brake GMC SIERRA 2024 Repair Manual

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
244 Driving and Operating
ACC can also be set while the vehicle is
stopped if ACC is on and the brake pedal is
applied.
The ACC indicator displays in the instrument
cluster and Head-Up Display (HUD),
if equipped. When ACC is turned on, the
indicator will be lit white. When the ACC is
active, the indicator turns green.
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+ up
briefly.
.If the vehicle is moving more than 5 km/h
(3 mph), it returns to the previous set
speed.
.If the vehicle is stopped with the brake
pedal applied, press RES+ and release the
brake pedal. ACC will hold the vehicle
until RES+ or the accelerator pedal is
pressed.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, the vehicle speed
will increase to the set speed under the
following conditions:
.There is no vehicle ahead.
.The vehicle ahead is beyond the selected
following gap.
.The vehicle speed is not being limited
because of a sharp turn.
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.
When the accelerator pedal is pressed,
ACC will not brake because it is
overridden. The ACC indicator will turn
blue on the instrument cluster and HUD,
if equipped.
.Press and hold RES+ until the desired set
speed is displayed, then release it.
.To increase vehicle speed in smaller
increments, press RES+ briefly. For each
press, the vehicle goes about 1 km/h
(1 mph) faster.
.To increase vehicle speed in larger
increments, hold RES+. While holding
RES+, the vehicle speed increases to the
next 5 km/h (5 mph) step, then continues
to increase by 5 km/h (5 mph) at a time.
The set speed can also be increased while
the vehicle is stopped.
.If stopped with the brake pedal applied,
press RES+ until the desired set speed is
displayed.
.If ACC is holding the vehicle at a stop and
there is another vehicle directly ahead,
pressing RES+ will increase the set speed.
.Pressing RES+ when there is no longer a
vehicle ahead or the vehicle ahead is
pulling away and the brake is not applied
with cause the ACC to resume.
When it is determined that there is no
vehicle ahead or the vehicle ahead is beyond
the selected following gap, then the vehicle
speed will increase to the set speed.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 245
Reducing Speed While ACC Is at a Set Speed
If ACC is already activated, do one of the
following:
.Use the brake to get to the desired lower
speed. Release the brake and press SET–.
The vehicle will now cruise at the lower
speed.
.Press and hold SET–until the desired
lower speed is reached, then release it.
.To decrease the vehicle speed in smaller
increments, press SET− briefly. For each
press, the vehicle goes about 1 km/h
(1 mph) slower.
.To decrease the vehicle speed in larger
increments, hold SET−. While holding
SET−, the vehicle speed decreases to the
next 5 km/h (5 mph) step, then continues
to decrease by 5 km/h (5 mph) at a time.
The set speed can also be decreased while
the vehicle is stopped.
.If stopped with the brake applied, press
or hold SET− until the desired set speed is
displayed. Selecting the Follow Distance Gap
When a slower moving vehicle is detected
ahead within the selected following gap,
ACC will adjust the vehicle's speed and
attempt to maintain the follow distance gap
selected.
Press
[on the steering wheel to adjust
the following gap. Each press cycles the gap
button through three settings: Far, Medium,
or Near.
When pressed, the current gap setting
displays briefly on the instrument cluster
and HUD, if equipped. The gap setting will
be maintained until it is changed.
Far Gap Setting
Medium Gap Setting
Near Gap Setting

