2020 CADILLAC CT6 service

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/14/19
254 DRIVING AND OPERATING
LCA displays may not come on when
passing a vehicle quickly, for a
stopped vehicle, or when towing a
trailer. The LCA detection zones that
extend back from the side of the
vehicle do not move further back
when a trailer is towed. Use caution
while changing lanes when towing a
trailer. LCA may alert to objects
attached to the vehicle, such as a
trailer, bicycle, or object extending out
to either side of the vehicle. Attached
objects may also interfere with the
detection of vehicles. This is normal
system operation; the vehicle does not
need service.
LCA may not always alert the driver to
vehicles in the next lane over,
especially in wet conditions or when
driving on sharp curves. The system
does not need to be serviced. The
system may light up due to guardrails,
signs, trees, shrubs, and other
non-moving objects. This is normal
system operation; the vehicle does not
need service.
LCA may not operate when the LCA
sensors in the left or right corners of
the rear bumper are covered withmud, dirt, snow, ice, or slush, or in
heavy rainstorms. For cleaning
instructions, see "Washing the
Vehicle" under
Exterior Care0349.
If the DIC still displays the system
unavailable message after cleaning
both sides of the vehicle toward the
rear corners of the vehicle, see your
dealer.
If the LCA displays do not light up
when moving vehicles are in the side
blind zone or are rapidly approaching
this zone and the system is clean, the
system may need service. Take the
vehicle to your dealer.
Radio Frequency Information
See Radio Frequency Statement 0386.
Lane Keep Assist (LKA)
If equipped, LKA may help avoid
crashes due to unintentional lane
departures. This system uses a camera
to detect lane markings between
60 km/h (37 mph) and 180 km/h
(112 mph). It may assist by gently
turning the steering wheel if the
vehicle approaches a detected lane
marking. It may also provide a Lane Departure Warning (LDW) alert if the
vehicle crosses a detected lane
marking. LKA can be overriden by
turning the steering wheel. This
system is not intended to keep the
vehicle centered in the lane. LKA will
not assist and alert if the turn signal
is active in the direction of lane
departure, or if it detects that you are
accelerating, braking or actively
steering.
{Warning
The LKA system does not
continuously steer the vehicle.
It may not keep the vehicle in the
lane or give a Lane Departure
Warning (LDW) alert, even if a lane
marking is detected.
The LKA and LDW systems
may not:
. Provide an alert or enough
steering assist to avoid a lane
departure or crash.
(Continued)

