2023 GMC SIERRA tow

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
96 Seats and Restraints
tether. SeeLower Anchors and Tethers
for Children (LATCH System) 082 for
more information on using the top
tether anchors.
7. Before placing a child in the child restraint, make sure it is securely held in
place. To check, grasp the child restraint
at the seat belt path and attempt to
move it side to side and back and forth.
When the child restraint is properly
installed, there should be no more than
2.5 cm (1 in) of movement.
To remove the child restraint, unbuckle the
vehicle seat belt and let it return to the
stowed position. If the top tether is attached
to a top tether anchor, disconnect it.
For outboard rear seating positions, if the
child restraint cannot be installed properly
with the head restraint in place, the head
restraint may be removed. See your dealer
for assistance with removal, and store the
removed head restraint in a secure place.
When the child restraint is removed,
reinstall the head restraint before the
seating position is used. For reinstallation
instructions, see “Head Restraint or Headrest
Removal and Reinstallation” underLower
Anchors and Tethers for Children (LATCH
System) 082.Securing Child Restraints (With
the Seat Belt in the Front
Passenger Seat)
This vehicle has airbags. A rear seat is a
safer place to secure a forward-facing child
restraint. See Where to Put the Restraint
0 80.
In addition, the vehicle has a passenger
sensing system which is designed to turn off
the front outboard passenger frontal airbag
under certain conditions. See Passenger
Sensing System 070 and
Passenger Airbag Status Indicator 0119 for
more information, including important
safety information.
Never put a rear-facing child restraint in the
front. This is because the risk to the
rear-facing child is so great, if the airbag
deploys.
{Warning
A child in a rear-facing child restraint can
be seriously injured or killed if the front
outboard passenger frontal airbag
inflates. This is because the back of the
rear-facing child restraint would be very
(Continued)
Warning (Continued)
close to the inflating airbag. A child in a
forward-facing child restraint can be
seriously injured or killed if the front
outboard passenger frontal airbag inflates
and the passenger seat is in a forward
position.
Even if the passenger sensing system has
turned off the front outboard passenger
frontal airbag, no system is fail-safe. No
one can guarantee that an airbag will not
deploy under some unusual circumstance,
even though it is turned off.
Secure rear-facing child restraints in a
rear seat, even if the airbag is off. If you
secure a forward-facing child restraint in
the front outboard passenger seat,
always move the seat as far back as it
will go. It is better to secure the child
restraint in a rear seat.
SeePassenger Sensing System 070 for
additional information.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Seats and Restraints 99
To remove the child restraint, unbuckle the
vehicle seat belt and let it return to the
stowed position.
Securing Child Restraints (With
the Seat Belt in the Center
Front Seat)
{Warning
A child in a child restraint in the center
front seat can be badly injured or killed
by the frontal airbags if they inflate.
Never secure a child restraint in the
center front seat. It is always better to
secure a child restraint in a rear seat.
Do not use child restraints in the center
front seat position.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Storage 101
Underseat Storage
There may be storage under the rear
passenger seat. Lift up on the seat bench to
access. Push the seat bench toward the floor
to close.
Rear Storage
There may be storage in the rear seat. Pull
the tab to access.
Push the storage door to close. The storage
door must be closed before installing child
restraints.
Center Console Storage
Bench Seat
Pull the strap on the side of the center
seatback to access the storage area and
cupholders. Do not use the center seatback
as a seating position when the seatback is
folded down.
To raise the seatback, push the seatback
rearward until it locks in the upright
position. Push and pull on the seatback to
make sure it is locked.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Instruments and Controls 121
Caution
If the vehicle is driven continually with
this light on, the emission control system
may not work as well, the fuel economy
may be lower, and the vehicle may not
run smoothly. This could lead to costly
repairs that might not be covered by the
vehicle warranty.
