2021 CADILLAC CT4 bulb

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
116 INSTRUMENTS AND CONTROLS
Navigation Overlay :This displays
digital speed for Tour/ Sport, current
gear for Track, indicators from speed
view along with Turn-by-Turn
Navigation information in some
vehicles. The compass heading is
displayed when navigation routing is
not active.
Navigation Turn-by-Turn Alerts
shown in the instrument cluster may
also be displayed in any HUD view.
Care of the HUD
Clean the inside of the windshield to
remove any dirt or film that could
reduce the sharpness or clarity of the
HUD image.
Clean the HUD lens with a soft cloth
sprayed with glass cleaner. Wipe the
lens gently, then dry it.
HUD Troubleshooting
If you cannot see the HUD image
when the ignition is on, check that:
.Nothing is covering the HUD lens.
.The HUD brightness setting is not
too dim or too bright.
.The HUD is adjusted to the proper
height.
.Polarized sunglasses are not worn.
.The windshield and HUD lens are
clean.
If the HUD image is not correct,
contact your dealer.
The windshield is part of the HUD
system. If windshield replacement is
required, see Windshield Replacement
0 328.
Vehicle Messages
Messages displayed on the Driver
Information Center (DIC) indicate the
status of the vehicle or some action
that may be needed to correct a
condition. Multiple messages may
appear one after another.
The messages that do not require
immediate action can be
acknowledged and cleared by pressing
the thumbwheel. 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

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 12/4/20
DRIVING AND OPERATING 303
Trailer Brakes
Loaded trailers over 450 kg (1,000 lb)
must be equipped with brake systems
and with brakes for each axle. Trailer
braking equipment conforming to
Canadian Standards Association (CSA)
requirement CAN3-D313, or its
equivalent, is recommended.
State or local regulations may require
trailers to have their own braking
system if the loaded weight of the
trailer exceeds certain minimums that
can vary from state to state. Read and
follow the instructions for the trailer
brakes so they are installed, adjusted,
and maintained properly. Never
attempt to tap into your vehicle's
hydraulic brake system. If you do,
both the vehicle anti-lock brakes and
the trailer brakes may not function,
which could result in a crash.
Trailer Lamps
Always check all trailer lamps are
working at the beginning of each trip,
and periodically on longer trips.
Turn Signals When Towing a
Trailer
When properly connected, the trailer
turn signals will illuminate to indicate
the vehicle is turning, changing lanes,
or stopping. When towing a trailer,
the arrows on the instrument cluster
will illuminate even if the trailer is not
properly connected or the bulbs are
burned out.
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) 097.
A device connected to the DLC —
such as an aftermarket fleet or
driver-behavior tracking device —
(Continued)
Warning (Continued)
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 057 and
Adding Equipment to the
Airbag-Equipped Vehicle 058.

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

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 329
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 0380.
Hood
Trunk
Liftgate
Headlamp Aiming
Front Headlamp Aiming
Headlamp aim has been preset and
should need no further adjustment.
If the vehicle is damaged in a crash,
the headlamp aim may be affected.
If adjustment to the headlamps is
necessary, see your dealer.
Bulb Replacement
For the proper type of replacement
bulbs, or any bulb changing procedure
not listed in this section, contact your
dealer.
Caution
Do not replace incandescent bulbs
with aftermarket LED replacement
bulbs. This can cause damage to
the vehicle electrical system.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
330 VEHICLE CARE
Halogen Bulbs
{Warning
Halogen bulbs have pressurized gas
inside and can burst if you drop or
scratch the bulb. You or others
could be injured. Be sure to read
and follow the instructions on the
bulb package.
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. If your vehicle is equipped with a beauty cover, remove the beauty
cover to get access to the bulb.3. Turn the bulb socketcounterclockwise to remove it from
the headlamp assembly.
4. Unplug the electrical connector from the bulb by releasing the clip
on the connector.
5. Replace the bulb and reverse Steps 1–4 to reinstall.
Electrical System
Electrical System Overload
The vehicle has fuses and circuit
breakers to protect against an
electrical system overload.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
422 INDEX
Appearance CareExterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
Apple CarPlay and Android Auto . . . . . . . . . . . . . . . . . . . . . . 174
Assistance Systems for Driving . . . . 283
Assistance Systems for Parking and Backing . . . . . . . . . . . . . . . . . . . . . . . 277
Audio Bluetooth . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Auto Stop
Stop/Start System . . . . . . . . . . . . . . . . 221
Automatic Dimming Mirrors . . . . . . . . . . . . . . . . . . 25
Door Locks . . . . . . . . . . . . . . . . . . . . . . . . . 17
Emergency Braking (AEB) . . . . . . . . 285
Headlamp System . . . . . . . . . . . . . . . . 128
Transmission . . . . . . . . . . . . . . . . 227, 229
Transmission Fluid . . . . . . . . . . . . . . . 315
Vehicle Hold Light . . . . . . . . . . . . . . . . 101
Automatic Transmission
Manual Mode . . . . . . . . . . . . . . . 234, 235
Automatic Vehicle Hold (AVH) . . . . 239
Avoiding Untrusted Media Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145B
Battery
Exterior Lighting BatterySaver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Load Management . . . . . . . . . . . . . . . . 132
Power Protection . . . . . . . . . . . . . . . . . . 133
Battery - North America . . . . . .326, 366
Blade Replacement, Wiper . . . . . . . . . 327
Bluetooth Overview . . . . . . . . . . . . . . . . . . . . 169, 170
Bluetooth Audio . . . . . . . . . . . . . . . . . . . . 148
Brake Electric Boost . . . . . . . . . . . . . . . . . . . . . 236
Parking, Electric . . . . . . . . . . . . . . . . . . 237
System Warning Light . . . . . . . . . . . . . 99
Brake Pad Life System . . . . . . . . . . . . . . 324
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 Antilock . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Assist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Pad Life System . . . . . . . . . . . . . . . . . . . 324
Braking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 Automatic Emergency (AEB) . . . . . 285
Braking System
Front Pedestrian (FPB) . . . . . . . . . . . 287
Break-In, New Vehicle . . . . . . . . . . . . . . 218
Buckle To Drive . . . . . . . . . . . . . . . . . . . . . . 41 Bulb Replacement
Front Turn Signal Lamps . . . . . . . . 330
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . 330
Headlamp Aiming . . . . . . . . . . . . . . . . 329
Headlamps . . . . . . . . . . . . . . . . . . . . . . . . 329
High Intensity Discharge(HID) Lighting . . . . . . . . . . . . . . . . . . . 330
Buying New Tires . . . . . . . . . . . . . . . . . . . 354
C
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
California Perchlorate MaterialsRequirements . . . . . . . . . . . . . . . . . . . 306
California Proposition 65 Warning . . . . . . . . . . . . .305, 326, 366, Back Cover
Canadian Vehicle Owners . . . . . . . . . . . . . 1
Capacities and Specifications . . . . . . 396
Carbon Monoxide Engine Exhaust . . . . . . . . . . . . . . . . . . . 226
Trunk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Winter Driving . . . . . . . . . . . . . . . . . . . . 213
Cargo Management System . . . . . . . . . . . . . . 80
Tie-Downs . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Caution, Danger, and Warning . . . . . . . . 2
Center Console Storage . . . . . . . . . . . . . . 79

