2021 CADILLAC XT6 Transmission service

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
116 INSTRUMENTS AND CONTROLS
Caution
Modifications to the engine,
transmission, exhaust, intake,
or fuel system, or the use of
replacement tires that do not meet
the original tire specifications, can
cause this light to come on. This
could lead to costly repairs not
covered by the vehicle warranty.
This could also affect the vehicle’s
ability to pass an Emissions
Inspection/Maintenance test. See
Accessories and Modifications0305.
If the light is f lashing : A
malfunction has been detected that
could damage the emission control
system and increase vehicle
emissions. Diagnosis and service may
be required.
To help prevent damage, reduce
vehicle speed and avoid hard
accelerations and uphill grades.
If towing a trailer, reduce the amount
of cargo being hauled as soon as
possible. If the light continues to flash, find a
safe place to park. Turn the vehicle off
and wait at least 10 seconds before
restarting the engine. If the light is
still flashing, follow the previous
guidelines and see your dealer for
service as soon as possible.
If the light is on steady :
A
malfunction has been detected.
Diagnosis and service may be
required.
Check the following:
.If fuel has been added to the vehicle
using the capless fuel funnel
adapter, make sure that it has been
removed. See “Filling the Tank with
a Portable Gas Can ”under Filling the
Tank 0287. The diagnostic system
can detect if the adapter has been
left installed in the vehicle, allowing
fuel to evaporate into the
atmosphere. A few driving trips with
the adapter removed may turn off
the light.
.Poor fuel quality can cause
inefficient engine operation and
poor driveability, which may go
away once the engine is warmed up.
If this occurs, change the fuel
brand. It may require at least one
full tank of the proper fuel to turn
the light off. See Recommended Fuel
(3.6L V6 Engine) 0286 or
Recommended Fuel (2.0L L4 Turbo
Engine) 0286.
If the light remains on, see your
dealer.
Emissions Inspection and
Maintenance Programs
If the vehicle requires an Emissions
Inspection/Maintenance test, the test
equipment will likely connect to the
vehicle's Data Link Connector (DLC).

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
130 INSTRUMENTS AND CONTROLS
pressingV. The messages that require
immediate action cannot be cleared
until that action is performed.
All messages should be taken
seriously; clearing the message does
not correct the problem.
If a SERVICE message appears, see
your dealer.
Follow the instructions given in the
messages. The system displays
messages regarding the following
topics:
.Service Messages
.Fluid Levels
.Vehicle Security
.Brakes
.Steering
.Ride Control Systems
.Driver Assistance Systems
.Cruise Control
.Lighting and Bulb Replacement
.Wiper/Washer Systems
.Doors and Windows
.Seat Belts
.Airbag Systems
.Engine and Transmission
.Tire Pressure
.Battery
Engine Power Messages
ENGINE POWER IS REDUCED
This message displays when the
vehicle's propulsion power is reduced.
A reduction in propulsion power can
affect the vehicle's ability to
accelerate. If this message is on, but
there is no observed reduction in
performance, proceed to your
destination. Under certain conditions
the performance may be reduced the
next time the vehicle is driven. The
vehicle may be driven while this
message is on, but maximum
acceleration and speed may be
reduced. Anytime this message stays
on, or displays repeatedly, the vehicle
should be taken to your dealer for
service as soon as possible.
Under certain operating conditions,
propulsion will be disabled. Try
restarting after the ignition has been
off for 30 seconds.
Vehicle Speed Messages
SPEED LIMITED TO
XXX KM/H (MPH)
This message shows that the vehicle
speed has been limited to the speed
displayed. The limited speed is a
protection for various propulsion and
vehicle systems, such as lubrication,
thermal, brakes, suspension, Teen
Driver if equipped, or tires.
Vehicle Personalization
The following are all possible vehicle
personalization features. Depending
on the vehicle, some may not be
available.
For System, Apps, and Personal
features and functions, see Settings
0 188.
To access the vehicle
personalization menu: 1. Touch the Settings icon on the Home Page of the infotainment
display.
2. Touch Vehicle to display a list of available options.

