CADILLAC CT4 2020 Owner's Manual

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270 VEHICLE CARE
When tire replacement is needed
replace with a self-sealing tire,
because the vehicle does not come
with a spare tire or tire changing
equipment.
Low-Profile Tires
If the vehicle has 225/45R17 91V,
235/40R18 91V, 235/40R18 XL
95Y, or 235/35R19 XL 91V size
tires, they are classified as
low-profile tires.Caution
Low-profile tires are more
susceptible to damage from road
hazards or curb impact than
standard profile tires. Tire and/or
wheel assembly damage can occur
when coming into contact with
road hazards like potholes, or sharp
edged objects, or when sliding into
a curb. The warranty does not cover
this type of damage. Keep tires set
to the correct inflation pressure and (Continued)
Caution (Continued)
when possible, avoid contact with
curbs, potholes, and other road
hazards.
Summer Tires
High Performance Summer Tires
This vehicle may come with 225/
45R17 SL 91V or 235/40R18 XL 95Y
high performance summer tires. These
tires have a special tread and
compound that are optimized for
maximum dry and wet road
performance. This special tread and
compound will have decreased
performance in cold climates, and on
ice and snow. It is recommended that
winter tires be installed on the vehicle
if frequent driving at temperatures
below approximately 5 °C (40 °F) or on
ice or snow covered roads is expected.
SeeWinter Tires 0268.
Caution
High performance summer tires
have rubber compounds that lose
flexibility and may develop surface
cracks in the tread area at
temperatures below −7 °C (20 °F).
Always store high performance
summer tires indoors and at
temperatures above −7 °C (20 °F)
when not in use. If the tires have
been subjected to −7 °C (20 °F) or
less, let them warm up in a heated
space to at least 5 °C (40 °F) for
24 hours or more before being
installed or driving a vehicle on
which they are installed. Do not
apply heat or blow heated air
directly on the tires. Always inspect
tires before use. See Tire Inspection
0 280.
Tire Sidewall Labeling
Useful information about a tire is
molded into its sidewall. The
example shows a typical passenger
tire sidewall.

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Passenger (P-Metric) Tire Example
(1) Tire Size:The tire size is a
combination of letters and
numbers used to define a
particular tire's width, height,
aspect ratio, construction type,
and service description. See the
“Tire Size ”illustration later in this
section.
(2) TPC Spec (Tire Performance
Criteria Specification)
:Original
equipment tires designed to GM's
specific tire performance criteria
have a TPC specification code molded onto the sidewall. GM's
TPC specifications meet or exceed
all federal safety guidelines.
(3) DOT (Department of
Transportation)
:The
Department of Transportation
(DOT) code indicates that the tire
is in compliance with the U.S.
Department of Transportation
Motor Vehicle Safety Standards.
DOT Tire Date of Manufacture
:
The last four digits of the TIN
indicate the tire manufactured
date. The first two digits represent
the week (01-52) and the last two
digits, the year. For example, the
third week of the year 2010 would
have a four-digit DOT date
of 0310.
(4) Tire Identification Number
(TIN)
:The letters and numbers
following the DOT code are the
Tire Identification Number (TIN).
The TIN shows the manufacturer
and plant code, tire size, and date
the tire was manufactured. The TIN is molded onto both sides of
the tire, although only one side
may have the date of
manufacture.
(5) Tire Ply Material
:The type
of cord and number of plies in the
sidewall and under the tread.
(6) Uniform Tire Quality
Grading (UTQG)
:Tire
manufacturers are required to
grade tires based on three
performance factors: treadwear,
traction, and temperature
resistance. For more information
see Uniform Tire Quality Grading
0 284.
(7) Maximum Cold Inf lation
Load Limit
:Maximum load that
can be carried and the maximum
pressure needed to support
that load.

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Tire Designations
Tire Size
The example shows a typical
passenger vehicle tire size.
(1) Passenger (P-Metric) Tire:
The United States version of a
metric tire sizing system. The
letter“P”as the first character in
the tire size means a passenger
vehicle tire engineered to
standards set by the U.S. Tire and
Rim Association.
(2) Tire Width
:The three-digit
number indicates the tire section
width in millimeters from sidewall
to sidewall.
(3) Aspect Ratio
:A two-digit
number that indicates the tire
height-to-width measurements. For example, if the tire size aspect
ratio is 60, as shown in item (3) of
the illustration, it would mean
that the tire's sidewall is
60 percent as high as it is wide.
(4) Construction Code
:A letter
code is used to indicate the type
of ply construction in the tire. The
letter “R”means radial ply
construction; the letter “D”means
diagonal or bias ply construction.
(5) Rim Diameter
:Diameter of
the wheel in inches.
(6) Service Description
:These
characters represent the load
index and speed rating of the tire.
The load index represents the load
carrying capacity a tire is certified
to carry. The speed rating is the
maximum speed a tire is certified
to carry a load.
Tire Terminology and
Definitions
Air Pressure:The amount of air
inside the tire pressing outward
on each square inch of the tire.
Air pressure is expressed in kPa
(kilopascal) or psi (pounds per
square inch).
Accessory Weight
:The combined
weight of optional accessories.
Some examples of optional
accessories are automatic
transmission, power windows,
power seats, and air conditioning.
Aspect Ratio
:The relationship of
a tire's height to its width.
Belt
:A rubber coated layer of
cords between the plies and the
tread. Cords may be made from
steel or other reinforcing
materials.
Bead
:The tire bead contains steel
wires wrapped by steel cords that
hold the tire onto the rim.

