VEHICLE GMC SIERRA 2023 Owners Manual

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 257
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.
To view available settings for this feature,
touch the Settings icon on the infotainment
home page. Select“Vehicle”to display the
list of available options and select “Collision/
Detection Systems”.
Turn off Park Assist when towing a trailer.
To turn the “Rear Camera Park Assist
Symbols” on or off, touch the Settings icon
on the infotainment home page. Select
“Vehicle” to display the list of available
options and select “Collision/Detection
Systems”.
Rear Cross Traffic Alert (RCTA)
System
If equipped, Rear Cross Traffic Alert (RCTA)
displays 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.
Driving With a Trailer
Use caution while backing up when towing
a trailer. The RCTA feature is automatically
disabled when a trailer is attached to the
vehicle.
Turning the Features On or Off
The
Xbutton on the center stack is used
to turn on or off the Rear Park Assist (RPA),
and Backing Warning and Reverse Automatic
Braking (RAB) systems at the same time.
The indicator light next to the button comes
on when the features are on and turns off
when the features have been disabled.
Turn off RPA, RCTA, and RAB when towing a
trailer.
RCTA can be turned on or off using the
infotainment system. 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),
Lane Keep Assist (LKA), 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 a
red flashing alert on the windshield and
rapidly beeps or pulses the driver seat. 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).

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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258 Driving and Operating
{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. SeeDefensive Driving
0 205.
FCA can be disabled through vehicle settings.
To view available settings from the
infotainment screen, touch Settings >
Vehicle > Collision/Detection Systems.
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,
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.

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Driving and Operating 259
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
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.
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, the AEB system 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 can help 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
0257.
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.
.Detect a vehicle when weather limits
visibility, such as in fog, rain, or snow. (Continued)

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260 Driving and Operating
Warning (Continued)
.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 engage the Electric
Parking Brake (EPB) to hold the vehicle at a
stop. Release the EPB or firmly press the
accelerator pedal.
{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 for this feature, touch the
Settings icon on the infotainment home
page. Select “Vehicle”to display the list of
available options and select “Collision/
Detection Systems”.
{Warning
Using AEB or IBA while towing a trailer
could cause you to lose control of the
vehicle and crash. Turn the system to
Alert or Off when towing a trailer.
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.
Side Blind Zone Alert (SBZA)
If equipped, the SBZA 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. 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 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

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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Driving and Operating 261
part of the Lane Change Alert (LCA) system,
read the entire LCA section before using this
feature.
Lane Change Alert (LCA)
If equipped, the LCA system is a
lane-changing aid that assists drivers with
avoiding lane change crashes that occur with
moving vehicles in the side blind zone (or
spot) areas or with vehicles rapidly
approaching these areas from behind. The
LCA warning display will light up in the
corresponding outside side mirror and will
flash if the turn signal is on.
{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
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
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.
The Side Blind Zone Alert (SBZA) warning
area starts at approximately the middle of
the vehicle and goes back 5 m (16 ft). Drivers
are also warned of vehicles rapidly
approaching from up to 70 m (230 ft) behind
the vehicle.
How the System Works
The LCA symbol lights up in the side mirrors
when the system detects a moving vehicle
in the next lane over that is in the side blind zone or rapidly approaching that zone
from behind. A lit LCA symbol indicates it
may be unsafe to change lanes. Before
making a lane change, check the LCA
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 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 the next lane over in
that blind zone or rapidly approaching that
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.
LCA can be disabled through vehicle settings.
When you disable LCA, SBZA is also disabled.
To view available settings from the

