engine GMC YUKON 2021 Repair Manual

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
234 Driving and Operating
Caution
The vehicle is not designed to stay in
N (Neutral) for extended periods of time.
It will automatically shift into P (Park) if
left in Car Wash Mode.
Car Wash Mode (Engine Off –Driver in
Vehicle)
To place the vehicle in N (Neutral) with the
engine off and the vehicle occupied:
1. Drive to the entrance of the car wash.
2. Apply the brake pedal.
3. Shift to N (Neutral).
4. Turn off the engine and release the brake pedal.
5. The indicator should continue to show N. If it does not, start the engine and
repeat Steps 2–4.
6. The vehicle is now ready for the car wash.
Car Wash Mode (Engine Off –Driver out of
Vehicle)
To place the vehicle in N (Neutral) with the
engine off and the vehicle unoccupied:
1. Drive to the entrance of the car wash.
2. Apply the brake pedal. 3. Open the door.
4. Shift to N (Neutral).
5. Turn off the engine and release the
brake pedal.
6. The indicator should continue to show N. If it does not, start the engine and
repeat Steps 2–5.
7. Exit the vehicle and close the door. The vehicle is now ready for the car wash.
8. The vehicle may automatically shift to P (Park) upon re-entry.
Car Wash Mode (Engine On –Driver in
Vehicle)
To place the vehicle in N (Neutral) with the
engine on and the vehicle occupied:
1. Drive to the entrance of the car wash.
2. Apply the brake pedal.
3. Shift to N (Neutral).
4. Release the brake pedal. The vehicle is now ready for the car wash.
Car Wash Mode (Engine On –Driver out of
Vehicle)
To place the vehicle in N (Neutral) with the
engine on and the vehicle unoccupied:
1. Drive to the entrance of the car wash. 2. Apply the brake pedal.
3. Open the door.
4. Shift to N (Neutral), then release the
brake pedal.
5. The indicator should continue to show N. If it does not, repeat Steps 2–4.
6. Exit the vehicle and close the door. The vehicle is now ready for the car wash.
7. The vehicle may automatically shift to P (Park) upon re-entry.
Caution
A transmission hot message may display
if the automatic transmission fluid is too
hot. Driving under this condition can
damage the vehicle. Stop and idle the
engine to cool the automatic
transmission fluid. This message clears
when the transmission fluid has cooled
sufficiently.
D : This position is for normal driving.
If more power is needed for passing, press
the accelerator pedal down.
To shift into D (Drive):
1. Bring the vehicle to a complete stop.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 235
2. Pull the D (Drive) switch on the centerstack.
To shift out of D (Drive): 1. Bring the vehicle to a complete stop.
2. Shift to the desired gear.
Downshifting the transmission in slippery
road conditions could result in skidding. See
“Skidding” underLoss of Control 0216.
Caution
Spinning the tires or holding the vehicle
in one place on a hill using only the
accelerator pedal may damage the
transmission. The repair will not be
covered by the vehicle warranty. If the
vehicle is stuck, do not spin the tires.
When stopping on a hill, use the brakes
to hold the vehicle in place.
Manual Mode
Electronic Range Select (ERS) Mode
ERS or manual mode allows for the selection
of the range of gear positions. Use this
mode when driving downhill or towing a
trailer to limit the top gear and vehicle
speed. The shift position indicator within the
Driver Information Center (DIC) will display a
number next to the L indicating the highest
available gear under manual mode and the
driving conditions when manual mode was
selected.
To use this feature:
1. With the vehicle in D (Drive), press the L (Low) button. 2. Press the plus or minus button to
increase or decrease the gear range
available.
When shifting to L (Low), the transmission
will shift to a preset lower gear range. For
this preset range, the highest gear available
is displayed next to the L in the DIC. See
Driver Information Center (DIC) 0120. All
gears below that number are available to
use. For example, when 4 (Fourth) is shown
next to the L, 1 (First) through 4 (Fourth)
gears are shifted automatically. To shift to
5 (Fifth) gear, press the + (Plus) button or
shift into D (Drive).
L (Low) will prevent shifting to a lower gear
range if the engine speed is too high.
If vehicle speed is not reduced within the
time allowed, the lower gear range shift will
not be completed. Slow the vehicle, then
press the −(Minus) button to the desired
lower gear range.
