GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Driving and Operating 203
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 off. On vehicles with an
automatic transmission, the
shift lever must be in P (Park)
to turn the ignition off.
4. Set the parking brake. See Parking Brake 0225.
{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 ENGINE START/
STOP 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 turn the ignition
on. Once engine cranking begins,
release the button. Engine cranking
will continue until the engine starts.
See Starting the Engine 0206. Service 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 Mode. The
instruments and audio systems will
operate as they do when the ignition
is on, but the vehicle will not be able
to be driven. The engine will not
start in Service Mode. Press the
button again to turn the ignition off.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
204 Driving and Operating
Ignition Positions (Key
Access)
0. Stopping the Engine/LOCK/OFF
1. ACC/ACCESSORY
2. ON/RUN
3. START
The ignition switch has four
positions.
To shift out of P (Park), the ignition
must be in ON/RUN and the brake
pedal must be applied.0 (Stopping the Engine/LOCK/
OFF) :
This position turns off the
vehicle. It also locks the ignition, the
transmission, and the steering
column, if equipped with a locking
steering column.
To turn off the vehicle:
1. Make sure that the vehicle is stopped.
2. Shift to P (Park).
3. Continue to hold the brake pedal, then set the parking
brake. See Parking Brake
0 225. 4. Push the key all the way in the
steering column (1), then turn
the key to LOCK/OFF (2).
5. Remove the key.
6. Release the brake pedal.
See your dealer if the key can be
removed in any other position.
Retained Accessory Power (RAP)
will remain active. See Retained
Accessory Power (RAP) 0209.
A warning chime will sound when
the driver door is opened and the
key is in the ignition.
If equipped with a locking steering
column, the steering can bind with
the front wheels turned off center,
which may prevent key rotation out
of LOCK/OFF. If this happens, move
the steering wheel from right to left
while turning the key to ACC/
ACCESSORY. If this does not work,
then the vehicle needs service.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Driving and Operating 205
{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, turn off the vehicle
only in an emergency.
In an emergency, if the vehicle
cannot be pulled over and must be
turned off while driving: 1. Push the key all the way in toward the steering column,
then turn the key to ACC/
ACCESSORY.
2. Brake using firm and steady pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
3. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. Continue
braking and steer the vehicle to
a safe location.
4. Come to a complete stop. 5. Shift to P (Park).
6. Push the key all the way in
toward the steering column (1),
then turn the ignition to
LOCK/OFF (2).
7. Set the parking brake. See Parking Brake 0225.
8. Remove the key.
9. Release the brake pedal.
Caution
Use the correct key, make sure it
is all the way in —or pushed all
the way in toward the steering
column when turning off the
vehicle —and turn it only with
your hand.
1 (ACC/ACCESSORY) : This
position allows features such as the
infotainment system to operate
while the vehicle is off. It also
unlocks the steering column,
if equipped with a locking steering
column. Use this position if the vehicle must be pushed or towed.
See
Retained Accessory Power
(RAP) 0209.
From ON/RUN, push the key all the
way in toward the steering column,
then turn the key to ACC/
ACCESSORY.
If the key is left in ACC/
ACCESSORY with the engine off,
the battery could drain and the
vehicle may not start.
A warning chime will sound when
the driver door is opened and the
key is in the ignition.
2 (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.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Driving and Operating 209
away from moving engine
parts. If you do not, it could be
damaged.
The length of time the heater should
remain plugged in depends on
several factors. Ask a dealer in the
area where you will be parking the
vehicle for the best advice on this.
Retained Accessory
Power (RAP)
When the ignition is turned from on
to off, the following features (if
equipped) will continue to function
for up to 10 minutes, or until the
driver door is opened. These
features will also work when the
ignition is in RUN or ACC/
ACCESSORY:
. Infotainment System
. Power Windows (during RAP
this functionality will be lost
when any door is opened)
. Sunroof (during RAP this
functionality will be lost when
any door is opened)
. Auxiliary Power Outlet .
Audio System
. OnStar System
Shifting Into Park
{Warning
It can be dangerous to get out of
the vehicle if the shift lever is not
fully in P (Park) with the parking
brake firmly set. The vehicle can
roll. If you have left the engine
running, the vehicle can move
suddenly. You or others could be
injured. To be sure the vehicle will
not move, even when you are on
fairly level ground, use the steps
that follow. If the vehicle has a
four-wheel-drive transfer case
with an N (Neutral) position, and
the transfer case is in N (Neutral),
the vehicle will be free to roll,
even if the shift lever is in
P (Park). Be sure the transfer
case is in a drive gear. If towing a
trailer, see Driving Characteristics
and Towing Tips 0259. 1. Hold the brake pedal down,
then set the parking brake. See
Parking Brake 0225.
