2021 GMC YUKON turn signal

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 301
Connection Trailer Lighting Faults Detected
The Trailering App System monitors for
electrical faults on the trailer lights.
A message about the lighting issue will
appear on the DIC. The infotainment display
will also show the lighting issue in the
Connection Status view. Repair your trailer
lights if needed. A trailer lighting issue is
not covered by your GM warranty.
Diagnose View
Touch Diagnose to see more information
about the connection problem.
This view will display the names of the
trailer connector pins, a graphic of the trailer
connector, and a graphic of the back of the
trailer.
Any connector pin that failed will be amber
color, and the location of the corresponding
connection will be highlighted on the
graphic of the back of the trailer.
The Running Lights connection may not
detect partial outages. Activate the light test
to check all trailer lamps. See“Light Test”
following. Light Test
Touch Start Light Test to cycle the trailer
lights on and off to determine if they are
working. The test follows this sequence:
1. The running lights turn on first and remain on throughout the sequence.
2. The brake lights turn on for about two seconds.
3. The left turn signal light flashes three times.
4. The right turn signal light flashes three times.
5. The reverse lights turn on for about two seconds.
6. Steps 2–5 repeat for approximately one minute and 45 seconds, or until the
test deactivates.
Touch Stop to stop the test. The test will
automatically end after one minute and
45 seconds.
The sequence also deactivates when any of
the following occur:
.The ignition is turned off.
.The transmission is shifted out of P (Park).
.The brake pedal is pressed.
.The turn signal is activated.
.The hazard warning lights are activated.
Tires
1. Trailer Tire Pressure/Temperature
Tire Pressure and Temperature
If the TTPMS sensor-to-vehicle learn process
was completed, the status view will display
the current tire pressure and temperature of
the trailer tires related to the active Trailer
Profile. If a tire’s pressure is low or high, the
color of the pressure value will be amber.
If a sensor malfunctions, the values are
dashed lines. If the screen displays “Service
Tire Pressure Monitoring System”, the
vehicle needs to be taken to a dealer for
service.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Vehicle Care 347
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
TPMS malfunction indicator is combined
with the low tire pressure telltale. When the
system detects a malfunction, the telltale
will flash for approximately one minute and
then remain continuously illuminated. This
sequence will continue upon subsequent
vehicle start-ups as long as the malfunction
exists.
When the malfunction indicator is
illuminated, the system may not be able to
detect or signal low tire pressure as
intended. TPMS malfunctions may occur for
a variety of reasons, including the
installation of replacement or alternate tires
or wheels on the vehicle that prevent the
TPMS from functioning properly. Alwayscheck the TPMS malfunction telltale after
replacing one or more tires or wheels on
your vehicle to ensure that the replacement
or alternate tires and wheels allow the
TPMS to continue to function properly.
See
Tire Pressure Monitor Operation 0347.
See Radio Frequency Statement 0407.
Tire Pressure Monitor Operation
This vehicle may have a Tire Pressure
Monitor System (TPMS). The TPMS is
designed to warn the driver when a low tire
pressure condition exists. TPMS sensors are
mounted onto each tire and wheel
assembly, excluding the spare tire and
wheel assembly. The TPMS sensors monitor
the air pressure in the tires and transmit the
tire pressure readings to a receiver located
in the vehicle.
When a low tire pressure condition is
detected, the TPMS illuminates the low tire
pressure warning light located on the instrument cluster. If the warning light
comes on, stop as soon as possible and
inflate the tires to the recommended
pressure shown on the Tire and Loading
Information label. See
Vehicle Load Limits
0 222.
A message to check the pressure in a
specific tire displays in the Driver
Information Center (DIC). The low tire
pressure warning light and the DIC warning
message come on at each ignition cycle
until the tires are inflated to the correct
inflation pressure. If the vehicle has DIC
buttons, tire pressure levels can be viewed.
For additional information and details about
the DIC operation and displays, see Driver
Information Center (DIC) 0120.
The low tire pressure warning light may
come on in cool weather when the vehicle is
first started, and then turn off as the vehicle
is driven. This could be an early indicator
that the air pressure is getting low and
needs to be inflated to the proper pressure.
A Tire and Loading Information label shows
the size of the original equipment tires and
the correct inflation pressure for the tires

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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348 Vehicle Care
when they are cold. SeeVehicle Load Limits
0 222, for an example of the Tire and
Loading Information label and its location.
Also see Tire Pressure 0344.
The TPMS can warn about a low tire
pressure condition but it does not replace
normal tire maintenance. See Tire Inspection
0 349, Tire Rotation 0350 and
Tires 0339.
Caution
Tire sealant materials are not all the
same. A non-approved tire sealant could
damage the TPMS sensors. TPMS sensor
damage caused by using an incorrect tire
sealant is not covered by the vehicle
warranty. Always use only the GM
approved tire sealant available through
your dealer or included in the vehicle.
