GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
226 Driving and Operating
Warning (Continued)
.Never stack heavier things, like
suitcases, inside the vehicle so
that some of them are above the
tops of the seats.
.Do not leave an unsecured child
restraint in the vehicle.
.When you carry something inside
the vehicle, secure it whenever
you can.
.Do not leave a seat folded down
unless you need to.
There is also important loading
information for off-road driving in this
manual. See “Loading Your Vehicle for
Off-Road Driving” underOff-Road
Driving 0216.
Starting and Operating
New Vehicle Break-In
Caution
The vehicle does not need an elaborate
break-in. But it will perform better in the
long run if you follow these guidelines:
.Keep the vehicle speed at 88 km/h
(55 mph) or less for the first 805 km
(500 mi).
.Do not drive at any one constant
speed, fast or slow, for the first
805 km (500 mi). Do not make
full-throttle starts. Avoid downshifting
to brake or slow the vehicle.
.Avoid making hard stops for the first
322 km (200 mi) or so. During this
time the new brake linings are not yet
broken in. Hard stops with new linings
can mean premature wear and earlier
replacement. Follow this breaking-in
guideline every time you get new
brake linings.
(Continued)
Caution (Continued)
.Do not tow a trailer during break-in.
See Trailer Towing 0284 for the
trailer towing capabilities of the
vehicle and more information.
Following break-in, engine speed and load
can be gradually increased.
Ignition Positions
Vehicles equipped with Keyless Access have
pushbutton starting.
The Remote Key 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
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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Driving and Operating 227
interference to the Keyless Access system.
SeeRemote Keyless Entry (RKE) System
Operation 08.
To shift out of P (Park), the ignition must be
on or in Service Mode, and the brake pedal
must be applied.
{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.
Stopping the Engine/LOCK/OFF (No Indicator
Lights) : When the vehicle is stopped, press
ENGINE START/STOP once to turn the
engine off.
If the vehicle is in P (Park), the ignition will
turn off, and Retained Accessory Power (RAP)
will remain active. See Retained Accessory
Power (RAP) 0229.
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). When the vehicle is
shifted into P (Park), the ignition system will
turn off. The vehicle may have an electric steering
column lock. The lock is activated when the
ignition is turned 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. Hold the brake pedal down and shift to P (Park). The
vehicle must be in P (Park) to turn the
ignition off.
4. Continue to hold the brake pedal down. 5. Set the parking brake. See
Electric
Parking Brake 0240.
6. Press ENGINE START/STOP once to turn the ignition off.
7. Release the brake pedal.
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 0228.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
228 Driving and Operating
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.
Starting the Engine
If the vehicle has a diesel engine, see the
Duramax diesel supplement.
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.
SeeAdd-On Electrical Equipment 0306. Shift the vehicle into P (Park) or N (Neutral).
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.
Starting Procedure
1. The remote key must be in the vehicle.
Press ENGINE START/STOP with the brake
pedal applied. When the engine begins
cranking, let go of the button.
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 light is on
and the FUEL LEVEL LOW message is
displayed in the Driver Information
Center (DIC), press the ENGINE START/
STOP position to continue engine
cranking.
Caution
Cranking the engine for long periods of
time, by trying to start the engine
immediately after cranking has ended,
can overheat and damage the cranking
motor, and drain the battery. Wait at
least 15 seconds between each try, to let
the cranking motor cool down.
2. If the engine does not start after five to 10 seconds, especially in very cold
weather (below −18 °C or 0 °F), it could
be flooded with too much gasoline. Try
pushing the accelerator pedal all the way
to the floor and holding it there while
pressing ENGINE START/STOP for up to a
maximum of 15 seconds. Wait at least
15 seconds between each try, to allow
the cranking motor to cool down. When
the engine starts, let go of the button
and accelerator. If the vehicle starts
briefly but then stops again, do the
same thing. This clears the extra gasoline
from the engine. Do not race the engine
immediately after starting it. Operate
the engine and transmission gently until
the oil warms up and lubricates all
moving parts.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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310 Vehicle Care
Also, seeAdding Equipment to the
Airbag-Equipped Vehicle 069.
Vehicle Checks
Doing Your Own Service Work
{Warning
It can be dangerous to work on your
vehicle if you do not have the proper
knowledge, service manual, tools,
or parts. Always follow owner’s manual
procedures and consult the service
manual for your vehicle before doing any
service work.
If doing some of your own service work, use
the proper service manual. It tells you much
more about how to service the vehicle than
this manual can. To order the proper service
manual, see Publication Ordering
Information 0406.
This vehicle has an airbag system. Before
attempting to do your own service work,
see Servicing the Airbag-Equipped Vehicle
0 69. If equipped with remote vehicle start, open
the hood before performing any service
work to prevent remote starting the vehicle
accidentally. See
Remote Vehicle Start 014.
Keep a record with all parts receipts and list
the mileage and the date of any service
work performed. See Maintenance Records
0 395.Caution
Even small amounts of contamination can
cause damage to vehicle systems. Do not
allow contaminants to contact the fluids,
reservoir caps, or dipsticks.
Hood
{Warning
For vehicles with auto engine stop/start,
turn the vehicle off before opening the
hood. If the vehicle is on, the engine will
start when the hood is opened. You or
others could be injured.
{Warning
Components under the hood can get hot
from running the engine. To help avoid
the risk of burning unprotected skin,
never touch these components until they
have cooled, and always use a glove or
towel to avoid direct skin contact.