While using ERS, cruise control can be used.
Tow/Haul Mode
The Tow/Haul Mode adjusts the
transmission shift pattern to reduce shift
cycling. This provides increased performance,
vehicle control, and enhanced transmission
and engine cooling when driving down steep

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
236 Driving and Operating
hills or mountain grades, when towing,
or when hauling heavy loads. SeeDriver
Mode Control 0245 to activate Tow/
Haul Mode.
Tow/Haul Mode Grade Braking
Tow/Haul Mode Grade Braking is only
enabled while the Tow/Haul Mode is
selected and the vehicle is not in the Range
Selection Mode. See Manual Mode0235.
Tow/Haul Mode Grade Braking assists in
maintaining desired vehicle speeds when
driving on downhill grades by using the
engine and transmission to slow the vehicle.
See Towing Equipment 0287.
Drive Systems
Four-Wheel Drive
If equipped, four-wheel drive engages the
front axle for extra traction.
Read the appropriate section for transfer
case operation before using.
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 4
nmay:
.Cause a vibration to be felt in the
steering system.
.Cause tires to wear faster.
{Warning
If equipped with four-wheel drive, the
vehicle will be free to roll if the transfer
case is in N (Neutral), even when the
transmission is in P (Park). You or
someone else could be seriously injured.
Be sure the transfer case is in a drive
gear —2
m, 4m, or 4n—or set the
parking brake before placing the transfer
case in N (Neutral). See Shifting Into Park
0 230.
Caution
Extended high-speed operation in 4n
may damage or shorten the life of the
drivetrain.
An engagement noise and bump is normal
when shifting between 4
nand 4mor
N (Neutral), with the engine running.
Shifting into 4
nwill turn Traction Control
and StabiliTrak/Electronic Stability Control
(ESC) off. See Traction Control/Electronic
Stability Control 0242.
Automatic Transfer Case
Two-Speed Transfer Case

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 239
If the parking brake and/or brake pedal
is not applied within 20 seconds, the
transfer case will remain in the original
state.
6. If the transmission is not shifted into N (Neutral) or the vehicle has not slowed
to 5 km/h (3 mph) within 20 seconds,
the transfer case will remain in its
original state. This will be indicated in
the instrument cluster.
Shifting Out of N (Neutral)
To shift out of N (Neutral): 1. Turn the ignition on with the engine off. See Ignition Positions 0226.
2. Set the parking brake. See Electric
Parking Brake 0240.
3. Shift the transmission to N (Neutral).
4. Shift the transfer case to 2
m. Transfer
case shifts out of N (Neutral) can only be
made into 2
m. When the shift to 2mis
complete, the graphic in the instrument
cluster will stop flashing. If the transfer
case cannot complete a shift, the graphic
will return to the previously selected
setting. Single Speed Transfer Case
If equipped, the transfer case controls are
used to shift into and out of four-wheel
drive.
To shift the transfer case, press the desired
button. The graphic in the instrument
cluster will flash while a shift is in progress.
The graphic displayed will change to indicate
the setting requested.
When the shift is complete the graphic will
stop flashing. The DIC message turns off
once the shift is complete. If the transfer
case cannot complete a shift request, 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.
4
m(Four-Wheel Drive High) : Use this
setting when extra traction is needed, such
as when driving on snowy or icy roads,
when off-roading, or when plowing snow.
AUTO (Automatic Four-Wheel Drive)
Use when road surface 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.
Shifts between 2
m, 4m, and AUTO
Any of these shifts can be made at normal
driving speed.
The actual 4x4 shift request is only made
after the button is released. The 4x4 graphic
will remain flashing until the shift request
has completed. A DIC message displays.
Once the 4x4 shift has completed, the DIC
message disappears, the 4x4 graphic stops
flashing, and the current setting is indicated.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
242 Driving and Operating
apply the brake pedal as the driving
situation dictates. Brake Assist disengages
when the brake pedal is released.
Hill Start Assist (HSA)
{Warning
Do not rely on the HSA feature. HSA does
not replace the need to pay attention
and drive safely. You may not hear or
feel alerts or warnings provided by this
system. Failure to use proper care when
driving may result in injury, death,
or vehicle damage. SeeDefensive Driving
0 214.
