light GMC YUKON XL 2018 Owners Manual

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/21/17
Driving and Operating 269Pressing this button at the end of
the shift lever turns on and off the
Tow/Haul Mode.
This indicator light on the instrument
cluster comes on when the Tow/
Haul Mode is on.
Tow/Haul is a feature that assists
when pulling a heavy trailer or a
large or heavy load. See Tow/Haul
Mode 0 222 .
Tow/Haul is designed to be most
effective when the vehicle and
trailer combined weight is at least
75 % of the vehicle's Gross
Combined Weight Rating (GCWR).
See “ Weight of the Trailer ” under
Trailer Towing 0 262 . Tow/Haul is
most useful under the following
driving conditions:
.
When pulling a heavy trailer or a
large or heavy load through
rolling terrain. .
When pulling a heavy trailer or a
large or heavy load in
stop-and-go traffic.
.
When pulling a heavy trailer or a
large or heavy load in busy
parking lots where improved low
speed control of the vehicle is
desired.
Operating the vehicle in Tow/Haul
when lightly loaded or with no trailer
at all will not cause damage.
However, there is no benefit to the
selection of Tow/Haul when the
vehicle is unloaded. Such a
selection when unloaded may result
in unpleasant engine and
transmission driving characteristics
and reduced fuel economy. Tow/
Haul is recommended only when
pulling a heavy trailer or a large or
heavy load. Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for use with electric trailer brakes or
most electric-over-hydraulic trailer
brakes.
This symbol is on the Trailer Brake
Control Panel on vehicles with an
ITBC system. The power output to
the trailer brakes is based on the
amount of brake pressure being
applied by the vehicle ’ s brake
system, and on the type of trailer
brakes detected. This available
power output to the trailer brakes
can be adjusted to a wide range of
trailering situations.
The ITBC system is integrated with
the vehicle ’ s brake, antilock brake,
and StabiliTrak systems. In trailering
conditions that cause the vehicle ’ s

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/21/17
Driving and Operating 2733. Wait 10 seconds, then turn the
ignition back to RUN.
4. If the CHECK TRAILER
WIRING message reappears,
the electrical fault is on the
vehicle side.
If the CHECK TRAILER
WIRING message only
reappears when connecting the
trailer wiring harness to the
vehicle, the electrical fault is on
the trailer side.
SERVICE TRAILER BRAKE
SYSTEM: This message will display
when there is a problem with the
ITBC system. If this message
continues over multiple ignition
cycles, there is a problem with the
ITBC system. Have the vehicle
serviced.
If either the CHECK TRAILER
WIRING or SERVICE TRAILER
BRAKE SYSTEM message displays
while driving, the ITBC system may
not be fully functional or may not
function at all. When traffic
conditions allow, carefully pull the
vehicle over to the side of the road
and turn the ignition off. Check the wiring connection to the trailer and
turn the ignition back on. If either of
these messages continues, either
the vehicle or trailer needs service.
A GM dealer may be able to
diagnose and repair problems with
the trailer. However, any diagnosis
and repair of the trailer is not
covered under the vehicle warranty.
Contact your trailer dealer for
assistance with trailer repairs and
trailer warranty information.
Trailer Sway
Control (TSC) The vehicle has a Trailer Sway
Control (TSC) feature as part of the
StabiliTrak system. If TSC detects
that the trailer is swaying, the
vehicle's brakes are automatically
applied. When TSC is applying the brakes,
the TCS/StabiliTrak indicator light
flashes to notify the driver to reduce
speed. If the trailer continues to
sway, StabiliTrak will reduce engine
torque to help slow the vehicle.
TSC will not function if StabiliTrak is
turned off. See Traction Control/
Electronic Stability Control 0 229 .
Electronic Trailer Sway Control
Devices Some trailers may come equipped
with an electronic device designed
to reduce or control trailer sway.
Aftermarket equipment
manufacturers also offer similar
devices that connect to the wiring
between the trailer and the vehicle.
These devices may interfere with
the vehicle ’ s trailer brake or other
systems, including integrated
anti-sway systems, if equipped.
