2021 CADILLAC CT4 warning light

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 325
How to Disable the Brake Pad
Life System
The brake pad life system can be
turned off. This may be necessary if
aftermarket brake pads without wear
sensors are installed. When the
system is turned off, the front and
rear brake pad life percentages will
not display. However, the built-in wear
indicators that make a high-pitched
warning sound when the brake pads
are worn can still determine when the
pads should be replaced. SeeBrakes
0 323.
To turn off the brake pad life system: 1. Display Brake Pad Life on the DIC. See Driver Information Center (DIC)
(Base Level) 0107 or
Driver Information Center (DIC)
(Uplevel) 0110.
2. Select DISABLE.
To turn the brake pad life system back
on, follow the above steps but select
ENABLE in Step 2.
Brake Fluid
The brake master cylinder reservoir is
filled with GM approved DOT 4 brake
fluid as indicated on the reservoir cap.
See Engine Compartment Overview
0 309 for the location of the reservoir.
Checking Brake Fluid
With the vehicle in P (Park) on a level
surface, the brake fluid level should be
between the minimum and maximum
marks on the brake fluid reservoir.
There are only two reasons why the
brake fluid level in the reservoir may
go down:
.Normal brake lining wear. When
new linings are installed, the fluid
level goes back up.
.A fluid leak in the brake hydraulic
system. Have the brake hydraulic
system fixed. With a leak, the
brakes will not work well. Always clean the brake fluid reservoir
cap and the area around the cap
before removing it.
Do not top off the brake fluid. Adding
fluid does not correct a leak. If fluid is
added when the linings are worn,
there will be too much fluid when
new brake linings are installed. Add or
remove fluid, as necessary, only when
work is done on the brake hydraulic
system.
{Warning
If too much brake fluid is added, it
can spill on the engine and burn,
if the engine is hot enough. You or
others could be burned, and the
vehicle could be damaged. Add
brake fluid only when work is done
on the brake hydraulic system.
When the brake fluid falls to a low
level, the brake warning light comes
on. See Brake System Warning Light
0 99.

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
VEHICLE CARE 349
soon as possible, and inflate them to
the proper pressure. Driving on a
significantly under-inflated tire causes
the tire to overheat and can lead to
tire failure. Under-inflation also
reduces fuel efficiency and tire tread
life, and may affect the vehicle's
handling and stopping ability.
Please note that the TPMS is not a
substitute for proper tire maintenance,
and it is the driver's responsibility to
maintain correct tire pressure, even if
under-inflation has not reached the
level to trigger illumination of the
TPMS low tire pressure telltale.
Your vehicle has also been equipped
with a TPMS malfunction indicator to
indicate when the system is not
operating properly. The TPMS
malfunction indicator is combined
with the low tire pressure telltale.
When the system detects a
malfunction, the telltale will flash for
approximately one minute and then
remain continuously illuminated. This
sequence will continue upon
subsequent vehicle start-ups as long
as the malfunction exists.When the malfunction indicator is
illuminated, the system may not be
able to detect or signal low tire
pressure as intended. TPMS
malfunctions may occur for a variety
of reasons, including the installation
of replacement or alternate tires or
wheels on the vehicle that prevent the
TPMS from functioning properly.
Always check the TPMS malfunction
telltale after replacing one or more
tires or wheels on your vehicle to
ensure that the replacement or
alternate tires and wheels allow the
TPMS to continue to function
properly.
See
Tire Pressure Monitor Operation
0 349.
See Radio Frequency Statement 0409.
Tire Pressure Monitor
Operation
This vehicle may have a Tire Pressure
Monitor System (TPMS). The TPMS is
designed to warn the driver when a
low tire pressure condition exists. TPMS sensors are mounted onto each
tire and wheel assembly, excluding the
spare tire and wheel assembly. The
TPMS sensors monitor the air
pressure in the tires and transmit the
tire pressure readings to a receiver
located in the vehicle.
When a low tire pressure condition is
detected, the TPMS illuminates the
low tire pressure warning light located
on the instrument cluster. If the
warning light comes on, stop as soon
as possible and inflate the tires to the
recommended pressure shown on the
Tire and Loading Information label.
See
Vehicle Load Limits 0214.
A message to check the pressure in a
specific tire displays in the Driver
Information Center (DIC). The low tire
pressure warning light and the DIC
warning message come on at each
ignition cycle until the tires are
inflated to the correct inflation

