brake GMC YUKON 2020 Manual PDF

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
276 Driving and Operating
.A trailer without electric brakes
is connected, no DIC message
will display
. A trailer with electric brakes has
become disconnected, a CHECK
TRAILER WIRING message
displays on the DIC
. There is a fault present in the
wiring to the trailer brakes, a
CHECK TRAILER WIRING
message displays on the DIC
. The ITBC system is not working
due to a fault, a SERVICE
TRAILER BRAKE SYSTEM
message displays in the DIC
Manual Trailer Brake Apply Lever
Slide this lever left to apply the
trailer ’s electric brakes independent
of the vehicle’s brakes. Use this
lever to adjust Trailer Gain to
achieve the proper power output to
the trailer brakes. The trailer's and
the vehicle's brake lamps will come
on when either vehicle brakes or
manual trailer brakes are applied
and properly connected. Trailer Gain Adjustment Procedure
Trailer Gain should be set for a
specific trailering condition and it
must be readjusted anytime 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.
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. Note
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.
Note
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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Driving and Operating 277
Other ITBC-Related DIC Messages
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.
CHECK TRAILER WIRING: This
message will display if:
.The ITBC system first
determines connection to a
trailer with electric brakes and
then the trailer harness becomes
disconnected the vehicle.
If the disconnect occurs while
the vehicle is stationary, this
message will automatically turn
off in about 30 seconds. This
message will also turn off if it is
acknowledged or if the trailer
harness is reconnected.
If the disconnect occurs while
the vehicle is moving, this
message will continue until the
ignition is turned off. This message will also turn off if it is
acknowledged or if the trailer
harness is reconnected.
. There is an electrical fault in the
wiring to the trailer brakes. This
message will continue as long
as there is an electrical fault in
the trailer wiring. This message
will also turn off if it is
acknowledged.
To determine whether the electrical
fault is on the vehicle side or trailer
side of the trailer wiring harness
connection: 1. Disconnect the trailer wiring harness from the vehicle.
2. Turn the ignition off.
3. 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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
278 Driving and Operating
Contact your trailer dealer for
assistance with trailer repairs and
trailer warranty information.
Trailer Sway
Control (TSC)
Vehicles with StabiliTrak have a
Trailer Sway Control (TSC) feature.
Trailer sway is unintended
side-to-side motion of a trailer while
towing. If the vehicle is towing a
trailer and the TSC detects that
sway is increasing, the vehicle
brakes are selectively applied at
each wheel, to help reduce
excessive trailer sway. If equipped
with the Integrated Trailer Brake
Control (ITBC) system, and the
trailer has an electric brake system,
StabiliTrak may also apply the trailer
brakes.If TSC is enabled, the Traction
Control System (TCS)/StabiliTrak
warning light will flash on the
instrument cluster. Reduce vehicle
speed by gradually removing your
foot from the accelerator. If trailer
sway continues, StabiliTrak can
reduce engine torque to help slow
the vehicle. TSC will not function if
StabiliTrak is turned off. See
Traction Control/Electronic Stability
Control0226.
{Warning
Trailer sway can result in a crash
and in serious injury or death,
even if the vehicle is equipped
with TSC.
(Continued)
Warning (Continued)
If the trailer begins to sway,
reduce vehicle speed by
gradually removing your foot from
the accelerator. Then pull over to
check the trailer and vehicle to
help correct possible causes,
including an improperly or
overloaded trailer, unrestrained
cargo, improper trailer hitch
configuration, or improperly
inflated or incorrect vehicle or
trailer tires. SeeTowing
Equipment 0270 for trailer ratings
and hitch setup
recommendations.
Aftermarket 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

