2015 GMC YUKON warning light

Black plate (22,1)GMC Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7063682) - 2015 - CRC - 6/5/14
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)
The vehicle has an electronic
keyless ignition with pushbutton
start.
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 (Keyless
Access) on page 2-7 orRemote
Keyless Entry (RKE) System
Operation (Key Access) on
page 2-5.
To shift out of P (Park), the vehicle
must be in ACC/ACCESSORY or
ON/RUN and the brake pedal must
be applied.

Black plate (24,1)GMC Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7063682) - 2015 - CRC - 6/5/14
9-24 Driving and Operating
{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. 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.

Black plate (37,1)GMC Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7063682) - 2015 - CRC - 6/5/14
Driving and Operating 9-37
{Warning
Shifting the transfer case to
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). You or someone else
could be seriously injured. Be
sure to set the parking brake
before placing the transfer case in
N (Neutral). SeeParking Brake on
page 9-42.
{Caution
Extended high-speed operation in
4
nmay damage or shorten the
life of the drivetrain.
Engagement noise and bump when
shifting between 4
nand 4mor from
N (Neutral), with the engine running,
is normal. Shifting into 4
nwill turn Traction
Control and StabiliTrak®off. See
Traction Control/Electronic Stability
Control on page 9-44.
Two Speed Automatic
Transfer Case
Use the transfer case knob next to
the steering wheel to shift into and
out of four-wheel drive.
Indicator lights display which setting
the transfer case is in. N (Neutral) is
indicated on the knob. The indicator
lights will display briefly when the ignition is turned on and one will
stay on. If the lights display
momentarily when the ignition is in
ON/RUN, but none stay on, the
knob may have been turned while
the vehicle was off. To see the
indicator, turn the knob to another
position so that it matches the
actual transfer case setting. If no
lights display, take the vehicle to
your dealer for service. An indicator
light flashes while shifting the
transfer case and remains
illuminated when the shift is
complete.
If the transfer case cannot make a
requested shift, it will return to the
last chosen setting. Turn the knob
back to the previous transfer case
setting to see the indicator.
The settings are:
N (Neutral):
Use only when the
vehicle needs to be towed. See
Recreational Vehicle Towing on
page 10-80 orTowing the Vehicle
on page 10-80.

Black plate (41,1)GMC Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7063682) - 2015 - CRC - 6/5/14
Driving and Operating 9-41
The settings are:
2
m(Two-Wheel Drive High):Use
for driving on most streets and
highways. The front axle is not
engaged. This setting provides the
best fuel economy.
AUTO (Automatic Four-Wheel
Drive): Use when road surface
traction conditions are variable.
When driving in AUTO, the front
axle is engaged, and the vehicle's
power is sent to the front and rear
wheels automatically based on
driving conditions. This setting
provides slightly lower fuel economy
than 2
m.
Do not use AUTO mode to park on
a steep grade with poor traction
such as ice, snow, mud, or gravel.
In AUTO mode only the rear wheels
will hold the vehicle from sliding
when parked. If parking on a steep
grade, use 4
mto keep all four
wheels engaged. 4
m(Four-Wheel Drive High):
Use
this position when extra traction is
needed, such as when driving on
snowy or icy roads, when
off-roading, or when plowing snow.
Service Four-Wheel Drive
If the SERVICE 4WD message
stays on, you should take the
vehicle to your dealer for service.
See “SERVICE 4WD” message
under Transmission Messages on
page 5-40.
Shifting Into 4
mor AUTO
Turn the knob to the 4
mor AUTO
position. This can be done at any
speed. The indicator light will flash
while shifting. It will remain on when
the shift is completed.
Shifting Into 2
m
Turn the knob to the 2mposition.
This can be done at any speed.
The indicator light will flash while
shifting. It will remain on when the
shift is completed.
Brakes
Antilock Brake
System (ABS)
This vehicle has ABS, an advanced
electronic braking system that helps
prevent a braking skid.
When the vehicle begins to drive
away, ABS checks itself.
A momentary motor or clicking noise
might be heard while this test is
going on, and it might even be
noticed that the brake pedal moves
a little. This is normal.
If there is a problem with ABS, this
warning light stays on. See Antilock
Brake System (ABS) Warning Light
on page 5-22.

