
Black plate (82,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
9-82 Driving and Operating
The trailer's and the vehicle's brake
lamps will come on when either
vehicle brakes or manual trailer
brakes are applied.
Trailer Gain Adjustment Procedure
Trailer Gain should be set for a
specific trailering condition and must
be adjusted any time vehicle
loading, trailer loading, or road
surface conditions change.
{Warning
Trailer brakes that are
over-gained or under-gained may
not stop the vehicle and the trailer
as intended and can result in a
crash. Always follow the
instructions to set the Trailer Gain
for the proper trailer stopping
performance.Use the following to adjust Trailer
Gain for each towing condition:
1. Drive the vehicle with the trailer
attached on a level road surface
representative of the towing
condition and free of traffic at
about 32 to 40 km/h (20 to
25 mph) and fully apply the
Manual Trailer Brake apply lever.
Adjusting Trailer Gain at speeds
lower than 32 to 40 km/h (20 to
25 mph) may result in an
incorrect gain setting.
2. Adjust the Trailer Gain, using the Trailer Gain adjustment buttons,
to just below the point of trailer
wheel lock-up, indicated by
trailer wheel squeal or tire
smoke when a trailer wheel
locks.
Trailer wheel lock-up may not
occur if towing a heavily loaded
trailer. In this case, adjust the
Trailer Gain to the highest
allowable setting for the towing
condition. 3. Readjust Trailer Gain any time
vehicle loading, trailer loading,
or road surface conditions
change or if trailer wheel lock-up
is noticed at any time while
towing.
Other ITBC-Related DIC Messages
In addition to displaying TRAILER
GAIN and OUTPUT through the
DIC, trailer connection and ITBC
system status are displayed on
the DIC.
TRAILER CONNECTED: This
message will briefly display when a
trailer with electric brakes is first
connected to the vehicle. This
message will automatically turn off
in about 10 seconds. This message
can be acknowledged before it
automatically turns off.

Black plate (1,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
Vehicle Care 10-1
Vehicle Care
General Information
General Information . . . . . . . . . . 10-2
California Proposition65 Warning . . . . . . . . . . . . . . . . . 10-2
California Perchlorate Materials Requirements . . . . 10-3
Accessories and Modifications . . . . . . . . . . . . . . . 10-3
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 10-3
Hood . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . 10-5
Engine Oil . . . . . . . . . . . . . . . . . . . 10-6
Engine Oil Life System . . . . . . 10-9
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . 10-10
Engine Air Cleaner/Filter . . . . 10-10
Cooling System . . . . . . . . . . . . 10-12
Engine Coolant . . . . . . . . . . . . . 10-13
Engine Overheating . . . . . . . . 10-16
Engine Fan . . . . . . . . . . . . . . . . . 10-17
Washer Fluid . . . . . . . . . . . . . . . 10-18
Brakes . . . . . . . . . . . . . . . . . . . . . 10-18 Brake Fluid . . . . . . . . . . . . . . . . . 10-19
Battery . . . . . . . . . . . . . . . . . . . . . 10-21
Four-Wheel Drive . . . . . . . . . . . 10-21
Front Axle . . . . . . . . . . . . . . . . . . 10-22
Rear Axle . . . . . . . . . . . . . . . . . . 10-23
Noise Control System . . . . . . 10-23
Starter Switch Check . . . . . . . 10-24
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . 10-25
Park Brake and P (Park) Mechanism Check . . . . . . . . 10-25
Wiper Blade Replacement . . . . . . . . . . . . . . 10-25
Glass Replacement . . . . . . . . 10-26
Windshield Replacement . . . 10-26
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . 10-27
Bulb Replacement
Bulb Replacement . . . . . . . . . . 10-27
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . 10-27
LED Lighting . . . . . . . . . . . . . . . 10-27
Fog Lamps . . . . . . . . . . . . . . . . . 10-27
Back-Up Lamps . . . . . . . . . . . . 10-28
License Plate Lamp . . . . . . . . 10-29
Replacement Bulbs . . . . . . . . . 10-30
Electrical System
Electrical System Overload . . . . . . . . . . . . . . . . . . 10-30
Fuses . . . . . . . . . . . . . . . . . . . . . . 10-31
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-31
Instrument Panel Fuse Block (Left) . . . . . . . . . . . . . . . 10-34
Instrument Panel Fuse Block (Right) . . . . . . . . . . . . . . . . . . . . 10-37
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-40
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . 10-41
All-Season Tires . . . . . . . . . . . . 10-42
Winter Tires . . . . . . . . . . . . . . . . 10-42
Low-Profile Tires . . . . . . . . . . . 10-43
All-Terrain Tires . . . . . . . . . . . . 10-43
Tire Sidewall Labeling . . . . . . 10-43
Tire Designations . . . . . . . . . . . 10-45
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . 10-46
Tire Pressure . . . . . . . . . . . . . . . 10-48
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . 10-50
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . . . 10-50