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Bias Ply Tire:A pneumatic tire in
which the plies are laid at
alternate angles less than
90 degrees to the centerline of the
tread.
Cold Tire Pressure
:The amount
of air pressure in a tire, measured
in kPa (kilopascal) or psi (pounds
per square inch) before a tire has
built up heat from driving. See
Tire Pressure 0275.
Curb Weight
:The weight of a
motor vehicle with standard and
optional equipment including the
maximum capacity of fuel, oil, and
coolant, but without passengers
and cargo.
DOT Markings
:A code molded
into the sidewall of a tire
signifying that the tire is in
compliance with the U.S.
Department of Transportation
(DOT) Motor Vehicle Safety
Standards. The DOT code includes
the Tire Identification Number
(TIN), an alphanumeric designator which can also identify the tire
manufacturer, production plant,
brand, and date of production.
GVWR
:Gross Vehicle Weight
Rating. See Vehicle Load Limits
0 154.
GAWR FRT
:Gross Axle Weight
Rating for the front axle. See
Vehicle Load Limits 0154.
GAWR RR
:Gross Axle Weight
Rating for the rear axle. See
Vehicle Load Limits 0154.
Intended Outboard Sidewall
:
The side of an asymmetrical tire
that must always face outward
when mounted on a vehicle.
Kilopascal (kPa)
:The metric unit
for air pressure.
Light Truck (LT-Metric) Tire
:A
tire used on light duty trucks and
some multipurpose passenger
vehicles. Load Index
:An assigned number
ranging from 1 to 279 that
corresponds to the load carrying
capacity of a tire.
Maximum Inf lation Pressure
:
The maximum air pressure to
which a cold tire can be inflated.
The maximum air pressure is
molded onto the sidewall.
Maximum Load Rating
:The load
rating for a tire at the maximum
permissible inflation pressure for
that tire.
Maximum Loaded Vehicle
Weight
:The sum of curb weight,
accessory weight, vehicle capacity
weight, and production options
weight.
Normal Occupant Weight
:The
number of occupants a vehicle is
designed to seat multiplied by
68 kg (150 lb). See Vehicle Load
Limits 0154.
Occupant Distribution
:
Designated seating positions.

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Outward Facing Sidewall:The
side of an asymmetrical tire that
has a particular side that faces
outward when mounted on a
vehicle. The side of the tire that
contains a whitewall, bears white
lettering, or bears manufacturer,
brand, and/or model name
molding that is higher or deeper
than the same moldings on the
other sidewall of the tire.
Passenger (P-Metric) Tire
:A tire
used on passenger cars and some
light duty trucks and
multipurpose vehicles.
Recommended Inf lation
Pressure
:Vehicle manufacturer's
recommended tire inflation
pressure as shown on the tire
placard. See Tire Pressure 0275
and
Vehicle Load Limits 0154.
Radial Ply Tire
:A pneumatic tire
in which the ply cords that extend
to the beads are laid at 90 degrees
to the centerline of the tread. Rim
:A metal support for a tire
and upon which the tire beads are
seated.
Sidewall
:The portion of a tire
between the tread and the bead.
Speed Rating
:An alphanumeric
code assigned to a tire indicating
the maximum speed at which a
tire can operate.
Traction
:The friction between
the tire and the road surface. The
amount of grip provided.
Tread
:The portion of a tire that
comes into contact with the road.
Treadwear Indicators
:Narrow
bands, sometimes called wear
bars, that show across the tread of
a tire when only 1.6 mm (1/16 in)
of tread remains. See When It Is
Time for New Tires 0282.
UTQGS (Uniform Tire Quality
Grading Standards)
:A tire
information system that provides
consumers with ratings for a tire's
traction, temperature, and treadwear. Ratings are determined
by tire manufacturers using
government testing procedures.
The ratings are molded into the
sidewall of the tire. See
Uniform
Tire Quality Grading 0284.
Vehicle Capacity Weight
:The
number of designated seating
positions multiplied by
68 kg (150 lb) plus the rated cargo
load. See Vehicle Load Limits 0154.
Vehicle Maximum Load on the
Tire
:Load on an individual tire
due to curb weight, accessory
weight, occupant weight, and
cargo weight.
Vehicle Placard
:A label
permanently attached to a vehicle
showing the vehicle capacity
weight and the original equipment
tire size and recommended
inflation pressure. See “Tire and
Loading Information Label” under
Vehicle Load Limits 0154.