Messages related to trailer
connections or trailer brakes could
appear on the Driver Information
Center (DIC). The effect that these
devices may have on vehicle
handling or trailer brake
performance is unknown.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/21/17
274 Driving and Operating
{ WarningUse of electronic trailer sway
control devices could result in
reduced trailer brake
performance, loss of trailer
brakes, or other malfunctions, and
could cause a crash. You or
others could be injured or killed.
Before using one of these
devices:
.
Ask the device or trailer
manufacturer if the device
has been thoroughly tested
for compatibility with the
make, model, and year of
the vehicle as well as
optional equipment installed
on the vehicle.
.
Before driving on the open
roads, check that the trailer
brakes are working properly.
Drive the vehicle with the
trailer attached on a level
road surface that is free of
traffic at about 32-40 km/h
(20-25 mph) and fully apply
(Continued) Warning (Continued) the manual trailer brake
apply lever. Also check that
the trailer brake lamps and
other lamps are functioning
correctly.
.
If the trailer brakes are not
operating properly at any
time, or if a DIC message
indicates problems with the
trailer connections or trailer
brakes, carefully pull the
vehicle over to the side of
the road when traffic
conditions allow. Conversions and
Add-Ons Add-On Electrical
Equipment
{ WarningThe Data Link Connector (DLC) is
used for vehicle service and
Emission Inspection/
Maintenance testing. See
Malfunction Indicator Lamp
(Check Engine Light) 0 143 .
A device connected to the DLC —
such as an aftermarket fleet or
driver-behavior tracking device —
may interfere with vehicle
systems. This could affect vehicle
operation and cause a crash.
Such devices may also access
information stored in the vehicle ’ s
systems.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
276 Vehicle Care
Vehicle Care General Information General Information . . . . . . . . . . 277
California Proposition
65 Warning . . . . . . . . . . . . . . . . . 277
California Perchlorate
Materials Requirements . . . . . 278
Accessories and
Modifications . . . . . . . . . . . . . . . . 278
Vehicle Checks Doing Your Own
Service Work . . . . . . . . . . . . . . . 278
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 279
Engine Compartment
Overview . . . . . . . . . . . . . . . . . . . . 280
Engine Oil . . . . . . . . . . . . . . . . . . . . 283
Engine Oil Life System . . . . . . . 285
Automatic Transmission Fluid
(6 Speed Transmission) . . . . . 286
Automatic Transmission Fluid
(8 and 10 Speed
Transmission) . . . . . . . . . . . . . . . 289
Engine Air Cleaner/Filter . . . . . . 290
Cooling System . . . . . . . . . . . . . . 291
Engine Overheating . . . . . . . . . . 294
Engine Fan . . . . . . . . . . . . . . . . . . . 296
Washer Fluid . . . . . . . . . . . . . . . . . 296
Brakes . . . . . . . . . . . . . . . . . . . . . . . 297 Brake Fluid . . . . . . . . . . . . . . . . . . . 297
Battery - North America . . . . . . 298
Four-Wheel Drive . . . . . . . . . . . . . 299
Front Axle . . . . . . . . . . . . . . . . . . . . 300
Rear Axle . . . . . . . . . . . . . . . . . . . . 300
Noise Control System . . . . . . . . 301
Starter Switch Check . . . . . . . . . 302
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 302
Ignition Transmission Lock
Check . . . . . . . . . . . . . . . . . . . . . . . 303
Park Brake and P (Park)
Mechanism Check . . . . . . . . . . 303
Wiper Blade Replacement . . . . 303
Glass Replacement . . . . . . . . . . 304
Windshield Replacement . . . . . 304
Gas Strut(s) . . . . . . . . . . . . . . . . . . 305
Headlamp Aiming Headlamp Aiming . . . . . . . . . . . . 306
Bulb Replacement Bulb Replacement . . . . . . . . . . . . 306
High Intensity Discharge (HID)
Lighting . . . . . . . . . . . . . . . . . . . . . 306
LED Lighting . . . . . . . . . . . . . . . . . 307
Fog Lamps . . . . . . . . . . . . . . . . . . . 307
Back-Up Lamps . . . . . . . . . . . . . . 307
License Plate Lamp . . . . . . . . . . 308 Electrical System Electrical System Overload . . . 309
Fuses and Circuit Breakers . . . 309
Engine Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . . . . 310
Instrument Panel Fuse
Block (Left) . . . . . . . . . . . . . . . . . 314
Instrument Panel Fuse Block
(Right) . . . . . . . . . . . . . . . . . . . . . . 317