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
226 DRIVING AND OPERATING
Warning (Continued)
occupants could drown. Do not
ignore police warnings and be very
cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water can
build up under the vehicle's tires so
they actually ride on the water. This
can happen if the road is wet enough
and you are going fast enough. When
the vehicle is hydroplaning, it has
little or no contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.Allow extra following distance.
.Pass with caution.
.Keep windshield wiping equipment
in good shape.
.Keep the windshield washer fluid
reservoir filled.
.Have good tires with proper tread
depth. SeeTires0337.
.Turn off cruise control.
Hill and Mountain Roads
Driving on steep hills or through
mountains is different than driving on
flat or rolling terrain. Tips include:
.Keep the vehicle serviced and in
good shape.
.Check all fluid levels and brakes,
tires, cooling system, and
transmission.
.Shift to a lower gear when going
down steep or long hills.
{Warning
Using the brakes to slow the vehicle
on a long downhill slope can cause
brake overheating, can reduce brake
performance, and could result in a
loss of braking. Shift the
transmission to a lower gear to let
the engine assist the brakes on a
steep downhill slope.
{Warning
Coasting downhill in N (Neutral) or
with the ignition off is dangerous.
This can cause overheating of the
brakes and loss of steering assist.
Always have the engine running
and the vehicle in gear.
.Drive at speeds that keep the
vehicle in its own lane. Do not
swing wide or cross the center line.
.Be alert on top of hills; something
could be in your lane (e.g., stalled
car, crash).
.Pay attention to special road signs
(e.g., falling rocks area, winding
roads, long grades, passing or
no-passing zones) and take
appropriate action.
Winter Driving
Driving on Snow or Ice
Snow or ice between the tires and the
road creates less traction or grip, so
drive carefully. Wet ice can occur at
about 0 °C (32 °F) when freezing rain

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
DRIVING AND OPERATING 233
Warning (Continued)
systems and disable the airbags.
While driving, only shut the vehicle
off in an emergency.
If the vehicle must be shut off in an
emergency: 1. Brake using a firm and steady pressure. Do not pump the brakes
repeatedly. This may deplete power
assist, requiring increased brake
pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the vehicle
is moving. After shifting to
N (Neutral), firmly apply the brakes
and steer the vehicle to a safe
location.
3. Come to a complete stop and shift to P (Park).
4. Set the parking brake. See Electric
Parking Brake 0246. Press ENGINE
START/STOP to turn the
vehicle off. If the vehicle cannot be pulled over
and must be shut off while driving,
press and hold ENGINE START/STOP
for longer than two seconds, or press
twice in five seconds.
ACC/ACCESSORY (Amber Indicator
Light) :
This mode allows you to use
some electrical accessories when the
engine is off.
With the ignition off, pressing
ENGINE START/STOP once without
the brake pedal applied will place the
ignition system in ACC/ACCESSORY.
The ignition will switch from ACC/
ACCESSORY to OFF after 10 minutes
to prevent battery rundown.
ON/RUN/START (Green Indicator
Light) : This mode is for driving and
starting. With the ignition off and the
brake pedal applied, pressing ENGINE
START/STOP once will place the
ignition system in ON/RUN/START.
Once engine cranking begins, release
the button. Engine cranking will
continue until the engine starts, and
the ignition will then remain ON. See
Starting the Engine 0233. Service Mode
This mode is available to verify the
proper operation of the malfunction
indicator lamp as may be required for
emissions inspection purposes and for
service and diagnostics.
With the vehicle off, and the brake
pedal not applied, pressing and
holding ENGINE START/STOP for
more than five seconds will place the
vehicle in Service Mode. The
instruments and audio systems will
operate as they do in ON/RUN, but
the vehicle will not be able to be
driven. The engine will not start in
Service Mode. Press ENGINE START/
STOP again to turn the vehicle off.
Starting the Engine
Place the transmission in the proper
gear, P (Park) or N (Neutral). To restart
the engine when the vehicle is already
moving, use N (Neutral).

