2021 CADILLAC CT4 heating

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
INSTRUMENTS AND CONTROLS 95
Metric
This gauge measures the temperature
of the vehicle's engine.
While driving under normal operating
conditions, if the red LED is
illuminated, the engine is too hot. Pull
off the road, stop the vehicle, and turn
off the engine as soon as possible.
Engine Coolant
Temperature Gauge
(Uplevel)
This gauge shows the engine coolant
temperature.
If the gauge pointer moves into the
red zone, the engine is too hot.
This reading indicates the same thing
as the warning light. It means that the
engine coolant has overheated. If the
vehicle has been operating under
normal driving conditions, pull off the
road, stop the vehicle, and turn off the
engine as soon as possible. See Engine
Overheating 0322 for more
information.
Seat Belt Reminders
Driver Seat Belt Reminder Light
There is a driver seat belt reminder
light on the instrument cluster.
When the vehicle is started, this light
flashes and a chime may come on to
remind the driver to fasten their
seat belt.
Then the light stays on solid until the
belt is buckled. This cycle may
continue several times if the driver
remains or becomes unbuckled while
the vehicle is moving.
If the driver seat belt is buckled,
neither the light nor the chime
comes on.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
INSTRUMENTS AND CONTROLS 103
If StabiliTrak/ESC is off, the Traction
Control System (TCS) is also off. To
turn ESC off and on, seeTraction
Control/Electronic Stability Control
0 239.
If ESC and TCS are off, the systems do
not assist in controlling the vehicle.
Adjust driving accordingly.
Traction Control System
(TCS)/StabiliTrak Light
This light comes on briefly when the
vehicle is turned on.
If the light does not come on, have
the vehicle serviced by your dealer.
If the system is working normally, the
indicator light turns off.
If the light is on and not flashing, the
TCS and potentially the StabiliTrak/
ESC system are not fully operational
and may not assist in maintaining
control. Adjust driving accordingly. If the condition persists, see your
dealer as soon as possible. A Driver
Information Center (DIC) message
may display.
The light flashes when the TCS and/or
the StabiliTrak/ESC system is actively
working.
See
Traction Control/Electronic Stability
Control 0239.
Engine Coolant
Temperature Warning Light
On some vehicles this light comes on
briefly while starting the vehicle. If it
does not, have the vehicle serviced by
the dealer. If the system is working
normally the indicator light goes off.
For vehicles with the reconfigurable
cluster, this light may not come on
when starting the vehicle.
Caution
The engine coolant temperature
warning light indicates that the
vehicle has overheated. Driving with
this light on can damage the engine
and it may not be covered by the
vehicle warranty. See Engine
Overheating 0322.
The engine coolant temperature
warning light comes on when the
engine has overheated.
If this happens pull over and turn off
the engine as soon as possible. See
Engine Overheating 0322.
Driver Mode Control Light
This light comes on when Sport Mode
is selected.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
196 CLIMATE CONTROLS
Climate Controls
Climate Control Systems
Dual Automatic Climate ControlSystem . . . . . . . . . . . . . . . . . . . . . . . . . . 196
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Maintenance
Passenger Compartment AirFilter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Climate Control Systems
Dual Automatic Climate Control System
The climate control buttons on the center stack and on the climate control
display are used to adjust the heating, cooling, and ventilation system. Center
Stack Climate Controls
1. ON/OFF (Power)
2. AUTO (Automatic Operation)
3. Air Delivery Mode Control
4. Driver Temperature Controls
5. Fan Control
6. Passenger Temperature Controls7. A/C (Air Conditioning)
8. Recirculation
9. SYNC (Synchronized Temperature)
10. Defrost
11. Rear Window Defogger

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
DRIVING AND OPERATING 209
Caution (Continued)
performance or race track driving.
SeeRecommended Fluids and
Lubricants 0391.
Brake Fade Warning Assist
The Brake Fade Warning Assist
system monitors the performance of
the brake system. If the system
detects brake fade, or if the brake
fluid is near the boiling point, the
driver will be alerted.
The Brake Fade Warning Assist
system is designed for use with the
factory-installed brake pads or
GM-approved replacement pads. If the
brake pads on the vehicle need to be
replaced, use GM-approved brake
pads. If this is not done, the brake
fade warning system may not function
properly.
Stage 1 : The Driver Information
Center (DIC) displays a “Reduce
Braking to Avoid Overheating”
message and brake pedal effort and
travel is increased. When the message
displays, the driver should decrease
brake pedal pressure. Stage 2 :
The Driver Information
Center (DIC) displays a “Brakes
Overheated Service Now ”message that
the brake fluid temperature is
excessive and is about to boil. The
system increases brake pedal effort
and travel, and will also limit vehicle
speed. The driver should immediately
start a cool down lap if on the track.
If this message displays, take the
vehicle to be serviced at your dealer.
Brake Burnishing
For vehicles equipped with front
Brembo brake systems:
Performance/racing brake pads are
required prior to racing or closed track
driving. Vehicles with option code JE2
have performance brake pads.
New brake pads must be burnished
before racing or other competitive
driving.
These procedures are specific to the
V-Series brake package. This
procedure should not be performed on
other models as damage may result.
Caution
Performing the brake burnish
procedure on a base brake system
can result in brake damage.
Caution
The new vehicle break-in period
should be completed before
performing the brake burnish
procedure, otherwise damage may
occur to the powertrain/engine. See
New Vehicle Break-In 0218.
Caution
Brake fade will occur during this
track burnish procedure and can
cause brake pedal travel and force
to increase. This could extend
stopping distance until the brakes
are fully burnished.
When this procedure is performed as
instructed, it will not damage the
brakes. The brake pads will smoke and
produce an odor. The braking force

