adjust GMC SIERRA 2021 Manual PDF

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 309
2. Touch Import Profile on the pop-up.
3. Select a trailer profile from the list.
4. Touch IMPORT.
A pop-up will indicate the import was
successful. Touch OK to return to the trailer
list and select the trailer profile. The Tow/
Haul Mode reminder, Brake Gain Setting and
Trailer Tire Pressure sensor learning,
if equipped, do not import.
Trailer Feature Setup
Tow/Haul Mode Reminder
To turn the Tow/Haul Mode Reminder
setting on, touch Yes. To turn it off,
touch No.
Trailer Tire Pressure Setup
If the Trailer Tire Pressure Monitoring
System (TTPMS) is detected, touch the Tire
Pressure Monitoring icon to set up tire
pressure monitoring. Touch Yes to set up
the sensors or touch No to return to the
previous screen.
The trailer tire pressure sensors can transmit
up to 7 m (23 feet) from the hitch receiver of
the vehicle. A trailer must be electrically connected to
the vehicle before starting the
sensor-to-vehicle learn process.
After selecting Start from the Learn Sensors
screen, use the Tool Method or the Manual
Method (described below) to learn each tire
sensor, during which the current tire number
will be highlighted.
Each sensor has a minimum of two minutes
to learn, shown by a timer. After a sensor is
learned, a checkmark appears next to the
tire, the vehicle horn will sound, the
vehicle’s brake lamps will flash, and all
working trailer lamps will flash. It then
moves to the next sensor.
To cancel the process touch Stop.
The recommended tire pressure must be
entered for the trailer tires. This allows the
vehicle to alert when the tire pressure is
high or low.
TTPMS must learn the location of the
installed tire sensors to show correct air
pressure and temperature for each tire. To
set up, use one of the following options or
see a tire or trailer dealer for service. The
learning process must be repeated when thetrailer tires are rotated or replaced. See
“Editing a Trailer Profile”
later in this section
for tire pressure sensor relearn information.
Tool Method: A TTPMS activation tool can
be purchased separately to learn the sensor
locations.
Manual Method: Without the tool, the air
pressure can be increased or decreased in
each tire for 10 seconds. Do not exceed the
maximum inflation pressure found on the
tire sidewalls. Make sure to re-adjust tire
pressure to the recommended level when
the process is complete.
Sensor Learning Steps
To complete the sensor-to-vehicle learn
process:
1. Touch Start on the Learn Sensors screen. The horn chirps twice and the Learning
Active screen appears on the
infotainment display.
2. Start with the driver side front trailer tire.
3. Activate the tool near the valve stem or adjust the air pressure of this tire until
the horn chirps and all working vehicle
and trailer lights flash.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 315
No Trailer Connected
When there is no trailer connected, Trailer
Profiles cannot be activated but most
options can be edited.
Trailer Brake Gain Memory
The system can memorize the brake gain
setting of a Trailer Profile or a Guest Trailer
Profile. When a Trailer Profile or Guest
Trailer Profile is selected, and a brake gain
setting is set for that Trailer Profile, a quick
notice will appear to indicate that the
system has recalled that profile’s brake gain
setting.
If a Trailer Profile is already active and the
brake gain setting had been set for that
Trailer Profile, the quick notice will trigger
whenever the ignition is turned on.
If there was an error in setting the brake
gain for a Trailer Profile, there will be a
notification. This pop-up will not appear if
the Guest Trailer Profile is active or if there
is no trailer connected.
Trailer brake gain should be set for a specific
trailering condition and must be adjusted
anytime vehicle loading, trailer loading,
or road surface conditions change.Editing a Trailer Profile
Trailer Profile View
Touch to edit any of the following options
in the Trailer Profile view:
.Trailer Name
.Towing Assistance Setup, if equipped
.Tire Pressure Setup, if equipped
.Trailer Maintenance
.Edit Mileage
.Reset Average Fuel Economy
Touch Save to save the new value to the
Trailer Profile. Touching Back will still save
the previously entered information.
Trailer Name
Touch to edit the Trailer Profile’s name. Use
at least one character and no spaces.
Touch Save.
Towing Assistance Setup
A trailer should be connected to complete
this portion of profile setup.
Touch to set up towing assistance features
for the Trailer Profile. See "Towing
Assistance" for details on the setup. Tire Pressure Setup
Touch to set up the Trailer Tire Pressure
Monitoring System (TTPMS) for the Trailer
Profile. See
“Trailer Tire Pressure Setup”
previously in this section for details on the
setup. Also, touch Tire Pressure Setup if the
trailer tires were rotated or if the tire
pressure sensors in the tires were replaced
for this Trailer Profile. The vehicle will need
to relearn the tire sensors and their
locations.
