warning light GMC YUKON 2021 Owner's Guide

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
112 Instruments and Controls
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 0278. 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 (5.3L Engine)
0 277 or
Recommended Fuel (6.2L Engine) 0277.
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
0 306. 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 before the
system is ready for inspection. This can
happen if the 12-volt battery has recently
been replaced or run down, or if the
vehicle has been recently serviced.
See your dealer if the vehicle will not pass
or cannot be made ready for the test.
Brake System Warning Light
MetricEnglish
This light should come on briefly when the
vehicle is turned on. If it does not come on
then, have it fixed so it will be ready to
warn you if there is a problem.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Instruments and Controls 113
If the light comes on and stays on at start
up, there is a brake problem. Have the brake
system inspected right away.
If the light comes on while driving, pull off
the road and stop carefully. The brake
system has electric brake boost. Vehicle
speed may be limited when the brake
system warning light comes on. The brake
pedal might be harder to push, or the brake
pedal may go closer to the floor. It could
take longer to stop. If the light is still on,
have the vehicle towed for service. See
Towing the Vehicle0370.
{Warning
The brake system might not be working
properly if the brake system warning
light is on. Driving with the brake system
warning light on can lead to a crash.
If the light is still on after the vehicle has
been pulled off the road and carefully
stopped, have the vehicle towed for
service.
Electric Parking Brake Light
MetricEnglish
This light comes on when the parking brake
is applied. If the light continues flashing
after the parking brake is released, or while
driving, there is a problem with the Electric
Parking Brake system. A message may also
display in the Driver Information
Center (DIC).
If the light does not come on, or remains
flashing, see your dealer.
Service Electric Parking Brake
Light
This light should come on briefly when
starting the vehicle. If it does not come on,
have it fixed so it will be ready to warn if
there is a problem.
If this light stays on, take the vehicle to
your dealer as soon as possible. See the
information for the Electric Parking Brake
under Electric Parking Brake 0240.
A message may also display in the Driver
Information Center (DIC).
Antilock Brake System (ABS)
Warning Light
This warning light should come on briefly
when the vehicle is turned on. If the light
does not come on, have it fixed so it will be
ready to warn if there is a problem.
If the light comes on while driving, safely
stop as soon as it is possible and turn off
the vehicle. Then turn on the vehicle again
to reset the system.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
114 Instruments and Controls
If the ABS warning light stays on, or comes
on again while driving, the vehicle needs
service. A chime may also sound when the
light stays on.
If the ABS warning light is the only light on,
the vehicle has regular brakes, but ABS is
not functioning.
If both the ABS warning light and the brake
system warning light are on, ABS is not
functioning and there is a problem with the
regular brakes. See your dealer for service.
SeeBrake System Warning Light 0112.
Four-Wheel-Drive Light
Auto Mode Shown, Other Modes Similar
If equipped, the four-wheel-drive light
displays what mode the vehicle is in. The
light will show each mode: 2WD, 4HI, AUTO
(all transfer cases); 4LOW and N (two-speed
transfer case only). The light will flash when a shift is in
progress. Once the shift is complete the
light will be steady.
If the light turns amber, there may be a
malfunction with the four-wheel-drive
system. See your dealer.
See
Four-Wheel Drive 0236.
Hill Descent Control Light
If equipped, the Hill Descent Control light
comes on when the system is ready for use.
When the light flashes, the system is active.
See Hill Descent Control (HDC) 0244.
Lane Keep Assist (LKA) Light
After the vehicle is started, this light turns
off and stays off if LKA has not been turned
on or is unavailable.
If equipped, this light is white if LKA is
turned on, but not ready to assist.
This light is green if LKA is turned on and is
ready to assist.
LKA may assist by gently turning the
steering wheel if the vehicle approaches a
detected lane marking. The LKA light is
amber when assisting.
This light flashes amber as a Lane Departure
Warning (LDW) alert, to indicate that the
lane marking has been crossed.
LKA will not assist or alert if the turn signal
is active in the direction of lane departure,
or if LKA detects that you are accelerating,
braking or actively steering.
See Lane Keep Assist (LKA) 0275.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Instruments and Controls 115
Vehicle Ahead Indicator
If equipped, this indicator will display green
when a vehicle is detected ahead and amber
when you are following a vehicle ahead
much too closely.
SeeForward Collision Alert (FCA) System
0 267.
Pedestrian Ahead Indicator
If equipped, this indicator will display amber
when a nearby pedestrian is detected in
front of the vehicle.
See Front Pedestrian Braking (FPB) System
0 270.
Traction Off Light
This light comes on briefly while starting
the engine. If it does not, have the vehicle
serviced by your dealer. If the system is
working normally, the indicator light then
turns off.
The traction off light comes on when the
Traction Control System (TCS) has been
turned off by pressing and releasing the
TCS/StabiliTrak/ESC button.
This light and the StabiliTrak/ESC OFF light
come on when StabiliTrak/Electronic Stability
Control (ESC) is turned off.
If the TCS is off, wheel spin is not limited.
Adjust driving accordingly.
See Traction Control/Electronic Stability
Control 0242.
