
Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-13183937) -
2020 - crc - 4/28/20
VEHICLE CARE 251
If the decision is made to lift the
hood, make sure the vehicle is parked
on a level surface.
Then check to see if the engine
cooling fan is running. If the engine is
overheating, the fan should be
running. If it is not, do not continue
to run the engine. Have the vehicle
serviced.
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.
If Steam Is Coming from the
Engine Compartment
{Warning
Steam and scalding liquids from a
hot cooling system are under
pressure. Turning the pressure cap,(Continued)
Warning (Continued)
even a little, can cause them to
come out at high speed and you
could be burned. Never turn the cap
when the cooling system, including
the pressure cap, is hot. Wait for
the cooling system and pressure
cap to cool.
If No Steam Is Coming from the
Engine Compartment
If an engine overheat warning is
displayed but no steam can be seen or
heard, the problem may not be too
serious. Sometimes the engine can get
a little too hot when the vehicle:
.Climbs a long hill on a hot day.
. Stops after high-speed driving.
. Idles for long periods in traffic.
If the overheat warning is displayed
with no sign of steam: 1. Turn the air conditioning off. 2. Turn the heater on to the highest
temperature and to the highest
fan speed. Open the windows as
necessary.
3. When it is safe to do so, pull off the road, shift to P (Park) or
N (Neutral) and let the
engine idle.
If the overheat warning no longer
displays, the vehicle can be driven.
Continue to drive the vehicle slowly
for about 10 minutes. Keep a safe
vehicle distance from the vehicle in
front. If the warning does not come
back on, continue to drive normally
and have the cooling system checked
for proper fill and function.
If the warning continues, pull over,
stop, and park the vehicle right away.
If there is no sign of steam, idle the
engine for three minutes while parked.
If the warning is still displayed, turn
off the engine until it cools down.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-13183937) -
2020 - crc - 4/28/20
VEHICLE CARE 257
Windshield Replacement
HUD System
The windshield is part of the HUD
system. If the windshield needs to be
replaced, be sure to get one that is
designed for HUD or the HUD image
may look out of focus.
Driver Assistance Systems
If the windshield needs to be replaced
and the vehicle is equipped with a
front camera sensor for the Driver
Assistance Systems, a GM
replacement windshield is
recommended. The replacement
windshield must be installed
according to GM specifications for
proper alignment. If it is not, these
systems may not work properly, they
may display messages, or they may
not work at all. See your dealer for
proper windshield replacement.
Acoustic Windshield
The vehicle is equipped with an
acoustic windshield. If the windshield
needs to be replaced be sure to get anacoustic windshield so you will
continue to have the benefits an
acoustic windshield can provide.
Gas Strut(s)
This vehicle is equipped with gas
strut(s) to provide assistance in lifting
and holding open the hood/trunk/
liftgate system in full open position.
{Warning
If the gas struts that hold open the
hood, trunk, and/or liftgate fail, you
or others could be seriously injured.
Take the vehicle to your dealer for
service immediately. Visually
inspect the gas struts for signs of
wear, cracks, or other damage
periodically. Check to make sure the
hood/trunk/liftgate is held open
with enough force. If struts are
failing to hold the hood/trunk/
liftgate, do not operate. Have the
vehicle serviced.
Caution
Do not apply tape or hang any
objects from gas struts. Also do not
push down or pull on gas struts.
This may cause damage to the
vehicle.
See Maintenance Schedule 0303.
Hood

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-13183937) -
2020 - crc - 4/28/20
VEHICLE CARE 259
High Intensity Discharge
(HID) Lighting
{Warning
The High Intensity Discharge (HID)
lighting system operates at a very
high voltage. If you try to service
any of the system components, you
could be seriously injured. Have
your dealer or a qualified technician
service them.
After an HID headlamp bulb has been
replaced, the beam might be a slightly
different shade than it was originally.
This is normal.
LED Lighting
This vehicle has several LED lamps.
For replacement of any LED lighting
assembly, contact your dealer.
Front Turn Signal Lamps
Uplevel
See your dealer for turn signal
replacement.
Base level
To replace one of these lamps: 1. Open the hood.
2. Turn the bulb socket counterclockwise to remove it
from the headlamp assembly.
3. Unplug the electrical connector from the bulb by releasing the
clip on the connector.
4. Replace the bulb and reverse Steps 1–3 to reinstall.
Electrical System
Electrical System Overload
The vehicle has fuses and circuit
breakers to protect against an
electrical system overload.
When the current electrical load is too
heavy, the circuit breaker opens and
closes, protecting the circuit until the
current load returns to normal or the
problem is fixed. This greatly reduces
the chance of circuit overload and fire
caused by electrical problems.
Fuses and circuit breakers 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, the
same amperage fuse can be borrowed.
Choose some feature of the vehicle
that is not needed to use and replace
it as soon as possible.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-13183937) -
2020 - crc - 4/28/20
348 INDEX
FusesEngine Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
Fuses and Circuit Breakers . . . . . . . 260
Instrument Panel Fuse Block . . . . 262
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
G
Garage Door Opener . . . . . . . . . . . . . . . . 121
Programming . . . . . . . . . . . . . . . . . . . . . . 121
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . 257
Gauges
Engine Coolant Temperature . . . . . . 97
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Speedometer . . . . . . . . . . . . . . . . . . . . . . . . 96
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . 96
Trip Odometer . . . . . . . . . . . . . . . . . . . . . . 96
Warning Lights and Indicators . . . . 92
General Information
Service and Maintenance . . . . . . . . 302
Towing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
Vehicle Care . . . . . . . . . . . . . . . . . . . . . . . 234
Glove Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
GM Mobility Reimbursement Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
H
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . 258
Hazard Warning Flashers . . . . . . . . . . 128
Head Restraints . . . . . . . . . . . . . . . . . . . . . . 34
Head-up Display . . . . . . . . . . . . . . . . . . . . 111
HeadlampsAiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
Automatic . . . . . . . . . . . . . . . . . . . . . . . . . 128
Bulb Replacement . . . . . . . . . . . . . . . . 258
Daytime RunningLamps (DRL) . . . . . . . . . . . . . . . . . . . . 127
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . 127
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . 259
High-Beam On Light . . . . . . . . . . . . . . 107
High/Low Beam Changer . . . . . . . . . 127
Lamps On Reminder . . . . . . . . . . . . . . 108
Heated Steering Wheel . . . . . . . . . . . . . . . . . . . . . . 86
Heated and Ventilated Front Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Heated Mirrors . . . . . . . . . . . . . . . . . . . . . . . 27
Heater Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
High-Beam On Light . . . . . . . . . . . . . . . . 107
High-Speed Operation . . . . . . . . . . . . . . 276
Hill and Mountain Roads . . . . . . . . . . 151 Hill Start Assist (HSA) . . . . . . . . . . . . . 181
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
How to Wear Seat Belts Properly . . . 45
HVAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
I
Ignition Positions . . . . . . . . . . . . . . . . . . . 158
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Indicator
Pedestrian Ahead . . . . . . . . . . . . . . . . . 104
Vehicle Ahead . . . . . . . . . . . . . . . . . . . . . 104
Infants and Young Children, Restraints . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Information Publication Ordering . . . . . . . . . . . . . 330
Infotainment . . . . . . . . . . . . . . . . . . . . . . . . 133
Infotainment System . . . . . . . . . . . . . . . 334
Instrument Cluster . . . . . . . . . . . . . . . . . . 93
Instrument Panel Overview . . . . . . . . . . . 5
Interior Rearview Mirrors . . . . . . . . . . . 28
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
J
Jump Starting - North America . . . . 288