2023 GMC SIERRA ECU

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
370 Vehicle Care
8. Do not let the other end touch metal.Connect it to the good battery
positive (+) terminal. Use a remote
positive (+) terminal if the vehicle
has one.
9. Connect one end of the black negative (–) cable to the good battery negative
(–) terminal. Use a remote negative (–)
terminal if the vehicle has one.
Do not let the other end touch anything
until the next step.
10. Connect the other end of the negative (–) cable to the discharged battery
negative (–) grounding point.
11. Start the vehicle with the good battery and run the engine for a while.
12. Try to start the vehicle that had the dead battery. If it will not start after a
few tries, it probably needs service.
Jumper Cable Removal
Reverse the sequence exactly when
removing the jumper cables.
After starting the disabled vehicle and
removing the jumper cables, allow it to idle
for several minutes.Towing the Vehicle
Transporting a Disabled Vehicle
Caution
Incorrectly transporting a disabled vehicle
may cause damage to the vehicle. Use
proper tire straps to secure the vehicle to
the flatbed tow truck. Do not strap or
hook to any frame, underbody,
or suspension component not specified
below. Do not move vehicles with drive
axle tires on the ground. Damage is not
covered by the vehicle warranty.
Caution
The vehicle may be equipped with an
electric parking brake and/or a
mechanical transmission range select
shifter. In the event of a loss of 12-volt
battery power, the electric parking brake
cannot be released, and the vehicle
cannot be shifted to N (Neutral). Tire
skates or dollies must be used under the
non-rolling tires to prevent damage while
(Continued)
Caution (Continued)
loading/unloading the vehicle. Dragging
the vehicle will cause damage not
covered by the vehicle warranty.
Caution
The vehicle may be equipped with a tow
eye. Improper use of the tow eye may
cause damage to the vehicle and is not
covered by the vehicle warranty.
If equipped, use the tow eye to load the
vehicle onto a flatbed tow truck from a
flat road surface, or to move the vehicle
a very short distance at a walking pace.
The tow eye is not designed for off-road
recovery. The vehicle must be in
N (Neutral) with the electric parking
brake released when using the tow eye.
Contact a professional towing service if the
disabled vehicle must be transported. GM
recommends a flatbed tow truck to
transport a disabled vehicle. Use ramps to
help reduce approach angles, if necessary.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
372 Vehicle Care
Caution
Use of a shield mounted in front of the
vehicle grille could restrict airflow and
cause damage to the transmission. The
repairs would not be covered by the
vehicle warranty. If using a shield, only
use one that attaches to the towing
vehicle.
Dinghy Towing (Two-Wheel-Drive
Vehicles and Vehicles with a
Single-Speed Transfer Case)
Caution
If a vehicle with two-wheel drive or a
single-speed transfer case is towed with
all four wheels on the ground, the
drivetrain components could be damaged.
The repairs would not be covered by the
vehicle warranty.
Two-wheel-drive vehicles and vehicles with a
single-speed transfer case should not be
towed with all four wheels on the ground.
Dinghy Towing (Vehicles with a
Two-Speed Transfer Case)
Only dinghy tow four-wheel-drive vehicles
with a two-speed transfer case that have an
N (Neutral) and a 4
n(Four-Wheel Drive
Low) setting.
{Warning
Shifting a four-wheel-drive vehicle's
transfer case into N (Neutral) can allow
the vehicle to move even if the
transmission is in P (Park). You or others
could be injured. Set the parking brake
and use wheel blocks before shifting the
transfer case to N (Neutral).
To dinghy tow: 1. Position the vehicle being towed behind the tow vehicle, facing forward and on a
level surface.
2. Securely attach the vehicle being towed to the tow vehicle.
3. Apply the parking brake and start the engine.
4. Shift the transfer case to N (Neutral). See “Shifting into N (Neutral)” under
Four-Wheel Drive 0234.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 373
5. With the engine running, release theparking brake and verify that the
transfer case is in N (Neutral) by shifting
the transmission to D (Drive) and then to
R (Reverse). There should be no
movement while shifting the
transmission.