Caution
Modifications to the engine, transmission,
exhaust, intake, or fuel system, or the
use of replacement tires that do not
meet the original tire specifications, can
cause this light to come on. This could
lead to costly repairs not covered by the
vehicle warranty. This could also affect
the vehicle’s ability to pass an Emissions
Inspection/Maintenance test. See
Accessories and Modifications0302.
If the light is flashing : A malfunction has
been detected that could damage the
emission control system and increase vehicle
emissions. Diagnosis and service may be
required. To help prevent damage, reduce vehicle
speed and avoid hard accelerations and
uphill grades. If towing a trailer, reduce the
amount of cargo being hauled as soon as
possible.
If the light continues to flash, find a safe
place to park. Turn the vehicle off and wait
at least 10 seconds before restarting the
engine. If the light is still flashing, follow
the previous guidelines and see your dealer
for service as soon as possible.
If the light is on steady :
A malfunction has
been detected. Diagnosis and service may be
required.
Check the following:
.If fuel has been added to the vehicle
using the capless funnel adapter, make
sure that it has been removed. See
“Filling the Tank with a Portable Gas Can”
under Filling the Tank (Chassis Cab and
Box Delete Models) 0266 or
Filling the Tank (Pickup Models) 0265.
The diagnostic system can detect if the
adapter has been left installed in the
vehicle, allowing fuel to evaporate into
the atmosphere. A few driving trips with
the adapter removed may turn off the
light.
.Poor fuel quality can cause inefficient
engine operation and poor driveability,
which may go away once the engine is
warmed up. If this occurs, change the fuel
brand. It may require at least one full
tank of the proper fuel to turn the light
off. See Recommended Fuel 0263.
If the light remains on, see your dealer.
Emissions Inspection and Maintenance
Programs
If the vehicle requires an Emissions
Inspection/Maintenance test, the test
equipment will likely connect to the
vehicle's Data Link Connector (DLC).
The DLC is under the instrument panel to
the left of the steering wheel. Connecting
devices that are not used to perform an
Emissions Inspection/Maintenance test or to
service the vehicle may affect vehicle

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
122 Instruments and Controls
operation. SeeAdd-On Electrical Equipment
0 297. See your dealer if assistance is
needed.
The vehicle may not pass inspection if:
.The light is on when the engine is
running.
.The light does not come on when the
ignition is on while the engine is off.
.Critical emission control systems have not
been completely diagnosed. If this
happens, the vehicle would not be ready
for inspection and might require
several days of routine driving before the
system is ready for inspection. This can
happen if the 12-volt battery has recently
been replaced or run down, or if the
vehicle has been recently serviced.
See your dealer if the vehicle will not pass
or cannot be made ready for the test.
Brake System Warning Light
MetricEnglish This light comes on briefly when the vehicle
is turned on to show that the light is
working. If it does not come on then, have
it fixed so it will be ready to warn you if
there is a problem.
If the light comes on and stays on, there is
a brake problem. Have the brake system
inspected right away. This light may come
on if the brake fluid is low. See
Brake Fluid
0 318.
If the light comes on while driving, pull off
the road and stop carefully. The brake pedal
might be harder to push, or the brake pedal
may go closer to the floor. It could take
longer to stop. If the light is still on, have
the vehicle towed for service. See
Transporting a Disabled Vehicle 0370.
{Warning
The brake system might not be working
properly if the brake system warning
light is on. Driving with the brake system
warning light on can lead to a crash.
If the light is still on after the vehicle has
been pulled off the road and carefully
stopped, have the vehicle towed for
service.
Electric Parking Brake Light
MetricEnglish
This light comes on when the parking brake
is applied. If the light continues flashing
after the parking brake is released, or while
driving, there is a problem with the Electric
Parking Brake system. A message may also
display in the Driver Information
Center (DIC).
If the light does not come on, or remains
flashing, see your dealer.
Service Electric Parking Brake
Light

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
132 Instruments and Controls
Engine Hours (Hourmeter) :Shows the total
number of hours the engine has run. This
display also shows the engine idle hours.