If TTPMS had been set up previously, the
Select Number of Sensors screen will appear
after touching Tire Pressure Setup. If the
number of sensors has changed, select the
number and touch Next.
If a new number of sensors is selected, the
Relearn Sensors pop-up will appear. Touch
Cancel to go back or touch Relearn to
overwrite the current sensors and begin the
relearning process. See “Trailer Tire Pressure
Setup” previously in this section.
If number of sensors has not changed, touch
Next and the Learn sensors screen will
appear.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
316 Driving and Operating
On the Learn Sensors screen. Touch Relearn
to overwrite the current sensors and begin
the relearning process. See“Trailer Tire
Pressure Setup” previously in this section.
On the Learn Sensors screen, touch Next to
go to the Edit Recommended Tire Pressure
screen.
On the Edit Recommended Tire Pressure
screen, touch a number on the keypad to
change the
Recommended Tire Pressure for the trailer’s
tires. This will change the number at which
the vehicle displays alerts related to trailer
tire pressure. Touch Done to return to the
Trailer Profile view.
Trailer Maintenance
Touch to view a list of maintenance
reminders for the Trailer Profile.
Touch a reminder to view, reset, delete,
or edit it.
Reset Reminder
Touch Maintenance Complete in the
reminder view to reset the reminder. On the
pop-up, touch Reset to reset the time and
mileage values for the reminder. Touch
Cancel to return to the previous view and
nothing will change. Edit Reminder
Touch to edit the mileage or time settings
for the reminder. Touch Save to save the
new settings to the Trailer Profile.
Delete Reminder
Touch to delete the maintenance reminder.
On the pop-up, touch Delete to delete the
reminder or touch Cancel to return to the
previous view and nothing will change.
New Maintenance Reminder
Touch + New Maintenance Reminder to set
up a new reminder. Suggested reminders
that were previously set will have
checkmarks next to them. Suggested
reminders that have not been set will have
empty boxes next to them. The maximum
number of reminders is 50.
Edit Mileage
Touch to edit the Trailer Profile’s mileage.
Touch Reset to reset trailer mileage to zero,
or enter a new value and touch Save.
Touching back will return to the Trailer
Profile view.
Effect on Maintenance Reminders
If the mileage is reset or changed, and
mileage has already accumulated, any
maintenance reminders that have been set
up will be adjusted accordingly.
Reset Average Fuel Economy
Touch to reset the average fuel economy for
the Trailer Profile. Touch Reset to change,
or touch Cancel to go back to the
previous view.
Delete/Remove Trailer
Touch to remove the Trailer Profile and all
of its settings.
On the pop-up, touch Remove to remove the
Trailer Profile from the vehicle. Touch Cancel
to dismiss the pop-up and return to the
previous view.
Remove will be displayed if there is a
connected OnStar plan active with the
vehicle. Removing a trailer profile will
remove the profile from the vehicle but the
profile will still be associated with the user
account. However, if there is not a
connected OnStar plan then the remove
button will read DELETE and the profile will
be deleted permanently.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 317
Settings View
Within the Trailering App, touch the Settings
tab to modify the following settings:
.Trailer Detection Alert
.Maintenance Alerts
.Theft Alert
.Tow/Haul Mode Reminder
.Trailer Length Indicator
Trailer Detection Alert
The Trailer Detection Alert setting will be on
by default. Turn it off to disable the Trailer
Detection pop-up from displaying when a
trailer is connected. The Guest Trailer Profile
will become the active Trailer Profile, unless
another Trailer Profile is selected manually
through the Trailering App. If this setting is
disabled while a Custom Trailer Profile is
active, that Trailer Profile will remain the
active profile until the trailer is
disconnected.
Maintenance Alerts
Touch Maintenance Alerts to view the
Maintenance Alerts settings page. These
alerts are based on the Trailer Profile, so the
settings for each Trailer Profile must beturned on or off. Touch a profile to view
more information or adjust the setting for
that profile.
The setting will be on by default for each
profile. All Maintenance Alerts for that active
Trailer Profile will be received.
Turn a setting off to not receive any of the
Maintenance Alerts when that Trailer Profile
is active.
Theft Alert
A theft alert can be set if a trailer is
connected and the alert is enabled. When
the trailer is disconnected and the vehicle is
off, an alarm will sound.
Touch Theft Alert in Settings to view the
Theft Alert settings page. These alerts are
based on the Trailer Profile, so the settings
for each Trailer Profile must be turned on or
off. Touch a profile to view more
information or adjust the setting for that
profile.