When the vehicle is stopped on a grade, Hill
Start Assist (HSA) prevents the vehicle from
rolling in an unintended direction during the
transition from brake pedal release to
accelerator pedal apply. The brakes release
when the accelerator pedal is applied. If the
accelerator pedal is not applied within a few
minutes, the Electric Parking Brake will
apply. The brakes may also release under
other conditions. Do not rely on HSA to hold
the vehicle. HSA is available when the vehicle is facing
uphill in a forward gear, or when facing
downhill in R (Reverse). The vehicle must
come to a complete stop on a grade for HSA
to activate.
Ride Control Systems
Traction Control/Electronic
Stability Control
System Operation
The vehicle has a Traction Control System
(TCS) and StabiliTrak/Electronic Stability
Control (ESC). These systems help limit
wheel spin and assist the driver in
maintaining control, especially on slippery
road conditions.
TCS activates if it senses that any of the
drive wheels are spinning or beginning to
lose traction. When this happens, TCS
applies the brakes to the spinning wheels
and reduces engine power to limit
wheel spin.
StabiliTrak/ESC activates when the vehicle
senses a difference between the intended
path and the direction the vehicle is actually
traveling. StabiliTrak/ESC selectively applies
braking pressure to any one of the vehiclewheel brakes to assist the driver in keeping
the vehicle on the intended path. Trailer
Sway Control (TSC) is also on automatically
when the vehicle is started. See
Trailer Sway
Control (TSC) 0295.
If cruise control is being used and traction
control or StabiliTrak/ESC begins to limit
wheel spin, cruise control will disengage.
Cruise control may be turned back on when
road conditions allow.
Both systems come on automatically when
the vehicle is started and begins to move.
The systems may be heard or felt while
they are operating or while performing
diagnostic checks. This is normal and does
not mean there is a problem with the
vehicle.
It is recommended to leave both systems on
for normal driving conditions, but it may be
necessary to turn TCS off if the vehicle gets
stuck in sand, mud, ice, or snow. See If the
Vehicle Is Stuck 0221 and “Turning the
Systems Off and On” later in this section.
When the transfer case (if equipped) is in
Four-Wheel Drive Low, the TCS and
StabiliTrak/ESC are automatically disabled,
g

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 243
comes on, and the appropriate message will
appear on the Driver Information
Center (DIC).
The indicator light for both systems is in the
instrument cluster. This light will:
.Flash when TCS is limiting wheel spin.
.Flash when StabiliTrak/ESC is activated.
.Turn on and stay on when either system
is not working. SeeTraction Control
System (TCS)/Electronic Stability Control
Light 0115.
If either system fails to turn on or to
activate, a message displays in the DIC, and
dcomes on and stays on to indicate that
the system is inactive and is not assisting
the driver in maintaining control. Without
the assistance of properly functioning
StabiliTrak/ESC the possibility of rollover is
increased. Adjust driving accordingly.
If
dcomes on and stays on:
1. Stop the vehicle. 2. Turn the engine off and wait 15 seconds.
3. Start the engine.
Drive the vehicle. If
dcomes on and stays
on, see your dealer.
Turning the Systems Off and On
The button for TCS and StabiliTrak/ESC is on
the instrument panel to the left of the
steering wheel.
Caution
Do not repeatedly brake or accelerate
heavily when TCS is off. The vehicle
driveline could be damaged. To turn off only TCS, press and release
g.
The traction off light
idisplays in the
instrument cluster. The appropriate message
will display in the DIC. To turn TCS on again,
press and release
g. The traction off light
idisplayed in the instrument cluster will
turn off.
If TCS is limiting wheel spin when
gis
pressed, the system will not turn off until
the wheels stop spinning.
To turn off both TCS and StabiliTrak/ESC,
press and hold
guntil the traction off light
iand the StabiliTrak OFF lightgcome on
and stay on in the instrument cluster, then
release. The appropriate message will
display in the DIC.
To turn TCS and StabiliTrak/ESC on again,
press and release
g. The traction off light
iand the StabiliTrak OFF lightgin the
instrument cluster turn off.
