air GMC YUKON 2020 Service Manual

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
136 Instruments and Controls
system. Have it checked by your
dealer. Driving while this light is on
could drain the battery.
When this light comes on, or is
flashing, the Driver Information
Center (DIC) also displays a
message.
If a short distance must be driven
with the light on, be sure to turn off
all accessories, such as the radio
and air conditioner.
Malfunction Indicator
Lamp (Check Engine
Light)
This light is part of the vehicle’s
emission control on-board
diagnostic system. If this light is on
while the engine is running, a
malfunction has been detected and
the vehicle may require service. The
light should come on to show that it
is working when the ignition is in
Service Mode. SeeIgnition
Positions (Keyless Access) 0202 or
Ignition Positions (Key Access)
0 204.
Malfunctions are often indicated by
the system before any problem is
noticeable. Being aware of the light
and seeking service promptly when
it comes on may prevent damage.
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 Modifications
0283.
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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
142 Instruments and Controls
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 0333.
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 at every ignition cycle.
See Tire Pressure Monitor
Operation 0336.Engine Oil Pressure Light
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.
This light should come on briefly as
the engine is started. If it does not
come on, have the vehicle serviced
by your dealer. If the light comes on and stays on, it
means that oil is not flowing through
the engine properly. The vehicle
could be low on oil and might have
some other system problem. See
your dealer.
Low Fuel Warning Light
This light is near the fuel gauge and
comes on briefly when the ignition is
turned on as a check to show it is
working.
It also comes on when the fuel tank
is low on fuel. The light turns off
when fuel is added. If it does not,
have the vehicle serviced.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Instruments and Controls 151
HUD Troubleshooting
If you cannot see the HUD image
when the ignition is on, check that:
.Nothing is covering the
HUD lens.
. The HUD brightness setting is
not too dim or too bright.
. The HUD is adjusted to the
proper height.
. Polarized sunglasses are
not worn.
. The windshield and HUD lens
are clean.
If the HUD image is not correct,
contact your dealer.
The windshield is part of the HUD
system. See Windshield
Replacement 0310.
Vehicle Messages
Messages displayed on the DIC
indicate the status of the vehicle or
some action that may be needed to
correct a condition. Multiple
messages may appear one after
another.
The messages that do not require
immediate action can be
acknowledged and cleared by
pressing
V. The messages that
require immediate action cannot be
cleared until that action is
performed.
All messages should be taken
seriously; clearing the message
does not correct the problem.
If a SERVICE message appears,
see your dealer.
Follow the instructions given in the
messages. The system displays
messages regarding the following
topics:
. Service Messages
. Fluid Levels
. Vehicle Security .
Brakes
. Steering
. Ride Control Systems
. Driver Assistance Systems
. Cruise Control
. Lighting and Bulb Replacement
. Wiper/Washer Systems
. Doors and Windows
. Seat Belts
. Airbag Systems
. Engine and Transmission
. Tire Pressure
. Battery
Engine Power Messages
ENGINE POWER IS REDUCED
This message displays when the
vehicle's propulsion power is
reduced. A reduction in propulsion
power can affect the vehicle's ability
to accelerate. If this message is on,
but there is no observed reduction
in performance, proceed to your
destination. The performance may

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
154 Instruments and Controls
Select Off or On.
Auto Volume
This feature adjusts the volume
based on vehicle speed and
ambient noise.
Select Off, Low, Medium-Low,
Medium, Medium-High, or High.
Maximum Startup Volume
This feature sets the maximum
startup volume. If the vehicle is
started and the volume is greater
than this level, the volume is
adjusted to this level. To set the
maximum startup volume, touch +
or−to increase or decrease.
Audio Cue Volume
This feature sets the volume of
audio files played at system startup
and shutdown.
Select On, then touch + or −to
increase or decrease the volume.
Vehicle
Select and the following may
display:
. Climate and Air Quality .
Collision/Detection Systems
. Comfort and Convenience
. Lighting
. Power Door Locks
. Remote Lock, Unlock, Start
Climate and Air Quality
Select and the following may
display:
.Auto Fan Speed
. Auto Defog
. Auto Rear Defog
Auto Fan Speed
This feature will set the auto fan
speed.
Select Low, Medium, or High.
Auto Defog
When set to On, the auto defog
comes on when the climate control
sensor detects high interior
humidity. Air will be directed to the
windshield.
Select Off or On. Auto Rear Defog
This feature will automatically turn
on the rear window defogger when
the vehicle is first started in cold
weather and turn off when the
vehicle is warmed.
Select Off or On.Collision/Detection Systems
Select and the following may
display:
.
Alert Type
. Forward Collision System
. Adaptive Cruise Go Notifier
. Park Assist
. Rear Cross Traffic Alert
. Lane Change Alert
Alert Type
This feature will set crash alerts to
beeps or seat vibrations. This
setting affects all crash alerts
including Forward Collision Alert,
Lane Departure Warning, and Park
Assist alerts.