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
350 VEHICLE CARE
pressure. Using the DIC, tire pressure
levels can be viewed. For additional
information and details about the DIC
operation and displays seeDriver
Information Center (DIC) (Base Level)
0 107 or
Driver Information Center (DIC)
(Uplevel) 0110.
The low tire pressure warning light
may come on in cool weather when
the vehicle is first started, and then
turn off as the vehicle is driven. This
could be an early indicator that the air
pressure is getting low and needs to
be inflated to the proper pressure.
A Tire and Loading Information label,
attached to your vehicle, shows the
size of the original equipment tires
and the correct inflation pressure for
the tires when they are cold. See
Vehicle Load Limits 0214, for an
example of the Tire and Loading
Information label and its location.
Also see Tire Pressure 0346.
The TPMS can warn about a low tire
pressure condition but it does not replace normal tire maintenance. See
Tire Inspection
0352, Tire Rotation
0 352 and
Tires 0339.
Caution
Tire sealant materials are not all
the same. A non-approved tire
sealant could damage the TPMS
sensors. TPMS sensor damage
caused by using an incorrect tire
sealant is not covered by the
vehicle warranty. Always use only
the GM approved tire sealant
available through your dealer or
included in the vehicle.
Factory-installed Tire Inflator Kits use
a GM-approved liquid tire sealant.
Using non-approved tire sealants
could damage the TPMS sensors. See
Tire Sealant and Compressor Kit 0360
for information regarding the inflator
kit materials and instructions.
TPMS Malfunction Light and
Message
The TPMS will not function properly if
one or more of the TPMS sensors are
missing or inoperable. When the
system detects a malfunction, the low
tire pressure warning light flashes for
about one minute and then stays on
for the remainder of the ignition cycle.
A DIC warning message also displays.
The malfunction light and DIC
warning message come on at each
ignition cycle until the problem is
corrected. Some of the conditions that
can cause these to come on are:
.One of the road tires has been
replaced with the spare tire. The
spare tire does not have a TPMS
sensor. The malfunction light and
DIC message should go off after the
road tire is replaced and the sensor
matching process is performed
successfully. See “TPMS Sensor
Matching Process” later in this
section.
.The TPMS sensor matching process
was not done or not completed
successfully after rotating the tires.
The malfunction light and the DIC

