2021 GMC YUKON maintenance

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
326 Vehicle Care
and rear brake pad life percentages will not
display. However, the built-in wear
indicators that make a high-pitched warning
sound when the brake pads are worn can
still determine when the pads should be
replaced. SeeBrakes0324.
To turn off the brake pad life system: 1. Display Brake Pad Life on the DIC. See Driver Information Center (DIC) 0120.
2. Select DISABLE.
To turn the brake pad life system back on,
follow the above steps but select ENABLE in
Step 2.
Brake Fluid
The brake master cylinder reservoir is filled
with GM approved DOT 4 brake fluid as
indicated on the reservoir cap. See Engine
Compartment Overview 0312 for the
location of the reservoir. 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.
{Warning
If 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 0112.
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 0384.
What to Add
Use only GM approved DOT 4 brake fluid
from a clean, sealed container. See
Recommended Fluids and Lubricants 0392.
{Warning
The wrong or contaminated brake fluid
could result in damage to the brake
system. This could result in the loss of
(Continued)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Vehicle Care 327
Warning (Continued)
braking leading to a possible injury.
Always use the proper GM approved
brake fluid.
Caution
If 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. SeeEngine Compartment
Overview 0312 for battery location.
The vehicle has an Absorbed Glass Mat
(AGM) 12-volt battery. Installation of a
standard 12-volt battery will result in
reduced 12-volt battery life.
When using a 12-volt battery charger on the
12-volt AGM battery, some chargers have an
AGM battery setting on the charger. If available, use the AGM setting on the
charger, to limit charge voltage to 14.8 volts.
Follow the charger manufacturer's
instructions.
Stop/Start System
This vehicle has a Stop/Start system to shut
off the engine to help conserve fuel. See
Stop/Start System
0229.
{Warning
WARNING: Battery posts, terminals, and
related accessories contain lead and lead
compounds, chemicals known to the
State of California to cause cancer and
birth defects or other reproductive harm.
Batteries also contain other chemicals
known to the State of California to cause
cancer. WASH HANDS AFTER HANDLING.
For more information go to
www.P65Warnings.ca.gov/
passenger-vehicle.
See California Proposition 65 Warning 0309
and the back cover.
Vehicle Storage
{Warning
Batteries have acid that can burn you and
gas that can explode. You can be badly
hurt if you are not careful. See Jump
Starting - North America 0367 for tips on
working around a battery without
getting hurt.
Infrequent Usage: Remove the black,
negative (−) cable from the battery to keep
the battery from running down.
Extended Storage: Remove the black,
negative (−) cable from the battery or use a
battery trickle charger.
Four-Wheel Drive
Transfer Case
When to Check Lubricant
Refer to Maintenance Schedule 0384 to
determine when to check the lubricant.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
328 Vehicle Care
How to Check Lubricant
1. Fill Plug
2. Drain Plug
To get an accurate reading, the vehicle
should be on a level surface.
If the level is below the bottom of the fill
plug (1) hole, located on the transfer case,
some lubricant will need to be added. Add
enough lubricant to raise the level to the
bottom of the fill plug (1) hole. Use care not
to overtighten the plug.
When to Change Lubricant
Refer toMaintenance Schedule 0384 to
determine how often to change the
lubricant. What to Use
Refer to
Recommended Fluids and Lubricants
0 392 to determine what kind of lubricant
to use.
Front Axle
When to Check Lubricant
It is not necessary to regularly check the
front axle fluid unless a leak is suspected or
an unusual noise is heard. A fluid loss could
indicate a problem. Have it inspected and
repaired. This service can be complex. See
your dealer.
Do not directly power wash the transfer
case and/or front/rear axle output seals.
High pressure water can overcome the seals
and contaminate the fluid. Contaminated
fluid will decrease the life of the transfer
case and/or drive axles and should be
replaced.
Rear Axle
When to Check Lubricant
It is not necessary to regularly check the
rear axle fluid unless a leak is suspected or
an unusual noise is heard. A fluid loss could indicate a problem. Have it inspected and
repaired. This service can be complex. See
your dealer.
Do not directly power wash the transfer
case and/or front/rear axle output seals.
High pressure water can overcome the seals
and contaminate the fluid. Contaminated
fluid will decrease the life of the transfer
case and/or drive axles and should be
replaced.
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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Vehicle Care 329
.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 0394.
Caution
Allowing the wiper 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 arm to touch the
windshield.