Clear any snow from the hood before
opening.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Vehicle Care 313
1. Remote Negative (–) Location. SeeJump
Starting - North America 0367.
2. Positive (+) Terminal (Under Cover). See Jump Starting - North America 0367.
3. Battery - North America 0327.
4. Engine Compartment Fuse Block 0332.
5. Engine Oil Dipstick. See “Checking Engine
Oil” under Engine Oil 0315.
6. Engine Cooling Fans (Out of View). See Cooling System 0319. 7. Engine Oil Fill Cap. See
“When to Add
Engine Oil” underEngine Oil 0315.
8. Coolant Surge Tank and Pressure Cap. See Cooling System 0319.
9. Engine Air Cleaner/Filter 0318.
10. Brake Fluid Reservoir. See Brake Fluid
0 326.
11. Windshield Washer Fluid Reservoir. See “Adding Washer Fluid” underWasher
Fluid 0324.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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314 Vehicle Care
6.2L V8 Engine
1. Remote Negative (–) Location. See Jump
Starting - North America 0367.
2. Positive (+) Terminal (Under Cover). See Jump Starting - North America 0367.
3. Battery - North America 0327.
4. Engine Compartment Fuse Block 0332. 5. Engine Oil Dipstick. See
“Checking Engine
Oil” under Engine Oil 0315.
6. Engine Cooling Fans (Out of View). See Cooling System 0319.
7. Engine Oil Fill Cap. See “When to Add
Engine Oil” underEngine Oil 0315. 8. Coolant Surge Tank and Pressure Cap.
See Cooling System 0319.
9. Engine Air Cleaner/Filter 0318.
10. Brake Fluid Reservoir. See Brake Fluid
0 326.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
368 Vehicle Care
Warning (Continued)
.They contain gas that can explode or
ignite.
.They contain enough electricity to
burn you.
If you do not follow these steps exactly,
some or all of these things can hurt you.
Caution
Ignoring these steps could result in costly
damage to the vehicle that would not be
covered by the vehicle warranty. Trying
to start the vehicle by pushing or pulling
it will not work, and it could damage the
vehicle.5.3L V8 Shown, 6.2L V8 Similar
1. Good Battery Positive Terminal
2. Good Battery Negative Terminal
3. Discharged Battery Remote Negative Terminal
4. Discharged Battery Remote Positive Terminal
The jump start positive post (1) and negative
post (2) are on the battery of the vehicle
providing the jump start.
The jump start positive post (4) and the
negative grounding point (3) for the
discharged battery are on the passenger side
of the vehicle. The positive jump start connection for the
discharged battery is under a cover. Slide
the cover to expose the terminal.
1. Check the other vehicle. It must have a 12-volt battery with a negative ground
system.
Caution
If the other vehicle does not have a
12-volt system with a negative ground,
both vehicles can be damaged. Only use
a vehicle that has a 12-volt system with a
negative ground for jump starting.
2. If you have a vehicle with a diesel engine with two batteries, you should
know before you begin that, especially in
cold weather, you may not be able to
get enough power from a single battery
in another vehicle to start your diesel
engine. If your vehicle has more than
one battery, using the battery that is
closer to the starter will reduce electrical
resistance. This is located on the
passenger side, in the rear of the engine
compartment.
3. Get the vehicles close enough so the jumper cables can reach, but be sure the
vehicles are not touching each other.
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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Vehicle Care 369
If they are, it could cause an unwanted
ground connection. You would not be
able to start your vehicle, and the bad
grounding could damage the electrical
systems.
To avoid the possibility of the vehicles
rolling, set the parking brake firmly on
both vehicles involved in the jump start
procedure. Put an automatic transmission
in P (Park) or a manual transmission in
Neutral before setting the parking brake.
If you have a four-wheel-drive vehicle, be
sure the transfer case is in a drive gear,
not in N (Neutral).
Caution
If any accessories are left on or plugged
in during the jump starting procedure,
they could be damaged. The repairs
would not be covered by the vehicle
warranty. Whenever possible, turn off or
unplug all accessories on either vehicle
when jump starting.
4. Turn the ignition off on both vehicles. Unplug unnecessary accessories plugged
into the accessory power outlets. Turn
off the radio and all the lamps that are not needed. This will avoid sparks and
help save both batteries. And it could
save the radio!
5. Open the hood on the other vehicle and locate the positive (+) and negative (−)
terminal locations on that vehicle.
The positive (+) terminal is under a red
plastic cover at the positive battery post.
To uncover the positive (+) terminal,
open the red plastic cover.
For more information on the location of
the remote positive (+) and remote
negative (−) terminals, see Engine
Compartment Overview 0312.{Warning
An electric fan can start up even when
the engine is not running and can injure
you. Keep hands, clothing, and tools
away from any underhood electric fan.
{Warning
Using a match near a battery can cause
battery gas to explode. People have been
hurt doing this, and some have been
blinded. Use a flashlight if you need
more light.
Battery fluid contains acid that can burn
you. Do not get it on you. If you
accidentally get it in your eyes or on
your skin, flush the place with water and
get medical help immediately.
{Warning
Fans or other moving engine parts can
injure you badly. Keep your hands away
from moving parts once the engine is
running.
6. Check that the jumper cables do not have loose or missing insulation. If they
do, you could get a shock. The vehicles
could be damaged too.
Before you connect the cables, here are
some basic things you should know.
Positive (+) will go to positive (+) or to a
remote positive (+) terminal if the