
Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-15283641) -
2022 - CRC - 10/12/21
LIGHTING 131
If the vehicle is started in a dark
garage, the automatic headlamp
system comes on immediately. If it is
light outside when the vehicle leaves
the garage, there is a slight delay
before the automatic headlamp
system turns off the headlamps.
During that delay, the instrument
cluster may not be as bright as usual.
Make sure the instrument panel
brightness control is in the full bright
position. SeeInstrument Panel
Illumination Control 0132.
When it is bright enough outside, the
headlamps will turn off.
The automatic headlamp system turns
off when the exterior lamp control is
turned to
Oor the ignition is off. For
vehicles sold in Canada, this control
only works when the transmission is
in P (Park).
Lights On with Wipers
If the windshield wipers are activated
in daylight with the engine on, and
the exterior lamp control is in AUTO,
the headlamps, parking lamps, and
other exterior lamps come on. The
transition time for the lamps coming on varies based on wiper speed. When
the wipers are not operating, these
lamps turn off. Move the exterior
lamp control to
Oor;to disable
this feature.
Hazard Warning Flashers
|: Press this button to make the
front and rear turn signal lamps flash
on and off. Release the button for at
least one second and press again to
turn the flashers off.
The hazard warning flashers turn on
automatically if the airbags deploy.
Turn and Lane-Change
Signals
Move the lever all the way up or down
to signal a turn.
An arrow on the instrument cluster
flashes in the direction of the turn or
lane change.
Raise or lower the lever until the
arrow starts to flash to signal a lane
change. Hold it there until the lane
change is completed. If the lever is
briefly pressed and released, the turn
signal flashes three times.
The turn and lane-change signal can
be turned off manually by moving the
lever back to its original position.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-15283641) -
2022 - CRC - 10/12/21
322 VEHICLE CARE
Vehicle Care
General Information
General Information . . . . . . . . . . . . . 323
California Perchlorate MaterialsRequirements . . . . . . . . . . . . . . . . . . . 323
Accessories and Modifications . . . . . . . . . . . . . . . . . . . 323
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . . . . . . 324
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . . . . . . 326
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . 331
Engine Oil Life System . . . . . . . . . . . 333
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
Manual Transmission Fluid . . . . . 335
Hydraulic Clutch . . . . . . . . . . . . . . . . . 335
Engine Air Filter Life System . . . . 335
Engine Air Cleaner/Filter . . . . . . . . . 336
Cooling System . . . . . . . . . . . . . . . . . . . 338
Engine Overheating . . . . . . . . . . . . . . 342
Washer Fluid . . . . . . . . . . . . . . . . . . . . . 343
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344 Brake Pad Life System (If
Equipped) . . . . . . . . . . . . . . . . . . . . . . . 346
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . 348
Battery - North America . . . . . . . . . 349
All-Wheel Drive . . . . . . . . . . . . . . . . . . 349
Park Brake and P (Park) Mechanism Check . . . . . . . . . . . . . . 350
Wiper Blade Replacement . . . . . . . 350
Windshield Replacement . . . . . . . . 351
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . 351Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . 352
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . 352
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . 352
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . . . . . . . 352
LED Lighting . . . . . . . . . . . . . . . . . . . . . 353
Front Turn Signal Lamps . . . . . . . . 353
Electrical System
Electrical System Overload . . . . . . 353
Fuses and Circuit Breakers . . . . . . 355
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
Instrument Panel Fuse Block . . . . 358
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
All-Season Tires . . . . . . . . . . . . . . . . . . 363
Winter Tires . . . . . . . . . . . . . . . . . . . . . . 364
Run-Flat Tires . . . . . . . . . . . . . . . . . . . . 364
Self-Sealing Tires . . . . . . . . . . . . . . . . . 365
Low-Profile Tires . . . . . . . . . . . . . . . . . 365
Summer Tires . . . . . . . . . . . . . . . . . . . . 365
Tire Sidewall Labeling . . . . . . . . . . . 366
Tire Designations . . . . . . . . . . . . . . . . . 367
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . . . . . 368
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . 370
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . 371
Tire Pressure Monitor System . . . 372
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . . . . . . 373
Tire Inspection . . . . . . . . . . . . . . . . . . . 376
Tire Rotation . . . . . . . . . . . . . . . . . . . . . 376
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
Buying New Tires . . . . . . . . . . . . . . . . 379
Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . 380
Uniform Tire Quality Grading . . . 380
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . . . . . . . . 382
Wheel Replacement . . . . . . . . . . . . . . 382
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . 383

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-15283641) -
2022 - CRC - 10/12/21
344 VEHICLE CARE
Open the cap with the washer symbol
on it. Add washer fluid until the tank
is full. SeeEngine Compartment
Overview 0326 for reservoir location.
