2024 GMC SIERRA DENALI lane assist

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 201
Steering
Caution
To avoid damage to the steering system,
do not drive over curbs, parking barriers,
or similar objects at speeds greater than
3 km/h (1 mph). Use care when driving
over other objects such as lane dividers
and speed bumps. Damage caused by
misuse of the vehicle is not covered by
the vehicle warranty.
Hydraulic Power Steering (2500/3500
Series)
(2500/3500 Series–All Regular Cab, Double
Cab/Crew Cab with Base Interior)
The power steering system may require
maintenance. See Power Steering Fluid
0 323.
If power steering assist is lost because the
engine stops or the system malfunctions,
the vehicle can be steered but may require
increased effort. See your dealer.
(2500/3500 Series –Double Cab/Crew Cab
with Uplevel Interior)
The vehicle has a power steering system
that varies the amount of effort required to
steer the vehicle. Less steering effort is
required at slower speeds. At faster speeds,
the required steering effort increases. The
system helps the steering wheel return to
center at low speeds. Pressing the Tow/Haul
mode button adjusts steering effort for
driving conditions described in Tow/Haul
Mode 0227.
The power steering system may require
maintenance. See Power Steering Fluid
0 323. If power steering assist is lost because the
engine stops or the system malfunctions,
the vehicle can be steered but may require
increased effort. See your dealer.
{Warning
Do not hold the brake pedal and press
the accelerator pedal at the same time.
Damage may occur to the power steering
and power brake systems which could
lead to reduced performance, up to and
including loss of steering and brake
assist.
Caution
Do not hold the steering wheel at full
rotation for more than 15 seconds and/or
at an elevated RPM. Damage may occur
to the power steering system and there
may be loss of power steering assist.
Curve Tips
.Take curves at a reasonable speed.
.Reduce speed before entering a curve.
.Maintain a reasonable steady speed
through the curve.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 207
Hydroplaning
Hydroplaning is dangerous. Water can build
up under the vehicle's tires so they actually
ride on the water. This can happen if the
road is 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.
SeeTires 0345.
.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, and
cooling system.
.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 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
Caution
To avoid damage to the wheels and
brake components, always clear snow and
ice from inside the wheels and
underneath the vehicle before driving.
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 freezing rain begins to fall.
Avoid driving on wet ice or in freezing rain
until roads can be treated.

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
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
Driving and Operating 265
shows the current setting on the DIC.
Additional button presses will change this
setting. The chosen setting will remain until
it is changed and will affect the timing of
both the Collision Alert and the Tailgating
Alert features. The timing of both alerts will
vary based on vehicle speed. The faster the
vehicle speed, the farther away the alert will
occur. Consider traffic and weather
conditions when selecting the alert timing.
The range of selectable alert timings may
not be appropriate for all drivers and driving
conditions.
If your vehicle is equipped with Adaptive
Cruise Control (ACC), changing the FCA
timing setting automatically changes the
following gap setting (Far, Medium,
or Near).
Following Distance Indicator
If equipped, the following distance to a
moving vehicle ahead in your path is
indicated in following time in seconds on
the Driver Information Center (DIC). See
Driver Information Center (DIC) (Base Level)
0131 or
Driver Information Center (DIC) (Uplevel)
0 133. The minimum following time is
0.5 seconds away. If there is no vehicle detected ahead, or the
vehicle ahead is out of sensor range, dashes
will be displayed.
Unnecessary Alerts
FCA may provide unnecessary alerts for
turning vehicles, vehicles in other lanes,
objects that are not vehicles, or shadows.
These alerts are normal operation and the
vehicle does not need service.
Cleaning the System
If the FCA system does not seem to operate
properly, this may correct the issue:
.Clean the outside of the windshield in
front of the rearview mirror.
.Clean the entire front of the vehicle.
.Clean the headlamps.
Automatic Emergency
Braking (AEB)
If equipped, AEB may help avoid or reduce
the harm caused by front-end crashes. AEB
also includes Intelligent Brake Assist (IBA).