Traction Control System (TCS)/
Electronic Stability Control Light
If equipped, the Electronic Stability Control
(ESC) or TCS indicator/warning light comes
on briefly when the engine is started.
If the light does not come on, have the
vehicle serviced by your dealer. If the
system is working normally, the indicator
light turns off.
If the light is on and not flashing, the TCS,
and potentially the ESC system have been
disabled.
If the indicator/warning light is on and
flashing, the TCS and/or the ESC system is
actively working.
See Traction Control/Electronic Stability
Control 0242.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
116 Instruments and Controls
Trailer Sway Control Light
This light will flash when Trailer Sway
Control is active. SeeTrailer Sway Control
(TSC) 0295.
Electronic Stability Control (ESC)
Off Light
This light comes on briefly while starting
the engine. If it does not, have the vehicle
serviced by your dealer.
This light comes on when the ESC system is
turned off. If ESC is off, the Traction Control
System (TCS) is also off. If the ESC and TCS are off, the system does
not assist in controlling the vehicle. Turn on
the TCS and the ESC systems and the
warning light turns off.
See
Traction Control/Electronic Stability
Control 0242.
Engine Coolant Temperature
Warning Light
This light comes on briefly while starting
the vehicle.
If it does not, have the vehicle serviced by
your dealer. If the system is working
normally the indicator light goes off.
Caution
The engine coolant temperature warning
light indicates that the vehicle has
overheated. Driving with this light on can
(Continued)
Caution (Continued)
damage the engine and it may not be
covered by the vehicle warranty. See
Engine Overheating 0322.
The engine coolant temperature warning
light comes on when the engine has
overheated.
If this happens, pull over and turn off the
engine as soon as possible. See Engine
Overheating 0322.
Driver Mode Control Light
This light comes on when Sport Mode is
selected.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
118 Instruments and Controls
Tire Pressure Light
For vehicles with the Tire Pressure Monitor
System (TPMS), this light comes on briefly
when the engine is started. It provides
information about tire pressures and
the TPMS.
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
0 344.
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
0 347.
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
A Low Fuel Warning Light near the fuel
gauge comes on briefly when the ignition is
turned on as a check to show it is working.
For vehicles with a reconfigurable cluster,
this light is in the display area and may not
come on when the ignition is turned on.
It also comes on when the fuel gauge
indicator nears empty. 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-13690468) - 2021 - crc - 8/14/20
124 Instruments and Controls
Speed Limit Style Adjustment
If equipped, the speed limit style can be
changed to a speed limit bar or speed limit
sign from the Options menu in the
instrument cluster. Press the thumbwheel
while Speed Limit Style is highlighted to
change the speed sign style or to turn it off.
HUD Views
There are four views in the HUD. Some
vehicle information and vehicle messages or
alerts may be displayed in any view.
English Shown, Metric Similar
Speed View : This displays the speedometer
reading in English or metric units, and speed
limit. Some information only appears on
vehicles that have these features, and when
they are active.
English Shown, Metric Similar
Active Safety View : This displays the speed
view along with a driver assistance graphic
on the left. Driver assistance graphics show
your vehicle, vehicle ahead, gap setting, and
lane status information. In addition to driver
assistance graphics, pedestrian advisory and
trailer sway indicators will be displayed.
English Shown, Metric Similar Navigation/Active OnStar View :
This
displays the speed view along with
indicators for vehicle ahead, Lane Departure
Warning/Lane Keep Assist, trailer sway, and
pedestrian advisory. Turn-by-Turn navigation
information is shown during active route.
The compass heading is displayed when
navigation routing is not active.
Navigation Turn-by-Turn Alerts shown in the
instrument cluster may also be displayed in
any HUD view.
English Shown, Metric Similar
Off Road View : This displays the speed
view along with indicators for vehicle ahead,
Lane Departure Warning/Lane Keep Assist,
trailer sway, four-wheel drive status, and
pedestrian advisory. Off-road information
such as pitch angle, steering angle, and
rolling angle is also shown.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
134 Lighting
Lighting
Exterior Lighting
Exterior Lamp Controls . . . . . . . . . . . . . . . . 134
Exterior Lamps Off Reminder . . . . . . . . . . 136
Headlamp High/Low-Beam Changer . . . 136
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Daytime Running Lamps (DRL) . . . . . . . . . 136
Automatic Headlamp System . . . . . . . . . . 136
Hazard Warning Flashers . . . . . . . . . . . . . . 137
Turn and Lane-Change Signals . . . . . . . . . 138
Fog Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Interior Lighting
Instrument Panel IlluminationControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Reading Lamps . . . . . . . . . . . . . . . . . . . . . . . . 139
Lighting Features
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . . . . 140
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Battery Load Management . . . . . . . . . . . . 140
Battery Power Protection . . . . . . . . . . . . . . 141
Exterior Lighting Battery Saver . . . . . . . . . 141
Exterior Lighting
Exterior Lamp Controls
The exterior lamp control is on the
instrument panel to the left of the steering
wheel.
There are four positions:
O: Turns off the automatic headlamps and
Daytime Running Lamps (DRL). Turn the
headlamp control to
Oagain to turn the
automatic headlamps or DRL back on.
