GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
74 Seats and Restraints
{Warning
For up to 10 seconds after the vehicle is
turned off and the battery is
disconnected, an airbag can still inflate
during improper service. You can be
injured if you are close to an airbag
when it inflates. Avoid yellow connectors.
They are probably part of the airbag
system. Be sure to follow proper service
procedures, and make sure the person
performing work for you is qualified to
do so.
Adding Equipment to the
Airbag-Equipped Vehicle
Adding accessories that change the vehicle's
frame, bumper system, height, front end,
or side sheet metal, may keep the airbag
system from working properly.
The operation of the airbag system can also
be affected by changing, including
improperly repairing or replacing, any parts
of the following:
.Airbag system, including airbag modules,
front or side impact sensors, sensing and
diagnostic module, or airbag wiring
.Front seats, including stitching, seams,
or zippers
.Seat belts
.Steering wheel, instrument panel,
overhead console, ceiling trim, or pillar
garnish trim
.Inner door seals, including speakers
Your dealer and the service manual have
information about the location of the airbag
modules and sensors, sensing and diagnostic
module, and airbag wiring along with the
proper replacement procedures.
In addition, the vehicle has a passenger
sensing system for the front outboard
passenger position, which includes sensors
that are part of the passenger seat. The
passenger sensing system may not operate
properly if the original seat trim is replaced
with non-GM covers, upholstery, or trim; or
with GM covers, upholstery, or trim
designed for a different vehicle. Any object,
such as an aftermarket seat heater or a
comfort-enhancing pad or device, installed
under or on top of the seat fabric, could
also interfere with the operation of the
passenger sensing system. This could either
prevent proper deployment of the passenger
airbag(s) or prevent the passenger sensing system from properly turning off the
passenger airbag(s). See
Passenger Sensing
System 070.
If the vehicle has rollover roof-rail airbags,
see Different Size Tires and Wheels 0353 for
additional important information.
If a snow plow is added to the vehicle, the
airbags should still work properly. The
airbag systems were designed to work
properly under a wide range of conditions,
including snow plowing with vehicles that
have the optional snow plow prep package
(RPO VYU). Do not change or defeat the
snow plow's “tripping mechanism.” If you
do, it can damage the snow plow and the
vehicle, and may cause an airbag
deployment.
If the vehicle must be modified because you
have a disability and have questions about
whether the modifications will affect the
vehicle's airbag system, or if you have
questions about whether the airbag system
will be affected if the vehicle is modified for
any other reason, call Customer Assistance.
See Customer Assistance Offices 0398.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
126 Instruments and Controls
This light comes on when Off-Road Mode is
selected.
This light comes on when the Tow/Haul
Mode is selected.
Tire Pressure Light
If equipped with the Tire Pressure Monitor
System (TPMS), this light comes on briefly
when the vehicle is started. It provides
information about tire pressures and
the TPMS.
When the Light Is On Steady
This indicates that one or more of the tires
are significantly underinflated.
A Driver Information Center (DIC) tire
pressure message may also display. Stop as
soon as possible, and inflate the tires to the
pressure value shown on the Tire and
Loading Information label. SeeTire Pressure
0 342.
When the Light Flashes First and Then Is On
Steady
If the light flashes for about a minute and
then stays on, there may be a problem with
the TPMS. If the problem is not corrected,
the light will come on every time the
vehicle is started. See Tire Pressure Monitor
Operation 0344.Engine Oil Pressure Light (Uplevel
Cluster)
Caution
Driving the vehicle with low engine oil
pressure can damage the engine and the
repairs would not be covered by the
vehicle warranty.
If the engine oil pressure light comes on
while driving:
1. Stop in a safe location and turn off the engine.
2. Check the oil level. See Engine Oil
0 306.
3. Add oil if the oil level is below the normal operating range.
4. Restart the vehicle. If the engine oil pressure light stays on for more
than 10 seconds, turn the vehicle
back off. Do not restart the vehicle.
See your dealer for service.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
204 Driving and Operating
Trailer Towing
General Towing Information . . . . . . . . . . 268
Driving Characteristics andTowing Tips . . . . . . . . . . . . . . . . . . . . . . . . . 268
Trailer Towing . . . . . . . . . . . . . . . . . . . . . . . . . 272
Towing Equipment . . . . . . . . . . . . . . . . . . . . 276
Trailer Sway Control (TSC) . . . . . . . . . . . . . 285
Trailering App . . . . . . . . . . . . . . . . . . . . . . . . . 287
Conversions and Add-Ons
Add-On Electrical Equipment . . . . . . . . . . . 297
Adding a Snow Plow or Similar Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . 298
Pickup Conversion to Chassis Cab . . . . . 300
Driving Information
Driving for Better Fuel Economy
Driving habits can affect fuel mileage. Here
are some driving tips to get the best fuel
economy possible:
.Set the climate controls to the desired
temperature after the engine is started,
or turn them off when not required.