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
INDEX 425
F
Filter,Engine Air Cleaner . . . . . . . . . . . . . . . . 316
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . 128
Flashers, Hazard Warning . . . . . . . . . . 129
Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
Fluid Automatic Transmission . . . . . . . . . 315
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Washer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Folding Mirrors . . . . . . . . . . . . . . . . . . . . . . 24
Forward Collision Alert (FCA) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
Frequency Statement Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
Front Pedestrian Braking (FPB) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
Front Seats
Heated and Ventilated . . . . . . . . . . . . 37
Front Turn Signal Lamps . . . . . . . . . . 330
Fuel Additives . . . . . . . . . . . . . . . . . . . . . . . . . . 294
Economy, Driving for Better . . . . . 203
Filling a Portable FuelContainer . . . . . . . . . . . . . . . . . . . . . . . . 296
Filling the Tank . . . . . . . . . . . . . . . . . . . 295
Foreign Countries . . . . . . . . . . . . . . . . . 294 Fuel (cont'd)
Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Low Fuel Warning Light . . . . . . . . . 105
Prohibited Fuels . . . . . . . . . . . . . . . . . . 294
Recommended . . . . . . . . . . . . . . 293, 294
Top Tier . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Fuses
Engine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
Fuses and Circuit Breakers . . . . . . . 331
Instrument Panel Fuse Block . . . . 334
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
G
Garage Door Opener . . . . . . . . . . . . . . . . 122Programming . . . . . . . . . . . . . . . . . . . . . . 122
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . 328
Gauges Engine CoolantTemperature . . . . . . . . . . . . . . . . . . 94, 95
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Speedometer . . . . . . . . . . . . . . . . . . . . . . . 93
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . 93
Trip Odometer . . . . . . . . . . . . . . . . . . . . . 93
Warning Lights and Indicators . . . 87 General Information
Service and Maintenance . . . . . . . . 379
Towing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
Vehicle Care . . . . . . . . . . . . . . . . . . . . . . . 305
Global Positioning System (GPS) . . . . . . . . . . . . . . . . . . . . . . 161
Glove Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
GM Mobility Reimbursement
Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
Guidance Problems with the Route . . . . . . . . . 162
H
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . 330
Hazard Warning Flashers . . . . . . . . . . 129
HD Radio Technology . . . . . . . . . . . . . . 143
Head Restraints . . . . . . . . . . . . . . . . . . . . . . 31
Head-up Display . . . . . . . . . . . . . . . . . . . . 112
Headlamps
Aiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329
Automatic . . . . . . . . . . . . . . . . . . . . . . . . . 128
Bulb Replacement . . . . . . . . . . . . . . . . 329
Daytime RunningLamps (DRL) . . . . . . . . . . . . . . . . . . . . 128
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . 128
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . 330
High-Beam On Light . . . . . . . . . . . . . . 105