Caution
.Do not use washer fluid that
contains any type of water
repellent coating. This can cause
the wiper blades to chatter
or skip.
.Do not use engine coolant
(antifreeze) in the windshield
washer. It can damage the
windshield washer system and
paint.
.Do not mix water with
ready-to-use washer fluid. Water
can cause the solution to freeze
and damage the washer fluid
tank and other parts of the
washer system.
.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
(Continued)
Caution (Continued)
expansion if freezing occurs,
which could damage the tank if
it is completely full.
Brakes
Disc brake linings, except J57 V-Series
Blackwing with carbon ceramic brakes,
have built-in wear indicators that
make a high-pitched warning sound
when the brake linings are worn and
new linings 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. The V-Series Blackwing has
electronic pad wear sensors. See Brake
Pad Life System (If Equipped) 0346
{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 linings could result in costly
brake repairs.
Properly torqued wheel nuts are
necessary to help prevent brake
pulsation. When tires are rotated,
inspect brake linings for wear and
evenly tighten wheel nuts in the
proper sequence to torque
specifications. See Capacities and
Specifications 0424.
Brake linings should be replaced as
complete axle sets.
Brake Squeal and Brake Dust
Some driving conditions or climates
can cause a brake squeal when the
brakes are first applied, clearing up
following several applies. This does
not mean something is wrong with
the brakes.
Vehicles equipped with high
performance brake systems provide
superior fade resistance, but will
produce increased brake squeal and

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-15283641) -
2022 - CRC - 10/12/21
350 VEHICLE CARE
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.
.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.
.Automatic transmission vehicles
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 and cracking. See
Maintenance Schedule 0408.
Replacement blades come in different
types and are removed in different
ways. For proper type and length, see
Maintenance Replacement Parts 0418.
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.
To replace the windshield wiper blade: 1. Pull the windshield wiper assembly away from the windshield.
2. Lift up on the latch in the middleof the wiper blade where the wiper
arm attaches.
3. With the latch open, pull the wiper blade down toward the windshield
far enough to release it from the
J-hooked end of the wiper arm.
4. Remove the wiper blade.
5. Reverse Steps 1–3 for wiper blade replacement.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-15283641) -
2022 - CRC - 10/12/21
VEHICLE CARE 355
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. Wiper function is
available immediately after the wiper
switch is set to off, and back to on.
To protect the wiper motor from
overheating, the wipers may slow
down when the windshield is dry for a
long period of time. If a period of dry
operation, or little moisture, exceeds
10 minutes, the wipers may switch to
intermittent operation, and remain
there. When moisture is again
detected on the windshield, wiper
operation will return to the operator
selected speed.
Although the circuit is protected from
electrical overload, overload due to
heavy snow or ice may cause wiperlinkage 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.
{Danger
Fuses and circuit breakers are
marked with their ampere rating.
Do not exceed the
specified amperage rating when
replacing fuses and circuit breakers.
Use of an oversized fuse or circuit
breaker can result in a vehicle fire.
You and others could be seriously
injured or killed.
{Warning
Installation or use of fuses that do
not meet GM’s original fuse
specifications is dangerous. The
fuses could fail, and result in a fire.
You or others could be injured or
killed, and the vehicle could be
damaged.
See Accessories and Modifications
0 323 and
General Information 0323.
To check or replace a blown fuse, see
Electrical System Overload 0353.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-15283641) -
2022 - CRC - 10/12/21
VEHICLE CARE 357
FusesUsage
13 Front Wiper
14 Exterior Lighting Module 6
15 Exterior Lighting Module 1
16 Exterior Lighting Module 5
17 Exterior Lighting Module 3
18 Aero Shutter
19 –
20 –
21 Virtual Key System/ Power Sounder
Module
22 Engine Control Module Battery
23 Transmission Control Module
24 Active Engine Mount
25 –
26 Engine Control Module Fuses
Usage
27 Injectors/Ignition 2
28 Charged Air Cooler
29 Transmission Aux Oil Pump/Transmission
Reverse Lock Out
30 Injectors/Ignition 1
31 Emissions 1
32 Emissions 2
33 Starter Solenoid
34 –
35 –
36 Starter Pinion
37 AC Clutch
38 –
39 –
40 –
41 –
42 Water Pump
43 –
44 – Relays
Usage
47 –
48 Front Wiper Speed
49 Front Wiper Control
51 –
52 Engine Control Module
53 Starter Solenoid
54 Starter Pinion
55 –
57 AC Clutch
58 –

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-15283641) -
2022 - CRC - 10/12/21
398 VEHICLE CARE
Caution
To avoid damage to a matte paint
finish, do not use an automatic car
wash equipped with brushes or
scrubbers. Only use touchless
automatic car washes.
