2020 GMC YUKON maint

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Instruments and Controls 137
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 fuel
funnel adapter, make sure that it
has been removed. See “Filling
the Tank with a Portable Gas
Can” under Filling the Tank
0 256. 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 (L83 5.3L
V8 Engine) 0254 or
Recommended Fuel (L86 6.2L
V8 Engine) 0254.
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 operation. See Add-On
Electrical Equipment 0280. See
your dealer if assistance is needed.
The vehicle may not pass
inspection if:
. The light is on when the engine
is running.
. The light does not come on
when the ignition is in
Service Mode.
. Critical emission control systems
have not been completely
diagnosed. If this happens, the
vehicle would not be ready for
inspection and might require
several days of routine driving

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
146 Instruments and Controls
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. It also shows if the
Active Fuel Management is active
and in V4 mode, or inactive and in
V8 mode. SeeActive Fuel
Management 0211.
The Instantaneous Fuel Economy
display shows the current fuel
economy in either liters per
100 kilometers (L/100 km) or miles
per gallon (mpg). This number
reflects only the approximate fuel
economy that the vehicle has right
now and changes frequently as
driving conditions change.
Timer and Fuel Used : Can be
used as a timer. To start the timer,
press
Vwhile 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
Vbriefly while this display is active and the timer is running. To
reset the timer to zero, press and
hold
Vwhile this display is active.
This also shows the number of
liters (L) or gallons (gal) of fuel used
since the last reset of this
menu item.
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 Oil0289.
In addition to the engine oil life
system monitoring the oil life,
additional maintenance is
recommended in the Maintenance
Schedule. See Maintenance
Schedule 0379.
The Oil Life display must be reset
after each oil change. It will not
reset itself. Do not to 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 the
engine oil life system, press and
holdVfor several seconds while
the Oil Life display is active. See
Engine Oil Life System 0291.
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 0335 and
Tire Pressure Monitor Operation
0 336.
Best Fuel Economy : Displays
average fuel economy, the best fuel
economy over the selected
distance, and a bar graph showing
instantaneous fuel economy.
Press
pto change the selected
distance. Press and hold
Vwhile
this display is active to reset the

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
Climate Controls 179
There is also an exterior
temperature sensor behind the front
grille. This sensor reads the outside
air temperature and helps maintain
the temperature inside the vehicle.
Any cover on the front of the
vehicle, including a snowplow, could
cause a false reading in the
displayed temperature.
The climate control system uses the
information from these sensors to
maintain comfort settings by
adjusting the outlet temperature, fan
speed, and air delivery mode. The
system may also supply cooler air to
the side of the vehicle facing the
sun. The recirculation mode will also
be used as needed to maintain cool
outlet temperatures.
Rear Climate Control
System
The rear climate control system is
located on the rear of the center
console storage. The rear climate
settings can be adjusted with this
system.
1. Fan Control
2. AUTO (Automatic Operation)
3. MODE (Air Delivery ModeControl)
4. TEMP (Temperature Control)
5. Heated Rear Seats (If Equipped)
If the dual automatic climate control
system rear climate control lockout
feature is locked, the rear climate
control settings can only be
adjusted from the front seat.
Automatic Operation
AUTO : Press AUTO to
automatically control the
temperature, air delivery, and fan
speed for rear seat passengers. A is
indicated in the display when
automatic operation is active.
If any of the rear climate control
settings are manually adjusted, full
automatic operation is cancelled.
Press AUTO to return to full
automatic operation.
The display only indicates climate
control functions when the system is
in rear independent mode.
Manual Operation
9: Turn clockwise or
counterclockwise to increase or
decrease the fan speed. Turn
completely counterclockwise to turn
the fan/power off.
TEMP : Turn clockwise or
counterclockwise to increase or
decrease the airflow temperature
into the passenger area. If the
SYNC button is pressed on the front

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Climate Controls 181
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.
SeeMaintenance Schedule 0379.
To find out what type of filter to use,
see Maintenance Replacement
Parts 0390.
1. Open the glove box completely. 2. Disconnect the glove box door
damper string from the glove
box door assembly. A pen or
pencil may be inserted through
the end of the damper string to
prevent the string from slipping
inside the door assembly.
3. Remove the six screws and
remove the access plate.
4. Release the two tabs holdingthe service door. Open the
service door and remove the
old filter.
5. Install the new air filter.
6. Close the service door and secure the tabs.
7. Reverse the steps to reinstall the glove box.
See your dealer if additional
assistance is needed.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
182 Climate Controls
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 Schedule0379.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
184 Driving and Operating
Recommended Fuel (L86 6.2LV8 Engine) . . . . . . . . . . . . . . . . . . 254
Prohibited Fuels . . . . . . . . . . . . . . 255
Fuels in Foreign Countries . . . 255
Fuel Additives . . . . . . . . . . . . . . . . 255
E85 or FlexFuel . . . . . . . . . . . . . . 255
Filling the Tank . . . . . . . . . . . . . . . 256
Filling a Portable Fuel Container . . . . . . . . . . . . . . . . . . . 258
Trailer Towing
General TowingInformation . . . . . . . . . . . . . . . . . . 259
Driving Characteristics and Towing Tips . . . . . . . . . . . . . . . . . 259
Trailer Towing . . . . . . . . . . . . . . . . 264
Towing Equipment . . . . . . . . . . . . 270
Trailer Sway Control (TSC) . . . 278
Conversions and Add-Ons
Add-On Electrical Equipment . . . . . . . . . . . . . . . . . . 280
Driving Information
Driving for Better Fuel
Economy
Driving habits can affect fuel
mileage. Here are some driving tips
to get the best fuel economy
possible:
. Set the climate controls to the
desired temperature after the
engine is started, or turn them
off when not required.
. Avoid fast starts and accelerate
smoothly.
. Brake gradually and avoid
abrupt stops.
. Avoid idling the engine for long
periods of time.
. When road and weather
conditions are appropriate, use
cruise control.
. Always follow posted speed
limits or drive more slowly when
conditions require.
. Keep vehicle tires properly
inflated. .
Combine several trips into a
single trip.
. Replace the vehicle's tires with
the same TPC Spec number
molded into the tire's sidewall
near the size.
. Follow recommended scheduled
maintenance.
Distracted Driving
Distraction comes in many forms
and can take your focus from the
task of driving. Exercise good
judgment and do not let other
activities divert your attention away
from the road. Many local
governments have enacted laws
regarding driver distraction. Become
familiar with the local laws in
your area.
To avoid distracted driving, keep
your eyes on the road, keep your
hands on the steering wheel, and
focus your attention on driving.