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/14/19
256 DRIVING AND OPERATING
Steer the vehicle to dismiss. LKA may
become temporarily unavailable after
repeated take steering alerts.
When the System Does Not
Seem to Work Properly
The system performance may be
affected by:
.Close vehicles ahead.
. Sudden lighting changes, such as
when driving through tunnels.
. Banked roads.
. Roads with poor lane markings,
such as two-lane roads.
A system unavailable message may
display if the camera is blocked. The
LKA system does not need service.
A camera blocked message may
display if the camera is blocked. Some
driver assistance systems may have
reduced performance or not work at
all. An LKA or LDW unavailable
message may display if the systems
are temporarily unavailable. This
message could be due to a blocked camera. The LKA system does not
need service. Clean the outside of the
windshield behind the rearview mirror.
LKA assistance and/or LDW alerts
may occur due to tar marks, shadows,
cracks in the road, temporary or
construction lane markings, or other
road imperfections. This is normal
system operation; the vehicle does not
need service. Turn LKA off if these
conditions continue.
Surround Vision Recorder
If equipped, this system records the
360° camera views to an SD card. Only
images are recorded, no sound. An SD
card will be needed for this system.
The recommended SD card is a 32GB
SDHC card with FAT32 file system,
Class 10 and over.
Insert an SD card into the card reader
in the trunk. Disable recording from
the playback screen before removing
the SD card from the reader. Do not
remove the card while recording is
enabled. This could corrupt the video
file and/or the SD card.
Other files should not be stored on
the same SD card as the surround
vision recorder files. Storing other files
on the same card may increase
recording start up and playback time
or result in a loss of data.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/14/19
DRIVING AND OPERATING 259
Recommended Fuel (4.2L
Twin Turbo V8 Engine)
Use premium unleaded gasoline
meeting ASTM specification D4814
with a posted octane rating of 93—
(R+M)/2. If unavailable, unleaded
gasoline with a posted octane rating
of 91 may be used, but with reduced
performance and fuel economy. If the
octane is less than 91, the engine
could be damaged and the repairs
would not be covered by the vehicle
warranty. If heavy knocking is heard
when using gasoline rated at
93 octane, the engine needs service.
Do not use any fuel labeled E85 or
FlexFuel. Do not use gasoline with
ethanol levels greater than 15% by
volume.
Prohibited Fuels
Caution
Do not use fuels with any of the
following conditions; doing so may
damage the vehicle and void its
warranty:
. For vehicles that are not
FlexFuel, fuel labeled greater
than 15% ethanol by volume,
such as mid-level ethanol
blends (16–50% ethanol), E85,
or FlexFuel.
. Fuel with any amount of
methanol, methylal, ferrocene,
and aniline. These fuels can
corrode metal fuel system
parts or damage plastic and
rubber parts.
. Fuel containing metals such
as methylcyclopentadienyl
manganese tricarbonyl
(MMT), which can damage
the emissions control system
and spark plugs.
(Continued)
Caution (Continued)
.Fuel with a posted octane
rating of less than the
recommended fuel. Using this
fuel will lower fuel economy
and performance, and may
decrease the life of the
emissions catalyst.
Fuels in Foreign Countries
The U.S., Canada, and Mexico post
fuel octane ratings in anti-knock index
(AKI). For fuel not to use in a foreign
country, see Prohibited Fuels 0259.
Fuel Additives
TOP TIER Detergent Gasoline is highly
recommended for use with your
vehicle. If your country does not have
TOP TIER Detergent Gasoline, add
ACDelco Fuel System Treatment Plus
−Gasoline to the vehicle’s gasoline fuel
tank at every oil change or 15 000 km
(9,000 mi), whichever occurs first. TOP
TIER Detergent Gasoline and ACDelco
Fuel System Treatment Plus−Gasoline

