towing GMC SIERRA 2023 User Guide

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
234 Driving and Operating
10-Speed Automatic TransmissionGear before shifting from D (Drive) to L (Manual Mode) 10th 9th 8th 7th 6th 5th 4th 3rd 2nd 1st
Range after shifting from D (Drive) to L (Manual
Mode) –Tow/Haul not engaged L7 L7 L7 L6 L5 L4 L3 L3 L2 L1
Range after shifting from D (Drive) to L (Manual
Mode) –Tow/Haul engaged L7 L7 L6 L5 L4 L3 L3 L3 L2 L1
Tow/Haul Mode
The Tow/Haul Mode adjusts the
transmission shift pattern to reduce shift
cycling. This provides increased performance,
vehicle control, and enhanced transmission
and engine cooling when driving down steep
hills or mountain grades, when towing,
or when hauling heavy loads. See
Driver
Mode Control 0243 to activate Tow/
Haul Mode.
For vehicles without Driver Mode Control,
press the Tow/Haul button on the center
stack.
If equipped with Active Hydraulic Assist, the
vehicle will provide a stiffer steering
response when Tow/Haul mode is engaged
to provide enhanced steering functionality.
Tow/Haul Mode Grade Braking
Tow/Haul Mode Grade Braking is only
enabled while the Tow/Haul Mode is
selected and the vehicle is not in the Range
Selection Mode. See Manual Mode0232.
Tow/Haul Mode Grade Braking assists in
maintaining desired vehicle speeds when
driving on downhill grades by using the
engine and transmission to slow the vehicle.
See Towing Equipment 0276.
Drive Systems
Four-Wheel Drive
If equipped, four-wheel drive engages the
front axle for extra traction.
Read the appropriate section for transfer
case operation before using.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 235
Caution
Do not drive on clean, dry pavement in
4
mand 4n(if equipped) for an extended
period of time. These conditions may
cause premature wear on the vehicle’s
powertrain.
Driving on clean, dry pavement in 4
mor
4
nmay:
.Cause a vibration to be felt in the
steering system.
.Cause tires to wear faster.
{Warning
If equipped with four-wheel drive, the
vehicle will be free to roll if the transfer
case is in N (Neutral), even when the shift
lever is in P (Park). You or someone else
could be seriously injured. Be sure the
transfer case is in a drive gear —2
m, 4m,
or 4
n— or set the parking brake before
placing the transfer case in N (Neutral).
See Shifting Into Park 0227.
Caution
Extended high-speed operation in 4n
may damage or shorten the life of the
drivetrain.
An engagement noise and bump is normal
when shifting between 4
nand 4mor
N (Neutral), with the engine running.
Shifting into 4
nwill turn Traction Control
and StabiliTrak/Electronic Stability Control
(ESC) off. See Traction Control/Electronic
Stability Control 0241.
Automatic Transfer Case
Two-Speed Transfer Case
If equipped, the transfer case controls are
used to shift into and out of four-wheel
drive.
To shift the transfer case, press the desired
button. The graphic in the instrument
cluster will flash while a shift is in progress.
The graphic displayed will change to indicate
the setting requested.
When the shift is complete the graphic will
stop flashing. The DIC message turns off
once the shift is complete. If the transfer
case cannot complete a shift request, it will
go back to its last chosen setting.
The settings are:
N (Neutral) : Use only when the vehicle
needs to be towed. See Recreational Vehicle
Towing 0371 or
Transporting a Disabled Vehicle 0370.
2
m(Two-Wheel Drive High) : Use for driving
on most streets and highways. The front
axle is not engaged. This setting provides
the best fuel economy.
AUTO (Automatic Four-Wheel Drive) : Use
when road surface conditions are variable.
When driving in AUTO, the front axle is
engaged, and the vehicle's power is sent to
the front and rear wheels automatically

