehicle > Collision/Detection
Systems.
Assistance Systems for Driving
If equipped, when driving the vehicle in a
forward gear, Forward Collision Alert (FCA),
Front Pedestrian Braking, (FPB), Lane
Departure Warning (LDW), Side Blind Zone
Alert (SBZA), Lane Change Alert (LCA), and/or
the Automatic Emergency Braking (AEB) can
help to avoid a crash or reduce crash
damage.
Forward Collision Alert (FCA)
System
If equipped, the FCA system may help to
avoid or reduce the harm caused by
front-end crashes. When approaching a
vehicle ahead too quickly, FCA provides ared flashing alert on the windshield and
rapidly beeps or pulses the drivers seat (if
equipped). FCA also lights an amber visual
alert if following another vehicle much too
closely.
FCA detects vehicles within a distance of
approximately 60 m (197 ft) and operates at
speeds above 8 km/h (5 mph).
{Warning
FCA is a warning system and does not
apply the brakes. When approaching a
slower-moving or stopped vehicle ahead
too rapidly, or when following a vehicle
too closely, FCA may not provide a
warning with enough time to help avoid
a crash. It also may not provide any
warning at all. FCA does not warn of
pedestrians, animals, signs, guardrails,
bridges, construction barrels, or other
objects. Be ready to take action and
apply the brakes. See
Defensive Driving
0 200.
FCA can be disabled. To view available
settings from the infotainment screen, touch
Settings > Vehicle > Collision/Detection
Systems.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
264 Driving and Operating
Detecting the Vehicle Ahead
FCA warnings will not occur unless the FCA
system detects a vehicle ahead. When a
vehicle is detected, the vehicle ahead
indicator will display green. Vehicles may
not be detected on curves, highway exit
ramps, or hills, due to poor visibility; or if a
vehicle ahead is partially blocked by
pedestrians or other objects. FCA will not
detect another vehicle ahead until it is
completely in the driving lane.
{Warning
FCA does not provide a warning to help
avoid a crash, unless it detects a vehicle.
FCA may not detect a vehicle ahead if
the FCA sensor is blocked by dirt, snow,
or ice, or if the windshield is damaged.
It may also not detect a vehicle on
winding or hilly roads, or in conditions
that can limit visibility such as fog, rain,(Continued)
Warning (Continued)
or snow, or if the headlamps or
windshield are not cleaned or in proper
condition. Keep the windshield,
headlamps, and FCA sensors clean and in
good repair.
Collision Alert
With Head-Up Display
Without Head-Up Display
When your vehicle approaches another
detected vehicle too rapidly, the red FCA
display will flash on the windshield. Also,
eight rapid high-pitched beeps will sound from the front, or both sides of the Safety
Alert Seat will pulse five times. When this
Collision Alert occurs, the brake system may
prepare for driver braking to occur more
rapidly which can cause a brief, mild
deceleration. Continue to apply the brake
pedal as needed.
Tailgating Alert
The vehicle ahead indicator will display
amber when you are following a vehicle
ahead much too closely.
Selecting the Alert Timing
The Collision Alert control is on the steering
wheel. Press
[to set the FCA timing to
Far, Medium, or Near. The first button press

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
266 Driving and Operating
Warning (Continued)
.Detect a vehicle when weather limits
visibility, such as in fog, rain, or snow.
.Detect a vehicle ahead if it is partially
blocked by pedestrians or other
objects.
Complete attention is always required
while driving, and you should be ready to
take action and apply the brakes and/or
steer the vehicle to avoid crashes.
AEB may slow the vehicle to a complete
stop to try to avoid a potential crash. If this
happens, AEB may stop the vehicle
momentarily. Firmly press the accelerator to
continue driving.
{Warning
AEB may automatically brake the vehicle
suddenly in situations where it is
unexpected and undesired. It could
respond to a turning vehicle ahead,
guardrails, signs, and other non-moving
objects. To override AEB, firmly press the
accelerator pedal, if it is safe to do so.
Intelligent Brake Assist (IBA)
IBA may activate when the brake pedal is
applied quickly by providing a boost to
braking based on the speed of approach and
distance to a vehicle ahead.
Minor brake pedal pulsations or pedal
movement during this time is normal and
the brake pedal should continue to be
applied as needed. IBA will automatically
disengage only when the brake pedal is
released.
{Warning
IBA may increase vehicle braking in
situations when it may not be necessary.
You could block the flow of traffic. If this
occurs, take your foot off the brake pedal
and then apply the brakes as needed.
AEB and IBA can be disabled. To view
available settings from the infotainment
screen, touch Settings > Vehicle >
Collision/Detection Systems.
A system unavailable message may
display if:
.The front of the vehicle or windshield is
not clean.
.Heavy rain or snow is interfering with
object detection.
.There is a problem with the StabiliTrak/
Electronic Stability Control (ESC) system.
The AEB system does not need service.
Front Pedestrian Braking (FPB)
System
If equipped, the FPB system may help avoid
or reduce the harm caused by front-end
crashes with pedestrians near the forward
path of the vehicle when driving in a
forward gear. FPB displays an amber
~
when a nearby pedestrian is detected ahead.
When approaching a detected pedestrian too
quickly, FPB provides a red flashing alert on
the windshield and rapidly beeps or pulses
the driver seat (if equipped with Safety Alert
Seat). FPB can provide a boost to braking or
automatically brake the vehicle. This system
includes Intelligent Brake Assist (IBA), and
the Automatic Emergency Braking (AEB)
system may also respond to pedestrians.
See Automatic Emergency Braking (AEB)
0 265.
The FPB system can detect and alert to
pedestrians in a forward gear at speeds
between 8 km/h (5 mph) and 80 km/h