6. Shift the transmission to D (Drive).
7. If equipped with an ignition key, turn the ignition to ACC/ACCESSORY.
If equipped with Keyless Access, turn the
engine off. Disregard the Shift to P (Park)
DIC message. See Ignition Positions (Key
Access) 0221 or
Ignition Positions (Keyless Access) 0223.
{Warning
To avoid death, serious injury,
or property damage, before dinghy
towing the vehicle, always disconnect and
secure the negative battery cable and
cover the negative battery post and cable
with a non-conductive material. If the
battery is left connected or the battery
cable contacts the post, the Electric
Parking Brake may activate during
towing, which could cause a crash. 8. Disconnect the negative (–) battery
cable. See “Negative Battery Cable
Disconnection” inBattery - North
America 0319.
9. Shift the transmission to P (Park).
Caution
If the steering column is locked, vehicle
damage may occur.
10. Move the steering wheel to make sure the steering column is unlocked.
11. If the vehicle has an ignition key, keep it in the towed vehicle in ACC/ACCESSORY
to prevent the steering column from
locking. If the vehicle is equipped with
Keyless Access, keep the RKE transmitter
outside of the vehicle and manually lock
the doors. Access the vehicle by using
the key in the door lock. See Door Locks
0 23.
Disconnecting the Towed Vehicle
Before disconnecting from the tow vehicle: 1. Park on a level surface. Secure the vehicle with wheel blocks.
2. Re-connect the negative (–) battery. See Battery - North America 0319. 3. Turn on the ignition with the engine off.
For vehicles with a key, turn the ignition
to ON/RUN with the engine off. If the
vehicle is equipped with Keyless Access,
with your foot off the brake pedal, press
and hold ENGINE START/STOP for
five seconds until the green light comes
on in the button. See Ignition Positions
(Key Access) 0221 or
Ignition Positions (Keyless Access) 0223.
4. Set the parking brake. See Electric
Parking Brake 0239.
5. Disconnect from the tow vehicle.
6. Shift the transmission to N (Neutral).
7. Shift the transfer case to 2
m(Two-Wheel
Drive High). When the shift to 2
m
(Two-Wheel Drive High) is complete, the
light in the instrument cluster will stop
flashing and stay lit. See
Four-Wheel-Drive Light 0123.
8. Start the engine. Check that the vehicle is in 2
m(Two-Wheel Drive High) by
starting the engine and shifting the
transmission to D (Drive) and then to
R (Reverse). There should be movement
of the vehicle while shifting.
9. Shift the transmission to P (Park) and turn off the ignition.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 383
.Use the floor mat/liner insert with the
correct side up. Do not turn it over.
.Do not place anything on top of the
driver side floor mat/liner.
.Use only a single floor mat/liner on the
driver side.
.Do not place one floor mat/liner on top
of another.
Removing and Replacing the Floor Mats/
Liners
Pull up on the rear of the driver side floor
mat/liner to unlock each retainer and
remove.
Reinstall by lining up the floor mat/liner
retainer openings over the carpet retainers
and snapping into position.
Make sure the floor mat/liner is properly
secured in place.
Verify the floor mat/liner does not interfere
with the pedals.
Removing and Replacing the Floor Liner
Inserts
Pull up on the edge of the driver side floor
liner insert to unlock each button clip and
remove.
Reinstall by lining up the floor liner insert
button clips over the liner retainers and
snapping into position.Make sure the floor liner insert is properly
secure in place using all button clips.
Verify the floor liner insert does not
interfere with the pedals.
Cleaning Rubber Floor Mats (All-Weather
Mats and Floor Liners)
See
“Vinyl/Rubber” underInterior Care 0379
for important cleaning information.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
386 Service and Maintenance
1 000 km/600 mi. If driven under the best
conditions, the engine oil life system may
not indicate the need for vehicle service
for up to a year. The engine oil and filter
must be changed at least once a year and
the oil life system must be reset. Your
trained dealer technician can perform this
work. If the engine oil life system is reset
accidentally, service the vehicle within
5 000 km/3,000 mi since the last service.
Reset the oil life system when the oil is
changed. SeeEngine Oil Life System
0 308.
.When the REPLACE AT NEXT OIL CHANGE
message displays, the engine air filter
should be replaced at the next engine oil
change. When the REPLACE ENGINE AIR
FILTER SOON message displays, the
engine air filter should be replaced at the
earliest convenience. Reset the engine air
filter life system after the engine air filter
is replaced. See Engine Air Filter Life
System 0309.
