2024 GMC SIERRA warning

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
212 Driving and Operating
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, accessories, and cargo
should never exceed the vehicle's
capacity weight. Certification/Tire Label
Label Example
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 AxleWeight 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 may also
contain 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-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 213
Using heavier suspension components
to get added durability might not
change the weight ratings. Ask your
dealer to help load the vehicle the
right way.
{Warning
Things you put inside the vehicle can
strike and injure people in a sudden
stop or turn, or in a crash.
.Put things in the cargo area of the
vehicle. Try to spread the weight
evenly.
.Never stack heavier things, like
suitcases, inside the vehicle so
that some of them are above the
tops of the seats.
.Do not leave an unsecured child
restraint in the vehicle.
.When you carry something inside
the vehicle, secure it whenever
you can.
.Do not leave a seat folded down
unless you need to. There is also important loading
information for off-road driving in this
manual. See
“Loading the Vehicle for
Off-Road Driving“ underOff-Road
Driving 0203.
Two-Tiered Loading
Depending on the model of the pickup,
an upper load platform can be created
by positioning three or four 5 cm (2 in)
by 15 cm (6 in) wooden planks across
the width of the pickup box. The planks
must be inserted in the pickup box
depressions.
When using this upper load platform,
be sure the load is securely tied down
to prevent it from shifting. The load's
center of gravity should be positioned
in a zone over the rear axle. The zone is
located in the area between the front
of each wheel well and the rear of each
wheel well. The center of gravity height
must not extend above the top of the
pickup box flareboard. Any load that extends beyond the
vehicle's taillamp area must be properly
marked according to local laws and
regulations.
Remember not to exceed the Gross Axle
Weight Rating (GAWR) of the front or
rear axle.
Add-On Equipment
When carrying removable items, a limit
on how many people carried inside the
vehicle may be necessary. Be sure to
weigh the vehicle before buying and
installing the new equipment.
Caution
Overloading the vehicle may cause
damage. Repairs would not be covered by
the vehicle warranty. Do not overload the
vehicle.
Remember not to exceed the Gross Axle
Weight Rating (GAWR) of the front or
rear axle.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 217
near a strong radio antenna signal causing
interference to the Keyless Access system.
SeeRemote Key Operation 015.
To shift out of P (Park), the vehicle must be
on and the brake pedal must be applied.
{Warning
Turning off the vehicle while moving may
cause loss of power assist in the brake
and steering systems and disable the
airbags. While driving, only shut the
vehicle off in an emergency.
Stopping the Engine/LOCK/OFF (No Indicator
Lights) : When the vehicle is stopped, press
ENGINE START/STOP once to turn the
engine off.
If the vehicle is in P (Park), the vehicle will
turn off, and Retained Accessory Power (RAP)
will remain active. See Retained Accessory
Power (RAP) 0220.
If the vehicle is not in P (Park), the vehicle
will return to accessory mode and display
the message SHIFT TO PARK in the Driver
Information Center (DIC). When the vehicle is
shifted into P (Park), the vehicle will turn off. The vehicle may have an electric steering
column lock. The lock is activated when the
ignition is turned off and driver door is
opened. A sound may be heard as the lock
actuates or releases. The steering column
lock may not release with the wheels turned
off center. If this happens, the vehicle may
not start. Move the steering wheel from left
to right while attempting to start the
vehicle. If this does not work, the vehicle
needs service.
Unless an emergency exists, do not turn the
engine off when the vehicle is moving. This
will cause a loss of power assist in the brake
and steering systems and disable the
airbags.
If the vehicle must be shut off in an
emergency:
1. If the vehicle cannot be pulled over, and must be shut off while driving, press and
hold ENGINE START/STOP button for
longer than two seconds, or press twice
in five seconds.
2. Brake using a firm and steady pressure. Do not pump the brakes repeatedly. This
may deplete power assist, requiring
increased brake pedal force. 3. Shift the vehicle to N (Neutral). This can
be done while the vehicle is moving.
