stop start GMC YUKON 2021 Workshop Manual

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
300 Driving and Operating
Vehicle
1. Transmission Fluid Temperature
2. Average Fuel Economy with TrailerProfile
Average Fuel Economy
Touch to view the average fuel economy of
the vehicle while the Trailer Profile is active.
Transmission Temperature
View the temperature of the transmission
fluid by looking at the graphic. The graphic
will indicate a dangerous level if the
temperature is at 130 °C–150 °C (270 °F–
300 °F).
Connections
1. Light Test Start Button
2. Trailer Electrical Diagnostics
Connections: OK
If a trailer connection is detected without
any faults, the view will display OK.
Trailer Connections Status
When a trailer is connected, the Trailering
App System detects the trailer connection
using the Stop/Turn Signal lighting circuits
and alerts the driver by requesting a trailer
profile setup through the Trailering App
System on the infotainment screen. The
Trailer Detection Alert setting must be
enabled for the alert to display when a trailer is connected. When a trailer is
connected and the ignition is off, the
Trailering App System will periodically pulse
the lighting circuits of the trailer to verify it
is still connected. The trailer lights may
periodically flash as a result of this trailer
connection detection. These flashes may be
more visible in dark ambient light
environments. The flashing or flickering
lights are a normal condition and the
Trailering App System has built-in
protections to prevent the battery from
draining. When Theft Alert is also enabled
the frequency and pattern of this flashing
will change.
Connection Problem
If any of the trailer connections are lost, a
message about the connection issue will
appear on the Driver Information Center
(DIC). The infotainment display will also
show the connection issue in the Connection
Status view.
If a trailer connection is not detected, the
Trailering App will not display the
Connection Status screen.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 301
Connection Trailer Lighting Faults Detected
The Trailering App System monitors for
electrical faults on the trailer lights.
A message about the lighting issue will
appear on the DIC. The infotainment display
will also show the lighting issue in the
Connection Status view. Repair your trailer
lights if needed. A trailer lighting issue is
not covered by your GM warranty.
Diagnose View
Touch Diagnose to see more information
about the connection problem.
This view will display the names of the
trailer connector pins, a graphic of the trailer
connector, and a graphic of the back of the
trailer.
Any connector pin that failed will be amber
color, and the location of the corresponding
connection will be highlighted on the
graphic of the back of the trailer.
The Running Lights connection may not
detect partial outages. Activate the light test
to check all trailer lamps. See“Light Test”
following. Light Test
Touch Start Light Test to cycle the trailer
lights on and off to determine if they are
working. The test follows this sequence:
1. The running lights turn on first and remain on throughout the sequence.
2. The brake lights turn on for about two seconds.
3. The left turn signal light flashes three times.
4. The right turn signal light flashes three times.
5. The reverse lights turn on for about two seconds.
6. Steps 2–5 repeat for approximately one minute and 45 seconds, or until the
test deactivates.
Touch Stop to stop the test. The test will
automatically end after one minute and
45 seconds.
The sequence also deactivates when any of
the following occur:
.The ignition is turned off.
.The transmission is shifted out of P (Park).
.The brake pedal is pressed.
.The turn signal is activated.
.The hazard warning lights are activated.
Tires
1. Trailer Tire Pressure/Temperature
Tire Pressure and Temperature
If the TTPMS sensor-to-vehicle learn process
was completed, the status view will display
the current tire pressure and temperature of
the trailer tires related to the active Trailer
Profile. If a tire’s pressure is low or high, the
color of the pressure value will be amber.
If a sensor malfunctions, the values are
dashed lines. If the screen displays “Service
Tire Pressure Monitoring System”, the
vehicle needs to be taken to a dealer for
service.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
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
322 Vehicle Care
Caution
Failure to follow the specific coolant fill
procedure could cause the engine to
overheat and could cause system
damage. If coolant is not visible in the
surge tank, contact your dealer.
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 indicated 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.
Caution
If the pressure cap is not tightly installed,
coolant loss and engine damage may
occur. Be sure the cap is properly and
tightly secured.
Engine Overheating
Caution
Do not run the engine if there is a leak
in the engine cooling system. This can
cause a loss of all coolant and can
damage the system and vehicle. Have
any leaks fixed right away.
The vehicle has several indicators to warn of
engine overheating.
There is a coolant temperature gauge and a
engine coolant temperature warning light in
the vehicle's instrument cluster. See Engine
Coolant Temperature Gauge 0108 and
Engine Coolant Temperature Warning Light
0 116.
In addition, there are ENGINE OVERHEATED
STOP ENGINE, ENGINE OVERHEATED IDLE
ENGINE, and ENGINE POWER IS REDUCED
messages in the Driver Information
Center (DIC).
If the decision is made not to lift the hood
when this warning appears, get service help
right away. See Roadside Assistance Program
0 402.