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Driving and Operating 279
the vehicle’s trailer brake systems
or other systems, including
integrated anti-sway systems,
if equipped. Messages related to
trailer connections or trailer brakes
could appear on the DIC. The
effects of these aftermarket devices
on vehicle handling or trailer brake
performance is not known.
{Warning
Use of aftermarket electronic
trailer sway control devices could
result in reduced trailer brake
performance, loss of trailer
brakes, or other malfunctions, and
result in a crash. You or others
could be seriously 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
(Continued)
Warning (Continued)
your vehicle and any
optional equipment installed
on your vehicle.
. Before driving, check the
trailer brakes are working
properly, if equipped. 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
the manual trailer brake
apply lever. Also, check 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.
Trailer Tires
Special Trailer (ST) tires differ from
vehicle tires. Trailer tires are
designed with stiff sidewalls to help
prevent sway and to support heavy
loads. These features can make it
difficult to determine if the trailer tire
pressures are low only based on a
visual inspection.
Always check all trailer tire
pressures before each trip when the
tires are cool. Low trailer tire
pressure is a leading cause of trailer
tire blow-outs.
Trailer tires deteriorate over time.
The trailer tire sidewall will show the
week and year the tire was
manufactured. Many trailer tire
manufacturers recommend
replacing tires more than six
years old.
Overloading is another leading
cause of trailer tire blow-outs. Never
load your trailer with more weight
than the tires are designed to
support. The load rating is located
on the trailer tire sidewall.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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Vehicle Care 281
Vehicle Care
General Information
General Information . . . . . . . . . . 282
California Proposition65 Warning . . . . . . . . . . . . . . . . . 282
California Perchlorate Materials Requirements . . . . . 283
Accessories and Modifications . . . . . . . . . . . . . . . . 283
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 283
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 284
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 286
Engine Oil . . . . . . . . . . . . . . . . . . . . 289
Engine Oil Life System . . . . . . . 291
Automatic Transmission Fluid (6-Speed Transmission) . . . . . 292
Automatic Transmission Fluid (10-Speed Transmission) . . . 295
Engine Air Cleaner/Filter . . . . . . 296
Cooling System . . . . . . . . . . . . . . 297
Engine Overheating . . . . . . . . . . 300
Engine Fan . . . . . . . . . . . . . . . . . . . 302
Washer Fluid . . . . . . . . . . . . . . . . . 302
Brakes . . . . . . . . . . . . . . . . . . . . . . . 303 Brake Fluid . . . . . . . . . . . . . . . . . . . 304
Battery - North America . . . . . . 305
Four-Wheel Drive . . . . . . . . . . . . . 305
Front Axle . . . . . . . . . . . . . . . . . . . . 306
Rear Axle . . . . . . . . . . . . . . . . . . . . 306
Noise Control System . . . . . . . . 306
Starter Switch Check . . . . . . . . . 308
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 308
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 308
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 309
Wiper Blade Replacement . . . . 309
Glass Replacement . . . . . . . . . . 310
Windshield Replacement . . . . . 310
Gas Strut(s) . . . . . . . . . . . . . . . . . . 310
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 312
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 312
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . . . 312
LED Lighting . . . . . . . . . . . . . . . . . 312
Fog Lamps . . . . . . . . . . . . . . . . . . . 312
Back-Up Lamps . . . . . . . . . . . . . . 313
License Plate Lamp . . . . . . . . . . 314
Electrical System
Electrical System Overload . . . 314
Fuses and Circuit Breakers . . . 315
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 315
Instrument Panel Fuse Block
(Right) . . . . . . . . . . . . . . . . . . . . . . 320
Instrument Panel Fuse Block (Left) . . . . . . . . . . . . . . . . . 323
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 325
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 326
All-Season Tires . . . . . . . . . . . . . . 327
Winter Tires . . . . . . . . . . . . . . . . . . 328
Low-Profile Tires . . . . . . . . . . . . . 328
All-Terrain Tires . . . . . . . . . . . . . . . 328
Tire Sidewall Labeling . . . . . . . . 329
Tire Designations . . . . . . . . . . . . . 330
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . 331
Tire Pressure . . . . . . . . . . . . . . . . . 333
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . 334
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . . . . . . 335
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . 336
Tire Inspection . . . . . . . . . . . . . . . . 340