Select Beeps or Safety Alert Seat.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
158 Instruments and Controls
Bluetooth
Select and the following may
display:
.Pair New Device
. Device Management
. Ringtones
. Voice Mail Numbers
. Text Message Alerts
Pair New Device
Select to pair a new device. See
“Pairing” in“Infotainment Controls”
under “Bluetooth” in the infotainment
manual.
Device Management
Select to connect to a different
phone source, disconnect a phone,
or delete a phone.
Ringtones
Select to change the ring tone for
the specific phone. The phone does
not need to be connected to change
the ring tone. Voice Mail Numbers
This feature displays the voice mail
number for all connected phones.
To change the voice mail number,
select EDIT. Type a new number,
then select Save.
Text Message Alerts
This allows the feature to be turned
on or off.
Select Off or On.
Apple CarPlay
Select and the following may
display:
.
Apple CarPlay
. Manage Apple CarPlay Devices
Apple CarPlay
This feature allows Apple devices to
be connected to the infotainment
system through a USB port.
Select Off or On.
Manage Apple CarPlay Devices
Select to manage Apple devices.
Apple CarPlay must be on for this
feature to be accessed.
Android Auto
Select and the following may
display:
. Android Auto
. Manage Android Auto Devices
Android Auto
This feature allows Android devices
to be connected to the infotainment
system through a USB port.
Select Off or On.
Manage Android Auto Devices
Select to manage Android devices.
Android Auto must be on for this
feature to be accessed.
Voice
Select and the following may
display:
. Confidence Threshold
. Prompt Length
. Audio Feedback Speed
. Display “What Can I Say?” Tips

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
166 Lighting
.The system detects a preceding
vehicle's taillamps.
. The outside light is bright
enough that high-beam
headlamps are not required.
. The vehicle's speed drops below
20 km/h (12 mph).
. The IntelliBeam system can be
disabled by the High/Low-Beam
Changer or the Flash-to-Pass
feature. If this happens, the
High/Low-Beam Changer must
be activated on then off within
two seconds to reactivate the
IntelliBeam system. The
instrument cluster light will come
on to indicate the IntelliBeam is
reactivated. See Headlamp
High/Low-Beam Changer 0166
and
Flash-to-Pass 0167.
The high beams may not turn off
automatically if the system cannot
detect another vehicle's lamps
because of any of the following: .
The other vehicle's lamps are
missing, damaged, obstructed
from view, or otherwise
undetected.
. The other vehicle's lamps are
covered with dirt, snow, and/or
road spray.
. The other vehicle's lamps cannot
be detected due to dense
exhaust, smoke, fog, snow, road
spray, mist, or other airborne
obstructions.
. The vehicle's windshield is dirty,
cracked, or obstructed by
something that blocks the view
of the light sensor.
. The vehicle is loaded such that
the front end points upward,
causing the light sensor to aim
high and not detect headlamps
and taillamps.
. The vehicle is being driven 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 ignition is
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 the turn signal lever toward you
and release it to return to low-beam
headlamps.
When the high-beam headlamps are
on, this indicator light on the
instrument cluster will also be on.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Climate Controls 175
Climate Controls
Climate Control Systems
Dual Automatic ClimateControl System . . . . . . . . . . . . . 175
Rear Climate Control System . . . . . . . . . . . . . . . . . . . . . . 179
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . 180
Maintenance
Passenger Compartment AirFilter . . . . . . . . . . . . . . . . . . . . . . . . 181
Service . . . . . . . . . . . . . . . . . . . . . . . 182
Climate Control
Systems
Dual Automatic Climate
Control System
With this system the heating,
cooling, and ventilation in the
vehicle can be controlled. Some
climate control settings can be
changed. See “Climate and Air
Quality” underVehicle
Personalization 0152.
1. Driver Temperature Control
2. A/C (Air Conditioning) 3. Air Delivery Mode Controls
4. Fan Control
5. Defrost
6. Passenger Temperature
Control
7. SYNC (Synchronized Temperature)
8. Rear Window Defogger
9. RCTRL (Rear Climate Control Lockout)
10. Rear Temperature Control
11. Rear Air Delivery Mode Control
12. Rear Fan Control
13. Front Climate Control Power Button
14. Rear AUTO (Automatic Operation)
15. Rear Climate Control Power Button
16. Air Recirculation
17. AUTO (Automatic Operation)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
176 Climate Controls
Front Climate Controls
Automatic Operation
The system automatically controls
the fan speed, air delivery, air
conditioning, and recirculation in
order to heat or cool the vehicle to
the desired temperature.
When AUTO is lit, all four functions
operate automatically. Each function
can also be manually set and the
setting is displayed. Functions not
manually set will continue to be
automatically controlled, even if the
AUTO indicator is not lit.
To place the system in
automatic mode:1. Press AUTO.
2. Set the driver and passenger temperature.
To find your comfort setting,
start with 22 °C (72 °F) and
allow the system time to
stabilize. Then adjust the
temperature as needed for best
comfort. To improve fuel efficiency and to
cool the vehicle faster, recirculation
may be automatically selected in
warm weather.
The recirculation light will not come
on when automatically controlled.
Press
@to manually select
recirculation; press it again to select
outside air.