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/14/19
DRIVING AND OPERATING 265
signs, trees, or other objects. Always
signal turns well in advance. Do not
steer or brake suddenly.
Driving on Grades
Reduce speed and shift to a lower gear
before starting down a long or steep
downhill grade. If the transmission is
not shifted down, the brakes may
overheat and result in reduced braking
efficiency.
Vehicles can tow in D (Drive). Shift
the transmission to a lower gear if the
transmission shifts too often under
heavy loads and/or hilly conditions.
When towing at higher altitudes,
engine coolant will boil at a lower
temperature than at lower altitudes.
If the engine is turned off immediately
after towing at high altitude on steep
uphill grades, the vehicle could show
signs similar to engine overheating. To
avoid this, let the engine run,
preferably on level ground, with the
transmission in P (Park) for a few
minutes before turning the engine off.
If the overheat warning comes on, see
Engine Overheating0288.
Parking on Hills
{Warning
To prevent serious injury or death,
always park your vehicle and trailer
on a level surface when possible.
When parking your vehicle and your
trailer on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn the
wheels into the curb if facing
downhill or into traffic if facing
uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the regular brakes
until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parking brake and shift
into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal. .Start the engine.
. 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 0359. It is
especially important to check the
automatic transmission fluid, 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.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/14/19
DRIVING AND OPERATING 269
Conversions and
Add-Ons
Add-On Electrical
Equipment
{Warning
The Data Link Connector (DLC) is
used for vehicle service and
Emission Inspection/Maintenance
testing. SeeMalfunction Indicator
Lamp (Check Engine Light) 0123.
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.
Caution
Some electrical equipment can
damage the vehicle or cause
components to not work and would
not be covered by the vehicle
warranty. Always check with your
dealer before adding electrical
equipment.
Add-on equipment can drain the
vehicle's 12-volt battery, even if the
vehicle is not operating.
The vehicle has an airbag system.
Before attempting to add anything
electrical to the vehicle, see Servicing
the Airbag-Equipped Vehicle 075 and
Adding Equipment to the
Airbag-Equipped Vehicle 076.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
270 VEHICLE CARE
Vehicle Care
General Information
General Information . . . . . . . . . . . . . 271
California Proposition65 Warning . . . . . . . . . . . . . . . . . . . . . 271
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . 272
Accessories and Modifications . . . . . . . . . . . . . . . . . . . 272
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . . . . . . 272
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . . . . . . 274
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . 277
Engine Oil Life System . . . . . . . . . . . 280
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
Engine Air Filter Life System . . . . 281
Engine Air Cleaner/Filter . . . . . . . . . 282
Cooling System . . . . . . . . . . . . . . . . . . . 284
Engine Overheating . . . . . . . . . . . . . . 288
Washer Fluid . . . . . . . . . . . . . . . . . . . . . 289
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
Brake Pad Life System . . . . . . . . . . . 291
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . 291 Battery - North America . . . . . . . . . 292
All-Wheel Drive . . . . . . . . . . . . . . . . . . 293
Starter Switch Check . . . . . . . . . . . . . 294
Park Brake and P (Park)
Mechanism Check . . . . . . . . . . . . . . 294
Wiper Blade Replacement . . . . . . . 295
Windshield Replacement . . . . . . . . 295
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . 296
Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . 297
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . 297
LED Lighting . . . . . . . . . . . . . . . . . . . . . 297
Electrical System
Electrical System Overload . . . . . . 298
Fuses and Circuit Breakers . . . . . . 298
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
Instrument Panel Fuse Block . . . . 306
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
All-Season Tires . . . . . . . . . . . . . . . . . . 316
Winter Tires . . . . . . . . . . . . . . . . . . . . . . 316
Low-Profile Tires . . . . . . . . . . . . . . . . . 317
Summer Tires . . . . . . . . . . . . . . . . . . . . 317
Tire Sidewall Labeling . . . . . . . . . . . 317 Tire Designations . . . . . . . . . . . . . . . . . 319
Tire Terminology and
Definitions . . . . . . . . . . . . . . . . . . . . . . 320
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . 322
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . 324
Tire Pressure Monitor System . . . 324
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . . . . . . 325
Tire Inspection . . . . . . . . . . . . . . . . . . . 329
Tire Rotation . . . . . . . . . . . . . . . . . . . . . 329
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
Buying New Tires . . . . . . . . . . . . . . . . 331
Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . 333
Uniform Tire Quality Grading . . . 333
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . . . . . . . . 334
Wheel Replacement . . . . . . . . . . . . . . 335
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . 335
If a Tire Goes Flat . . . . . . . . . . . . . . . . 336
Tire Changing . . . . . . . . . . . . . . . . . . . . . 337
Compact Spare Tire . . . . . . . . . . . . . . 342Jump Starting
Jump Starting - North America . . . . . . . . . . . . . . . . . . . . . . . . . 343

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
VEHICLE CARE 271
Towing the Vehicle
Towing the Vehicle . . . . . . . . . . . . . . . 346
Recreational Vehicle Towing . . . . 348
Appearance Care
Exterior Care . . . . . . . . . . . . . . . . . . . . . . 349
Interior Care . . . . . . . . . . . . . . . . . . . . . . 353
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . 356
General Information
For service and parts needs, visit your
dealer. You will receive genuine GM
parts and GM-trained and supported
service people.
Genuine GM parts have one of these
marks:
California Proposition
65 Warning
{Warning
Most motor vehicles, including this
one, as well as many of its service
parts and fluids, contain and/or
emit chemicals known to the State
of California to cause cancer and
birth defects or other reproductive
harm. Engine exhaust, many parts
and systems, many fluids, and
some component wear by-products
contain and/or emit these
chemicals. For more information go
to www.P65Warnings.ca.gov/
passenger-vehicle.
See Battery - North America 0292 and
Jump Starting - North America 0343
and the back cover.

Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/11/19
272 VEHICLE CARE
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 076.
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 0385.
This vehicle has an airbag system.
Before attempting to do your own
service work, see Servicing the
Airbag-Equipped Vehicle 075.