For vehicles without four corner air
suspension StabiliTrak/ESC will automatically
turn on if the vehicle exceeds 56 km/h
(35 mph). Traction control will remain off.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 245
When enabled, if the vehicle speed is above
30 km/h (19 mph) and below 60 km/h
(37 mph), a DIC message will display.
Driver Mode Control
Driver Mode Control (DMC) allows the driver
to adjust the overall driving experience to
better suit preference by adjusting multiple
sub-system simultaneously. Drive Mode
availability and affected vehicle subsystems
are dependent upon vehicle trim level,
region, and optional features.
Normal Mode will be the default mode at
every ignition cycle. A unique and persistent
indicator will be displayed in the instrument
cluster for each mode.
Depending on trim level, Normal, Sport,
Snow/Ice, Off-Road, Tow/Haul, and Terrain
modes may be available.
To activate each mode, turn the Mode knob
on the instrument panel to the left of the
steering wheel.
To activate Terrain mode, press the Terrain
Mode button located next to the
Mode knob.
Normal Mode :Use for normal city and
highway driving to provide a smooth ride.
This setting provides balance between
comfort and handling. This is the standard/
default mode. There is no persistent
indicator in the instrument cluster for
this mode.
8Sport Mode : Use where road conditions
or personal preference demand a more
controlled response. When you enter this
mode you will immediately feel a down
shift. In this mode, the vehicle also monitors
driving behaviors and automatically enables
Performance Shift Features when spirited
driving is detected. These features maintain
lower transmission gears to increase
available engine braking and improve
acceleration response. The vehicle will exit
these features and return to normal
operation after a short period when no
spirited driving is detected. The steering will
change to provide more precise control.
If the vehicle has Magnetic Ride Control, the
suspension will change to provide better
cornering performance.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
246 Driving and Operating
6Snow/Ice Mode :Snow/Ice improves
vehicle acceleration on snow and ice covered
roads. When active, Snow/Ice Mode will
adjust acceleration to optimize traction on
slippery surfaces. This can compromise the
acceleration on dry asphalt. This feature is
not intended for use when the vehicle is
stuck in sand, mud, ice, snow, or gravel.
If the vehicle becomes stuck see If the
Vehicle Is Stuck 0221.
7Off-Road Mode : Use this mode for
off-road recreational driving. Off-Road Mode
should be used to improve driving at
moderate speeds, on grass, gravel, dirt,
unpaved roads, or snow-covered roads. The
accelerator pedal is tuned for off-road use.
This mode modifies pedal mapping, AWD,
steering, ride height, ABS, ESC, and TCS
performance. For more information on
off-road driving, see Off-Road Driving0216.
_Tow/Haul Mode : For more
information on Tow/Haul Mode, see Tow/
Haul Mode 0235.
If equipped, select Terrain Mode by pressing
the
gbelow the 4mtransfer case
button.
gTerrain Mode : Use this mode when
traveling on very rough roads at very low
speeds, such as a two-track or heavily rutted
road. This can also be used for pulling a
boat out of the water on a trailer. When in
Terrain Mode, the vehicle will shift
automatically but will hold a lower gear
longer to maximize engine torque. This
mode has a unique pedal map and
transmission shift pattern for better control
at lower speeds and over rough terrain. This
mode modifies accelerator pedal mapping, transmission shift pattern, ride height,
suspension, steering, AWD, eSLD, ESC
performance and TCS performance.
When the vehicle comes to a stop on an
upward grade, Automatic Vehicle Hold is
engaged until the driver presses the
accelerator pedal. Stop/Start and cruise
control are disabled in Terrain Mode.
Active Braking during lift throttle will be
engaged. This feature automatically applies
light braking to simulate heavy engine
braking of four-wheel-dive low. It also
applies light braking in D (Drive) until the
vehicle is at idle speeds. In M1 and M2 light
braking will typically bring the vehicle to a
stop. Active Braking during lift throttle will
also reduce trailer braking.
Terrain Mode will automatically exit to
Normal Mode if the brake temperatures
become too hot, electronic parking brake
becomes inoperable or the vehicle cannot
perform braking or vehicle hold.