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
212 DRIVING AND OPERATING
{Warning
Wet brakes can cause crashes. They
might not work as well in a quick
stop and could cause pulling to one
side. You could lose control of the
vehicle.
After driving through a large puddle
of water or a car/vehicle wash,
lightly apply the brake pedal until
the brakes work normally.
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
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 enoughand 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. See
Tires0339.
.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.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
DRIVING AND OPERATING 223
3. Plug it into a normal, grounded110-volt AC outlet.
{Warning
Improper use of the heater cord or
an extension cord can damage the
cord and may result in overheating
and fire.
.Plug the cord into a three-prong
electrical utility receptacle that is
protected by a ground fault
detection function. An
ungrounded outlet could cause
an electric shock.
.Use a weatherproof, heavy-duty,
15 amp-rated extension cord if
needed. Failure to use the
recommended extension cord in
good operating condition,
or using a damaged heater or
extension cord, could make it
(Continued)
Warning (Continued)
overheat and cause a fire,
property damage, electric shock,
and injury.
.Do not operate the vehicle with
the heater cord permanently
attached to the vehicle. Possible
heater cord and thermostat
damage could occur.
.While in use, do not let the
heater cord touch vehicle parts
or sharp edges. Never close the
hood on the heater cord.
.Before starting the vehicle,
unplug the cord, reattach the
cover to the plug, and securely
fasten the cord. Keep the cord
away from any moving parts.
4. Before starting the engine, be sure to unplug and store the cord as it
was before to keep it away from
moving engine parts. If you do not,
it could be damaged.
Contact your dealer for information
on how long to use the heater in your
particular area.
Retained Accessory
Power (RAP)
When the ignition is turned from on
to off, the following features (if
equipped) will continue to function
for up to 10 minutes, or until the
driver door is opened. These features
will also work when the ignition is in
RUN or ACC/ACCESSORY:
.Infotainment System
.Power Windows (during RAP this
functionality will be lost when any
door is opened)
.Sunroof (during RAP this
functionality will be lost when any
door is opened)
.Auxiliary Power Outlet
.Audio System
.OnStar System
Shifting Into Park
(Mechanical Shifter)
1. Hold the brake pedal down and set the parking brake. See Electric
Parking Brake 0237.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
300 DRIVING AND OPERATING
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 Overheating0322.
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, gradually release the brake
pedal to allow the chocks to absorb
the load of the trailer.
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 0380. 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.
Engine Cooling when Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. See
Engine Overheating
0 322.
Trailer Towing (LSY 2.0L L4
Engine)
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.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
304 VEHICLE CARE
Vehicle Care
General Information
General Information . . . . . . . . . . . . . 305
California Proposition65 Warning . . . . . . . . . . . . . . . . . . . . . 305
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . 306
Accessories and Modifications . . . . . . . . . . . . . . . . . . . 306
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . . . . . . 306
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . . . . . . 309
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . 312
Engine Oil Life System . . . . . . . . . . . 314
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
Engine Air Filter Life System . . . . 315
Engine Air Cleaner/Filter . . . . . . . . . 316
Cooling System . . . . . . . . . . . . . . . . . . . 317
Engine Overheating . . . . . . . . . . . . . . 322
Washer Fluid . . . . . . . . . . . . . . . . . . . . . 323
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 Brake Pad Life System (If
Equipped) . . . . . . . . . . . . . . . . . . . . . . . 324
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . 325
Battery - North America . . . . . . . . . 326
All-Wheel Drive . . . . . . . . . . . . . . . . . . 327
Park Brake and P (Park) Mechanism Check . . . . . . . . . . . . . . 327
Wiper Blade Replacement . . . . . . . 327
Windshield Replacement . . . . . . . . 328
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . 328
Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . 329
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . 329
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . 330
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . . . . . . . 330
LED Lighting . . . . . . . . . . . . . . . . . . . . . 330
Front Turn Signal Lamps . . . . . . . . 330
Electrical System
Electrical System Overload . . . . . . 330
Fuses and Circuit Breakers . . . . . . 331
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
Instrument Panel Fuse Block . . . . 334
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
All-Season Tires . . . . . . . . . . . . . . . . . . 339
Winter Tires . . . . . . . . . . . . . . . . . . . . . . 340
Run-Flat Tires . . . . . . . . . . . . . . . . . . . . 340
Self-Sealing Tires . . . . . . . . . . . . . . . . . 341
Low-Profile Tires . . . . . . . . . . . . . . . . . 341
Summer Tires . . . . . . . . . . . . . . . . . . . . 341
Tire Sidewall Labeling . . . . . . . . . . . 342
Tire Designations . . . . . . . . . . . . . . . . . 343
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . . . . . 344
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . 346
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . 347
Tire Pressure Monitor System . . . 348
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . . . . . . 349
Tire Inspection . . . . . . . . . . . . . . . . . . . 352
Tire Rotation . . . . . . . . . . . . . . . . . . . . . 352
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
Buying New Tires . . . . . . . . . . . . . . . . 354
Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . 356
Uniform Tire Quality Grading . . . 356
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . . . . . . . . 357