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 283
California Perchlorate
Materials Requirements
Certain types of automotive
applications, such as airbag
initiators, seat belt pretensioners,
and lithium batteries contained in
electronic keys, may contain
perchlorate materials. Perchlorate
Material–special handling may
apply. 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 and
handling, 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 suspension components
caused by modifying vehicle height
outside of factory settings will not be
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 084.
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
0 405.
This vehicle has an airbag system.
Before attempting to do your own
service work, see Servicing the
Airbag-Equipped Vehicle 084.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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Vehicle Care 287
1. Positive (+) Terminal. SeeJump Starting - North America
0360.
2. Battery - North America 0305.
3. Coolant Surge Tank and Pressure Cap. See Cooling
System 0297.
4. Engine Air Cleaner/Filter 0296.
5. Automatic Transmission Dipstick. See “How to Check
Automatic Transmission Fluid”
under Automatic Transmission
Fluid (6-Speed Transmission)
0 292 or
Automatic Transmission Fluid
(10-Speed Transmission)
0 295.
6. Remote Negative (–) Location (Out of View). See Jump
Starting - North America 0360.
7. Engine Cooling Fans (Out of View). See Cooling System
0 297.
8. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil 0289. 9. Engine Oil Dipstick. See
“Checking Engine Oil” under
Engine Oil 0289.
10. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer Fluid
0 302.
11. Brake Fluid Reservoir. See Brake Fluid 0304.
12. Engine Compartment Fuse
Block 0315.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 289
1. Positive (+) Terminal. SeeJump Starting - North America
0360.
2. Battery - North America 0305.
3. Coolant Surge Tank and Pressure Cap. See Cooling
System 0297.
4. Engine Air Cleaner/Filter 0296.
5. Remote Negative (–) Location (Out of View). See Jump
Starting - North America 0360.
6. Engine Cooling Fans (Out of View). See Cooling System
0 297.
7. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil 0289.
8. Engine Oil Dipstick. See “Checking Engine Oil” under
Engine Oil 0289.
9. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer Fluid
0 302.
10. Brake Fluid Reservoir. See Brake Fluid 0304. 11.
Engine Compartment Fuse
Block 0315.
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:
.
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 0291.
. 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.
Check the oil level before filling to
the recommended level. If the oil is
not low and this message remains
on, see your dealer.
Check the engine oil level regularly,
every 650 km (400 mi), especially
prior to a long trip. The engine oil
dipstick handle is a loop. See
Engine Compartment Overview
0286 for the location.
{Warning
The engine oil dipstick handle
may be hot; it could burn you.
Use a towel or glove to touch the
dipstick handle.
Follow these guidelines:
. To get an accurate reading, park
the vehicle on level ground.
Check the engine oil level after
the engine has been off for at
least two hours. Checking the

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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Vehicle Care 293
Caution (Continued)
automatic transmission fluid. See
Recommended Fluids and
Lubricants0388.
Change the fluid and filter at the
scheduled maintenance intervals
listed in Maintenance Schedule
0 379. Be sure to use the
transmission fluid listed in
Recommended Fluids and
Lubricants 0388.
How to Check Automatic
Transmission Fluid
Caution
Too much or too little fluid can
damage the transmission. Too
much can mean that some of the
fluid could come out and fall on
hot engine parts or exhaust
system parts, starting a fire. Too
little fluid could cause the (Continued)
Caution (Continued)
transmission to overheat. Be sure
to get an accurate reading if
checking the transmission fluid.
Before checking the fluid level,
prepare the vehicle: 1. Start the engine and park the vehicle on a level surface.
Keep the engine running.
2. Apply the parking brake and place the shift lever in P (Park).
3. With your foot on the brake pedal, move the shift lever
through each gear range,
pausing for about
three seconds in each range.
Then, move the shift lever back
to P (Park).
4. Allow the engine to idle (500– 800 rpm) for at least
one minute. Slowly release the
brake pedal.
5. Keep the engine running and check the transmission fluid
temperature on the Driver Information Center (DIC). See
Driver Information Center (DIC)
0
144.
6. Using the transmission fluid temperature reading, determine
and perform the appropriate
check procedure. If the
transmission fluid temperature
reading is not within the
required temperature ranges,
allow the vehicle to cool,
or operate the vehicle until the
appropriate transmission fluid
temperature is reached.
Cold Check Procedure
Use this procedure only as a
reference to determine if the
transmission has enough fluid to be
operated safely until a hot check
procedure can be made. The hot
check procedure is the most
accurate method to check the fluid
level. Perform the hot check
procedure at the first opportunity.
Use this cold check procedure to
check fluid level when the
transmission temperature is
between 27 °C and 32 °C (80 °F and
90 °F).

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Caution (Continued)
.When using concentrated
washer fluid, follow the
manufacturer instructions for
adding water.
. Fill the washer fluid tank
only three-quarters full when
it is very cold. This allows
for fluid expansion if
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.
Caution
Continuing 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 0393.
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.