.Avoid fast starts and accelerate smoothly.
.Brake gradually and avoid abrupt stops.
.Avoid idling the engine for long periods
of time.
.When road and weather conditions are
appropriate, use cruise control.
.Always follow posted speed limits or
drive more slowly when conditions
require.
.Keep vehicle tires properly inflated.
.Combine several trips into a single trip.
.Replace the vehicle's tires with the same
TPC Spec number molded into the tire's
sidewall near the size.
.Follow recommended scheduled
maintenance.
Distracted Driving
Distraction comes in many forms and can
take your focus from the task of driving.
Exercise good judgment and do not let other
activities divert your attention away from
the road. Many local governments have
enacted laws regarding driver distraction.
Become familiar with the local laws in
your area.
To avoid distracted driving, keep your eyes
on the road, keep your hands on the
steering wheel, and focus your attention on
driving.
.Do not use a phone in demanding driving
situations. Use a hands-free method to
place or receive necessary phone calls.
.Watch the road. Do not read, take notes,
or look up information on phones or
other electronic devices.
.Designate a front seat passenger to
handle potential distractions.
.Become familiar with vehicle features
before driving, such as programming
favorite radio stations and adjusting
climate control and seat settings. Program
all trip information into any navigation
device prior to driving.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
208 Driving and Operating
Off-Road Driving
Four-wheel-drive vehicles can be used for
off-road driving. Vehicles without four-wheel
drive and vehicles not equipped with All
Terrain (AT) or On-Off Road (OOR) tires must
not be driven off-road except on a level,
solid surface. For contact information about
the original equipment tires, see the
warranty manual.
One of the best ways for successful off-road
driving is to control the speed.
{Warning
When driving off-road, bouncing and
quick changes in direction can easily
throw you out of position. This could
cause you to lose control and crash. You
and your passengers should always wear
seat belts.
Before Driving Off-Road
.Have all necessary maintenance and
service work completed.
.Fuel the vehicle, fill fluid levels, and check
inflation pressure in all tires, including the
spare, if equipped.
.Read all the information about
four-wheel-drive vehicles in this manual.
.Remove any underbody air deflector,
if equipped. Re-attach the air deflector
after off-road driving.
.Know the local laws that apply to off-road
driving.
To gain more ground clearance if needed, it
may be necessary to remove the front fascia
lower air dam, if equipped. However, driving
without the air dam reduces fuel economy.
Caution
Operating the vehicle for extended
periods without the front fascia lower air
dam installed can cause improper airflow
to the engine. Reattach the front fascia
air dam after off-road driving.
Loading the Vehicle for Off-Road Driving
{Warning
.Unsecured cargo on the load floor can
be tossed about when driving over
rough terrain. You or your passengers
can be struck by flying objects. Secure
the cargo properly. (Continued)
Warning (Continued)
.Keep cargo in the cargo area as far
forward and as low as possible. The
heaviest things should be on the floor,
forward of the rear axle.
.Heavy loads on the roof raise the
vehicle's center of gravity, making it
more likely to roll over. You can be
seriously or fatally injured if the
vehicle rolls over. Put heavy loads
inside the cargo area, not on the roof.
For more information about loading the
vehicle, see Vehicle Load Limits 0215 and
Tires 0337.
Environmental Concerns
.Always use established trails, roads, and
areas that have been set aside for public
off-road recreational driving and obey all
posted regulations.
.Do not damage shrubs, flowers, trees,
or grasses or disturb wildlife.
.Do not park over things that burn. See
Parking over Things That Burn 0229.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
212 Driving and Operating
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 0337.
.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-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 215
If equipped, there are recovery hooks at the
front of the vehicle. Use them if the vehicle
is stuck off-road and needs to be pulled
some place to continue driving.
Vehicle Load Limits
It is very important to know how much
weight the vehicle can carry. This
weight is called the vehicle capacity
weight and includes the weight of all
occupants, cargo, and all
nonfactory-installed options. Two labels
on the vehicle may show how much
weight it was designed to carry: the
Tire and Loading Information label and
the Certification/Tire label.
{Warning
Do not load the vehicle any heavier
than the Gross Vehicle Weight Rating
(GVWR), or either the maximum
front or rear Gross Axle Weight
Rating (GAWR). This can cause
systems to break and change the
way the vehicle handles. This could
cause loss of control and a crash.
(Continued)
Warning (Continued)
Overloading can also reduce stopping
performance, damage the tires, and
shorten the life of the vehicle.