Black plate (42,1)GMC Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7063682) - 2015 - CRC - 6/5/14
9-42 Driving and Operating
If driving safely on a wet road and it
becomes necessary to slam on the
brakes and continue braking to
avoid a sudden obstacle, a
computer senses the wheels are
slowing down. If one of the wheels
is about to stop rolling, the computer
will separately work the brakes at
each wheel.
ABS can change the brake pressure
to each wheel, as required, faster
than any driver could. This can help
you steer around the obstacle while
braking hard.
As the brakes are applied, the
computer keeps receiving updates
on wheel speed and controls
braking pressure accordingly.
Remember: ABS does not change
the time needed to get a foot up to
the brake pedal or always decrease
stopping distance. If you get too
close to the vehicle in front of you,
there will not be enough time to
apply the brakes if that vehiclesuddenly slows or stops. Always
leave enough room up ahead to
stop, even with ABS.
Using ABS
Do not pump the brakes. Just hold
the brake pedal down firmly and let
ABS work. You may hear the ABS
pump or motor operating and feel
the brake pedal pulsate. This is
normal.
Braking in Emergencies
ABS allows you to steer and brake
at the same time. In many
emergencies, steering can help
more than even the very best
braking.
Parking Brake
Set the parking brake by holding the
regular brake pedal down, then
pushing down the parking brake
pedal.
If the ignition is on, the brake
system warning light will come on.
See
Brake System Warning Light on
page 5-21.

Black plate (43,1)GMC Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7063682) - 2015 - CRC - 6/5/14
Driving and Operating 9-43
{Caution
Driving with the parking brake on
can overheat the brake system
and cause premature wear or
damage to brake system parts.
Make sure that the parking brake
is fully released and the brake
warning light is off before driving.
To release the parking brake, hold
the regular brake pedal down, then
push down momentarily on the
parking brake pedal until you feel
the pedal release. Slowly pull your
foot up off the parking brake pedal.
If the parking brake is not released
when you begin to drive, the brake
system warning light will flash and a
chime will sound warning you that
the parking brake is still on.
If you are towing a trailer and are
parking on a hill, see Driving
Characteristics and Towing Tips on
page 9-74.
Brake Assist
The Brake Assist feature is
designed to assist the driver in
stopping or decreasing vehicle
speed in emergency driving
conditions. This feature uses the
stability system hydraulic brake
control module to supplement the
power brake system under
conditions where the driver has
quickly and forcefully applied the
brake pedal in an attempt to quickly
stop or slow down the vehicle. The
stability system hydraulic brake
control module increases brake
pressure at each corner of the
vehicle until the ABS activates.
Minor brake pedal pulsation or
pedal movement during this time is
normal and the driver should
continue to apply the brake pedal as
the driving situation dictates The
Brake Assist feature will
automatically disengage when the
brake pedal is released or brake
pedal pressure is quickly
decreased.
Hill Start Assist (HSA)
Vehicles with StabiliTrak have an
HSA feature, which may be useful
when the vehicle is stopped on a
grade. This feature is designed to
prevent the vehicle from rolling,
either forward or rearward, during
vehicle drive off. After the driver
completely stops and holds the
vehicle in a complete standstill on a
grade, HSA will be automatically
activated. During the transition
period between when the driver
releases the brake pedal and starts
to accelerate to drive off on a grade,
HSA holds the braking pressure for
a maximum of two seconds to
ensure that there is no rolling. The
brakes will automatically release
when the accelerator pedal is
applied within the two-second
window. If the vehicle is equipped
with the Integrated Trailer Brake
Control (ITBC) system, HSA may
also apply the trailer brakes. It will