Front Wiper Blade Replacement
To replace the wiper blade assembly:
1. Pull the windshield wiper assembly away from the windshield.
2. Press the button in the middle of thewiper arm connector, and pull the wiper
blade away from the arm connector.
3. Remove the wiper blade.
4. Reverse Steps 1–3 for wiper blade replacement.
Rear Wiper Blade Replacement
To replace the rear wiper blade: 1. With the rear wiper in the off position,
open the liftglass to access the rear
wiper arm/blade.
The rear wiper blade will not lock in a
vertical position so use care when pulling
it away from the vehicle.
2. Push the release lever (2) to disengagethe 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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
330 Vehicle Care
Glass Replacement
If the windshield or front side glass must be
replaced, see your dealer to determine the
correct replacement glass.
Windshield Replacement
HUD System
The windshield is part of the HUD system.
If the windshield must be replaced, get one
that is designed for HUD or the HUD image
may look out of focus.
Driver Assistance Systems
If the windshield needs to be replaced and
the vehicle is equipped with a front camera
sensor for the Driver Assistance Systems, a
GM replacement windshield is
recommended. The replacement windshield
must be installed according to GM
specifications for proper alignment. If it is
not, these systems may not work properly,
they may display messages, or they may
not work at all. See your dealer for proper
windshield replacement.
Gas Strut(s)
This vehicle is equipped with gas strut(s) to
provide assistance in lifting and holding
open the hood/trunk/liftgate system in full
open position.
{Warning
If the gas struts that hold open the hood,
trunk, and/or liftgate fail, you or others
could be seriously injured. Take the
vehicle to your dealer for service
immediately. Visually inspect the gas
struts for signs of wear, cracks, or other
damage periodically. Check to make sure
the hood/trunk/liftgate is held open with
enough force. If struts are failing to hold
the hood/trunk/liftgate, do not operate.
Have the vehicle serviced.
Caution
Do not apply tape or hang any objects
from gas struts. Also do not push down
or pull on gas struts. This may cause
damage to the vehicle.
See Maintenance Schedule 0384.
Hood
Trunk

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Vehicle Care 347
failure. Under-inflation also reduces fuel
efficiency and tire tread life, and may affect
the vehicle's handling and stopping ability.
Please note that the TPMS is not a
substitute for proper tire maintenance, and
it is the driver's responsibility to maintain
correct tire pressure, even if under-inflation
has not reached the level to trigger
illumination of the TPMS low tire pressure
telltale.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate when
the system is not operating properly. The
TPMS malfunction indicator is combined
with the low tire pressure telltale. When the
system detects a malfunction, the telltale
will flash for approximately one minute and
then remain continuously illuminated. This
sequence will continue upon subsequent
vehicle start-ups as long as the malfunction
exists.
When the malfunction indicator is
illuminated, the system may not be able to
detect or signal low tire pressure as
intended. TPMS malfunctions may occur for
a variety of reasons, including the
installation of replacement or alternate tires
or wheels on the vehicle that prevent the
TPMS from functioning properly. Alwayscheck the TPMS malfunction telltale after
replacing one or more tires or wheels on
your vehicle to ensure that the replacement
or alternate tires and wheels allow the
TPMS to continue to function properly.
See
Tire Pressure Monitor Operation 0347.
See Radio Frequency Statement 0407.
Tire Pressure Monitor Operation
This vehicle may have a Tire Pressure
Monitor System (TPMS). The TPMS is
designed to warn the driver when a low tire
pressure condition exists. TPMS sensors are
mounted onto each tire and wheel
assembly, excluding the spare tire and
wheel assembly. The TPMS sensors monitor
the air pressure in the tires and transmit the
tire pressure readings to a receiver located
in the vehicle.
When a low tire pressure condition is
detected, the TPMS illuminates the low tire
pressure warning light located on the instrument cluster. If the warning light
comes on, stop as soon as possible and
inflate the tires to the recommended
pressure shown on the Tire and Loading
Information label. See
Vehicle Load Limits
0 222.
A message to check the pressure in a
specific tire displays in the Driver
Information Center (DIC). The low tire
pressure warning light and the DIC warning
message come on at each ignition cycle
until the tires are inflated to the correct
inflation pressure. If the vehicle has DIC
buttons, tire pressure levels can be viewed.
For additional information and details about
the DIC operation and displays, see Driver
Information Center (DIC) 0120.
The low tire pressure warning light may
come on in cool weather when the vehicle is
first started, and then turn off as the vehicle
is driven. This could be an early indicator
that the air pressure is getting low and
needs to be inflated to the proper pressure.