2. Move the shift lever into the P (Park) position by pulling the
shift lever toward you and
moving it up as far as it will go.
3. Be sure the transfer case is in a drive gear –not in
N (Neutral).
4. Push the ignition key in, towards the steering column
and then turn the ignition off.
5. Remove the key and take it with you. If you can leave the
vehicle with the ignition key in
your hand, the vehicle is in
P (Park).
Leaving the Vehicle with the
Engine Running
{Warning
It can be dangerous to leave the
vehicle with the engine running.
The vehicle could move suddenly
(Continued)
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Driving and Operating 219
To disable or enable Tow/Haul
Grade Braking within the current
ignition cycle, press and hold the
Tow/Haul button for five seconds.
When the button is released, the
requested mode change is made.
A DIC message is displayed.
SeeTowing Equipment 0270.
For other forms of grade braking,
see Automatic Transmission 0213
and
Cruise Control 0230.Drive Systems
Four-Wheel Drive
If equipped, four-wheel drive
engages the front axle for extra
traction.
Caution
Do not drive on clean, dry
pavement in 4
mand 4n(if
equipped) for an extended period
of time. These conditions may
cause premature wear on the
vehicle’s powertrain.
Driving on clean, dry pavement in 4
mor 4nmay:
. Cause a vibration to be felt in
the steering system.
. Cause tires to wear faster.
. Make the transfer case harder to
shift, and cause it to run noisier.
{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). See Parking Brake
0 225.
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.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
220 Driving and Operating
Shifting into 4nwill turn Traction
Control and StabiliTrak/Electronic
Stability Control off. See Traction
Control/Electronic Stability Control
0 226.
Two Speed Automatic
Transfer Case
If equipped, use the transfer case
knob next to the steering wheel to
shift into and out of four-wheel drive.
All of the lights will blink on then off
momentarily when the ignition
turned on. The light that remains on
will indicate the state of the
transfer case. If the indicator mark on the switch
does not match up with the light
then that likely means the switch
was moved when the ignition
was off.
The indicator mark on the switch
must line up with the indicator light
before a shift can be commanded.
To command a shift rotate the
transfer case switch to the new
desired position. The light will blink
meaning that the shift is in progress.
When the shift is completed the new
position will be illuminated. If the
transfer case cannot complete a
shift command, it will go back to its
last chosen setting.
The settings are:
N (Neutral) :
Use only when the
vehicle needs to be towed. See
Recreational Vehicle Towing 0364
or
Towing the Vehicle 0363.
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,
if equipped, 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.
4
n(Four-Wheel Drive Low) : This
setting engages the front axle and
delivers extra torque. Choose 4
n
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Driving and Operating 223
Single Speed Automatic
Transfer Case
Use the transfer case knob, next to
the steering wheel, to shift into and
out of four-wheel drive for extra
traction.
All of the lights will blink on then off
momentarily when the ignition is
turned on. The light that remains on
will indicate the state of the
transfer case.If the indicator mark on the switch
does not match up with the light
then that likely means the switch
was moved when the ignition
was off.
The indicator mark on the switch
must line up with the indicator light
before a shift can be commanded.
To command a shift rotate the
transfer case switch to the new
desired position. The light will blink
meaning that the shift is in progress.
When the shift is completed the new
position will be illuminated. If the
transfer case can not complete a
shift command, it will go back to its
last chosen setting.
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 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.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
224 Driving and Operating
Shifting Into 4mor 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)
The Antilock Brake System (ABS)
helps prevent a braking skid and
maintain steering while
braking hard.
ABS performs a system check when
the vehicle is first driven.
A momentary motor or clicking noise
may be heard while this test is going
on, and the brake pedal may move
slightly. This is normal.
If there is a problem with ABS, this
warning light stays on. See Antilock
Brake System (ABS) Warning Light
0 138. ABS does not change the time
needed to get a foot on the brake
pedal and does not always
decrease stopping distance. If you
get too close to the vehicle ahead,
there will not be enough time to
apply the brakes if that vehicle
suddenly slows or stops. Always
leave enough room ahead to stop,
even with ABS.
Using ABS
Do not pump the brakes. Just hold
the brake pedal down firmly.
Hearing or feeling ABS operate is
normal.
Braking in Emergencies
ABS allows steering and braking at
the same time. In many
emergencies, steering can help
even more than braking.