After shifting to N (Neutral), firmly apply
the brakes and steer the vehicle to a
safe location.
4. Come to a complete stop, shift to P (Park), and make sure engine is off.
The shift lever must be in P (Park) to
turn the vehicle off.
5. Set the parking brake. See Electric
Parking Brake 0234.
{Warning
Turning off the vehicle while moving may
cause loss of power assist in the brake
and steering systems and disable the
airbags. While driving, only shut the
vehicle off in an emergency.
Accessory Mode (Amber Indicator Light) :
This mode allows some electrical accessories
to be used when the engine is off.
With the vehicle off, pressing the ENGINE
START/STOP button one time without the
brake pedal applied will place the vehicle in
accessory mode.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
218 Driving and Operating
The vehicle will switch from accessory mode
to off after five minutes to prevent battery
rundown.
ON/RUN/START (Green Indicator Light) :This
mode is for driving and starting. With the
vehicle off, and the brake pedal applied,
pressing ENGINE START/STOP button once
will turn the ignition on. Once engine
cranking begins, release the button. Engine
cranking will continue until the engine
starts. See Starting the Engine 0218.
Service Mode
This power mode is available for service and
diagnostics, and to verify the proper
operation of the malfunction indicator lamp
as may be required for emission inspection
purposes. With the vehicle off, and the
brake pedal not applied, pressing and
holding the ENGINE START/STOP button for
more than five seconds will place the vehicle
in Service Mode. The instruments and audio
systems will operate as they do when the
vehicle is on, but the vehicle will not be able
to be driven. The engine will not start in
Service Mode. Press the ENGINE START/STOP
button again to turn the vehicle off.Starting the Engine
If the vehicle has a diesel engine, see the
Duramax diesel supplement.
Caution
If you add electrical parts or accessories,
you could change the way the engine
operates. Any resulting damage would
not be covered by the vehicle warranty.
See Add-On Electrical Equipment 0306.
Move the shift lever to P (Park) or
N (Neutral). To restart the engine when the
vehicle is already moving, use
N (Neutral) only.
Caution
Do not try to shift to P (Park) if the
vehicle is moving. If you do, you could
damage the transmission. Shift to P (Park)
only when the vehicle is stopped.
Starting Procedure
1. The remote key must be in the vehicle. Press ENGINE START/STOP with the brake
pedal applied. When the engine begins
cranking, let go of the button. The driver may observe a minor, and
temporary, brake pedal kickback when
starting the vehicle. This is normal.
The idle speed will go down as the
engine gets warm. Do not race the
engine immediately after starting it.
Operate the engine and transmission
gently to allow the oil to warm up and
lubricate all moving parts.
When the low fuel warning light is on
and the FUEL LEVEL LOW message is
displayed in the Driver Information
Center (DIC), press ENGINE START/STOP
to continue engine cranking.
Caution
Cranking the engine for long periods of
time, by returning the ignition to the
START position immediately after
cranking has ended, can overheat and
damage the cranking motor, and drain
the battery. Wait at least 15 seconds
between each try, to let the cranking
motor cool down.
2. If the engine does not start after five to 10 seconds, especially in very cold
weather (below −18 °C or 0 °F), it could
be flooded with too much gasoline. Try

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 219
pushing the accelerator pedal all the way
to the floor and holding it there while
pressing ENGINE START/STOP for up to a
maximum of 15 seconds. Wait at least
15 seconds between each try, to allow
the cranking motor to cool down. When
the engine starts, let go of the button
and accelerator. If the vehicle starts
briefly but then stops again, do the
same thing. This clears the extra gasoline
from the engine. Do not race the engine
immediately after starting it. Operate
the engine and transmission gently until
the oil warms up and lubricates all
moving parts.
Engine Heater
If equipped, the engine heater can provide
easier starting and better fuel economy
during engine warm-up in cold weather
conditions at or below−18 °C (0 °F). Vehicles
with an engine heater should be plugged in
at least four hours before starting. An
internal thermostat in the plug-end of the
cord may exist, which will prevent engine
heater operation at temperatures above
−18 °C (0 °F).