Do not cover the solar sensor on the
top of the instrument panel near the
windshield. This sensor regulates
air temperature based on sun load.
See “Sensors” later in this section.
Manual Operation
O:Press to turn the climate control
system on or off. When off is
selected, the system will stop air
from flowing into the cabin. If on is
selected, a button is pressed, or a
knob is turned, the climate control
system will turn on and operate at
the current setting.
9: Turn clockwise or
counterclockwise to increase or
decrease the fan speed. Press
AUTO to return to automatic
operation.
The maximum auto fan speed can
be adjusted. See “Climate and Air
Quality” underVehicle
Personalization 0152.
Driver and Passenger
Temperature Control : The
temperature can be adjusted
separately for the driver and
passenger.
Turn the knob clockwise or
counterclockwise to increase or
decrease the driver or passenger
temperature setting.
SYNC : Press to link the passenger
and rear climate temperature
settings to the driver setting. The
SYNC indicator light will turn on.
When the passenger or rear climate
settings are adjusted, the SYNC
indicator light turns off.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Climate Controls 177
Air Delivery Mode Control :Press
Y,\,[, or-to change the
direction of the airflow. An indicator
light comes on in the selected mode
button.
Changing the mode cancels the
automatic operation of the mode.
Press AUTO to return to automatic
operation.
Y: Air is directed to the instrument
panel outlets.
\: Air is divided between the
instrument panel and floor outlets.
[: Air is directed to the floor
outlets, with some to the windshield,
side window outlets, and second
row floor outlets.
-: This mode clears the windows
of fog or moisture. Air is directed to
the windshield, floor outlets, and
side window vents.
0: Press to clear the windshield
of fog or frost more quickly. Air is
directed to the windshield and the
side window vents. The system
automatically forces outside air into
the vehicle and the air conditioning compressor will run, unless the
outside temperature is close to
freezing.
Do not drive the vehicle until all
windows are clear.
See
Air Vents 0180.
A/C : Press to turn the air
conditioning system on or off. An
indicator light comes on to show
that the air conditioning is enabled.
If the fan is turned off, the air
conditioner will not run. The A/C
light will stay on even if the outside
temperatures are below freezing.
@: Press to turn on recirculation.
An indicator light comes on. Air is
recirculated to quickly cool the
inside of the vehicle. It can also be
used to help reduce outside air and
odors that enter the vehicle. The air
conditioning compressor also comes
on when this mode is activated.
Auto Defog : The climate control
system uses a sensor to
automatically detect high humidity
inside the vehicle. When high
humidity is detected, the climate
control system may adjust to outside air supply, turn on the air
conditioner, and direct more air to
the windshield. If the climate control
system does not detect possible
window fogging, it returns to normal
operation. To turn Auto Defog off or
on, see
“Climate and Air Quality”
under Vehicle Personalization
0 152.
Rear Window Defogger
The rear window defogger uses a
warming grid to remove fog from the
rear window.
K:Press to turn the rear window
defogger on or off. An indicator light
on the button comes on to show that
the rear window defogger is on.
The rear window defogger only
works when the ignition is on. The
defogger turns off if the ignition is
turned off or to ACC/ACCESSORY.
The rear window defogger can be
set to automatic operation. When
Auto Rear Defog is selected, the
rear window defogger turns on
automatically when the vehicle is
first started in cold weather and
turns off when the vehicle is

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
178 Climate Controls
warmed. To turn Auto Rear Defog
on or off, see“Climate and Air
Quality” underVehicle
Personalization 0152.
Caution
Using a razor blade or sharp
object to clear the inside rear
window can damage the rear
window defogger. Repairs would
not be covered by the vehicle
warranty. Do not clear the inside
rear window with sharp objects.
Heated Mirror : If equipped with
heated outside mirrors, the mirrors
heat to help clear fog or frost from
the surface of the mirror when the
rear window defog button is
pressed. See Heated Mirrors 039.
Rear Climate Controls
O:Press to turn the rear climate
control system on or off.
AUTO : Press AUTO to control the
rear passenger temperature, air
delivery, and fan speed. AUTO
appears in the display when automatic operation is active. If any
of the climate control settings
except rear temperature are
manually adjusted, this cancels full
automatic operation.
Fan Control :
Press up or down to
increase or decrease the rear
passenger area fan speed.
Air Delivery Mode Control : Press
up or down to change the direction
of the rear passenger airflow.
Repeatedly press the switch until
the desired mode appears on the
display. Multiple presses will cycle
through the delivery selections.
Temperature Control : Press up or
down to increase or decrease the
airflow temperature into the rear
passenger area.
RCTRL : Press to lock or unlock
control of the rear climate control
system from the rear seat
passengers. When locked, the rear
climate control can only be adjusted
from the front seat. Remote Start Climate Control
Operation
If equipped with the remote start
feature, the climate control system
will come on when the vehicle is
started remotely, depending on the
outside temperature. The rear
window defogger and heated seats,
if equipped, may also come on. See
Remote Vehicle Start
023 and
Heated and Ventilated Front Seats
0 54.
SensorsThe solar sensor monitors the solar
heat. Do not cover the solar sensor
or the system will not work properly.