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
240 Driving and Operating
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, or at the request of other
safety functions that utilize the EPB.
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 red parking
brake status light is off.
If the amber service parking brake warning
light is on, release the EPB by pressing and
holding the EPB switch. Continue to hold the
switch until the red parking brake status
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.
If you are towing a trailer and parking on a
hill, see Driving Characteristics and Towing
Tips 0268.
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
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 Driving
0 205.
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
244 Driving and Operating
System (ABS), StabiliTrak/Electronic Stability
Control (ESC), and Traction Control System
(TCS) performance.
For more information on off-road driving see
Off-Road Driving0208.
_Tow/Haul Mode : Use this mode
when hauling heavy loads to provide
increased performance and vehicle control.
Tow/Haul Mode adjusts the transmission
shift pattern, trailer sway, and steering.
If the vehicle is turned off with Tow/Haul
Mode active and then restarted within four
hours or less, Tow/Haul will remain active.
Otherwise, the vehicle will start in
Normal Mode.
If the vehicle has a diesel engine, exhaust
braking is automatically activated when
Tow/Haul Mode is selected. It maintains
vehicle speed by automatically
implementing a shift pattern that uses the
engine and the transmission to slow the
vehicle. The system will command
downshifts and use the turbocharger on the
engine to reduce vehicle speed when the
brake is applied. The normal tow/haul shift
pattern will return once the vehicle is on a
low grade or when the accelerator pedal is
pressed. While in the Electronic Range Select (ERS)
Mode, grade breaking is deactivated,
allowing the driver to select a range and
limiting the highest gear available. See
Manual Mode
0232.
For more information on trailer weight
specifications, see Towing Equipment 0276.
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 (Continued)
Warning (Continued)
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 0241. If a
collision alert occurs when cruise control is
activated, cruise control is disengaged. See
Forward Collision Alert (FCA) System 0257.
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 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
254 Driving and Operating
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
mounted on the rear of the cab.
Additionally, up to two accessory cameras
can be mounted to the rear and/or interior
of the trailer. See your dealer for accessory
trailer cameras. To access, touch CAMERA on
the infotainment display or shift to
R (Reverse). To return to the previous screen
when not in reverse, touch the Home or
Back buttons on the infotainment display.
Certain trailer views require a compatible
trailer profile be configured and selected.
A compatible trailer is a box type trailer
(cargo, camper, etc.) with a conventional
hitch.Available camera views:
.Front/Rear Standard View
.Front/Rear Top-Down View
.Rear Bowl View
.Front/Rear Side View
.Hitch View
.Bed View
.Rear trailer View
.Rear Side view with a available
articulation functionality
.Picture-in-Picture Side View
.Interior Trailer View
.Transparent trailer View
.Surround View
.Guidance Lines
.Hitch Guidance
Surround Vision (360 Degrees)
If equipped, the Surround Vision system can
display various views surrounding the
vehicle in the infotainment display using
four cameras mounted around the vehicle.
The front camera is in the grille under the
front emblem, the side cameras are on the
bottom of the outside mirrors, and the rear
camera is in the tailgate handle. The Surround Vision system can be accessed
by selecting CAMERA in the infotainment
display or when the vehicle is shifted into
R (Reverse). To return to the previous screen
sooner, when not in R (Reverse), press the
Home or Back button on the infotainment
system, shift into P (Park), or, while in D
(Drive), reach a vehicle speed of
approximately 12 km/h (8 mph).
Available camera views:
.Front/Rear Standard View
.Front/Rear Top-Down View
.Rear Bowl View
.Front/Rear Side View
.Hitch View
.Surround View
.Guidance Lines
.Hitch Guidance
Surround Vision
If equipped, this feature provides, additional
views to aid in trailering/towing. The Front
Vision Camera and Surround Vision cameras
are not supported. The system can show
various views in the infotainment display
using cameras mounted in and around the
vehicle and trailer. The rear camera is in the
tailgate handle and the cargo bed camera is

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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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-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
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)

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
268 Driving and Operating
Filling a Portable Fuel Container
{Warning
Never fill a portable fuel container while
it is in the vehicle. Static electricity
discharge from the container can ignite
the fuel vapor. You or others could be
badly burned and the vehicle could be
damaged. To help avoid injury to you
and others:
.Dispense fuel only into approved
containers.
.Do not fill a container while it is
inside a vehicle, in a vehicle's trunk, in
a pickup bed, or on any surface other
than the ground.
.Bring the fill nozzle in contact with
the inside of the fill opening before
operating the nozzle. Maintain contact
until filling is complete.
.Keep sparks, flames, and smoking
materials away from fuel.
.Avoid using electronic devices while
pumping fuel.(Continued)
Warning (Continued)
.When transporting a fuel container or
other material that can catch fire in
the truck bed, secure the container to
prevent spills.
Trailer Towing
General Towing Information
Only use towing equipment that has been
designed for the vehicle. Contact your dealer
or trailering dealer for assistance with
preparing the vehicle to tow a trailer. Read
the entire section before towing a trailer.
To tow a disabled vehicle, see Transporting
a Disabled Vehicle 0370. To tow the vehicle
behind another vehicle such as a motor
home, see Recreational Vehicle Towing 0371.
Driving Characteristics and
Towing Tips
{Warning
You can lose control when towing a
trailer if the correct equipment is not
used or the vehicle is not driven properly.
(Continued)
Warning (Continued)
For example, if the trailer is too heavy or
the trailer brakes are inadequate for the
load, the vehicle may not stop as
expected. You and others could be
seriously injured. The vehicle may also be
damaged, and the repairs would not be
covered by the vehicle warranty. Pull a
trailer only if all the steps in this section
have been followed. Ask your dealer for
advice and information about towing a
trailer with the vehicle.
Driving with a Trailer
Trailering is different than just driving the
vehicle by itself. Trailering affects handling,
acceleration, braking, and durability.
Successful and safe trailering requires proper
use of the correct equipment.
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:

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Driving and Operating 269
.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 800 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 Mode0234. If the transmission
downshifts too often, a lower gear may
be selected using Manual Mode. See
Manual Mode 0232.
If equipped, the following driver assistance
features should be turned off when towing
a trailer:
.Park Assist
.Automatic Parking Assist (APA)
.Reverse Automatic Braking (RAB)
If equipped, the following driver assistance
features should be turned to alert or off
when towing a trailer, unless equipped with
Super Cruise:
.Automatic Emergency Braking (AEB)
.Front Pedestrian Braking (FPB)
If equipped with Lane Change Alert (LCA),
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.
If equipped with Rear Cross Traffic Alert
(RCTA), 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.
{Warning
To prevent serious injury or death from
carbon monoxide (CO), when towing a
trailer: (Continued)
Warning (Continued)
.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 0229.
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
and attachments, safety chains, electrical
connectors, lamps, tires, and mirrors. See
Towing Equipment 0276. If the trailer has
electric brakes, start the combination