Black plate (55,1)GMC Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7063682) - 2015 - CRC - 6/5/14
Driving and Operating 9-55
times. See“Collision/Detection
Systems” underVehicle
Personalization on page 5-43.
See Defensive Driving on page 9-3.
Approaching and Following a
Vehicle
The vehicle ahead symbol is in the
instrument cluster.
The vehicle ahead symbol only
displays when a vehicle is detected
in your vehicle’s path moving in the
same direction.
If this symbol is not displaying, ACC
will not respond to or brake to
vehicles ahead.
ACC automatically slows the vehicle
down and adjusts vehicle speed to
follow the vehicle in front at the
selected follow gap. The vehicle speed increases or decreases to
follow the vehicle in front of you, but
will not exceed the set speed. It may
apply limited braking, if necessary.
When braking is active, the brake
lights will come on. The automatic
braking may feel or sound different
than if the brakes were applied
manually. This is normal.
Stationary or Very Slow-Moving
Objects
{Warning
Adaptive Cruise Control (ACC)
may not detect and react to
stopped or slow-moving vehicles
ahead of you. For example, the
system may not brake for a
vehicle that it has never detected
moving. This can occur in
stop-and-go traffic or when a
vehicle suddenly appears due to
a vehicle ahead changing lanes.
Your vehicle may not stop and
could cause a crash. Use caution
(Continued)
Warning (Continued)
when using ACC. Your complete
attention is always required while
driving and you should be ready
to take action and apply the
brakes.
ACC Automatically Disengages
ACC may automatically disengage
and the driver will need to manually
apply the brakes to slow the
vehicle when:
.Your vehicle speed goes below
the minimum speed of 25 km/h
(16 mph).
.The sensors are blocked.
.The Traction Control System
(TCS) or electronic stability
control system has activated or
been disabled.
.No traffic or other objects are
being detected.
.There is a fault in the system.

Black plate (62,1)GMC Yukon/Yukon XL Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7063682) - 2015 - CRC - 6/5/14
9-62 Driving and Operating
Assistance Systems for
Driving
If equipped, when driving the
vehicle forward, Forward Collision
Alert (FCA), Lane Departure
Warning (LDW), Side Blind Zone
Alert (SBZA), Lane Change Alert
(LCA), and/or the Active Emergency
Braking System can help to avoid a
crash or reduce crash damage.
Forward Collision Alert
(FCA) System
If equipped, the FCA system may
help to avoid or reduce the harm
caused by front-end crashes. When
approaching a vehicle ahead too
quickly, FCA provides a red flashing
alert on the windshield and rapidly
beeps or pulses the driver seat.
FCA also lights an amber visual
alert if following another vehicle
much too closely.
FCA detects vehicles within a
distance of approximately 60 m
(197 ft) and operates at speedsabove 40 km/h (25 mph). If the
vehicle has Adaptive Cruise Control
(ACC), it can detect vehicles to
distances of approximately 110 m
(360 ft) and operates at all speeds.
See
Adaptive Cruise Control on
page 9-51.
{Warning
FCA is a warning system and
does not apply the brakes. When
approaching a slower-moving or
stopped vehicle ahead too rapidly,
or when following a vehicle too
closely, FCA may not provide a
warning with enough time to help
avoid a crash. FCA does not warn
of pedestrians, animals, signs,
guardrails, bridges, construction
barrels, or other objects. Be ready
to take action and apply the
brakes. For more information, see
Defensive Driving on page 9-3. FCA can be disabled with the FCA
steering wheel control, or if your
vehicle is equipped with Adaptive
Cruise Control (ACC), through
vehicle personalization. See the
“Auto Collision Preparation”
portion
of “Collision/Detection Systems”
under Vehicle Personalization on
page 5-43.Detecting the Vehicle Ahead
FCA warnings will not occur unless
the FCA system detects a vehicle
ahead. When the vehicle is
detected, the vehicle-ahead
indicator will display green. Vehicles
may not be detected on curves,
highway exit ramps, or hills; or due
to poor visibility. FCA will not detect
another vehicle ahead until it is
completely in the driving lane.