
Black plate (20,1)GMC 2015i Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431503) - 2015 - crc - 8/11/14
5-20 Instruments and Controls
a check to show the light is working.
It should go out when the engine is
started.
If the light stays on, or comes on
while driving, there may be a
problem with the electrical charging
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.
SeeBattery Voltage and Charging
Messages on page 5-31.
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
A computer system called OBD II
(On-Board Diagnostics-Second
Generation) monitors the operation
of the vehicle to ensure emissions are at acceptable levels, helping to
maintain a clean environment. The
malfunction indicator lamp comes
on when the vehicle is placed in
ON/RUN, as a check to show it is
working. If it does not, have the
vehicle serviced by your dealer. See
Ignition Positions (Key Access) on
page 9-20
orIgnition Positions
(Keyless Access) on page 9-22.
If the malfunction indicator lamp
comes on while the engine is
running, this indicates that the OBD
II system has detected a problem
and diagnosis and service might be
required.
Malfunctions often are indicated by
the system before any problem is
apparent. Being aware of the light
can prevent more serious damage
to the vehicle. This system also assists the service technician in
correctly diagnosing any
malfunction.
{Caution
If the vehicle is continually driven
with this light on, the emission
controls might not work as well,
the vehicle fuel economy might
not be as good, and the engine
might not run as smoothly. This
could lead to costly repairs that
might not be covered by the
vehicle warranty.
{Caution
Modifications made to the engine,
transmission, exhaust, intake,
or fuel system of the vehicle or
the replacement of the original
tires with other than those of the
same Tire Performance Criteria
(Continued)

Black plate (24,1)GMC 2015i Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431503) - 2015 - crc - 8/11/14
5-24 Instruments and Controls
Tow/Haul Mode Light
For vehicles with the Tow/Haul
Mode feature, this light comes on
when the Tow/Haul Mode has been
activated.
SeeTow/Haul Mode on page 9-36.
Lane Departure Warning
(LDW) Light
If equipped, this light comes on
briefly while starting the vehicle. If it does not come on, have the
vehicle serviced.
This light is green if LDW is on and
ready to operate.
This light changes to amber and
flashes to indicate that the lane
marking has been crossed without
using a turn signal in that direction.
See
Lane Departure Warning (LDW)
on page 9-68.
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.
See Forward Collision Alert (FCA)
System on page 9-61.
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
button.
This light and the StabiliTrak OFF
light come on when StabiliTrak is
turned off.
If the TCS is off, wheel spin is not
limited. Adjust driving accordingly.
See Traction Control/Electronic
Stability Control on page 9-44.

Black plate (25,1)GMC 2015i Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431503) - 2015 - crc - 8/11/14
Instruments and Controls 5-25
StabiliTrak®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
StabiliTrak system is turned off.
If StabiliTrak is off, the Traction
Control System (TCS) is also off.
If the StabiliTrak and TCS are off,
the system does not assist in
controlling the vehicle. Turn on the
TCS and the StabiliTrak systems
and the warning light turns off.
SeeTraction Control/Electronic
Stability Control on page 9-44.
Traction Control System
(TCS)/StabiliTrak®Light
This 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 StabiliTrak
system have been disabled. A DIC
message may display. Check the
DIC messages to determine which
feature(s) is no longer functioning
and whether the vehicle requires
service. If the indicator/warning light is on
and flashing, the TCS and/or the
StabiliTrak system is actively
working.
See
Traction Control/Electronic
Stability Control on page 9-44.
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.

Black plate (26,1)GMC 2015i Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431503) - 2015 - crc - 8/11/14
5-26 Instruments and Controls
A Driver Information Center (DIC)
tire pressure message may also
display. SeeTire Messages on
page 5-40. Stop as soon as
possible, and inflate the tires to the
pressure value shown on the Tire
and Loading Information label. See
Tire Pressure on page 10-51.
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 on page 10-54.
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.
Security Light
The security 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
system is working normally, the
indicator light turns off. If the light stays on and the engine
does not start, there could be a
problem with the theft-deterrent
system. See
Immobilizer Operation
(Keyless Access) on page 2-27 or
Immobilizer Operation (Key Access)
on page 2-26.
High-Beam On Light
This light comes on when the
high-beam headlamps are in use.
See Headlamp High/Low-Beam
Changer on page 6-2.