{Warning
Do not plug in the engine block heater
while the vehicle is parked in a garage or
under a carport. Property damage or
personal injury may result. Always park
the vehicle in a clear open area away
from buildings or structures.
To Use the Engine Heater
1. Turn off the engine.
2. Check the heater cord for damage. If it is damaged, do not use it. See your dealer
for a replacement. Inspect the cord for
damage yearly. 3. Plug the heater cord into the connector
on the vehicle.
4. Plug the cord into a grounded 110-volt AC outlet that is protected by a ground
fault detection function.
{Warning
Improper use of the heater cord or an
extension cord can damage the cord and
may result in overheating and fire.
.Plug the cord into a three-prong
electrical utility receptacle that is
protected by a ground fault detection
function. An ungrounded outlet could
cause an electric shock.
.Use a weatherproof, heavy-duty,
15 amp-rated extension cord if needed.
Failure to use the recommended
extension cord in good operating
condition, or using a damaged heater
or extension cord, could make it
overheat and cause a fire, property
damage, electric shock, and injury.
(Continued)

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
220 Driving and Operating
Warning (Continued)
.Do not operate the vehicle with the
heater cord permanently attached to
the vehicle. Possible heater cord and
thermostat damage could occur.
.While in use, do not let the heater
cord touch vehicle parts or sharp
edges. Never close the hood on the
heater cord.
.Before starting the vehicle, unplug the
cord, reattach the cover to the plug,
and securely fasten the cord. Keep the
cord away from any moving parts.
5. Before starting the engine, be sure to unplug and store the cord.
The length of time the heater should remain
plugged in depends on several factors. Ask a
dealer in the area where you will be parking
the vehicle for the best advice on this.
Retained Accessory Power (RAP)
When the vehicle is turned from on to off,
the following features (if equipped) will
continue to function for up to 10 minutes,
or until the driver door is opened. These
features will also work when the vehicle is
on or in accessory mode:
.Infotainment System
.Power Windows (during RAP this
functionality will be lost when any door
is opened)
.Sunroof (during RAP this functionality will
be lost when any door is opened)
.Auxiliary Power Outlet
.Audio System
.OnStar System
Vehicle Shutdown
Your vehicle is equipped with a sophisticated
on-board system to diagnose any potential
issues. Many of these operations can occur
after you shut off the engine. You may hear
fans, pumps, solenoids, etc. running for an
extended period after you shut down.
Shifting Into Park
{Warning
Parking on grades with poor traction such
as ice, snow, mud, or gravel may cause
the vehicle to unintentionally move and
could result in injury, death, and/or
vehicle damage. If equipped with
four-wheel drive, use AUTO or 4 (High) to
provide additional traction. Be sure to
apply the parking brake. See Electric
Parking Brake 0234 and
Four-Wheel Drive 0228.
{Warning
It can be dangerous to get out of the
vehicle if the shift lever is not fully in
P (Park) with the parking brake firmly set.
The vehicle can roll. If you have left the
engine running, the vehicle can move
suddenly. You or others could be injured.
To be sure the vehicle will not move,
even when you are on fairly level ground,
use the steps that follow. With
four-wheel drive, if the transfer case is in
N (Neutral), the vehicle will be free to
(Continued)

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 221
Warning (Continued)
roll, even if the shift lever is in P (Park).
Be sure the transfer case is in a drive
gear. If towing a trailer, seeDriving
Characteristics and Towing Tips 0276.
1. Hold the brake pedal down, then set the parking brake. See Electric Parking Brake
0 234.
2. Move the shift lever into P (Park) by pulling the shift lever toward you and
moving it up as far as it will go.
3. Be sure the transfer case, if equipped, is in a drive gear, not in N (Neutral).
4. Turn the vehicle off.
5. Take the remote key with you.
Leaving the Vehicle with the Engine
Running
{Warning
It can be dangerous to leave the vehicle
with the engine running. The vehicle
could move suddenly if the shift lever is
not fully in P (Park) with the parking
brake firmly set. (Continued)
Warning (Continued)
If you have four-wheel drive and the
transfer case is in N (Neutral), the vehicle
will be free to roll, even if the shift lever
is in P (Park). So be sure the transfer case
is in a drive gear–not in N (Neutral).
