maintenance GMC SIERRA 2023 Owners Manual

2023 Sierra/Sierra Denali 2500 HD/3500 HDScan to Access
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84883882 A
Sierra/Sierra Denali
2500 HD/3500 HD
Owner’s Manual
Roadside Assistance1-800-268-6800
Canada
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GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Keys, Doors, and Windows . . . . . . . . . . . . . . . 8
Seats and Restraints . . . . . . . . . . . . . . . . . . . . 49
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Instruments and Controls . . . . . . . . . . . . . . 104
Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Infotainment System . . . . . . . . . . . . . . . . . . . 148
Climate Controls . . . . . . . . . . . . . . . . . . . . . . . 196
Driving and Operating . . . . . . . . . . . . . . . . . 203
Vehicle Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
Service and Maintenance . . . . . . . . . . . . . . . 384
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . 392
Customer Information . . . . . . . . . . . . . . . . . . 396
Reporting Safety Defects . . . . . . . . . . . . . . . 404
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
Connected Services . . . . . . . . . . . . . . . . . . . . . 413
Index . . . . . . . . . . . . . . . . . . . . . . . . . . 416
Introduction
California Proposition 65 Warning
Litho in U.S.A.
Part No. 84883882 A First Printing©2022 General Motors LLC. All Rights Reserved.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Seats and Restraints 75
Airbag System Check
The airbag system does not need regularly
scheduled maintenance or replacement.
Make sure the airbag readiness light is
working. SeeAirbag Readiness Light 0119.
Caution
If an airbag covering is damaged, opened,
or broken, the airbag may not work
properly. Do not open or break the airbag
coverings. If there are any opened or
broken airbag coverings, have the airbag
covering and/or airbag module replaced.
For the location of the airbags, see Where
Are the Airbags? 067. See your dealer
for service.
Replacing Airbag System Parts
after a Crash
{Warning
A crash can damage the airbag systems
in the vehicle. A damaged airbag system
may not properly protect you and your
passenger(s) in a crash, resulting in
serious injury or even death. To help
make sure the airbag systems are
working properly after a crash, have
them inspected and any necessary
replacements made as soon as possible.
If an airbag inflates, you will need to
replace airbag system parts. See your dealer
for service.
If the airbag readiness light stays on after
the vehicle is started or comes on when you
are driving, the airbag system may not work
properly. Have the vehicle serviced right
away. See Airbag Readiness Light 0119.
Child Restraints
Older Children
Older children who have outgrown booster
seats should wear the vehicle’s seat belts.
Refer to How to Wear Seat Belts Properly
0 59.
The manufacturer instructions that come
with the booster seat state the weight and
height limitations for that booster. Use a
booster seat with a lap-shoulder belt until
the child passes the fit test below:
.Sit all the way back on the seat. Do the
knees bend at the seat edge? If yes,
continue. If no, return to the booster seat.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Instruments and Controls 117
indicates oil pressure outside the normal
operating range, check the engine oil as
soon as possible.
SeeEngine Oil 0306.
Caution
Lack of proper engine oil maintenance
can damage the engine. Driving with the
engine oil low can also damage the
engine. The repairs would not be covered
by the vehicle warranty. Check the oil
level as soon as possible. Add oil if
required, but if the oil level is within the
operating range and the oil pressure is
still low, have the vehicle serviced.
Always follow the maintenance schedule
for changing engine oil.
If the vehicle has a diesel engine, see the
Duramax diesel supplement.
Engine Coolant Temperature
Gauge
Metric Uplevel Shown, Midlevel and Base Level Similar
English Uplevel Shown, Midlevel and Base Level Similar
This gauge measures the temperature of the
vehicle's engine coolant.
While driving under normal operating
conditions, if the needle moves into the red
warning area, the engine is too hot. Pull off
the road, shift to P (Park) or N (Neutral) and
let the engine idle.

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
Instruments and Controls 129
Digital Speedometer
The speedometer shows how fast the
vehicle is moving in either kilometers per
hour (km/h) or miles per hour (mph). The
speedometer cannot be reset.
Trip 1 or 2 and Average Fuel Economy
Turn the trip odometer reset stem until TRIP
1 or TRIP 2 displays. The current distance
traveled, in either kilometers (km) or
miles (mi), since the last reset for the trip
odometer is shown, as well as the average
fuel economy. The trip odometer and the
average fuel economy can be reset by
pressing and holding the trip odometer
reset stem.