When the system detects a vehicle ahead in
your path that is traveling in the same
direction that you may be about to crash
into, it can provide a boost to braking or
automatically brake the vehicle. This canhelp avoid or lessen the severity of crashes
when driving in a forward gear. Depending
on the situation, the vehicle may
automatically brake moderately or hard. This
automatic emergency braking can only occur
if a vehicle is detected. This is shown by the
FCA vehicle ahead indicator being lit. See
Forward Collision Alert (FCA) System
0263.
The system works when driving in a forward
gear between 8 km/h (5 mph) and 80 km/h
(50 mph). It can detect vehicles up to
approximately 60 m (197 ft).
{Warning
AEB is an emergency crash preparation
feature and is not designed to avoid
crashes. Do not rely on AEB to brake the
vehicle. AEB will not brake outside of its
operating speed range and only responds
to detected vehicles.
AEB may not:
.Detect a vehicle ahead on winding or
hilly roads.
.Detect all vehicles, especially vehicles
with a trailer, tractors, muddy
vehicles, etc. (Continued)

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
268 Driving and Operating
8 km/h (5 mph) and 80 km/h (50 mph).
Automatic braking levels may be reduced
under certain conditions, such as higher
speeds.
FPB may slow the vehicle to a complete
stop to try and avoid a potential collision
with a pedestrian. If this happens, Automatic
Braking may hold the vehicle at a stop
momentarily. Firmly press the accelerator
pedal to release Automatic Braking.
{Warning
FPB may alert or automatically brake the
vehicle suddenly in situations where it is
unexpected and undesired. It could falsely
alert or brake for objects similar in shape
or size to pedestrians, including shadows.
This is normal operation and the vehicle
does not need service. To override
Automatic Braking, firmly press the
accelerator pedal, if it is safe to do so.
Automatic Braking can be disabled through
vehicle settings. To view available settings
from the infotainment screen, touch
Settings > Vehicle > Collision/Detection
Systems > Front Pedestrian Detection.
Cleaning the System
If FPB does not seem to operate properly,
cleaning the outside of the windshield in
front of the rearview mirror may correct the
issue.
Lane Change Alert (LCA)
If equipped, the Lane Change Alert (LCA)
system is a lane-changing aid that can assist
drivers with avoiding lane change crashes
with moving vehicles in the side blind zone,
or blind spot areas or with vehicles rapidly
approaching these areas from behind. When
a vehicle is detected in the blind zone, the
LCA warning display will light up in the
corresponding side mirror and will flash if
the turn signal is on. The Side Blind Zone
Alert (SBZA) system is included as part of
the LCA system.
{Warning
LCA does not alert the driver to vehicles
outside of the system detection zones,
pedestrians, bicyclists, or animals. It may
not provide alerts when changing lanes
under all driving conditions. Failure to use
proper care when changing lanes may (Continued)
Warning (Continued)
result in injury, death, or vehicle damage.
Before making a lane change, always
check mirrors, glance over your shoulder,
and use the turn signals.
LCA Detection Zones
1. SBZA Detection Zone
2. LCA Detection Zone
When towing a trailer, LCA feature is
disabled. When not towing a trailer, the LCA
sensor covers a zone of approximately one
lane over from both sides of the vehicle,
or 3.5 m (11 ft). The height of the zone is
approximately between 0.5 m (1.5 ft) and
2 m (6 ft) off the ground. Drivers are also

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 269
warned of vehicles rapidly approaching this
area up to approximately 70 m (230 ft)
behind the vehicle.
Trailer Side Blind Zone Area (TSBZA)
If equipped, the TSBZA system is a
lane-changing aid that assists drivers with
avoiding crashes that occur with moving
vehicles in the side blind zone, or blind spot
areas. The trailer side blind zone area adds
the blind zone area along the side of a
trailer that the host vehicle is pulling.
When the vehicle is in a forward gear, the
left or right side mirror display will light up
if a moving vehicle is detected in that trailer
blind zone. If the turn signal is activated and
a vehicle is also detected on the same side,
the display will flash as an extra warning
not to change lanes. Since this system is
part of the Lane Change Alert system, read
the entire Lane Change Alert section before
using this feature.