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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262 Driving and Operating
infotainment screen, touch Settings >
Vehicle > Collision/Detection Systems. If LCA
is disabled by the driver, the LCA mirror
displays will not light up.
When the System Does Not Seem to
Work Properly
The LCA system requires some driving for
the system to calibrate to maximum
performance. This calibration may occur
more quickly if the vehicle is driving on a
straight highway road with traffic and
roadside objects (e.g., guardrails, barriers).
During a trip, the LCA system is not
operational until the vehicle reaches
24 km/h (15 mph).
LCA displays may not come on when
passing a vehicle quickly, for a stopped
vehicle, or when towing a trailer. The LCA
detection zones that extend back from the
side of the vehicle do not move further back
when a trailer is towed. Use caution while
changing lanes when towing a trailer. LCA
may alert to objects attached to the vehicle,
such as a trailer, bicycle, or object extending
out to either side of the vehicle. Attached
objects may also interfere with the
detection of vehicles. This is normal system
operation; the vehicle does not need service.LCA may not always alert the driver to
vehicles in the next lane over, especially in
wet conditions or when driving on sharp
curves. The system does not need to be
serviced. The system may light up due to
guardrails, signs, trees, shrubs, and other
non-moving objects. This is normal system
operation; the vehicle does not need service.
LCA may not operate when the LCA sensors
in the left or right corners of the rear
bumper are covered with mud, dirt, snow,
ice, or slush, or in heavy rainstorms. For
cleaning instructions, see "Washing the
Vehicle" under
Exterior Care0374. If the DIC
still displays the system unavailable
message after cleaning both sides of the
vehicle toward the rear corners of the
vehicle, see your dealer.
If the LCA displays do not light up when
moving vehicles are in the side blind zone or
are rapidly approaching this zone and the
system is clean, the system may need
service. Take the vehicle to your dealer.
Radio Frequency Information
See Radio Frequency Statement 0404.
Lane Departure Warning (LDW)
If equipped, LDW may help avoid crashes
due to unintentional lane departures. LDW
uses a camera sensor to detect the lane
markings at speeds of 56 km/h (35 mph) or
greater. It may provide an alert if the
vehicle is crossing a lane without using a
turn signal in that direction. LDW light will
not alert if the turn signal is active in the
direction of lane departure, or if LDW
detects that you are accelerating, braking or
actively steering.
{Warning
The LDW system does not steer the
vehicle. The LDW system may not:
.Provide enough time to avoid a crash.
.Detect lane markings under poor
weather or visibility conditions. This
can occur if the windshield or
headlamps are blocked by dirt, snow,
or ice; if they are not in proper
condition; or if the sun shines directly
into the camera.
.Detect road edges.
.Detect lanes on winding or hilly roads.
(Continued)

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Driving and Operating 263
Warning (Continued)
If LDW only detects lane markings on one
side of the road, it will only warn you
when departing the lane on the side
where it has detected a lane marking.
Always keep your attention on the road
and maintain proper vehicle position
within the lane, or vehicle damage,
injury, or death could occur. Always keep
the windshield, headlamps, and camera
sensors clean and in good repair. Do not
use LDW in bad weather conditions.
How the System Works
LDW utilizes a camera sensor installed on
the windshield ahead of the rearview mirror
to detect lane markings.
To turn LDW on and off, press
@on the
center stack. The control indicator will light
when LDW is on.
When LDW is on,@is green if LDW is
available to warn of a lane departure. If the
vehicle crosses a detected lane marking
without using the turn signal in that
direction,
@changes to amber and flashes.
Additionally, there will be three beeps, on
the right or left, depending on the lane
departure direction. LDW will not alert if the
turn signal is active in the direction of lane
departure or if LDW detects that you are
accelerating, braking or actively steering.
Fuel
Top Tier Fuel
GM recommends the use of TOP TIER
Detergent Gasoline to keep the engine clean,
reduce engine deposits, and maintain
optimal vehicle performance. Look for the
TOP TIER Logo or see www.toptiergas.com
for a list of TOP TIER Detergent Gasoline
marketers and applicable countries.
Recommended Fuel
For diesel engine vehicles, see “Fuel for
Diesel Engines” in the Duramax diesel
supplement.
If the vehicle has a yellow sticker on the
fuel door, E85 or FlexFuel can be used. If the
vehicle does not have a yellow sticker, do
not use gasoline with ethanol levels greater
than 15% by volume. See E85 or FlexFuel
0 264.

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264 Driving and Operating
Regular unleaded gasoline meeting ASTM
specification D4814 with a posted octane
rating (R+M)/2 of 87 or greater is
recommended. Do not use gasoline with a
posted octane rating of less than 87, as this
will result in reduced performance and
driveability. If heavy knocking is heard when
using gasoline rated at 87 or greater, the
engine needs service.
Prohibited Fuels
Caution
Do not use fuels with any of the
following conditions; doing so may
damage the vehicle and void its
warranty:
.For vehicles that are not FlexFuel, fuel
labeled greater than 15% ethanol by
volume, such as mid-level ethanol
blends (16–50% ethanol), E85,
or FlexFuel.
.Fuel with any amount of methanol,
methylal, ferrocene, and aniline. These
fuels can corrode metal fuel system
parts or damage plastic and rubber
parts.
(Continued)
Caution (Continued)
.Fuel containing metals such as
methylcyclopentadienyl manganese
tricarbonyl (MMT), which can damage
the emissions control system and
spark plugs.
.Fuel with a posted octane rating of
less than the recommended fuel. Using
this fuel will lower fuel economy and
performance, and may decrease the
life of the emissions catalyst.
Fuels in Foreign Countries
The U.S., Canada, and Mexico post fuel
octane ratings in anti-knock index (AKI). For
fuel not to use in a foreign country, see
Prohibited Fuels0264.
Fuel Additives
TOP TIER Detergent Gasoline is highly
recommended for use with your vehicle.
If your country does not have TOP TIER
Detergent Gasoline, add ACDelco Fuel
System Treatment Plus−Gasoline to the
vehicle’s gasoline fuel tank at every oil
change or 15 000 km (9,000 mi), whichever
occurs first. TOP TIER Detergent Gasoline
and ACDelco Fuel System Treatment Plus−Gasoline will help keep your vehicle’s
engine fuel deposit free and performing
optimally.
E85 or FlexFuel
Vehicles with a yellow fuel sticker on the
fuel door can use either unleaded gasoline
or fuel containing up to 85% ethanol (E85).
All other vehicles should use only the
unleaded gasoline as described in
Recommended Fuel
0263.
The use of E85 or FlexFuel is encouraged
when the vehicle is designed to use it. E85
or FlexFuel is made from renewable sources.
To help locate fuel stations that carry E85 or
FlexFuel, the U.S. Department of Energy has
an alternative fuel website. See
www.afdc.energy.gov/afdc/locator/stations.
E85 or FlexFuel should meet ASTM
Specification D 5798 or CAN/CGSB–3.512 in
Canada. Do not use the fuel if the ethanol
content is greater than 85%. Fuel mixtures
that do not meet ASTM or CGSB
specifications can affect driveability and
could cause the malfunction indicator lamp
to come on.