Fuel Range
This display shows the approximate distance
the vehicle can be driven without refueling.
The fuel range estimate is based on an
average of the vehicle's fuel economy over
recent driving history and the amount of
fuel remaining in the fuel tank. Fuel range
cannot be reset.Tire Pressure
Turn the trip odometer reset stem until a
vehicle with the approximate pressures of all
four tires displays. Tire pressure is displayed
in either kilopascal (kPa) or in pounds per
square inch (psi).
See
Tire Pressure Monitor System 0343 and
Tire Pressure Monitor Operation 0344.
Remaining Oil Life
Turn the trip odometer reset stem until
REMAINING OIL LIFE displays. An estimate of
the oil's remaining useful life is shown.
REMAINING OIL LIFE 99% means 99% of the
current oil life remains.
When the remaining oil life is low, the
CHANGE ENGINE OIL SOON message will
appear on the display. The oil should be
changed as soon as possible. See Engine Oil
0 306. In addition to the engine oil life
system monitoring the oil life, additional
maintenance is recommended. See
Maintenance Schedule 0385.
The Oil Life display must be reset after each
oil change. It will not reset itself. Do not
reset the Oil Life display at any time other
than when the oil has just been changed. It cannot be reset accurately until the next
oil change. To reset, see
Engine Oil Life
System 0308.
Air Filter Life
Turn the trip odometer reset stem until AIR
FILTER LIFE displays. This displays an
estimate of the engine air filter’s remaining
useful life and the state of the system.
Engine Air Filter Life 95% means 95% of the
current air filter life remains. Messages will
display based on the engine air filter life
and the state of the system.
When the REPLACE AT NEXT OIL CHANGE
message displays, the engine air filter
should be replaced at the time of the next
oil change. When the REPLACE SOON
message displays, the engine air filter
should be replaced at the earliest
convenience.
The Air Filter Life display must be reset after
the engine air filter replacement. To reset,
see Engine Air Filter Life System 0309.
Brake Pad Life
This displays an estimate of the remaining
life of the front and rear brake pads.
Messages will display based on brake pad

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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Instruments and Controls 131
approximate average fuel economy that the
vehicle has right now, and will change as
driving conditions change.
Press the thumbwheel while this display is
active to reset the trip odometer and the
average fuel economy.
Fuel Range :Shows the approximate
distance the vehicle can be driven without
refueling. LOW will be displayed when the
vehicle is low on fuel. The fuel range
estimate is based on an average of the
vehicle's fuel economy over recent driving
history and the amount of fuel remaining in
the fuel tank.
Timer : This display can be used as a timer.
To start the timer, press the thumbwheel
while this display is active. The display will
show the amount of time that has passed
since the timer was last reset. To stop the
timer, press the thumbwheel briefly while
this display is active and the timer is
running.
Press the thumbwheel while this display is
active to reset the timer.
Oil Life : Shows an estimate of the oil's
remaining useful life. If REMAINING OIL LIFE
99% is displayed, that means 99% of the
current oil life remains. When the remaining oil life is low, the
CHANGE ENGINE OIL SOON message will
appear on the display. The oil should be
changed as soon as possible. See
Engine Oil
0 306. In addition to the engine oil life
system monitoring the oil life, additional
maintenance is recommended. See
Maintenance Schedule 0385.
The Oil Life display must be reset after each
oil change. It will not reset itself. Do not
reset the Oil Life display at any time other
than when the oil has just been changed.
It cannot be reset accurately until the next
oil change. To reset, see Engine Oil Life
System 0308.
Tire Pressure : Shows the approximate
pressures of all four tires. Tire pressure is
displayed in either kilopascal (kPa) or in
pounds per square inch (psi). If the pressure
is low, the value for that tire is shown in
amber. See Tire Pressure Monitor System
0 343 and
Tire Pressure Monitor Operation 0344.
Air Filter Life : Shows an estimate of the
engine air filter’s remaining useful life and
the state of the system. Engine Air Filter Life
95% means 95% of the current air filter life
remains. Messages will display based on the
engine air filter life and the state of the system. When the REPLACE AT NEXT OIL
CHANGE message displays, the engine air
filter should be replaced at the time of the
next oil change. When the REPLACE SOON
message displays, the engine air filter
should be replaced at the earliest
convenience.
The Air Filter Life display must be reset after
the engine air filter replacement. To reset,
see
Engine Air Filter Life System 0309.