For vehicles first sold in Canada, the off
position will only work when the vehicle is
shifted into P (Park). AUTO :
Automatically turns on the
headlamps, parking lamps, taillamps,
instrument panel lights, roof marker lamps
(if equipped), and license plate lamps.
;: Turns on the parking lamps including
all lamps, except the headlamps.
2: Turns on the headlamps with the
parking lamps and instrument panel lights.
When the headlamps are turned on while
the vehicle is on, the headlamps turn off
automatically 10 minutes after the ignition
is turned off. When the headlamps are
turned on while the vehicle is off, the
headlamps will stay on for 10 minutes
before turning off to prevent the battery
from being drained. Turn the headlamp
control off and then back to the headlamp
on position to make the headlamps stay on
for an additional 10 minutes.
To keep the lamps on for more than
10 minutes, the ignition must be on or in
ACC/ACCESSORY.
IntelliBeam System
If equipped, this system turns the vehicle's
high-beam headlamps on and off according
to surrounding traffic conditions.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Lighting 137
There is a light sensor on top of the
instrument panel. Do not cover the sensor,
otherwise the headlamps will come on when
they are not needed.
The system may also turn on the headlamps
when driving through a parking garage or
tunnel.
If the vehicle is started in a dark garage, the
automatic headlamp system comes on
immediately. If it is light outside when the
vehicle leaves the garage, there is a slight
delay before the automatic headlamp
system changes to the DRL. During that
delay, the instrument cluster may not be as
bright as usual. Make sure the instrumentpanel brightness control is in the full bright
position. See
Instrument Panel Illumination
Control 0139.
When it is bright enough outside, the
headlamps will turn off or may change to
Daytime Running Lamps (DRL).
The automatic headlamp system turns off
when the exterior lamp control is turned to
Oor the ignition is off.
Lights On with Wipers
If the windshield wipers are activated in
daylight with the engine on, and the
exterior lamp control is in AUTO, the
headlamps, parking lamps, and other
exterior lamps come on. The transition time
for the lamps coming on varies based on
wiper speed. When the wipers are not
operating, these lamps turn off. Move the
exterior lamp control to
Oor;to disable
this feature.
Hazard Warning Flashers
Yukon/Yukon XL is shown, Denali similar
|: Press this button to make the front
and rear turn signal lamps flash on and off.
Press again to turn the flashers off.
When the hazard warning flashers are on,
the vehicle's turn signals will not work.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Infotainment System 195
Set Teen Driver Speed Warning :Displays a
warning in the DIC when exceeding a
selectable speed. Choose the desired speed
warning level. The speed warning does not
limit the speed of the vehicle.
SiriusXM Explicit Content Filter (if
equipped) : Allows the SiriusXM Explicit
Content Filter to be turned ON or OFF.
When ON, the teen driver will not be able
to listen to SiriusXM stations that contain
explicit content, and the Explicit Content
Filter selection in the Audio Settings will be
unavailable for change.
When Teen Driver is Active:
.If equipped with Buckle to Drive, shifting
out of P (Park) will be prevented if the
driver seat belt, and in some vehicles the
front passenger seat belt, is not buckled.
.The radio will mute when the driver seat
belt, and in some vehicles the front
passenger seat belt, is not buckled. The
audio from any device paired to the
vehicle will also be muted.
.An object placed on the front passenger
seat, such as a briefcase, handbag,
grocery bag, laptop, or other electronic
device, could cause the passenger sensing
system to falsely sense an unbuckled
front passenger and mute the radio. If this happens, remove the object from
the seat. See
Passenger Sensing System
0 66.
.Some safety systems, such as Forward
Collision Alert, if equipped, cannot be
turned off.
.The gap setting for the Forward Collision
Alert and Adaptive Cruise Control,
if equipped, cannot be changed.
.When trying to change a safety feature
that is not configurable in Teen Driver,
the DIC displays a message indicating
that Teen Driver is active and the action
is not available.
.Super Cruise, if equipped, is not available.
.Enhanced Low Fuel Warning (if equipped)
–When the vehicle is low on fuel, the
low fuel light on the instrument cluster
flashes and the DIC low fuel warning
cannot be dismissed.
.Do not tow a trailer.
Report Card
The vehicle owner must secure the driver’s
consent to record certain vehicle data when
the vehicle is driven with a registered Teen
Driver key. There is one Report Card per vehicle. Data is only recorded when a
registered Teen Driver key is used to
operate the vehicle.
The Report Card data is collected from the
time Teen Driver is activated or the last
time the Report Card was reset. The
following items may be recorded:
.Distance Driven
–the total distance
driven.
.Maximum Speed –the maximum vehicle
speed detected.
.Overspeed Warnings –the number of
times the speed warning setting was
exceeded.
.Wide Open Throttle –the number of
times the accelerator pedal was pressed
nearly all the way down.
.Forward Collision Alerts –the number of
times the driver was notified when
approaching a vehicle ahead too quickly
and at potential risk for a crash.
.Forward Automatic Braking, also called
Automatic Emergency Braking (if
equipped) –the number of times the
vehicle detected that a forward collision
was imminent and applied the brakes.