{Warning
TSBZA does not alert the driver to
vehicles outside of the system detection
zones, pedestrians, bicyclists, or animals.
It may not provide alerts when changing(Continued)
Warning (Continued)
lanes under all driving conditions. Failure
to use proper care when changing lanes
may result in injury, death, or vehicle
damage. Before making a lane change,
always check mirrors, glance over your
shoulder, and use the turn signals.
TSBZA Detection Zones
1. SBZA Detection Zone
2. TSBZA Detection Zone
3. LCA Detection Zone
The Side Blind Zone Alert (SBZA) warning
area starts at approximately the middle of
the vehicle and goes back 5 m (16 ft). The
Trailer Side Blind Zone Alert (TSBZA) warning
area starts at approximately 3 m (10 ft) to
the trailing edge of the vehicle and goes
back up to 21 m (69 ft) behind the vehicle.
The maximum trailer length is 18 m (59 ft).
How the System Works
The LCA/TSBZA symbol lights up in the side
mirrors when the system detects a moving
vehicle in the next lane over that is in the
trailer side blind zone. This indicates it may
be unsafe to change lanes. Before making a
lane change, check the SBZA display, check
mirrors, glance over your shoulder, and use
the turn signals.
Left Side Mirror DisplayRight Side Mirror Display
When the vehicle is started, both outside
mirror LCA/TSBZA displays will briefly come
on to indicate the system is operating.
When the vehicle is in a forward gear, the
left- or right-side mirror display will light up
if a moving vehicle is detected in that blind
zone. If the turn signal is activated in the
same direction as a detected vehicle, this
display will flash as an extra warning not to
change lanes.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 277
The following information has many
time-tested, important trailering tips and
safety rules. Many of these are important
for your safety and that of your passengers.
Read this section carefully before towing a
trailer.
When towing a trailer:
.Become familiar with, and follow all state
and local laws that apply to trailer
towing. These requirements vary from
state to state.
.State laws may require the use of
extended side view mirrors. If your
visibility is limited or restricted while
towing, install extended side view mirrors
on your vehicle, even if not required.
.Do not tow a trailer during the first
800 km (500 mi) of vehicle use to prevent
damage to the engine, axle, or other
parts.
.Perform the first oil change before heavy
towing.
.Do not drive over 80 km/h (50 mph) and
do not make starts at full throttle during
the first 800 km (500 mi) of trailer
towing.
.Tow in D (Drive). Tow/Haul Mode is
recommended for heavier trailers. See
Tow/Haul Mode0227. If the transmission
downshifts too often, a lower gear may
be selected using Manual Mode. See
Manual Mode 0226.
The following advanced driver assistance
features should be turned off when towing
a trailer, and may turn off automatically
when a trailer is detected:
.Park Assist
.Reverse Automatic Braking (RAB)
.Rear Cross Traffic Alert (RCTA)
.Rear Cross Traffic Braking (RCTB)
.Lane Change Alert (LCA)
.Super Cruise and Adaptive Cruise Control
(ACC), unless equipped with trailering
functionality, see Adaptive Cruise Control
(Camera) 0241.
Automatic Emergency Braking (AEB) and
Front Pedestrian Braking (FPB) should be set
to Alert unless equipped with Super Cruise.
Do not use Automatic Parking Assist (APA)
while towing a trailer.
{Warning
To prevent serious injury or death from
carbon monoxide (CO), when towing a
trailer:
.Do not drive with the liftgate, trunk/
hatch, or rear-most window open.
.Fully open the air outlets on or under
the instrument panel.
.Adjust the climate control system to a
setting that brings in only outside air.
See “Climate Control Systems” in the
Index.
For more information about carbon
monoxide, see Engine Exhaust 0222.
Towing a trailer requires experience. The
combination of the vehicle and trailer is
longer and not as responsive as the vehicle
itself. Get used to the handling and braking
of the combination by driving on a level
road surface before driving on public roads.
The trailer structure, the tires, and the
brakes must all be rated to carry the
intended cargo. Inadequate trailer
equipment can cause the combination to
operate in an unexpected or unsafe manner.
Before driving, inspect all trailer hitch parts