For more information on off-road driving,
see
Off-Road Driving 0216 and
Hill and Mountain Roads 0220.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 247
Terrain Mode DriveSelect Expected Vehicle Behavior Ideal Terrain
Drive (L3-Lx) Minor deceleration when off
throttle and mild ability to
modulate throttle; mimics
performance of 4
nwithout torque
multiplication. Grassy fields,
mild two tracks,
rutted roads,
large rolling hills,
L2 Moderate deceleration when off
throttle and moderate ability to
modulate throttle; will bring vehicle
to a stop in most cases. Mild rock crawling,
heavy ruts,
short, steeper grades,
L1 Significant deceleration when off
throttle and significant ability to
modulate throttle; will bring vehicle
to a stop in most cases. Rock crawling downhill
Vehicle Hold Features:
.When the vehicle comes to a stop on an
incline grade in forward gear or on a
decline grade in reverse gear, Vehicle
Hold is engaged until the accelerator
pedal is pressed.
.When the vehicle is in forward gear on a
decline, the vehicle is allowed to creep
down the hill when the brake pedal is released without pressing the accelerator
pedal. The vehicle will also creep forward
on flat ground.
.If the driver seat belt is removed and the
driver door is opened while the vehicle is
being held, EPB will be engaged.
.EPB will engage if the vehicle is held for
an extended period.Terrain Mode is only available on vehicles
equipped with the single speed
transfer case.
Terrain Mode can only be active when:
.Vehicle speed is less than 80 km/h
(50 mph).
.The transfer case is in 4m.
Frequent use of this mode may cause brake
wear due to the light braking.
The vehicle will automatically exit the mode
if the brakes get too hot. Terrain Mode can
be turned back on after the brakes have
cooled.
When Terrain Mode is selected:
.Auto Engine Start/Stop will be disabled.
.The Terrain Mode indicator displays on
the instrument cluster.
Magnetic Ride Control
This vehicle may have a semi-active damping
system called Magnetic Ride Control. With
this feature, improved vehicle ride and
handling is provided under a variety of
passenger and loading conditions.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
252 Driving and Operating
Resuming a Set Speed
If the cruise control is set at a desired speed
and then the brakes are applied or
*is
pressed, the cruise control is disengaged
without erasing the set speed from memory.
Once the vehicle reaches about 40 km/h
(25 mph) or more, press RES+ up briefly. The
vehicle returns to the previously set speed.
Increasing Speed While Using Cruise Control
Do one of the following:
.Press and hold +RES up until the desired
speed is reached, then release it.
.To increase vehicle speed in small
increments, press +RES up briefly. For
each press, the vehicle goes about 1 km/h
(1 mph) faster.
The speedometer reading can be displayed
in either English or metric units. See
Instrument Cluster 0104. The increment
value used depends on the units displayed.
Reducing Speed While Using Cruise Control
Do one of the following:
.Press and hold SET– down until the
desired lower speed is reached, then
release it.
.To slow down in small increments, press
SET– down briefly. For each press, the
vehicle goes about 1 km/h (1 mph) slower.
The speedometer reading can be displayed
in either English or metric units. See
Instrument Cluster 0104. The increment
value used depends on the units displayed.
Passing Another Vehicle While Using Cruise
Control
Use the accelerator pedal to increase the
vehicle speed. When you take your foot off
the pedal, the vehicle will slow down to the
previously set cruise speed. While pressing
the accelerator pedal or shortly following
the release to override cruise control, briefly
pressing SET– will result in cruise control set
to the current vehicle speed.
Using Cruise Control on Hills
How well the cruise control works on hills
depends on the vehicle speed, the load, and
the steepness of the hills. When going up
steep hills, pressing the accelerator pedal
may be necessary to maintain vehicle speed.
While going downhill, cruise braking helps
maintain driver selected speed. Cruise Grade Braking is enabled when the
vehicle is started and cruise control is active.
It is not enabled in Range Selection Mode.
It assists in maintaining driver selected
speed when driving on downhill grades by
using the engine and transmission to slow
the vehicle.
For other forms of descent control, see
Hill
Descent Control (HDC) 0244, Automatic
Transmission 0232, and Tow/Haul Mode
0 235.
Ending Cruise Control
There are four ways to end cruise control:
.Step lightly on the brake pedal.
.Press*.
.Shift the transmission to N (Neutral).
.To turn off cruise control, press5.
Erasing Speed Memory
The cruise control set speed is erased from
memory if
5is pressed or the ignition is
turned off.