Tire and Loading Information Label
Label Example
A vehicle-specific Tire and Loading
Information label is attached to the
center pillar (B-pillar). The Tire and
Loading Information label shows the
number of occupant seating positions (1), and the maximum vehicle
capacity weight (2) in kilograms and
pounds.
The Tire and Loading Information label
also shows the size of the original
equipment tires (3) and the
recommended cold tire inflation
pressures (4). For more information on
tires and inflation see
Tires0337 and
Tire Pressure 0342.
There is also important loading
information on the vehicle Certification/
Tire label. It may show the Gross
Vehicle Weight Rating (GVWR) and the
Gross Axle Weight Rating (GAWR) for
the front and rear axles. See
“Certification/Tire Label” later in this
section.“Steps for Determining Correct Load Limit–
1.
Locate the statement "The combined
weight of occupants and cargo
should never exceed XXX kg or
XXX lbs." on your vehicle’s placard.
2.Determine the combined weight of
the driver and passengers that will
be riding in your vehicle.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 217
Example 3
1. Vehicle Capacity Weight for Example 3= 453 kg (1,000 lb)
2. Subtract Occupant Weight @ 91 kg (200 lb) × 5 = 453 kg (1,000 lb)
3. Available Cargo Weight = 0 kg (0 lb)
Refer to the Tire and Loading
Information label for specific
information about the vehicle's capacity
weight and seating positions. The
combined weight of the driver,
passengers, and cargo should never
exceed the vehicle's capacity weight.
Certification/Tire Label
A vehicle-specific Certification/Tire label
is attached to the center pillar (B-pillar).
The label may show the size of the
vehicle's original tires and the inflation
pressures needed to obtain the gross
weight capacity of the vehicle. This is
called Gross Vehicle Weight
Rating (GVWR). The GVWR includes the
weight of the vehicle, all occupants, and
cargo.
The Certification/Tire label also may
show the maximum weights for the
front and rear axles, called Gross Axle
Weight Rating (GAWR). To determine the actual loads on the front and rear
axles, weigh the vehicle at a weigh
station. Your dealer can help with this.
Be sure to spread the load equally on
both sides of the centerline.
The Certification/Tire label also contains
important information about the Front
Axle Reserve Capacity.
{Warning
In the case of a sudden stop or
collision, things carried in the bed of
your truck could shift forward and
come into the passenger area,
injuring you and others. If you put
things in the bed of your truck, you
should make sure they are properly
secured.
Caution
Overloading the vehicle may cause
damage. Repairs would not be covered by
the vehicle warranty. Do not overload the
vehicle.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
278 Driving and Operating
MeasurementHeight Example 2500/3500 (mm)
H1 1 040
H2 1 080
H2−H1 40
(H2−H1)/4 10
H2−[(H2−H1)/4] 1 070
Tires
.Do not tow a trailer while using a
compact spare tire on the vehicle.
.Tires must be properly inflated to support
loads while towing a trailer. SeeTires
0 337 for instructions on proper tire
inflation.
Fifth-Wheel and Gooseneck Trailering
Fifth-wheel and gooseneck trailers can be
used with many pickup models. These
trailers place a larger percentage of the
weight (kingpin weight) on the tow vehicle
than conventional trailers. Make sure this
weight does not cause the vehicle to exceed
Gross Axle Weight Rating (GAWR) or Gross
Vehicle Weight Rating (GVWR). Fifth-wheel
or gooseneck kingpin weight should be
15 –25% of the trailer weight up to the maximum amount specified on the Trailering
Information Label. See
“Trailer Weight"
under Trailer Towing 0272.
The hitch should be in the pickup bed so
that its centerline is over or near the rear
axle. Take care that it is not so far forward
that it will contact the back of the cab in
sharp turns. This is especially important for
short box pickups. Trailer pin box extensions
and sliding fifth-wheel hitch assemblies may
be used. There should be at least 15 cm
(6 in) of clearance between the top of the
pickup box and the bottom of the trailer
shelf that extends over the box.
Attach the hitch to the tow vehicle frame
rails. Do not use the pickup box for support.
Two Inch Adapter Sleeve and
Retainer Pin
The 2500/3500 series vehicles are equipped
with a 2-1/2” square receiver. An adapter is
provided to allow the use of a 2” draw bar,
along with a hitch retainer pin, and
retainer clip.
Safety Chains
Always attach safety chains between the
vehicle and the trailer. Instructions about
safety chains may be provided by the hitch
manufacturer or by the trailer manufacturer.
If the trailer being towed weighs up to
2 271 kg (5,000 lb) with a factory-installed
step bumper, safety chains may be attached