Rear Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . . . . 319
Wheels and Tires Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 320
All-Season Tires . . . . . . . . . . . . . . 321
Winter Tires . . . . . . . . . . . . . . . . . . 321
Low-Profile Tires . . . . . . . . . . . . . 322
All-Terrain Tires . . . . . . . . . . . . . . . 322
Tire Sidewall Labeling . . . . . . . . 322
Tire Designations . . . . . . . . . . . . . 324
Tire Terminology and
Definitions . . . . . . . . . . . . . . . . . . 324
Tire Pressure . . . . . . . . . . . . . . . . . 327
Tire Pressure for High-Speed
Operation . . . . . . . . . . . . . . . . . . . 328
Tire Pressure Monitor
System . . . . . . . . . . . . . . . . . . . . . . 329
Tire Pressure Monitor
Operation . . . . . . . . . . . . . . . . . . . 330
Tire Inspection . . . . . . . . . . . . . . . . 333
Tire Rotation . . . . . . . . . . . . . . . . . 334

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
290 Vehicle Care Change the fluid and filter at the
scheduled maintenance intervals
listed in Maintenance Schedule
0 370 . Be sure to use the
transmission fluid listed in
Recommended Fluids and
Lubricants 0 379 .
Engine Air Cleaner/Filter See Engine Compartment Overview
0 280 for the location of the engine
air cleaner/filter.
When to Inspect the Engine Air
Cleaner/Filter For intervals on changing and
inspecting the engine air cleaner/
filter, see Maintenance Schedule
0 370 .
How to Inspect the Engine Air
Cleaner/Filter
Do not start the engine or have the
engine running with the engine air
cleaner/filter housing open. Before
removing the engine air cleaner/
filter, make sure that the engine air
cleaner/filter housing and nearby
components are free of dirt and
debris. Remove the engine air cleaner/filter. Lightly tap and shake
the engine air cleaner/filter (away
from the vehicle), to release loose
dust and dirt. Inspect the engine air
cleaner/filter for damage, and
replace if damaged. Do not clean
the engine air cleaner/filter or
components with water or
compressed air.
To inspect or replace the engine air
cleaner/filter:
1. Screws (4)
2. Electrical Connector
3. Air Duct Clamp 1. Locate the air cleaner/filter
assembly. See Engine
Compartment Overview 0 280 .
2. Disconnect the outlet duct by
loosening the air duct
clamp (3).
3. Disconnect the electrical
connector (2) and the
connector harness from the
cover.
4. Remove the four screws (1) on
top of the cover of the housing
and lift up the cover.
5. Remove the engine air cleaner/
filter from the housing. Take
care to dislodge as little dirt as
possible.
6. Clean the engine air cleaner/
filter sealing surfaces and the
housing.
7. Inspect or replace the engine
air cleaner/filter.
8. Reverse Steps 2-4 to reinstall
the filter cover housing.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Vehicle Care 297Caution (Continued) freezing occurs, which could
damage the tank if it is
completely full.
Brakes Disc brake pads have built-in wear
indicators that make a high-pitched
warning sound when the brake pads
are worn and new pads are needed.
The sound can come and go or can
be heard all the time when the
vehicle is moving, except when
applying the brake pedal firmly.
{ Warning
The brake wear warning sound
means that soon the brakes will
not work well. That could lead to
a crash. When the brake wear
warning sound is heard, have the
vehicle serviced. CautionContinuing to drive with worn-out
brake pads could result in costly
brake repair.
Some driving conditions or climates
can cause a brake squeal when the
brakes are first applied or lightly
applied. This does not mean
something is wrong with the brakes.
Properly torqued wheel nuts are
necessary to help prevent brake
pulsation. When tires are rotated,
inspect brake pads for wear and
evenly tighten wheel nuts in the
proper sequence to torque
specifications. See Capacities and
Specifications 0 384 .
Brake pads should be replaced as
complete sets.
Brake Pedal Travel
See your dealer if the brake pedal
does not return to normal height,
or if there is a rapid increase in
pedal travel. This could be a sign
that brake service may be required. Replacing Brake System Parts Always replace brake system parts
with new, approved replacement
parts. If this is not done, the brakes
may not work properly. The braking
performance expected can change
in many other ways if the wrong
replacement brake parts are
installed or if parts are improperly
installed.