Black plate (35,1)GMC 2015i Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431503) - 2015 - crc - 8/11/14
Instruments and Controls 5-35
possible and have the vehicle
serviced by your dealer. SeeEngine
Oil on page 10-6.
Engine Power Messages
ENGINE POWER IS REDUCED
This message displays and a chime
may sound when the cooling system
temperature gets too hot and the
engine further enters the engine
coolant protection mode. See
Engine Overheating on page 10-18
for more information.
This message also displays when
the vehicle's engine power is
reduced. Reduced engine power
can affect the vehicle's ability to
accelerate. If this message is on,
but there is no reduction in
performance, proceed to your
destination. The performance may
be reduced the next time the vehicle
is driven. The vehicle may be driven
at a reduced speed while this
message is on, but acceleration and
speed may be reduced. Anytime this message stays on, the vehicle
should be taken to your dealer for
service as soon as possible.
Fuel System Messages
FUEL LEVEL LOW
This message displays and a chime
may sound if the fuel level is low.
Refuel as soon as possible. See
Fuel Gauge on page 5-14
andFuel
on page 9-69.
TIGHTEN GAS CAP
This message may display along
with the malfunction indicator lamp
on the instrument cluster if the
vehicle's fuel cap is not tightened
properly. See Malfunction Indicator
Lamp on page 5-20. Reinstall the
fuel cap fully. See Filling the Tank
on page 9-72. The diagnostic
system can determine if the fuel cap
has been left off or improperly
installed. A loose or missing fuel
cap allows fuel to evaporate into the atmosphere. A few driving trips with
the cap properly installed should
turn this light and message off.
Key and Lock Messages
NO REMOTE DETECTED
This message displays when the
transmitter battery may be weak.
See
“Starting the Vehicle with a Low
Transmitter Battery” underRemote
Keyless Entry (RKE) System
Operation (Key) on page 2-5 or
Remote Keyless Entry (RKE)
System Operation (Keyless) on
page 2-8.
NO REMOTE KEY WAS
DETECTED PLACE KEY IN
TRANSMITTER POCKET THEN
START YOUR VEHICLE
This message displays when trying
to start the vehicle if an RKE
transmitter is not detected. The
transmitter battery may be weak.

Black plate (22,1)GMC 2015i Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431503) - 2015 - crc - 8/11/14
9-22 Driving and Operating
2 (ACC/ACCESSORY):This
position lets things like the radio
and the windshield wipers operate
while the engine is off. It also
unlocks the steering wheel. Use this
position if the vehicle must be
pushed or towed.
3 (ON/RUN): This position can be
used to operate the electrical
accessories and to display some
instrument cluster warning and
indicator lights. This position can
also be used for service and
diagnostics, and to verify the proper
operation of the malfunction
indicator lamp as may be required
for emission inspection purposes.
The switch stays in this position
when the engine is running. The
transmission is also unlocked in this
position on automatic transmission
vehicles.
If the key is left in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. The vehicle may not
start if the battery is allowed to drain
for an extended period of time. 4 (START):
This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.
A warning tone will sound when the
driver door is opened and the
ignition is in ACC/ACCESSORY or
LOCK/OFF, and the key is in the
ignition.
Ignition Positions
(Keyless Access)
Vehicles with Keyless Access have
pushbutton starting.
Pressing the button cycles it through
three modes: ACC/ACCESSORY,
ON/RUN/START, and Stopping the
Engine/OFF.
The transmitter must be in the
vehicle for the system to operate.
If the pushbutton start is not
working, the vehicle may be near a
strong radio antenna signal causing
interference to the Keyless Access
system. See Remote Keyless Entry
(RKE) System Operation (Key) on
page 2-5 orRemote Keyless Entry
(RKE) System Operation (Keyless)
on page 2-8.
To shift out of P (Park), the vehicle
must be in ACC/ACCESSORY or
ON/RUN and the brake pedal must
be applied.
Stopping the Engine/LOCK/
OFF (No Indicator Lights): When
the vehicle is stopped, press the
ENGINE START/STOP button once
to turn the engine off.