Every 36 000 km (22,500 mi)
.Replace passenger compartment air filter.
Or every 24 months, whichever comes
first. More frequent passenger
compartment air filter replacement may
be needed if driving in areas with heavy traffic, poor air quality, high dust levels,
or environmental allergens. Passenger
compartment air filter replacement may
also be needed if there is reduced airflow,
window fogging, or odors. Your GM
dealer can help determine when to
replace the filter.
Every 80 500 km (50,000 mi)
.Change transfer case fluid, if equipped
with 4WD. Do not directly power wash
the transfer case and/or front/rear axle
output seals. High pressure water can
overcome the seals and contaminate the
transfer case fluid. Contaminated fluid will
decrease the life of the transfer case and/
or axles and should be replaced.
Every 156 000 km (97,500 mi)
.Replace spark plugs. Inspect spark plug
wires and/or boots.
Every 161 000 km (100,000 mi)
.Replace hood and/or body lift support gas
struts. Or every 10 years, whichever
comes first. See Gas Strut(s)0324.
Every 240 000 km (150,000 mi)
.Drain and fill engine cooling system. Or
every six years, whichever comes first.
See Cooling System 0311.
Severe Conditions Requiring More
Frequent Maintenance*
.Public service, military, or commercial use
vehicles to include the following:
‐ Ambulances, police cars, and
emergency rescue vehicles.
‐ Civilian vehicles such as light duty
pick-up trucks, SUVs, and passenger
cars that are used in military
applications.
‐ Recovery vehicles such as tow trucks
and flatbed single vehicle carriers or
any vehicle that is consistently used in
towing trailers or other loads.
‐ High use commercial vehicles such as
courier delivery vehicles, private
security patrol vehicles, or any vehicles
that operate on a 24–hour basis.
‐ Any vehicle consistently operated in a
high sand or dust environment such as
those used on oil pipelines and similar
applications.
.Vehicles that are regularly used for short
trips of 6 km (4 mi) or less.
The oil life indicator will show you when
to change the oil and filter. Under severe
conditions the indicator may come on
before 12 000 km (7,500 mi).

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
388 Service and Maintenance
Systems, Fluids, and Visible Leak
Inspection
.Engine oil
.Transmission
.Drive axle
.Transfer case
.Engine cooling system
.Power steering, if equipped
.Fuel system
.Windshield washer fluid
Tire Inspection
.Tire pressure, tread depth, and wear
.Rotation, if applicable
.Alignment check, optional
.Reset tire pressure monitor
.Check tire sealant expiration date,
if equipped
.Check spare tire, if equipped
Brakes
.Check brake system
Visible and Functional Inspections
.Seat belt components
.Exhaust system
.Accelerator pedal
.Passenger compartment air filter,
if equipped
.Engine air filter
.Hoses
.Belts
.Shocks and struts
.Steering components
.Axle boots or driveshaft and u-joints
.Compartment lift struts, if equipped
.Floor mats secured, no interference with
pedals
.Horn
.Ignition lock, if equipped
.Starter switch
.Evaporative control system
Lubricate
.Chassis components
Special Application Services
.Vehicles with Dual Wheels: Check dual
wheel nut torque at 160, 1 600, and
10 000 km (100, 1,000, and 6,000 mi) of
driving. Repeat this service whenever a
tire/wheel is serviced or removed.
.Severe Commercial Use Vehicles Only:
Lubricate chassis components every oil
change.