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Driving and Operating 265
The starting characteristics of E85 or FlexFuel
make it unsuitable for use when
temperatures fall below−18 °C (0 °F). Use
gasoline or add gasoline to the E85 or
FlexFuel.
Because E85 or FlexFuel has less energy per
liter (gallon) than gasoline, the vehicle will
need to be refilled more often. See Filling
the Tank (Chassis Cab and Box Delete
Models) 0266 or
Filling the Tank (Pickup Models) 0265.
The only GM approved aftermarket additive
is ACDelco Fuel System Treatment
Plus-FlexFuel. Follow the instructions on the
bottle for proper use. This product is
available at your GM dealer.
Caution
Some additives are not compatible with
E85 or FlexFuel and can harm the
vehicle's fuel system. Use only additives
approved by GM for E85 or FlexFuel
vehicles. Damage caused by unapproved
additives would not be covered by the
vehicle warranty.
Caution
Do not use fuel containing methanol.
It can corrode metal parts in the fuel
system and also damage plastic and
rubber parts. That damage would not be
covered under the vehicle warranty.
To help keep the engine running efficiently,
fill the tank with gasoline, up to E15, after
filling the tank with E85 one or two times.
Filling the Tank (Pickup Models)
If the vehicle has a diesel engine, see the
Duramax diesel supplement.
An arrow on the fuel gauge indicates which
side of the vehicle the fuel door is on. See
Fuel Gauge 0115.
{Warning
Fuel vapors and fuel fires burn violently
and can cause injury or death.
Follow these guidelines to help avoid
injuries to you and others:
.Read and follow all the instructions on
the fuel pump island.
.Turn off the engine when refueling.
(Continued)
Warning (Continued)
.Keep sparks, flames, and smoking
materials away from fuel.
.Do not leave the fuel pump
unattended.
.Avoid using electronic devices while
refueling.
.Do not re-enter the vehicle while
pumping fuel.
.Keep children away from the fuel
pump and never let children
pump fuel.
.Before touching the fill nozzle, touch a
metallic object to discharge static
electricity from your body.
.Fuel can spray out if the fill nozzle is
inserted too quickly. This spray can
happen if the tank is nearly full, and is
more likely in hot weather. Insert the
fill nozzle slowly and wait for any hiss
noise to stop before beginning to
flow fuel.

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266 Driving and Operating
The capless refueling system does not have
a fuel cap. Fully insert and latch the fill
nozzle, begin fueling.
{Warning
Overfilling the fuel tank by more than
three clicks of a standard fill nozzle may
cause:
.Vehicle performance issues, including
engine stalling and damage to the fuel
system.
.Fuel spills.
.Under certain conditions, fuel fires.Be careful not to spill fuel. Wait five seconds
after you have finished pumping before
removing the fill nozzle. Clean fuel from
painted surfaces as soon as possible. See
Exterior Care
0374. Push the fuel door
closed.
{Warning
If a fire starts while you are refueling, do
not remove the fill nozzle. Shut off the
flow of fuel by shutting off the pump or
by notifying the station attendant. Leave
the area immediately.
Filling the Tank with a Portable Fuel
Container
If the vehicle runs out of fuel and must be
filled from a portable fuel container:
1. Locate the capless funnel adapter.
2. Insert and latch the funnel into the capless fuel system.
{Warning
Attempting to refuel from a portable fuel
container without using the funnel
adapter may cause fuel spillage and
damage the capless fuel system. This
could cause a fire. You or others could be
badly burned and the vehicle could be
damaged.
3. Remove and clean the funnel adapter and return it to the storage location.
Filling the Tank (Chassis Cab and
Box Delete Models)
If the vehicle has a diesel engine, see the
Duramax diesel supplement.
An arrow on the fuel gauge indicates which
side of the vehicle the fuel fill is on. See
Fuel Gauge 0115.