This setting will be off by default for each
Trailer Profile, including the Guest Trailer
Profile.
A smartphone will receive a notification that
the trailer related to the selected Trailer
Profile is disconnected from the vehicle,
if the setting is on for the active Trailer
Profile, the vehicle has an OnStar or
connected service plan and the smartphone
number has been added to the account for
this notification.
If the setting is turned off for a given Trailer
Profile, the smartphone will not receive this
security notification even if the Trailer
Profile is active.
Tow/Haul Mode Reminder
This is a reminder to turn on the Tow/Haul
Mode when towing a trailer. See
Tow/Haul
Mode 0242.
Touch Tow/Haul Mode Reminder in Settings
to view the Tow/Haul Mode Reminder
settings page. These alerts are based on the
Trailer Profile, so the settings for each
Trailer Profile must be turned on or off.
Touch a profile to view more information or
to adjust the setting for that profile.
This setting will default to OFF for each
Trailer Profile, including the Guest Trailer
Profile.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
350 Vehicle Care
Headlamp Aiming
Front Headlamp Aiming
Headlamp aim has been preset and should
need no further adjustment.
If the vehicle is damaged in a crash, the
headlamp aim may be affected.
If adjustment to the headlamps is necessary,
see your dealer.
Bulb Replacement
For the proper type of replacement bulbs,
or any bulb changing procedure not listed in
this section, contact your dealer.
Caution
Do not replace incandescent bulbs with
aftermarket LED replacement bulbs. This
can cause damage to the vehicle electrical
system.
Halogen Bulbs
{Warning
Halogen bulbs have pressurized gas inside
and can burst if you drop or scratch the
bulb. You or others could be injured. Be
sure to read and follow the instructions
on the bulb package.
LED Lighting
This vehicle has several LED lamps. For
replacement of any LED lighting assembly,
contact your dealer.
Headlamps, Front Turn Signal,
Sidemarker, and Parking Lamps
Base Level Headlamp Assembly
1. Turn Signal Lamps
Headlamp Replacement
See your dealer for headlamp replacement.
Turn Signal Lamp Replacement
Base Level1. Open the hood.
2. Turn the bulb socket counterclockwise to remove it from the headlamp assembly
and pull it straight out.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
368 Vehicle Care
comfort. Never load the vehicle with
more weight than it was designed to
carry.
When to Check
Check the pressure of the tires once a
month or more.
Do not forget the spare tire, if the
vehicle has one. SeeFull-Size Spare Tire
0 390 for additional information.
How to Check
Use a good quality pocket-type gauge
to check tire pressure. Proper tire
inflation cannot be determined by
looking at the tire. Check the tire
inflation pressure when the tires are
cold, meaning the vehicle has not been
driven for at least three hours or no
more than 1.6 km (1 mi).
Remove the valve cap from the tire
valve stem. Press the tire gauge firmly
onto the valve to get a pressure
measurement. If the cold tire inflation
pressure matches the recommended
pressure on the Tire and Loading
Information label, no further adjustment is necessary. If the inflation pressure is
low, add air until the recommended
pressure is reached. If the inflation
pressure is high, press on the metal
stem in the center of the tire valve to
release air.
Re-check the tire pressure with the tire
gauge.
Put the valve caps back on the valve
stems to keep out dirt and moisture.
Use only valve caps designed for the
vehicle by GM. TPMS sensors could be
damaged and would not be covered by
the vehicle warranty.
Tire Pressure Monitor System
The Tire Pressure Monitor System (TPMS)
uses radio and sensor technology to check
tire pressure levels. The TPMS sensors
monitor the air pressure in your tires and
transmit tire pressure readings to a receiver
located in the vehicle.
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure
recommended by the vehicle manufacturer
on the vehicle placard or tire inflation pressure label. (If your vehicle has tires of a
different size than the size indicated on the
vehicle placard or tire inflation pressure
label, you should determine the proper tire
inflation pressure for those tires.)
As an added safety feature, your vehicle has
been equipped with a tire pressure
monitoring system (TPMS) that illuminates a
low tire pressure telltale when one or more
of your tires is significantly under-inflated.
Accordingly, when the low tire pressure
telltale illuminates, you should stop and
check your tires as soon as possible, and
inflate them to the proper pressure. Driving
on a significantly under-inflated tire causes
the tire to overheat and can lead to tire
failure. Under-inflation also reduces fuel
efficiency and tire tread life, and may affect
the vehicle's handling and stopping ability.