A Tire and Loading Information label shows
the size of the original equipment tires and
the correct inflation pressure for the tires

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
348 Vehicle Care
when they are cold. SeeVehicle Load Limits
0 222, for an example of the Tire and
Loading Information label and its location.
Also see Tire Pressure 0344.
The TPMS can warn about a low tire
pressure condition but it does not replace
normal tire maintenance. See Tire Inspection
0 349, Tire Rotation 0350 and
Tires 0339.
Caution
Tire sealant materials are not all the
same. A non-approved tire sealant could
damage the TPMS sensors. TPMS sensor
damage caused by using an incorrect tire
sealant is not covered by the vehicle
warranty. Always use only the GM
approved tire sealant available through
your dealer or included in the vehicle.
TPMS Malfunction Light and Message
The TPMS will not function properly if one
or more of the TPMS sensors are missing or
inoperable. When the system detects a
malfunction, the low tire pressure warning
light flashes for about one minute and then
stays on for the remainder of the ignition
cycle. A DIC warning message also displays.
The malfunction light and DIC warning message come on at each ignition cycle
until the problem is corrected. Some of the
conditions that can cause these to come
on are:
.One of the road tires has been replaced
with the spare tire. The spare tire does
not have a TPMS sensor. The malfunction
light and the DIC message should go off
after the road tire is replaced and the
sensor matching process is performed
successfully. See "TPMS Sensor Matching
Process" later in this section.
.The TPMS sensor matching process was
not done or not completed successfully
after rotating the tires. The malfunction
light and the DIC message should go off
after successfully completing the sensor
matching process. See "TPMS Sensor
Matching Process" later in this section.
.One or more TPMS sensors are missing or
damaged. The malfunction light and the
DIC message should go off when the
TPMS sensors are installed and the sensor
matching process is performed
successfully. See your dealer for service.
.Replacement tires or wheels do not match
the original equipment tires or wheels.
Tires and wheels other than those
recommended could prevent the TPMS
from functioning properly. See
Buying
New Tires 0351.
.Operating electronic devices or being near
facilities using radio wave frequencies
similar to the TPMS could cause the TPMS
sensors to malfunction.
If the TPMS is not functioning properly, it
cannot detect or signal a low tire pressure
condition. See your dealer for service if the
TPMS malfunction light and DIC message
come on and stay on.
Tire Fill Alert (If Equipped)
This feature provides visual and audible
alerts outside the vehicle to help when
inflating an underinflated tire to the
recommended cold tire pressure.
When the low tire pressure warning light
comes on: 1. Park the vehicle in a safe, level place.
2. Set the parking brake firmly.
3. Place the vehicle in P (Park).
4. Add air to the tire that is underinflated. The turn signal lamp will flash.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
350 Vehicle Care
.The tire has a puncture, cut, or other
damage that cannot be repaired well
because of the size or location of the
damage.
Tire Rotation
Tires should be rotated every 12 000 km
(7,500 mi). SeeMaintenance Schedule
0 384.
Tires are rotated to achieve a more
uniform wear for all tires. The first
rotation is the most important.
Anytime unusual wear is noticed, rotate
the tires as soon as possible, check for
proper tire inflation pressure, and check
for damaged tires or wheels. If the
unusual wear continues after the
rotation, check the wheel alignment.
See When It Is Time for New Tires 0351
and
Wheel Replacement 0354.
Use this rotation pattern when rotating
the tires.
Do not include the spare tire in the tire
rotation.
Adjust the front and rear tires to the
recommended inflation pressure on the
Tire and Loading Information label after
the tires have been rotated. See Tire
Pressure 0344 and
Vehicle Load Limits 0222.
Reset the Tire Pressure Monitor System.
See Tire Pressure Monitor Operation
0 347. Check that all wheel nuts are properly
tightened. See
“Wheel Nut Torque”
under Capacities and Specifications
0 396.
{Warning
Rust or dirt on a wheel, or on the
parts to which it is fastened, can
cause wheel nuts to become loose
over time. The wheel could come off
and cause a crash. When changing a
wheel, remove any rust or dirt from
places where the wheel attaches to
the vehicle. In an emergency, a cloth
or paper towel can be used; however,
use a scraper or wire brush later to
remove all rust or dirt.
Lightly coat the inner diameter of the
wheel hub opening with wheel bearing
grease after a wheel change or tire
rotation to prevent corrosion or rust
build-up.