.Have underbody flushing service
performed. See “Underbody Maintenance”
in Exterior Care 0374.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
396 Customer Information
Customer Information
Customer Information
Customer Satisfaction Procedure . . . . . . 396
Customer Assistance Offices . . . . . . . . . . . 398
Customer Assistance for Text Telephone(TTY) Users . . . . . . . . . . . . . . . . . . . . . . . . . . 398
Online Account . . . . . . . . . . . . . . . . . . . . . . . . 398
GM Mobility Reimbursement Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
Roadside Assistance Program . . . . . . . . . . 399
Scheduling Service Appointments . . . . . . 401
Courtesy Transportation Program . . . . . 401
Collision Damage Repair . . . . . . . . . . . . . . 402
Publication Ordering Information . . . . . 404
Radio Frequency Statement . . . . . . . . . . . 404
Reporting Safety Defects
Reporting Safety Defects to the United States Government . . . . . . . . . . . . . . . . . . 404
Reporting Safety Defects to the Canadian Government . . . . . . . . . . . . . . . 405
Reporting Safety Defects to General Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405
Vehicle Data Recording and Privacy
Vehicle Data Recording and Privacy . . . 405
Cybersecurity . . . . . . . . . . . . . . . . . . . . . . . . . 406
Event Data Recorders . . . . . . . . . . . . . . . . . 406
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
Infotainment System . . . . . . . . . . . . . . . . . . 407Customer Information
Customer Satisfaction Procedure
Your satisfaction and goodwill are important
to your dealer and to GMC. Normally, any
concerns with the sales transaction or the
operation of the vehicle will be resolved by
your dealer's sales or service departments.
Sometimes, however, despite the best
intentions of all concerned,
misunderstandings can occur. If your concern
has not been resolved to your satisfaction,
the following steps should be taken:
STEP ONE : Discuss your concern with a
member of dealership management.
Normally, concerns can be quickly resolved
at that level. If the matter has already been
reviewed with the sales, service, or parts
manager, contact the owner of your
dealership or the general manager.
STEP TWO : If after contacting a member of
dealership management, it appears your
concern cannot be resolved by your
dealership without further help, in the U.S.,
call 1-800-462-8782. In Canada, call General
Motors of Canada Customer Care Centre at
1-800-263-3777 (English), or 1-800-263-7854
(French).

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
400 Customer Information
Coverage
Services are provided for the duration of the
vehicle's powertrain warranty.
In the U.S., anyone driving the vehicle is
covered. In Canada, a person driving the
vehicle without permission from the owner
is not covered.
Roadside Assistance is not a part of the New
Vehicle Limited Warranty. General Motors
North America and GMC reserve the right to
make any changes or discontinue the
Roadside Assistance program at any time
without notification.
General Motors North America and GMC
reserve the right to limit services or
payment to an owner or driver if they
decide the claims are made too often, or the
same type of claim is made many times.
Services Provided
.Emergency Fuel Delivery:Delivery of
enough fuel for the vehicle to get to the
nearest service station.
.Lock-Out Service: Service to unlock the
vehicle if you are locked out. A remote
unlock may be available if you have OnStar. For security reasons, the driver
must present identification before this
service is given.
.Emergency Tow from a Public Road or
Highway:
Tow to the nearest GMC dealer
for warranty service, or if the vehicle was
in a crash and cannot be driven.
Assistance is not given when the vehicle
is stuck in the sand, mud, or snow.
.Flat Tire Change: Service to change a flat
tire with the spare tire. The spare tire,
if equipped, must be in good condition
and properly inflated. It is the owner's
responsibility for the repair or
replacement of the tire if it is not covered
by the warranty.
.Battery Jump Start: Service to jump start
a dead battery.
.Trip Interruption Benefits and Assistance:
If your trip is interrupted due to a
warranty event, incidental expenses may
be reimbursed within the Powertrain
warranty period. Items considered are
reasonable and customary hotel, meals,
rental car, or a vehicle being delivered
back to the customer, up to 500 miles.
Services Not Included in Roadside
Assistance
.Impound towing caused by violation of
any laws
.Legal fines
.Mounting, dismounting, or changing of
snow tires, chains, or other traction
devices
Service is not provided if a vehicle is in an
area that is not accessible to the service
vehicle or is not a regularly traveled or
maintained public road, which includes ice
and winter roads. Off-road use is not
covered.
Services Specific to Canadian-Purchased
Vehicles
.Fuel Delivery: Reimbursement is up to 7 L.
Diesel fuel delivery may be restricted.
Propane and other fuels are not provided
through this service.
.Lock-Out Service: Vehicle registration is
required.
.Trip Interruption Benefits and Assistance:
Must be over 150 km from where your
trip was started to qualify.
Pre-authorization, original detailed
receipts, and a copy of the repair orders
are required. Once authorization has been