TPMS Malfunction Light and Message
The TPMS will not function properly if one
or more of the TPMS sensors are missing or
inoperable. When the system detects a
malfunction, the low tire pressure warning
light flashes for about one minute and then
stays on for the remainder of the ignition
cycle. A DIC warning message also displays.
The malfunction light and DIC warning message come on at each ignition cycle
until the problem is corrected. Some of the
conditions that can cause these to come
on are:
.One of the road tires has been replaced
with the spare tire. The spare tire does
not have a TPMS sensor. The malfunction
light and the DIC message should go off
after the road tire is replaced and the
sensor matching process is performed
successfully. See "TPMS Sensor Matching
Process" later in this section.
.The TPMS sensor matching process was
not done or not completed successfully
after rotating the tires. The malfunction
light and the DIC message should go off
after successfully completing the sensor
matching process. See "TPMS Sensor
Matching Process" later in this section.
.One or more TPMS sensors are missing or
damaged. The malfunction light and the
DIC message should go off when the
TPMS sensors are installed and the sensor
matching process is performed
successfully. See your dealer for service.
.Replacement tires or wheels do not match
the original equipment tires or wheels.
Tires and wheels other than those
recommended could prevent the TPMS
from functioning properly. See
Buying
New Tires 0351.
.Operating electronic devices or being near
facilities using radio wave frequencies
similar to the TPMS could cause the TPMS
sensors to malfunction.
If the TPMS is not functioning properly, it
cannot detect or signal a low tire pressure
condition. See your dealer for service if the
TPMS malfunction light and DIC message
come on and stay on.
Tire Fill Alert (If Equipped)
This feature provides visual and audible
alerts outside the vehicle to help when
inflating an underinflated tire to the
recommended cold tire pressure.
When the low tire pressure warning light
comes on: 1. Park the vehicle in a safe, level place.
2. Set the parking brake firmly.
3. Place the vehicle in P (Park).
4. Add air to the tire that is underinflated. The turn signal lamp will flash.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Vehicle Care 349
When the recommended pressure is
reached, the horn sounds once and the
turn signal lamp will stop flashing and
briefly turn solid.
Repeat these steps for all underinflated tires
that have illuminated the low tire pressure
warning light.
{Warning
Overinflating a tire could cause the tire
to rupture and you or others could be
injured. Do not exceed the maximum
pressure listed on the tire sidewall. See
Tire Sidewall Labeling 0341 and
Vehicle Load Limits 0222.
If the tire is overinflated by more than
35 kPa (5 psi), the horn will sound multiple
times and the turn signal lamp will continue
to flash for several seconds after filling
stops. To release and correct the pressure,
while the turn signal lamp is still flashing,
briefly press the center of the valve stem.
When the recommended pressure is reached,
the horn sounds once.
If the turn signal lamp does not flash within
15 seconds after starting to inflate the tire,
the tire fill alert has not been activated or is
not working. If the hazard warning flashers are on, the
tire fill alert visual feedback will not work
properly.
The TPMS will not activate the tire fill alert
properly under the following conditions:
.There is interference from an external
device or transmitter.
.The air pressure from the inflation device
is not sufficient to inflate the tire.
.There is a malfunction in the TPMS.
.There is a malfunction in the horn or turn
signal lamps.
.The identification code of the TPMS
sensor is not registered to the system.
.The battery of the TPMS sensor is low.
If the tire fill alert does not operate due to
TPMS interference, move the vehicle about
1 m (3 ft) back or forward and try again.
If the tire fill alert feature is not working,
use a tire pressure gauge.
TPMS Sensor Matching Process —Auto
Learn Function
Each TPMS sensor has a unique
identification code. The identification code
needs to be matched to a new tire/wheel
position after rotating the tires or replacing
one or more of the TPMS sensors. When a tire is installed, the vehicle must be
stationary for about 20 minutes before the
system recalculates. The following relearn
process takes up to 10 minutes, driving at a
minimum speed of 20 km/h (12 mph).
A dash (-) or pressure value will display in
the DIC. See
Driver Information Center (DIC)
0 120. A warning message displays in the
DIC if a problem occurs during the relearn
process.
Tire Inspection
We recommend that the tires, including
the spare tire, if the vehicle has one, be
inspected for signs of wear or damage
at least once a month.
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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
410 OnStar
OnStar
OnStar Overview
OnStar Overview . . . . . . . . . . . . . . . . . . . . . . 410
OnStar Services
Emergency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
OnStar Additional Information
OnStar Additional Information . . . . . . . . . 411
OnStar Overview
=Voice Command Button
QBlue OnStar Button
>Red Emergency Button
This vehicle may be equipped with a
comprehensive, in-vehicle system that can
connect to an OnStar Advisor for Emergency,
Security, Navigation, Connections, and
Diagnostics Services. OnStar services may
require a paid service plan and data plan.