Transmission Fluid Temperature : Shows the
temperature of the automatic transmission
fluid in either degrees Celsius (°C) or degrees
Fahrenheit (°F).
Trailer Brake : On vehicles with the
Integrated Trailer Brake Control (ITBC)
system, the trailer brake display appears in
the DIC.
TRAILER GAIN shows the trailer gain setting.
This setting can be adjusted from 0.0 to 10.0
with either a trailer connected or
disconnected.
TRAILER OUTPUT shows the power output to
the trailer any time a trailer with electric
brakes is connected. Output is displayed as a
bar graph. Dotted lines may appear in the
OUTPUT display if a trailer is not connected.
Off Road : Displays vehicle pitch and roll
information, road wheel angle, and
four-wheel drive (4WD) status.
Follow Distance : If equipped, the current
follow time to the vehicle ahead is displayed
as a time value on this page. Driver Assistance :
If equipped, shows
information for Lane Departure Warning
(LDW) and Forward Collision Alert (FCA).
Info Page Options : Scroll to choose which
info pages appear on the DIC. Press the
thumbwheel to select or deselect.
Blank Page : Shows no information.
Head-Up Display (HUD)
{Warning
If the HUD image is too bright or too
high in your field of view, it may take
you more time to see things you need to
see when it is dark outside. Be sure to
keep the HUD image dim and placed low
in your field of view.
If equipped with HUD, some information
about the operation of the vehicle is
projected onto the windshield. The image is
projected through the HUD lens on top of
the instrument panel. The information
appears as an image focused out toward the
front of the vehicle.
Caution
If you try to use the HUD image as a
parking aid, you may misjudge the
distance and damage your vehicle. Do not
use the HUD image as a parking aid.
The HUD information can be displayed in
various languages. The speedometer reading
and other numerical values can be displayed
in either English or metric units.
The language selection is changed through
the radio, and the units of measurement are
changed through the instrument cluster. See
Settings 0182 and “Options” under
Instrument Cluster 0111.
HUD Display on the Windshield

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Lighting 141
.Driving on winding or hilly roads.
The automatic high-beam headlamps may
need to be disabled if any of the above
conditions exist.
Exterior Lamps Off Reminder
A reminder chime sounds when the
headlamps or parking lamps are manually
turned on, the vehicle is turned off, and a
door is open. To disable the chime, turn the
lamps off.
Headlamp High/Low-Beam
Changer
Push the turn signal lever toward the
instrument panel to change the headlamps
from low to high beam.
Pull or push the turn signal lever to return
to low-beam headlamps.
When the high-beam headlamps are on, this
indicator light on the instrument cluster will
also be on.
Flash-to-Pass
This feature lets you use the high-beam
headlamps to signal a driver in front of you
that you want to pass. It works even if the
headlamps are in the automatic position.
To use it, pull the turn signal lever toward
you, then release it.
If the headlamps are in the automatic
position or on low beam, the high-beam
headlamps will turn on. Depending on the
type of headlamp, they will either turn off
after a short duration or stay on as long as
you hold the lever toward you. The
high-beam indicator on the instrument
cluster will come on. Release the lever to
return to normal operation.
Daytime Running Lamps (DRL)
DRL can make it easier for others to see the
front of the vehicle during the day. Fully
functional DRL are required on all vehicles
first sold in Canada.
The DRL system comes on when the
following conditions are met:
.The ignition is on.
.The exterior lamp control is in AUTO.
.The light sensor determines it is daytime. When the DRL system is on, only the DRL
are on. The taillamps, sidemarker lamps,
instrument panel lights, and other lamps
will not turn on.
When it begins to get dark, the automatic
headlamp system switches from DRL to the
headlamps.
To turn off the DRL, turn the exterior lamp
control to
Oand then release. For vehicles
first sold in Canada, off will only work when
the vehicle is parked.
Automatic Headlamp System
When the exterior lamp control is set to
AUTO and it is dark enough outside, the
headlamps come on automatically.