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Tire Pressure
Tires need the correct amount of
air pressure to operate effectively.
{Warning
Neither tire underinflation nor
overinflation is good.
Underinflated tires, or tires that
do not have enough air, can
result in:
.Tire overloading and
overheating, which could
lead to a blowout.
.Premature or
irregular wear.
.Poor handling.
.Reduced fuel economy.
Overinflated tires, or tires that
have too much air, can result in:
.Unusual wear.
.Poor handling.
(Continued)
Warning (Continued)
.Rough ride.
.Needless damage from
road hazards.
The Tire and Loading Information
label on the vehicle indicates the
original equipment tires and the
correct cold tire inflation
pressures. The recommended
pressure is the minimum air
pressure needed to support the
vehicle's maximum load carrying
capacity. See Vehicle Load Limits
0 154.
How the vehicle is loaded affects
vehicle handling and ride comfort.
Never load the vehicle with more
weight than it was designed to
carry.
When to Check
Check the pressure of your tires
once a month or more. How to Check
Use a good quality pocket-type
gauge to check the tire pressure.
Proper tire inflation cannot be
determined by looking at the tire.
Check the tire inflation pressure
when the tires are cold, meaning
the vehicle has not been driven for
at least three hours or no more
than 1.6 km (1 mi).
Remove the valve cap from the
tire valve stem. Press the tire
gauge firmly onto the valve to get
the pressure measurement. If the
cold tire inflation pressure
matches the recommended
pressure on the Tire and Loading
Information label, no further
adjustment is necessary.
If the inflation pressure is low,
add air until the recommended
pressure is reached. If the
inflation pressure in high, press
on the metal stem in the center of

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the tire valve to release air.
Re-check the tire pressure with
the tire gauge.
Put the valve caps back on the
valve stems to keep out dirt and
moisture and prevent leaks. Use
only valve caps designed for the
vehicle by GM. TPMS sensors
could be damaged and would not
be covered by the vehicle
warranty.
Tire Pressure for
High-Speed Operation
{Warning
Driving at high speeds, 160 km/h
(100 mph) or higher, puts additional
strain on tires. Sustained
high-speed driving causes excessive
heat buildup and can cause sudden
tire failure. This could cause a
crash, and you or others could be
killed. Some high-speed rated tires
require inflation pressure(Continued)
Warning (Continued)
adjustment for high-speed
operation. When speed limits and
road conditions allow the vehicle to
be driven at high speeds, make sure
the tires are rated for high-speed
operation, are in excellent
condition, and are set to the correct
cold tire inflation pressure for the
vehicle load.
Vehicles with 225/45R17 91V or 235/
40R18 91V size tires require inflation
pressure adjustment when driving the
vehicle at speeds of
160 km/h (100 mph) or higher. Set the
cold tire inflation pressure to 280
kPa (41 psi).
Vehicles with 235/40R18 XL 95Y size
tires require inflation pressure
adjustment when driving the vehicle
at speeds of 160 km/h (100 mph) or
higher. Set the cold tire inflation
pressure to 340 kPa (49 psi).
Vehicles with 235/35R19 XL 91V size
tires require inflation pressure
adjustment when driving the vehicle at speeds of 160 km/h (100 mph) or
higher. Set the cold tire inflation
pressure to 320 kPa (46 psi).
Sustained operation at speeds over
160 km/h (100 mph) requires a load
limit of the driver and one passenger,
with no additional cargo. When loaded
above this level, up to the GVW, do
not operate the vehicle above
160 km/h (100 mph).
Return the tires to the recommended
cold tire inflation pressure when
high-speed driving has ended. See
Vehicle Load Limits
0154 and
Tire Pressure 0275.
Tire Pressure Monitor
System
The Tire Pressure Monitor System
(TPMS) uses radio and sensor
technology to check tire pressure
levels. The TPMS sensors monitor the
air pressure in your tires and transmit
tire pressure readings to a receiver
located in the vehicle.
Each tire, including the spare (if
provided), should be checked monthly
when cold and inflated to the

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inflation pressure recommended by
the vehicle manufacturer on the
vehicle placard or tire inflation
pressure label. (If your vehicle has
tires of a different size than the size
indicated on the vehicle placard or tire
inflation pressure label, you should
determine the proper tire inflation
pressure for those tires.)
As an added safety feature, your
vehicle has been equipped with a tire
pressure monitoring system (TPMS)
that illuminates a low tire pressure
telltale when one or more of your tires
is significantly under-inflated.
Accordingly, when the low tire
pressure telltale illuminates, you
should stop and check your tires as
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 tomaintain 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
0 277.
See Radio Frequency Statement 0330.
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.

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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.
SeeVehicle Load Limits 0154.
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
pressure. Using the DIC, tire pressure
levels can be viewed. For additional
information and details about the DIC
operation and displays see Driver
Information Center (DIC) 0109.
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
0154, for an
example of the Tire and Loading
Information label and its location.
Also see Tire Pressure 0275.
The TPMS can warn about a low tire
pressure condition but it does not
replace normal tire maintenance. See
Tire Inspection 0280, Tire Rotation
0 281 and
Tires 0267.
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.
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

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light and the DIC message should
go off after successfully
completing the sensor matching
process.
. 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. See Buying
New Tires 0282.
. 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
comes on and stays 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 0270 and
Vehicle Load Limits 0154.
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.