Please note that the TPMS is not a
substitute for proper tire maintenance, and
it is the driver's responsibility to maintain
correct tire pressure, even if under-inflation
has not reached the level to trigger
illumination of the TPMS low tire pressure
telltale.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate when
the system is not operating properly. The

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
374 Vehicle Care
Replace the tire if:
.The indicators at three or more
places around the tire can be seen.
.There is cord or fabric showing
through the tire's rubber.
.The tread or sidewall is cracked, cut,
or snagged deep enough to show
cord or fabric.
.The tire has a bump, bulge, or split.
.The tire has a puncture, cut, or other
damage that cannot be repaired well
because of the size or location of the
damage.
Tire Rotation
Tires should be rotated every 12 000 km
(7,500 mi). SeeMaintenance Schedule
0 409.
Tires are rotated to achieve a more
uniform wear for all tires. The first
rotation is the most important.
Anytime unusual wear is noticed, rotate
the tires as soon as possible, check for
proper tire inflation pressure, and check
for damaged tires or wheels. If the unusual wear continues after the
rotation, check the wheel alignment.
See
When It Is Time for New Tires 0375
and
Wheel Replacement 0378.Use this rotation pattern when rotating
the tires.
Do not include the spare tire in the tire
rotation.
Adjust the front and rear tires to the
recommended inflation pressure on the
Tire and Loading Information label after the tires have been rotated. See
Tire
Pressure 0367 and
Vehicle Load Limits 0222.
Reset the Tire Pressure Monitor System.
See Tire Pressure Monitor Operation
0 369.
Check that all wheel nuts are properly
tightened. See “Wheel Nut Torque”
under Capacities and Specifications
0 424.
{Warning
Rust or dirt on a wheel, or on the
parts to which it is fastened, can
cause wheel nuts to become loose
over time. The wheel could come off
and cause a crash. When changing a
wheel, remove any rust or dirt from
places where the wheel attaches to
the vehicle. In an emergency, a cloth
or paper towel can be used; however,
use a scraper or wire brush later to
remove all rust or dirt.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
378 Vehicle Care
times as well on the government course
as a tire graded 100. The relative
performance of tires depends upon the
actual conditions of their use, however,
and may depart significantly from the
norm due to variations in driving habits,
service practices and differences in road
characteristics and climate.
Traction
The traction grades, from highest to
lowest, are AA, A, B, and C. Those
grades represent the tire's ability to
stop on wet pavement as measured
under controlled conditions on specified
government test surfaces of asphalt and
concrete. A tire marked C may have
poor traction performance. Warning:
The traction grade assigned to this tire
is based on straight-ahead braking
traction tests, and does not include
acceleration, cornering, hydroplaning,
or peak traction characteristics.Temperature
The temperature grades are A (the
highest), B, and C, representing the
tire's resistance to the generation of
heat and its ability to dissipate heat
when tested under controlled conditions
on a specified indoor laboratory test
wheel. Sustained high temperature can
cause the material of the tire to
degenerate and reduce tire life, and
excessive temperature can lead to
sudden tire failure. The grade C
corresponds to a level of performance
which all passenger car tires must meet
under the Federal Motor Safety
Standard No. 109. Grades B and A
represent higher levels of performance
on the laboratory test wheel than the
minimum required by law. Warning:
The temperature grade for this tire is
established for a tire that is properly
inflated and not overloaded. Excessive
speed, underinflation, or excessive
loading, either separately or in
combination, can cause heat buildup
and possible tire failure.Wheel Alignment and Tire
Balance
The tires and wheels were aligned and
balanced at the factory to provide the
longest tire life and best overall
performance. Adjustments to wheel
alignment and tire balancing are not
necessary on a regular basis. Consider an
alignment check if there is unusual tire wear
or the vehicle is significantly pulling to one
side or the other. Some slight pull to the
left or right, depending on the crown of the
road and/or other road surface variations
such as troughs or ruts, is normal. If the
vehicle is vibrating when driving on a
smooth road, the tires and wheels may
need to be rebalanced. See your dealer for
proper diagnosis.
Wheel Replacement
Replace any wheel that is bent, cracked,
or badly rusted or corroded. If wheel nuts
keep coming loose, the wheel, wheel bolts,
and wheel nuts should be replaced. If the
wheel leaks air, replace it. Some aluminum
wheels can be repaired. See your dealer if
any of these conditions exist.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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Vehicle Care 379
Your dealer will know the kind of wheel that
is needed.
Each new wheel should have the same
load-carrying capacity, diameter, width,
offset, and be mounted the same way as
the one it replaces.