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
238 DRIVING AND OPERATING
Warning (Continued)
move suddenly. You or others could
be injured. To be sure the vehicle
will not move, even when you are
on fairly level ground, always set
the parking brake and shift to
P (Park). SeeShifting Into Park 0237
. If you are towing a trailer, see
Driving Characteristics and Towing
Tips 0290.
If you have to leave the vehicle with
the engine running, be sure the
vehicle is in P (Park) and the parking
brake is set before you leave it.
If you are towing a trailer and parking
on a hill, see Driving Characteristics
and Towing Tips 0290.
Shifting out of Park
This vehicle is equipped with an
electronic transmission. The shift lock
release button is designed to prevent
inadvertent shifting out of P (Park).
To shift out of P (Park):
1. Ensure the engine is running.
2. Apply the brake pedal. 3. Press and hold the shift lock
release button on the shift lever.
4. Move the shift lever to the desired position. For N (Neutral) hold the
lever in the N (Neutral) position
until the N indicator
illuminates red.
5. The P indicator will turn white and the gear indicator will turn red
when the vehicle is no longer in
P (Park).
After releasing the shift lever, it will
return to the center position.
If the vehicle cannot shift from
P (Park), a Driver Information Center
(DIC) message may be displayed.
Check that the ignition is on, the
engine is running, the brake pedal is
applied, and the shift lock release
button is pressed when you are
attempting to shift out of P (park).
If all of these are met but the vehicle
will not shift out of P (Park), see your
dealer for service.
Parking over Things
That Burn
{Warning
Things that can burn could touch
hot exhaust parts under the vehicle
and ignite. Do not park over papers,
leaves, dry grass, or other things
that can burn.
Active Fuel Management
This vehicle's engine may be equipped
with Active Fuel Management, which
allows the engine to operate on either
all of its cylinders, or in reduced
cylinder operation mode, depending
on the driving conditions.
When less power is required, such as
cruising at a constant vehicle speed,
the system will operate in reduced
cylinder operation mode, allowing the
vehicle to achieve better fuel economy.
When greater power demands are
required, such as accelerating from a
stop, passing, or merging onto a
freeway, the system will maintain
full-cylinder operation.

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
DRIVING AND OPERATING 241
This vehicle is equipped with an
electronically controlled transmission.
The shift lock release button is
designed to prevent inadvertent
shifting out of P (Park) unless the
ignition is on, the brake pedal is
applied, and the shift lock release
button is pressed.
When the vehicle is stopped, press
ENGINE START/STOP to turn off the
vehicle. The transmission will shift to
P (Park) automatically unless the
vehicle is in N (Neutral), See“Car
Wash Mode ”later in this section.
The vehicle will not shift into P (Park)
if it is moving too fast. Stop the
vehicle and shift into P (Park). To shift into and out of P (Park), see
Shifting Into Park
0237 and
Shifting out of Park 0238.
Service Shift Lever Message
If the message SERVICE SHIFTER SEE
OWNER’S MANUAL appears in the
Driver Information Center (DIC), the
shift lever needs service. Have the
vehicle serviced as soon as possible.
If the vehicle is automatically shifting
into P (Park), check to see if the
P (Park) button on top of the shift
lever is stuck. To operate the vehicle,
hold the shift lever in the desired gear,
R (Reverse) or D (Drive), until vehicle
speed exceeds 15 km/h (10 mph), then
release the shift lever.
R : Use this gear to back up.
If the vehicle is shifted from either
R (Reverse) to D (Drive) or M (Manual
Mode), or M (Manual Mode) or
D (Drive) to R (Reverse) while the
speed is too high, the vehicle will shift
to N (Neutral). Reduce the vehicle
speed and try the shift again.
To shift into R (Reverse): 1. Bring the vehicle to a complete stop. 2. Press and hold the shift lock
release button on the side of the
shift lever.
3. From the center position, move the shift lever forward through the first
detent to the end of travel. R is
illuminated in red.
4. After releasing the shift lever, it will return to the center position.
To shift out of R (Reverse): 1. Bring the vehicle to a complete stop.
2. Shift to the desired gear.
3. After releasing the shift lever, it will return to the center position.
At low vehicle speeds, R (Reverse) can
be used to rock the vehicle back and
forth to get out of snow, ice, or sand
without damaging the transmission.
See If the Vehicle Is Stuck 0228.
N : In this position, the engine does
not connect with the wheels. To
restart the engine when the vehicle is
already moving, use N (Neutral) only.