OnStar requires the vehicle battery and
electrical system, cellular service, and GPS
satellite signals to be available and
operating. OnStar acts as a link to existing
emergency service providers. OnStar may
collect information about you and your
vehicle, including location information. See
OnStar User Terms, Privacy Statement, and
Software Terms for more details including
system limitations at www.onstar.com (U.S.)
or www.onstar.ca (Canada). The OnStar system status light is next to
the OnStar buttons. If the status light is:
.Solid Green: System is ready.
.Flashing Green: On a call.
.Red: Indicates a problem.
.Off: System is off. PressQtwice to
speak with an OnStar Advisor.
Press
Qor call 1-888-4ONSTAR
(1-888-466-7827) to speak to an Advisor.
Functionality of the Voice Command button
may vary by vehicle and region.
Press
=to:
.Open the OnStar app on the infotainment
display. See OnStar System 0155 for
information on how to use the
OnStar app.
Or
.Give OnStar Turn-by-Turn Navigation voice
commands.
.Obtain and customize the Wi-Fi hotspot
name or SSID and password, if equipped.
Press
Qto connect to an Advisor to:
.Verify account information or update
contact information.
.Get driving directions.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
412 OnStar
Reactivation for Subsequent Owners
PressQand follow the prompts to speak to
an Advisor as soon as possible. The Advisor
will update vehicle records and explain
OnStar or connected service options.
How OnStar Service Works
Automatic Crash Response, Emergency
Services, Crisis Assist, Stolen Vehicle
Assistance, Remote Services, and Roadside
Assistance are available on most vehicles.
Not all OnStar services are available
everywhere or on all vehicles. For more
information, a full description of OnStar
services, system limitations, and OnStar User
Terms, Privacy Statement, and Software
Terms:
.Call 1-888-4ONSTAR (1-888-466-7827).
.See www.onstar.com (U.S.).
.See www.onstar.ca (Canada).
.Call TTY 1-877-248-2080.
.PressQto speak with an Advisor.
OnStar or connected services cannot work
unless the vehicle is in a place where OnStar
has an agreement with a wireless service
provider for service in that area. The
wireless service provider must also have
coverage, network capacity, reception, and technology compatible with OnStar or
connected services. Service involving location
information about the vehicle cannot work
unless GPS signals are available,
unobstructed, and compatible with the
OnStar hardware. OnStar or connected
services may not work if the OnStar
equipment is not properly installed or it has
not been properly maintained. If equipment
or software is added, connected,
or modified, OnStar or connected services
may not work. Other problems beyond the
control of OnStar
—such as hills, tall
buildings, tunnels, weather, electrical system
design and architecture of the vehicle,
damage to the vehicle in a crash, or wireless
phone network congestion or jamming —
may prevent service.
See Radio Frequency Statement 0407.
Services for People with Disabilities
Advisors provide services to help with
physical disabilities and medical conditions.
Press
Qto help:
.Locate a gas station with an attendant to
pump gas.
.Find a hotel, restaurant, etc., that meets
accessibility needs.
.Provide directions to the closest hospital
or pharmacy in urgent situations.
TTY Users
OnStar has the ability to communicate to
deaf, hard-of-hearing, or speech-impaired
customers while in the vehicle. The available
dealer-installed TTY system can provide
in-vehicle access to all OnStar services,
except Virtual Advisor and OnStar
Turn-by-Turn Navigation.
If equipped, TTY mode can be turned on or
off by touching Settings, then Apps, and
then Phone. When TTY mode is on, phone
calls can be made or received with OnStar
using the infotainment display.
OnStar Personal Identification
Number (PIN)
A PIN is needed to access some OnStar
services. The PIN will need to be changed
the first time when speaking with an
Advisor. To change the OnStar PIN, contact
an OnStar Advisor by pressing
Qor calling
1-888-4ONSTAR.
Warranty
OnStar equipment may be warranted as part
of the vehicle warranty.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
OnStar 413
Languages
The vehicle can be programmed to respond
in multiple languages. Press
Qand ask for
an Advisor. Advisors are available in English,
Spanish, and French. Available languages
may vary by country.
Potential Issues
OnStar cannot perform Remote Door Unlock
or Stolen Vehicle Assistance after the vehicle
has been off continuously for 10 days
without an ignition cycle. If the vehicle has
not been started for 10 days, OnStar can
contact Roadside Assistance or a locksmith
to help gain access to the vehicle.
Global Positioning System (GPS)
.Obstruction of the GPS can occur in a
large city with tall buildings; in parking
garages; around airports; in tunnels and
underpasses; or in an area with very
dense trees. If GPS signals are not
available, the OnStar system should still
operate to call OnStar. However, OnStar
could have difficulty identifying the exact
location.