And, if you leave the vehicle with the
engine running, it could overheat and
even catch fire. You or others could be
injured. Do not leave the vehicle with the
engine running unless you have to.
If you have to leave the vehicle with the
engine running, be sure the vehicle is in
P (Park) and the parking brake is firmly set
before you leave it. After moving the shift
lever into P (Park), hold the regular brake
pedal down. Then, see if you can move the
shift lever away from P (Park) without first
pulling it toward you. If you can, it means
that the shift lever was not fully locked into
P (Park).
Torque Lock
If you are parking on a hill and you do not
shift the transmission into P (Park) properly,
the weight of the vehicle may put too much
force on the parking pawl in the transmission. You may find it difficult to pull
the shift lever out of P (Park). This is called
torque lock. To prevent torque lock, set the
parking brake and then shift into P (Park)
properly before you leave the driver seat.
When you are ready to drive, move the
shift lever out of P (Park) before you release
the parking brake.
If torque lock does occur, you may need to
have another vehicle push yours a little
uphill to take some of the pressure from the
parking pawl in the transmission. You will
then be able to pull the shift lever out of
P (Park).
Shifting out of Park
This vehicle is equipped with an electronic
shift lock release system. The system is
designed to prevent movement of the shift
lever out of P (Park), unless the brake pedal
is applied and the ignition is on or in
Service Mode.
The shift lock release is always functional
except in the case of an uncharged or low
voltage
–less than 9 volt –battery.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
222 Driving and Operating
If the vehicle has an uncharged or low
voltage battery, try charging or jump
starting the battery. SeeJump Starting -
North America 0376.
To shift out of P (Park): 1. Apply the brake pedal.
2. Release the parking brake if it is applied. See Electric Parking Brake 0234.
3. Pull the shift lever toward you, then move it to the desired position, and
release.
If the vehicle still cannot be shifted out of
P (Park): 1. Ease the pressure on, or release the shift lever.
2. While holding the brake pedal, push the shift lever all the way into P (Park).
3. Pull the shift lever toward you, then move it to the desired position, and
release.
If equipped, the Buckle to Drive feature may
prevent shifting from P (Park). See Buckle To
Drive 058.
If there is still a problem shifting, have the
vehicle serviced soon.Parking over Things That Burn
{Warning
Things that can burn could touch hot
exhaust parts under the vehicle and
ignite. Do not park over papers, leaves,
dry grass, or other things that can burn.
Extended Parking
It is best not to park with the vehicle
running. If the vehicle is left running, be
sure it will not move and there is adequate
ventilation.
See Shifting Into Park 0220 and
Engine Exhaust 0222.
If the vehicle is left parked and running with
the remote key outside the vehicle, it will
continue to run for up to 15 minutes.
If the vehicle is left parked and running with
the remote key inside the vehicle, it will
continue to run for up to 30 minutes.
The vehicle could turn off sooner if it is
parked on a hill, due to lack of
available fuel.
The timer will reset if the vehicle is taken
out of P (Park) while it is running. When the vehicle was produced, it came
with the auto-shutdown feature enabled.
If you are not the primary owner of your
vehicle, please note that this feature may
have been disabled by a previous owner.
The vehicle owners can have this feature
re-enabled at owner cost at any GM service
center.
Engine Exhaust
{
Warning
Engine exhaust contains carbon monoxide
(CO), which cannot be seen or smelled.
Exposure to CO can cause
unconsciousness and even death.
Exhaust may enter the vehicle if:
.The vehicle idles in areas with poor
ventilation (parking garages, tunnels,
deep snow that may block underbody
airflow or tail pipes).
.The exhaust smells or sounds strange
or different.
.The exhaust system leaks due to
corrosion or damage. (Continued)