Black plate (3,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
Vehicle Care 10-3
cause cancer and birth defects or
other reproductive harm. Engine
exhaust, many parts and systems,
many fluids, and some component
wear by-products contain and/or
emit these chemicals.
California Perchlorate
Materials Requirements
Certain types of automotive
applications, such as airbag
initiators, safety belt pretensioners,
and lithium batteries contained in
Remote Keyless Entry transmitters,
may contain perchlorate materials.
Special handling may be necessary.
For additional information, see
www.dtsc.ca.gov/hazardouswaste/
perchlorate.
Accessories and
Modifications
Adding non‐dealer accessories or
making modifications to the vehicle
can affect vehicle performance and
safety, including such things as
airbags, braking, stability, ride andhandling, emissions systems,
aerodynamics, durability, and
electronic systems like antilock
brakes, traction control, and stability
control. These accessories or
modifications could even cause
malfunction or damage not covered
by the vehicle warranty.
Damage to vehicle components
resulting from modifications or the
installation or use of non‐GM
certified parts, including control
module or software modifications, is
not covered under the terms of the
vehicle warranty and may affect
remaining warranty coverage for
affected parts.
GM Accessories are designed to
complement and function with other
systems on the vehicle. See your
dealer to accessorize the vehicle
using genuine GM Accessories
installed by a dealer technician.
Also, see
Adding Equipment to the
Airbag-Equipped Vehicle on
page 3-37.
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 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 Service
Publications Ordering Information
on page 13-11.

Black plate (6,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
10-6 Vehicle Care
1. Positive (+) Terminal. SeeJump
Starting on page 10-74.
2. Battery on page 10-21.
3. Coolant Surge Tank and Pressure Cap. See Cooling
System on page 10-12.
4. Engine Air Cleaner/Filter on
page 10-10.
5. Remote Negative (–) Location (Out of View). See Jump Starting
on page 10-74.
6. Engine Cooling Fans (Out of View). See Cooling System on
page 10-12.
7. Engine Oil Fill Cap. See “When
to Add Engine Oil” underEngine
Oil on page 10-6.
8. Engine Oil Dipstick. See “Checking Engine Oil” under
Engine Oil on page 10-6.
9. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer Fluid on
page 10-18. 10. Brake Fluid Reservoir. See
Brake Fluid on page 10-19.
11. Engine Compartment Fuse
Block on page 10-31.
Engine Oil
To ensure proper engine
performance and long life, careful
attention must be paid to engine oil.
Following these simple, but
important steps will help protect
your investment:
.Always use engine oil approved
to the proper specification and of
the proper viscosity grade. See
“Selecting the Right Engine Oil”
in this section.
.Check the engine oil level
regularly and maintain the
proper oil level. See “Checking
Engine Oil” and“When to Add
Engine Oil” in this section.
.Change the engine oil at the
appropriate time. See Engine Oil
Life System on page 10-9.
.Always dispose of engine oil
properly. See “What to Do with
Used Oil” in this section.
Checking Engine Oil
If equipped, the ENGINE OIL LOW
ADD OIL message displays when
the engine oil level may be too low.
SeeEngine Oil Messages on
page 5-40. Check the oil level
before filling to the recommended
level. If the oil is not low and this
message remains on, see your
dealer.
It is also a good idea to check the
engine oil level at each fuel fill. In
order to get an accurate reading,
the vehicle must be on level ground.
The engine oil dipstick handle is a
loop. See Engine Compartment
Overview on page 10-5 for the
location of the engine oil dipstick.
Obtaining an accurate oil level
reading is essential:
1. If the engine has been running
recently, turn off the engine and
allow several minutes for the oil