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
DRIVING AND OPERATING 293
.Shift into a gear.
.Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer
Towing
The vehicle needs service more often
when used to tow trailers. See
Maintenance Schedule 0380. It is
especially important to check the
transmission for fluid leaks, engine
oil, axle lubricant, belts, cooling
system, and brake system before and
during each trip.
Check periodically that all nuts and
bolts on the trailer hitch are tight.
Engine Cooling When Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. See Engine Overheating
0 320.
Trailer Towing
Caution
Towing a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To tow a trailer
correctly, follow the directions in
this section and see your dealer for
important information about
towing a trailer with the vehicle.
Trailer Weight
{Warning
Never exceed the towing capacity
for your vehicle.
Safe trailering requires monitoring the
weight, speed, altitude, road grades,
outside temperature, dimensions of
the front of the trailer, and how
frequently the vehicle is used to tow a
trailer.
Trailer Weight Ratings
When towing a trailer, the combined
weight of the vehicle, vehicle contents,
trailer, and trailer contents must be
below all of the maximum weight
ratings for the vehicle including:
.GCWR: Gross Combined Weight
Rating
.GVWR: Gross Vehicle Weight Rating
.Maximum Trailer Weight Rating
.Maximum Trailer Tongue Weight
See “Weight-Distributing Hitch
Adjustment ”under Towing Equipment
0 297 to determine if equalizer bars
are required to obtain the maximum
trailer weight rating.
See “Trailer Brakes ”under Towing
Equipment 0297 to determine if
brakes are required based on your
trailer's weight.
The only way to be sure the weight is
not exceeding any of these ratings is
to weigh the tow vehicle and trailer
combination, fully loaded for the trip,
getting individual weights for each of
these items.

Cadillac XT6 Owner Manual (GMNA-Localizing-U.S./Canada-14574701) -
2021 - CRC - 2/8/21
VEHICLE CARE 303
Vehicle Care
General Information
General Information . . . . . . . . . . . . . 304
California Proposition65 Warning . . . . . . . . . . . . . . . . . . . . . 304
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . 305
Accessories and Modifications . . . . . . . . . . . . . . . . . . . 305
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . . . . . . 305
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . . . . . . 308
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . 311
Engine Oil Life System . . . . . . . . . . . 313
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
Engine Air Filter Life System . . . . 314
Engine Air Cleaner/Filter . . . . . . . . . 315
Cooling System . . . . . . . . . . . . . . . . . . . 316
Engine Overheating . . . . . . . . . . . . . . 320
Washer Fluid . . . . . . . . . . . . . . . . . . . . . 321
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . 322 Battery - North America . . . . . . . . . 323
All-Wheel Drive . . . . . . . . . . . . . . . . . . 324
Park Brake and P (Park)
Mechanism Check . . . . . . . . . . . . . . 324
Wiper Blade Replacement . . . . . . . 325
Windshield Replacement . . . . . . . . 326
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . 326
Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . 327
Bulb Replacement
LED Lighting . . . . . . . . . . . . . . . . . . . . . 327
Electrical System
Electrical System Overload . . . . . . 327
Fuses and Circuit Breakers . . . . . . 328
Engine Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329
Instrument Panel Fuse Block . . . . 332
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
All-Season Tires . . . . . . . . . . . . . . . . . . 337
Winter Tires . . . . . . . . . . . . . . . . . . . . . . 338
Summer Tires . . . . . . . . . . . . . . . . . . . . 338
Tire Sidewall Labeling . . . . . . . . . . . 339 Tire Designations . . . . . . . . . . . . . . . . . 340
Tire Terminology and
Definitions . . . . . . . . . . . . . . . . . . . . . . 341
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . 343
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . 345
Tire Pressure Monitor System . . . 346
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . . . . . . 347
Tire Inspection . . . . . . . . . . . . . . . . . . . 350
Tire Rotation . . . . . . . . . . . . . . . . . . . . . 351
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352
Buying New Tires . . . . . . . . . . . . . . . . 353
Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . 354
Uniform Tire Quality Grading . . . 354
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . . . . . . . . 356
Wheel Replacement . . . . . . . . . . . . . . 356
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . 356
If a Tire Goes Flat . . . . . . . . . . . . . . . . 357
Tire Changing . . . . . . . . . . . . . . . . . . . . . 358
Compact Spare Tire . . . . . . . . . . . . . . 364
Jump Starting
Jump Starting - North America . . . . . . . . . . . . . . . . . . . . . . . . . 364