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
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VEHICLE CARE 351
message should go off after
successfully completing the sensor
matching process. See "TPMS
Sensor Matching Process" later in
this section.
.One or more TPMS sensors are
missing or damaged. The
malfunction light and the DIC
message should go off when the
TPMS sensors are installed and the
sensor matching process is
performed successfully. See your
dealer for service.
.Replacement tires or wheels do not
match the original equipment tires
or wheels. Tires and wheels other
than those recommended could
prevent the TPMS from functioning
properly. SeeBuying New Tires
0 354.
.Operating electronic devices or
being near facilities using radio
wave frequencies similar to the
TPMS could cause the TPMS
sensors to malfunction.
If the TPMS is not functioning
properly it cannot detect or signal a
low tire pressure condition. See your dealer for service if the TPMS
malfunction light and DIC message
come on and stay on.
Tire Fill Alert (If Equipped)
This feature provides visual and
audible alerts outside the vehicle to
help when inflating an underinflated
tire to the recommended cold tire
pressure.
When the low tire pressure warning
light comes on:
1. Park the vehicle in a safe, level place.
2. Set the parking brake firmly.
3. Place the vehicle in P (Park).
4. Add air to the tire that is underinflated. The turn signal lamp
will flash.
When the recommended pressure
is reached, the horn sounds once
and the turn signal lamp will stop
flashing and briefly turn solid.
Repeat these steps for all
underinflated tires that have
illuminated the low tire pressure
warning light.
{Warning
Overinflating a tire could cause the
tire to rupture and you or others
could be injured. Do not exceed the
maximum pressure listed on the
tire sidewall. See Tire Sidewall
Labeling 0342 and
Vehicle Load Limits 0214.
If the tire is overinflated by more than
35 kPa (5 psi), the horn will sound
multiple times and the turn signal
lamp will continue to flash for several
seconds after filling stops. To release
and correct the pressure, while the
turn signal lamp is still flashing,
briefly press the center of the valve
stem. When the recommended
pressure is reached, the horn
sounds once.
If the turn signal lamp does not flash
within 15 seconds after starting to
inflate the tire, the tire fill alert has
not been activated or is not working.
If the hazard warning flashers are on,
the tire fill alert visual feedback will
not work properly.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
VEHICLE CARE 353
rotation, check the wheel
alignment. SeeWhen It Is Time for
New Tires 0353 and
Wheel Replacement 0357.
Use this rotation pattern when
rotating the tires.
Adjust the front and rear tires to
the recommended inflation
pressure on the Tire and Loading
Information label after the tires
have been rotated. See Tire
Pressure 0346 and
Vehicle Load Limits 0214. Reset the Tire Pressure Monitor
System. See
Tire Pressure Monitor
Operation 0349.
Check that all wheel nuts are
properly tightened. See “Wheel
Nut Torque ”under Capacities and
Specifications 0396.
{Warning
Rust or dirt on a wheel, or on
the parts to which it is fastened,
can cause wheel nuts to become
loose over time. The wheel
could come off and cause a
crash. When changing a wheel,
remove any rust or dirt from
places where the wheel attaches
to the vehicle. In an emergency,
a cloth or paper towel can be
used; however, use a scraper or
wire brush later to remove all
rust or dirt. Lightly coat the inner diameter of
the wheel hub opening with wheel
bearing grease after a wheel
change or tire rotation to prevent
corrosion or rust build-up.
{Warning
Do not apply grease to the
wheel mounting surface, wheel
conical seats, or the wheel nuts
or bolts. Grease applied to these
areas could cause a wheel to
become loose or come off,
resulting in a crash.
When It Is Time for New
Tires
Factors, such as maintenance,
temperatures, driving speeds, vehicle
loading, and road conditions affect the
wear rate of the tires.

Cadillac CT4 Owner Manual (GMNA-Localizing-U.S./Canada-14584335) -
2021 - CRC - 11/23/20
356 VEHICLE CARE
Different Size Tires and
Wheels
If wheels or tires are installed that are
a different size than the original
equipment wheels and tires, vehicle
performance, including its braking,
ride and handling characteristics,
stability, and resistance to rollover
may be affected. If the vehicle has
electronic systems such as antilock
brakes, rollover airbags, traction
control, electronic stability control,
or All-Wheel Drive, the performance
of these systems can also be affected.
{Warning
If different sized wheels are used,
there may not be an acceptable
level of performance and safety if
tires not recommended for those
wheels are selected. This increases
the chance of a crash and serious
injury. Only use GM specific wheel
and tire systems developed for the
vehicle, and have them properly
installed by a GM certified
technician.See
Buying New Tires 0354 and
Accessories and Modifications 0306.
Uniform Tire Quality
Grading
The following information relates
to the system developed by the
United States National Highway
Traffic Safety Administration
(NHTSA), which grades tires by
treadwear, traction, and
temperature performance. This
applies only to vehicles sold in the
United States. The grades are
molded on the sidewalls of most
passenger car tires. The Uniform
Tire Quality Grading (UTQG)
system does not apply to deep
tread, winter tires, compact spare
tires, tires with nominal rim
diameters of 10 to 12 inches
(25 to 30 cm), or to some
limited-production tires.
While the tires available on
General Motors passenger cars
and light trucks may vary with
respect to these grades, they must also conform to federal safety
requirements and additional
General Motors Tire Performance
Criteria (TPC) standards.
Quality grades can be found where
applicable on the tire sidewall
between tread shoulder and
maximum section width. For
example:
Treadwear 200 Traction AA
Temperature A
All Passenger Car Tires Must
Conform to Federal Safety
Requirements In Addition To
These Grades.
Treadwear
The treadwear grade is a
comparative rating based on the
wear rate of the tire when tested
under controlled conditions on a
specified government test course.
For example, a tire graded
150 would wear one and one-half
(1½) times as well on the
government course as a tire