Replace wheels, wheel bolts, wheel nuts,
or Tire Pressure Monitor System (TPMS)
sensors with new GM original equipment
parts.
{Warning
Using the wrong replacement wheels,
wheel bolts, or wheel nuts can be
dangerous. It could affect the braking and
handling of the vehicle. Tires can lose air,
and cause loss of control, causing a crash.
Always use the correct wheel, wheel
bolts, and wheel nuts for replacement.
Caution
The wrong wheel can also cause
problems with bearing life, brake cooling,
speedometer or odometer calibration,
headlamp aim, bumper height, vehicle
ground clearance, and tire or tire chain
clearance to the body and chassis.
Used Replacement Wheels
{Warning
Replacing a wheel with a used one is
dangerous. How it has been used or how
far it has been driven may be unknown.
It could fail suddenly and cause a crash.
When replacing wheels, use a new GM
original equipment wheel.
Tire Chains
{Warning
If the vehicle has 275/50R22, 275/60R20,
LT265/60R20, LT265/70R17, or LT275/65R18
size tires, do not use tire chains. There is
not enough clearance. Tire chains used on
a vehicle without the proper amount of
clearance can cause damage to the
brakes, suspension, or other vehicle parts.
The area damaged by the tire chains
could cause loss of control and a crash.
Use another type of traction device only
if its manufacturer recommends it for the
vehicle's tire size combination and road
conditions. Follow that manufacturer's(Continued)
Warning (Continued)
instructions. To avoid vehicle damage,
drive slow and readjust or remove the
traction device if it is contacting the
vehicle. Do not spin the wheels.
If traction devices are used, install them
on the rear tires.
Caution
If the vehicle is equipped with a tire size
other than 275/50R22, 275/60R20,
LT265/60R20, LT265/70R17, or LT275/65R18
use tire chains only where legal and only
when necessary. Use chains that are the
proper size for the tires. Install them on
the tires of the rear axle. Do not use
chains on the tires of the front axle.
Tighten them as tightly as possible with
the ends securely fastened. Drive slowly
and follow the chain manufacturer's
instructions. If the chains contact the
vehicle, stop and retighten them. If the
contact continues, slow down until it
stops. Driving too fast or spinning the
wheels with chains on will damage the
vehicle.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
416 Service and Maintenance
.Trained dealer technicians have the
diagnostic equipment to test the battery
and ensure that the connections and
cables are corrosion-free.
Belts
.Belts may need replacing if they squeak
or show signs of cracking or splitting.
.Trained dealer technicians have access to
tools and equipment to inspect the belts
and recommend adjustment or
replacement when necessary.
Brakes
Brakes stop the vehicle and are crucial to
safe driving.
.Signs of brake wear may include chirping,
grinding, or squealing noises, or difficulty
stopping.
.Trained dealer technicians have access to
tools and equipment to inspect the brakes
and recommend quality parts engineered
for the vehicle.
Fluids
Proper fluid levels and approved fluids
protect the vehicle’s systems and
components. See Recommended Fluids and
Lubricants 0418 for GM approved fluids.
.Engine oil and windshield washer fluid
levels should be checked at every fuel fill.
.Instrument cluster lights may come on to
indicate that fluids may be low and need
to be filled.
Hoses
Hoses transport fluids and should be
regularly inspected to ensure that there are
no cracks or leaks. With a multi-point
inspection, your dealer can inspect the hoses
and advise if replacement is needed.
Lamps
Properly working headlamps, taillamps, and
brake lamps are important to see and be
seen on the road.
.Signs that the headlamps need attention
include dimming, failure to light, cracking,
or damage. The brake lamps need to be
checked periodically to ensure that they
light when braking.
.With a multi-point inspection, your dealer
can check the lamps and note any
concerns.
Shocks and Struts
Shocks and struts help aid in control for a
smoother ride.
.Signs of wear may include steering wheel
vibration, bounce/sway while braking,
longer stopping distance, or uneven
tire wear.
.As part of the multi-point inspection,
trained dealer technicians can visually
inspect the shocks and struts for signs of
leaking, blown seals, or damage, and can
advise when service is needed.
Tires
Tires need to be properly inflated, rotated,
and balanced. Maintaining the tires can save
money and fuel, and can reduce the risk of
tire failure.
.Signs that the tires need to be replaced
include three or more visible treadwear
indicators; cord or fabric showing through
the rubber; cracks or cuts in the tread or
sidewall; or a bulge or split in the tire.
.Trained dealer technicians can inspect and
recommend the right tires. Your dealer
can also provide tire/wheel balancing
services to ensure smooth vehicle
operation at all speeds. Your dealer sells
and services name brand tires.