Black plate (15,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
Vehicle Care 10-15
{Caution
This vehicle has a specific
coolant fill procedure. Failure to
follow this procedure could cause
the engine to overheat and be
severely damaged.
{Warning
Steam and scalding liquids from a
hot cooling system can blow out
and burn you badly. Never turn
the cap when the cooling system,
including the surge tank pressure
cap, is hot. Wait for the cooling
system and surge tank pressure
cap to cool.
If no coolant is visible in the surge
tank, add coolant.
1. Remove the coolant surge tank pressure cap when the cooling
system, including the coolant
surge tank pressure cap and
upper radiator hose, is no
longer hot.
Turn the pressure cap slowly
counterclockwise about one full
turn. If a hiss is heard, wait for
that to stop. A hiss means there
is still some pressure left.
2. Keep turning the pressure cap slowly, and remove it.
3. Fill the coolant surge tank with the proper mixture to the FULL
COLD mark. 4. With the coolant surge tank
pressure cap off, start the
engine and let it run until the
engine coolant temperature
gauge indicates approximately
90°C (195°F).
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper
mixture to the coolant surge tank
until the level reaches the FULL
COLD mark.
5. Replace the pressure cap tightly.
6. Verify coolant level after the engine is shut off and the
coolant is cold. If necessary,
repeat coolant fill procedure
Steps 1–6.

Black plate (25,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
Vehicle Care 10-25
Automatic Transmission
Shift Lock Control
Function Check
{Warning
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Apply the parking brake. Be ready to apply the regular brake
immediately if the vehicle begins
to move.
3. With the engine off, turn the ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with normal effort. If the shift lever
moves out of P (Park), contact
your dealer for service.
Park Brake and P (Park)
Mechanism Check
{Warning
When you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move.
Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake.
.To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.
.To check the P (Park)
mechanism's holding ability:
With the engine running, shift to
P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement
Windshield wiper blades should be
inspected for wear or cracking.
For the proper type and size, see
Maintenance Replacement Parts on
page 11-13.
Front Wiper Blade
Replacement
To replace the wiper blade
assembly:
1. Pull the windshield wiper assembly away from the
windshield.

Black plate (26,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
10-26 Vehicle Care
2. Lift up on the latch in the middleof the wiper blade where the
wiper arm attaches.
3. With the latch open, pull the wiper blade down toward the
windshield far enough to release
it from the J-hooked end of the
wiper arm.
4. Remove the wiper blade. Allowing the wiper blade arm to
touch the windshield when no
wiper blade is installed could
damage the windshield. Any
damage that occurs would not
be covered by the vehicle warranty. Do not allow the wiper
blade arm to touch the
windshield.
5. Reverse Steps 1–3 for wiper blade replacement.
Rear Wiper Blade Replacement
To replace the rear wiper blade:
1. Pull the wiper blade assemblyaway from the backglass.
The rear wiper blade will not lock
in a vertical position so care
should be used when pulling it
away from the vehicle.
2. Push the release lever (2) todisengage the hook and push
the wiper arm (1) out of the
blade assembly (3).
3. Push the new blade assembly securely in the wiper arm hook
until the release lever clicks into
place.
4. Return the wiper arm and blade assembly to the rest position on
the glass.
Glass Replacement
If the windshield or front side glass
must be replaced, see your dealer
to determine the correct
replacement glass.
Windshield Replacement
The windshield is part of the HUD
system. If the vehicle has to have
the windshield replaced, get one
that is designed for HUD or the
HUD image may look out of focus.

Black plate (28,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
10-28 Vehicle Care
3. Turn the bulb counter clockwiseto remove it from the housing.
Back-Up Lamps
To replace a back-up bulb:
1. Open the liftgate. See Liftgate
on page 2-13.
2. Remove the taillamp closeout cover from the lamp assembly
by pulling rearward from the top
and bottom at the same time to
unfasten the snap tabs.
3. Remove the two screws from thetaillamp assembly.
4. Pull the taillamp assembly straight back to remove.5. Turn the bulb socketcounterclockwise to remove it
from the taillamp assembly.
6. Pull the bulb straight out from the socket.
7. Press a new bulb into the socket, insert it into the taillamp
assembly, and turn the bulb
socket clockwise until it clicks.
8. Reinstall the taillamp assembly and tighten the screws.
9. Reinstall the taillamp cover by snapping it into place.