Black plate (23,1)GMC 2015i Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
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Driving and Operating 9-23
If the vehicle is in P (Park), the
ignition will turn off, and Retained
Accessory Power (RAP) will remain
active. SeeRetained Accessory
Power (RAP) on page 9-27.
If the vehicle is not in P (Park), the
ignition will return to ACC/
ACCESSORY and display the
message SHIFT TO PARK in the
Driver Information Center (DIC).
See Transmission Messages on
page 5-41. When the vehicle is
shifted into P (Park), the ignition
system will switch to OFF.
Do not turn the engine off when the
vehicle is moving. This will cause a
loss of power assist in the brake
and steering systems and disable
the airbags.
The vehicle may have an electric
steering column lock. The lock is
activated when the vehicle is
switched to OFF and either front
door is opened. A sound may be
heard as the lock actuates or
releases. The steering column lock
may not release with the wheels turned off center. If this happens,
the vehicle may not start. Move the
steering wheel from left to right
while attempting to start the vehicle.
If this does not work, the vehicle
needs service.
If the vehicle must be shut off in an
emergency:
1. Brake using a firm and steady
pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. After shifting
to N (Neutral), firmly apply the
brakes and steer the vehicle to a
safe location.
3. Come to a complete stop, shift to P (Park), and turn the ignition
to OFF. On vehicles with an
automatic transmission, the shift
lever must be in P (Park) to turn
the ignition switch to the OFF
position. 4. Set the parking brake. See
Parking Brake on page 9-42.
{Warning
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering
systems and disable the airbags.
While driving, only shut the
vehicle off in an emergency.
If the vehicle cannot be pulled over,
and must be shut off while driving,
press and hold the ENGINE START/
STOP button for longer than
two seconds, or press twice in
five seconds.
ACC/ACCESSORY (Amber
Indicator Light): This mode allows
some electrical accessories to be
used when the engine is off.
With the ignition off, pressing the
button one time without the brake
pedal applied will place the ignition
system in ACC/ACCESSORY.

Black plate (24,1)GMC 2015i Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431503) - 2015 - crc - 8/11/14
9-24 Driving and Operating
The ignition will switch from ACC/
ACCESSORY to OFF after
five minutes to prevent battery
rundown.
ON/RUN/START (Green Indicator
Light):This mode is for driving and
starting. With the ignition off, and
the brake pedal applied, pressing
the button once will place the
ignition system in ON/RUN/START.
Once engine cranking begins,
release the button. Engine cranking
will continue until the engine starts.
See Starting the Engine on
page 9-24. The ignition will then
remain in ON/RUN.
Service Only Mode
This power mode is available for
service and diagnostics, and to
verify the proper operation of the
malfunction indicator lamp as may
be required for emission inspection
purposes. With the vehicle off, and
the brake pedal not applied,
pressing and holding the button for
more than five seconds will place
the vehicle in Service Only Mode. The instruments and audio systems
will operate as they do in ON/RUN,
but the vehicle will not be able to be
driven. The engine will not start in
Service Only Mode. Press the
button again to turn the vehicle off.
Starting the Engine
Move the shift lever to P (Park) or
N (Neutral). The engine will not start
in any other position. To restart the
engine when the vehicle is already
moving, use N (Neutral) only.
{Caution
Do not try to shift to P (Park) if the
vehicle is moving. If you do, you
could damage the transmission.
Shift to P (Park) only when the
vehicle is stopped.
{Caution
If you add electrical parts or
accessories, you could change
the way the engine operates. Any
resulting damage would not be
covered by the vehicle warranty.
See
Add-On Electrical Equipment
on page 9-89.
Starting Procedure (Key
Access)
1. With your foot off the accelerator pedal, turn the ignition key to
START. When the engine starts,
let go of the key. The idle speed
will go down as the engine gets
warm. Do not race the engine
immediately after starting it.
Operate the engine and
transmission gently to allow the
oil to warm up and lubricate all
moving parts.
When the low fuel warning lamp
is on and the FUEL LEVEL LOW
message is displayed in the