If using an automatic car wash, follow
the car wash instructions. The
windshield wiper and rear window
wiper, if equipped, must be off.
Remove any accessories that may be
damaged or interfere with the car
wash equipment.
Hand Wash
Rinse the vehicle well, before and after
washing, to remove all cleaning agents
completely. If they are allowed to dry
on the surface, they could stain.
Dry the finish with a soft, clean
chamois or an all-cotton towel to
avoid surface scratches and water
spotting. Cleaning Underhood ComponentsCaution
Do not power wash any component
under the hood that has this
e
symbol.
This could cause damage to the
vehicle that would not be covered
by the vehicle warranty.
Avoid using solvents or abrasive
cleaners that may harm underhood
components. GM recommends using
only water to clean underhood
components.
If using a pressure washer, ensure the
following criteria is met:
.Water pressure must be kept below
14 000 KPa (2,000 PSI).
.Water temperature must be below
80 °C (180 °F).
.A spray nozzle with a 40 degree
wide angle spray pattern or wider
must be used, and must be kept at
least 30 cm (1 ft) away from all
surfaces.
Finish Care
Application of aftermarket clearcoat
sealant/wax materials is not
recommended. If painted surfaces are
damaged, see your dealer to have the
damage assessed and repaired.
Materials such as calcium chloride
and other salts, ice melting agents,
road oil and tar, tree sap, bird
droppings, chemicals from industrial
chimneys, etc., can damage the vehicle
finish if they remain on painted
surfaces. Wash the vehicle as soon as
possible. If necessary, use
non-abrasive cleaners that are marked
safe for painted surfaces to remove
foreign matter.
Occasional hand waxing or mild
polishing should be done to remove
residue from the paint finish. See your
dealer for approved cleaning products.
Caution
Do not apply waxes or polishes to
uncoated plastic, vinyl, rubber,
decals, simulated wood, or matte
paint as damage can occur.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-15283641) -
2022 - CRC - 10/12/21
400 VEHICLE CARE
Caution
Using wax on low gloss black finish
stripes can increase the gloss level
and create a non-uniform finish.
Clean low gloss stripes with soap
and water only.
Air Intakes
Clear debris from the air intakes
between the hood and windshield
when washing the vehicle.
Shutter System
The vehicle may have a shutter
system designed to help improve fuel
economy. Always keep the shuttersystem clear of debris, snow and ice.
If the check engine light is activated,
please check to see if the shutter
system is clear of debris, snow or ice.
Windshield and Wiper Blades
Clean the outside of the windshield
with glass cleaner.
Clean rubber wiper blades using a
lint-free cloth or paper towel soaked
with windshield washer fluid or a mild
detergent. Wash the windshield
thoroughly when cleaning the blades.
Bugs, road grime, sap, and a buildup
of vehicle wash/wax treatments may
cause wiper streaking.
Replace the wiper blades if they are
worn or damaged. Damage can be
caused by extreme dusty conditions,
sand, salt, heat, sun, snow, and ice.
Weatherstrips
Apply weatherstrip lubricant on
weatherstrips to make them last
longer, seal better, and not stick or
squeak. Lubricate weatherstrips at
least once a year. Hot, dry climates
may require more frequent
application. Black marks from rubber
material on painted surfaces can be
removed by rubbing with a clean
cloth. See
Recommended Fluids and
Lubricants 0417.
Tires
Use a stiff brush with tire cleaner to
clean the tires.
Caution
Using petroleum-based tire dressing
products on the vehicle may
damage the paint finish and/or
tires. When applying a tire dressing,
always wipe off any overspray from
all painted surfaces on the vehicle.
Wheels and Wheel Trim
Use a soft, clean cloth with mild soap
and water to clean the wheels. After
rinsing thoroughly with clean water,
dry with a soft, clean towel. A wax
may then be applied.
Caution
Chrome wheels and chrome wheel
trim may be damaged if the vehicle
is not washed after driving on roads
(Continued)