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
Vehicle Care 331
Liftgate
Headlamp Aiming
Front 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
LED Lighting
This vehicle has several LED lamps. For
replacement of any LED lighting assembly,
contact your dealer.
Electrical System
Electrical System Overload
The vehicle has fuses to protect against an
electrical system overload. Fuses also protect
power devices in the vehicle.
Replace a bad fuse with a new one of the
identical size and rating.
If there is a problem on the road and a fuse
needs to be replaced, there are some spare
fuses and a fuse puller in the left
instrument panel fuse block. The
same amperage fuse can also be borrowed.
Choose some feature of the vehicle that is
not needed to use and replace it as soon as
possible.
Headlamp Wiring
An electrical overload may cause the lamps
to go on and off, or in some cases to
remain off. Have the headlamp wiring
checked right away if the lamps go on and
off or remain off.
Windshield Wipers
If the wiper motor overheats due to heavy
snow or ice, the windshield wipers will stop
until the motor cools and will then restart.
Although the circuit is protected from
electrical overload, overload due to heavy
snow or ice may cause wiper linkage
damage. Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an electrical
problem and not snow or ice, be sure to get
it fixed.
Fuses and Circuit Breakers
The wiring circuits in the vehicle are
protected from short circuits by a
combination of fuses and circuit breakers.
This greatly reduces the chance of damage
caused by electrical problems.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Vehicle Care 335
FusesUsage
69 Starter pinion 71 Cool fan motor lower
72 Right cool fan motor/ Lower
73 Left trailer stop turn lamp
74 TIM 2 75 DEFC
76 ELEC RNG BDS
78 ECM
79 –
80 Cabin cool pump 17W 81 Right trailer stop turn lamp
82 TIM 1
83 FTZM
84 Trailer battery 85 Engine
86 ECM 87 Injector B even
88 02 B sensor Fuses
Usage
89 02 A sensor
90 Injector A odd 91 ECM throttle control
92 Cool fan clutch AERO shutter
Relays Usage
5 –
18 DC/AC inverter
23 –
35 Park lamp
36 Run/Crank
43 Secondary axle motor
59 A/C clutch
64 Starter motor 70 Starter pinion 77 PowertrainInstrument Panel Fuse Block
The right instrument panel fuse block access
door is on the passenger side edge of the
instrument panel.
Pull off the cover to access the fuse block.

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
Vehicle Care 349
When the recommended pressure is
reached, the horn sounds once and the
turn signal lamp will stop flashing and
briefly turn solid.
Repeat these steps for all underinflated tires
that have illuminated the low tire pressure
warning light.
{Warning
Overinflating a tire could cause the tire
to rupture and you or others could be
injured. Do not exceed the maximum
pressure listed on the tire sidewall. See
Tire Sidewall Labeling 0341 and
Vehicle Load Limits 0222.
If the tire is overinflated by more than
35 kPa (5 psi), the horn will sound multiple
times and the turn signal lamp will continue
to flash for several seconds after filling
stops. To release and correct the pressure,
while the turn signal lamp is still flashing,
briefly press the center of the valve stem.
When the recommended pressure is reached,
the horn sounds once.
If the turn signal lamp does not flash within
15 seconds after starting to inflate the tire,
the tire fill alert has not been activated or is
not working. If the hazard warning flashers are on, the
tire fill alert visual feedback will not work
properly.
The TPMS will not activate the tire fill alert
properly under the following conditions:
.There is interference from an external
device or transmitter.
.The air pressure from the inflation device
is not sufficient to inflate the tire.
.There is a malfunction in the TPMS.
.There is a malfunction in the horn or turn
signal lamps.
.The identification code of the TPMS
sensor is not registered to the system.
.The battery of the TPMS sensor is low.
If the tire fill alert does not operate due to
TPMS interference, move the vehicle about
1 m (3 ft) back or forward and try again.
If the tire fill alert feature is not working,
use a tire pressure gauge.
TPMS Sensor Matching Process —Auto
Learn Function
Each TPMS sensor has a unique
identification code. The identification code
needs to be matched to a new tire/wheel
position after rotating the tires or replacing
one or more of the TPMS sensors. When a tire is installed, the vehicle must be
stationary for about 20 minutes before the
system recalculates. The following relearn
process takes up to 10 minutes, driving at a
minimum speed of 20 km/h (12 mph).
A dash (-) or pressure value will display in
the DIC. See
Driver Information Center (DIC)
0 120. A warning message displays in the
DIC if a problem occurs during the relearn
process.
Tire Inspection
We recommend that the tires, including
the spare tire, if the vehicle has one, be
inspected for signs of wear or damage
at least once a month.
Replace the tire if:
.The indicators at three or more
places around the tire can be seen.
.There is cord or fabric showing
through the tire's rubber.
.The tread or sidewall is cracked, cut,
or snagged deep enough to show
cord or fabric.
.The tire has a bump, bulge, or split.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Vehicle Care 363
12. Tighten the nuts firmly in a crisscrosssequence as shown by turning the wheel
wrench clockwise.
{Warning
Wheel nuts that are improperly or
incorrectly tightened can cause the
wheels to become loose or come off. The
wheel nuts should be tightened with a
torque wrench to the proper torque
specification after replacing. Follow the
torque specification supplied by the
aftermarket manufacturer when using
(Continued)
Warning (Continued)
accessory locking wheel nuts. See
Capacities and Specifications0396 for
original equipment wheel nut torque
specifications.
Caution
Improperly tightened wheel nuts can lead
to brake pulsation and rotor damage. To
avoid expensive brake repairs, evenly
tighten the wheel nuts in the proper
sequence and to the proper torque
specification. See Capacities and
Specifications 0396 for the wheel nut
torque specification.
When reinstalling the regular wheel and tire,
also reinstall either the center cap or the
bolt-on hub cap, depending on which one
the vehicle has.
.For center caps, line up the tab on the
center cap with the slot in the wheel. The
cap only goes in one way. Place the cap
on the wheel and press until it snaps into
place.
.For bolt-on hub caps, line up the plastic
nut caps with the wheel nuts and tighten
clockwise by hand to get them started.
Then tighten with the wheel wrench
until snug.
Storing a Flat or Spare Tire and Tools
{Warning
Storing a jack, a tire, or other equipment
in the passenger compartment of the
vehicle could cause injury. In a sudden
stop or collision, loose equipment could
strike someone. Store all these in the
proper place.
{Warning
Failure to follow these tire storage
instructions carefully could result in
personal injury or property damage if the
hoist cable fails or if the tire comes loose.
Make sure the tire is stored securely
before driving.