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
Driving and Operating 249
{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 and in the HUD,
if equipped, to indicate that automatic
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.
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 (Continued)
Warning (Continued)
attention in curves and be ready 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.
If equipped, the curve speed control
indicator
bmay illuminate green when
ACC is actively controlling the vehicle speed
and detects a sharp curve on the road
ahead.
ACC automatically slows the vehicle down
while navigating the curve and may increase
speed out of the curve, but will not exceed
the set speed.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
250 Driving and Operating
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.Other Vehicle Lane Changes
ACC will not detect a vehicle ahead until it
is completely in the lane. The brakes may
need to be manually applied.
Objects Not Directly in Front of Your Vehicle
The detection of objects in front of the
vehicle may not be possible if:
.The vehicle or object ahead is not within
your lane.
.The vehicle ahead is shifted, not centered,
or is shifted to one side of the lane.
Driving in Narrow Lanes
Vehicles in adjacent traffic lanes or roadside
objects may be incorrectly detected when
located along the roadway. Do Not Use ACC on Hills
Do not use ACC when driving on steep hills
as ACC may not detect a vehicle ahead.
Towing with ACC
If equipped when towing a trailer, ACC
driving characteristics such as following gap,
acceleration rates and braking rates may be
modified to provide a better towing
experience.
When ACC is used with vehicles equipped
with aftermarket trailer brake controller,
disengage ACC before applying the manual
trailer brake. ACC will not automatically
disengage when manual trailer brake is
applied.
ACC may be used when towing a trailer
when trailer attached is within GM-approved
allowable size and weight limits. See
Trailer
Towing 0280.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 251
When towing a trailer with ACC, it is
important to properly set the Trailer Gain.
See“Integrated Trailer Brake Control
System” inTowing Equipment 0284 for
Trailer Gain Adjustment Procedure.
Use Tow/Haul mode when driving down
steep hills or mountain grades, or when
hauling heavy loads. See Driver Mode
Control 0238.
Disengaging ACC
There are three ways to disengage ACC:
.Step lightly on the brake pedal.
.Press*.
.PressJ.
Erasing Speed Memory
The ACC set speed is erased from memory if
Jis pressed or if the ignition is turned off.
Weather Conditions Affecting ACC
If the interior temperature is extremely
high, the instrument cluster may indicate
that ACC is temporarily unavailable. This can
be caused by extreme hot weather
conditions with direct sunlight on the front
camera. ACC will return to normal operation
once the cabin temperature is lower. Conditions that are associated with low
visibility, such as fog, rain, snow, or road
spray, may limit ACC performance. Water
droplets from rain or snow that remain on
the windshield may also limit ACC’s ability
to detect objects.
System operation may be limited under
snow, heavy rain, or road spray conditions.
{Warning
Camera visibility may be limited and the
ACC system may not work properly if the
windshield is not clear. Do not use ACC if
moisture is present on the inside of the
windshield or the windshield washer is
used in cold weather. Turn on the front
defroster and make sure the windshield is
clear before using ACC. Before driving,
check that the windshield wipers are in
good condition and replace them if worn.
Lighting Conditions Affecting ACC
The ACC front camera can be affected by
poor lighting conditions, and ACC may have
limited performance when:
.There are changes in brightness, such as
entering and exiting tunnels, bridges, and
overpasses.
.Low sun angles cause the camera to not
detect objects, or it is more difficult to
detect objects in the same traffic lane.
.Lighting is poor in the evening or early
morning
.There are multiple changes in brightness
or shadows along the vehicle roadway.
.In a tunnel without the headlamps on,
or in a tunnel when there is a vehicle in
front that does not have its taillamps on.
.Subjected to strong light from opposing
lane traffic in the front of the vehicle,
such as high-beam headlamps from
oncoming traffic.
Accessory Installations and Vehicle
Modifications
Do not install or place any object around
the front camera windshield area that would
obstruct the front camera view.
Do not install objects on top of the vehicle
that overhang and obstruct the front
camera, such as a canoe, kayak, or other
items that can be transported on the
vehicle roof.
Do not modify the hood, headlamps, or fog
lamps, as this may limit the camera’s ability
to detect an object.

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
256 Driving and Operating
2. Front/Rear Top-Down View
Displays a front or rear overhead view
of the vehicle. To view, select Front/
Rear Top-Down View on the
infotainment display when the camera
app is active.
3. Front/Rear side View
Displays a view that shows objects
next to the front or rear sides of the
vehicle. To select, touch Front/Rear
Side View on the infotainment display
when a camera view is active. Touch
the button to toggle between front
and rear camera views. Park Assist and
RCTA overlays are not available when
Front/Rear Side View is active.
4. Hitch View
Displays a zoomed-in view of the hitch
area to assist with aligning the
vehicle’s hitch ball with the trailer
coupler and monitoring the trailer
connection. To view, select Hitch View
on the infotainment display 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
Hitch View. The view will close after
eight seconds and can be closed earlyby selecting X, Home or Back. Shifting
into P (Park) while in this view will
automatically engage the Electric
Parking Brake (EPB).
5. Surround View
Displays an image of the area
surrounding the vehicle. Surround
View is displayed alongside the
currently selected view when below
12 km/h (8 mph). Surround View is
disabled when above 12 km/h (8 mph).
6. Camera App Guidance Lines
The Camera App supports three
possible guidance modes: No
Guidance, Vehicle Guidance and
Trailering Guidance. To change
guidance mode, select the appropriate
guidance icon. Depending on the
guidance mode and view selected,
different guidance lines may appear.
A grayed-out icon indicates that
guidance lines are not available.
Certain views do not support Guidance
lines.
.Standard Guidance Lines are
available in Front/Rear Standard
Views, Front/Rear Top-Down Views
and Surround View when the
vehicle guidance mode is selected.
Standard Guidance Lines show
current and intended vehicle path.
.Hitch Guidance Line is available in
Rear Standard View or Cargo Bed
View when the Trailering Guidance
mode is selected. Hitch Guidance
displays a single centered guidance
line on the infotainment display to
assist with aligning the vehicle’s
hitch with a trailer coupler. Align
the Hitch Guidance Line with the
trailer coupler by continuously
steering the vehicle to keep the
guidance line centered on the
coupler when backing. Park Assist
overlays will not display when the
Hitch Guidance Line is active.
.Rear Trailer Guidance Lines are
available in the Rear Trailer View
when the Trailering Guidance
mode is selected and the rear
trailer camera calibration has been
successfully completed. Rear Trailer
Guidance Lines show the intended
path (yellow) and the current path
(blue) of the trailer. The current
path guidance lines will converge
with the intended path guidance
lines.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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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.