Brake Pad Life : This displays an estimate of
the remaining life of the front and rear
brake pads. Messages will display based on
brake pad wear and the state of the system.
Reset the Brake Pad Life display after
replacing the brake pads. See Brake Pad Life
System 0317.
Fuel Economy : Displays average fuel
economy, the best fuel economy over the
selected distance, and a bar graph showing
instantaneous fuel economy.
Press the thumbwheel to change the
selected distance. Press and hold the
thumbwheel while this display is active to
reset the best fuel economy and average
fuel economy. This display can also be reset
by selecting reset in the menu.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
196 Climate Controls
Climate Controls
Climate Control Systems
Climate Control Systems . . . . . . . . . . . . . . 196
Dual Automatic Climate ControlSystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Maintenance
Passenger Compartment Air Filter . . . . . 201
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Climate Control Systems
The heating, cooling, and ventilation in the vehicle can be controlled with this system.
1. Fan Control
2. MAX Defrost
3. Air Delivery Mode Controls
4. A/C (Air Conditioning)
5. TEMP (Temperature Control)
6. Recirculation
7. Rear Window Defogger (If Equipped) or Heated Mirrors (If Equipped)9:Turn clockwise or counterclockwise to
increase or decrease the fan speed. Turn the
knob all the way counterclockwise to turn
the fan off.
TEMP : Turn clockwise or counterclockwise
to increase or decrease the temperature
inside the vehicle.
Air Delivery Mode Controls : Press
z,Y,
or
[to change the direction of the
airflow. Any combination of the three
controls can be selected. An indicator light
comes on in the selected mode button.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Climate Controls 201
The solar sensor, on top of the instrument
panel near the windshield, monitors the
solar heat.
The climate control system uses the sensor
information to adjust the temperature, fan
speed, recirculation, and air delivery mode
for best comfort.
Do not cover the sensor; otherwise the
automatic climate control system may not
work properly.
Afterblow Feature
If equipped, under certain conditions, the
fan may stay on or may turn on and off
several times after you turn off and lock the
vehicle. This is normal.
Air Vents
Use the sliding knobs on the center and side
air vents to change the direction of the
airflow.
Air vents blow warm air on the side
windows in cold weather. If Floor, Defog,
or Defrost modes are selected, a small
amount of air will come from the vents
close to the window.To close the front a/c vents, move the
sliding knobs to the full down position.
To close the rear a/c vents, move the sliding
knobs to the full inboard position.
Operation Tips
.Clear away any ice, snow, or leaves from
air inlets at the base of the windshield
that could block the flow of air into the
vehicle.
.Clear snow off the hood to improve
visibility and help decrease moisture
drawn into the vehicle.
.Keep the path under the front seats clear
of objects to help circulate the air inside
of the vehicle more effectively.
.Use of non-GM approved hood deflectors
can adversely affect the performance of
the system. Check with your dealer
before adding equipment to the outside
of the vehicle.
.Do not attach any devices to the air vent
slats. This will restrict airflow and may
cause damage to the air vents.
Maintenance
Passenger Compartment Air Filter
The filter reduces the dust, pollen, and other
airborne irritants from outside air that is
pulled into the vehicle.
The filter should be replaced as part of
routine scheduled maintenance. See
Maintenance Schedule
0385. To find out
what type of filter to use, see Maintenance
Replacement Parts 0390.
1. Open the lower glove box door
completely.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
202 Climate Controls
2. Push the dampener arm to the left untilit releases the glovebox.
3. Press the sides of the glove box doorinward and rotate the door downward to
remove.
4. Pull lever on left side of the filter doorand slide left, then remove the door.
Remove the old filter.
5. Install the new air filter.
6. Reinstall the filter door.
7. Reverse the steps to reinstall the glove box.
See your dealer if additional assistance is
needed.
Service
All vehicles have a label underhood that
identifies the refrigerant used in the vehicle.
The refrigerant system should only be
serviced by trained and certified technicians.
The air conditioning evaporator should never
be repaired or replaced by one from a
salvage vehicle. It should only be replaced
by a new evaporator to ensure proper and
safe operation.
During service, all refrigerants should be
reclaimed with proper equipment. Venting
refrigerants directly to the atmosphere is
harmful to the environment and may also
create unsafe conditions based on
inhalation, combustion, frostbite, or other
health-based concerns.
The air conditioning system requires periodic
maintenance. See Maintenance Schedule
0 385.