.In emergency situations, OnStar can use
the last stored GPS location to send to
emergency responders. A temporary loss of GPS can cause loss of
the ability to send a Turn-by-Turn
Navigation route. The Advisor may give a
verbal route or may ask for a call back after
the vehicle is driven into an open area.
Cellular and GPS Antennas
Cellular reception is required for OnStar to
send remote signals to the vehicle. Do not
place items over or near the antenna to
prevent blocking cellular and GPS signal
reception.
Unable to Connect to OnStar Message
If there is limited cellular coverage or the
cellular network has reached maximum
capacity, this message may come on. Press
Qto try the call again or try again after
driving a few miles into another
cellular area.
Vehicle and Power Issues
OnStar services require a vehicle electrical
system, wireless service, and GPS satellite
technologies to be available and operating
for features to function properly. These
systems may not operate if the battery is
discharged or disconnected.
Add-on Electrical Equipment
The OnStar system is integrated into the
electrical architecture of the vehicle. Do not
add any electrical equipment. See Add-On
Electrical Equipment 0306. Added electrical
equipment may interfere with the operation
of the OnStar system and cause it to not
operate.
Vehicle Software Updates
OnStar or GM may remotely deliver
software updates or changes to the vehicle
without further notice or consent. These
updates or changes may enhance or
maintain safety, security, or the operation
of the vehicle or the vehicle systems.
Software updates or changes may affect or
erase data or settings that are stored in the
vehicle, such as saved navigation
destinations or pre-set radio stations.
Neither OnStar nor GM is responsible for
any affected or erased data or settings.
These updates or changes may also collect
personal information. Such collection is
described in the OnStar privacy statement or
separately disclosed at the time of
installation. These updates or changes may
also cause a system to automatically
communicate with GM servers to collect
information about vehicle system status,

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
416 Connected Services
PressQ, then ask the Advisor to download
directions to the vehicle’s navigation system,
if equipped. After the call ends, the
navigation screen will provide prompts to
begin driving directions. Routes that are sent
to the navigation screen can only be
canceled through the navigation system.
See www.onstar.com (U.S.) or www.onstar.ca
(Canada).
Connections
The following services help with staying
connected.
For coverage maps, see www.onstar.com
(U.S.) or www.onstar.ca (Canada).
Ensuring Security
.Change the default passwords for the
Wi-Fi hotspot and myGMC mobile
application. Make these passwords
different from each other and use a
combination of letters and numbers to
increase the security.
.Change the default name of the SSID
(Service Set Identifier). This is your
network’s name that is visible to other
wireless devices. Choose a unique name
and avoid family names or vehicle
descriptions. Wi-Fi Hotspot (If Equipped)
The vehicle may have a built-in Wi-Fi
hotspot that provides access to the Internet
and web content at 4G LTE speed. Up to
seven mobile devices can be connected.
A data plan is required. Use the in-vehicle
controls only when it is safe to do so.
1. To retrieve Wi-Fi hotspot information, press
=to open the OnStar app on the
infotainment display, then select Wi-Fi
Hotspot. On some vehicles, touch Wi-Fi
or Wi-Fi Settings on the screen.
2. The Wi-Fi settings will display the Wi-Fi hotspot name (SSID), password, and on
some vehicles, the connection type (no
Internet connection, 3G, 4G, 4G LTE), and
signal quality (poor, good, excellent). The
LTE icon shows connection to Wi-Fi. It is
possible that the icon may not illuminate
even though the vehicle has an active
connection.
3. To change the SSID or password, press
Qor call 1-888-4ONSTAR to connect
with an Advisor. On some vehicles, the
SSID and password can be changed in
the Wi-Fi Hotspot menu. After initial set-up, your vehicle’s Wi-Fi
hotspot will connect automatically to your
mobile devices. Manage data usage by
turning Wi-Fi on or off on your mobile
device, using the myGMC mobile app, or by
contacting an OnStar Advisor. On some
vehicles, Wi-Fi can also be managed from
the Wi-Fi Hotspot menu.
MyGMC Mobile App (If Available)
Download the myGMC mobile app to
compatible Apple and Android smartphones.
GMC users can access the following services
from a smartphone:
.Remotely start/stop the vehicle,
if factory-equipped.
.Lock/unlock doors, if equipped with
automatic locks.
.Activate the horn and lamps.
.Check the vehicle’s fuel level, oil life,
or tire pressure, if factory-equipped with
the Tire Pressure Monitor System.
.Send destinations to the vehicle.
.Locate the vehicle on a map (U.S.
market only).
.Turn the vehicle's Wi-Fi hotspot on/off,
manage settings, and monitor data
consumption, if equipped.
.Locate a dealer and schedule service.