Brake Fluid
The brake master cylinder reservoir
is filled with GM approved DOT 3
brake fluid as indicated on the
reservoir cap. See Engine
Compartment Overview 0 280 for
the location of the reservoir.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
298 Vehicle Care Checking Brake Fluid
With the vehicle in P (Park) on a
level surface, the brake fluid level
should be between the minimum
and maximum marks on the brake
fluid reservoir.
There are only two reasons why the
brake fluid level in the reservoir may
go down:
.
Normal brake lining wear. When
new linings are installed, the
fluid level goes back up.
.
A fluid leak in the brake
hydraulic system. Have the
brake hydraulic system fixed.
With a leak, the brakes will not
work well.
Always clean the brake fluid
reservoir cap and the area around
the cap before removing it.
Do not top off the brake fluid.
Adding fluid does not correct a leak.
If fluid is added when the linings are
worn, there will be too much fluid
when new brake linings are
installed. Add or remove fluid, as
necessary, only when work is done
on the brake hydraulic system. { WarningIf too much brake fluid is added, it
can spill on the engine and burn,
if the engine is hot enough. You
or others could be burned, and
the vehicle could be damaged.
Add brake fluid only when work is
done on the brake hydraulic
system.
When the brake fluid falls to a low
level, the brake warning light comes
on. See Brake System Warning
Light 0 145 .
Brake fluid absorbs water over time
which degrades the effectiveness of
the brake fluid. Replace brake fluid
at the specified intervals to prevent
increased stopping distance. See
Maintenance Schedule 0 370 .
What to Add
Use only GM approved DOT 3
brake fluid from a clean, sealed
container. See Recommended
Fluids and Lubricants 0 379 .{ WarningThe wrong or contaminated brake
fluid could result in damage to the
brake system. This could result in
the loss of braking leading to a
possible injury. Always use the
proper GM approved brake fluid.
CautionIf brake fluid is spilled on the
vehicle's painted surfaces, the
paint finish can be damaged.
Immediately wash off any painted
surface.
Battery - North America The original equipment battery is
maintenance free. Do not remove
the cap and do not add fluid.
Refer to the replacement number
shown on the original battery label
when a new battery is needed. See
Engine Compartment Overview
0 280 for battery location.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
306 Vehicle Care
Liftgate
Headlamp Aiming Headlamp aim has been preset and
should need no further adjustment.
If the vehicle is damaged in a crash,
the headlamp aim may be affected.
If adjustment to the headlamps is
necessary, see your dealer.
Bulb Replacement For the proper type of replacement
bulbs, or any bulb changing
procedure not listed in this section,
contact your dealer.
High Intensity Discharge
(HID) Lighting
{ WarningThe High Intensity Discharge
(HID) lighting system operates at
a very high voltage. If you try to
service any of the system
components, you could be
seriously injured. Have your
dealer or a qualified technician
service them.
After an HID headlamp bulb has
been replaced, the beam might be a
slightly different shade than it was
originally. This is normal.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Vehicle Care 307
LED Lighting This vehicle has several LED lamps.
For replacement of any LED lighting
assembly, contact your dealer.
Fog Lamps
To replace the front fog lamp bulb:
1. Locate the fog lamp under the
front bumper.
2. Disconnect the electrical
connector from the fog lamp
bulb assembly by pressing the
connector release.
3. Turn the bulb counterclockwise
to remove it from the housing. Back-Up Lamps To replace a back-up bulb:
1. Open the liftgate. See Liftgate
0 43 .
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
the taillamp assembly.
4. Pull the taillamp assembly
straight back to remove.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Vehicle Care 315
The vehicle may not be equipped
with all of the fuses, relays, and
features shown. Fuses Usage
1 –
2 – Fuses Usage
3 –
4 Accessory power
outlet 1
5 Retained accessory
power
6 APO/BATT
7 Universal garage door
opener/Interior
rearview mirror
8 SEO/Retained
accessory power
9 –
10 Body control module 3
11 Body control module 5
12 Steering wheel control
backlighting
13 –
14 –
15 –
16 Discrete logic ignition
sensor
17 Video processing
module