service CADILLAC CTS 2004 1.G Repair Manual

Tire Sidewall Labeling
Useful information about a tire is molded into its
sidewall. The examples below show a typical passenger
car tire and a compact spare tire sidewall.
(A) Tire Size Code:The tire size code is a combination
of letters and numbers used to dene a particular
tire’s width, height, aspect ratio, construction type and
service description. See the “Tire Size” illustration
later in this section for more detail.(B) Tire Performance Criteria Specication
(TPC Spec):Original equipment tires designed to
GM’s specic tire performance criteria have a
TPC specication code molded onto the sidewall.
GM’s TPC specications meet or exceed all federal
safety guidelines.
(C) Department of Transportation (DOT):The
Department of Transportation (DOT) code indicates that
the tire is in compliance with the U.S. Department of
Transportation Motor Vehicle Safety Standards.
(D) Tire Identication Number (TIN):The letters and
numbers following DOT code are the Tire Identication
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.
(E) Tire Ply Material:The type of cord and number of
plies in the sidewall and under the tread.
(F) 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 on page 5-75.
(G) Maximum Cold Ination Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. For information on
recommended tire pressure seeInation - Tire Pressure
on page 5-67andLoading Your Vehicle on page 4-34. Passenger Car Tire Example
5-60

(A) Temporary Use Only:The compact spare tire or
temporary use tire has a tread life of approximately
3,000 miles (5 000 km) and should not be driven
at speeds over 65 mph (105 km/h). The compact spare
tire is for emergency use when a regular road tire
has lost air and gone at. If your vehicle has a spare
tire, seeCompact Spare Tire on page 5-91andIf a Tire
Goes Flat on page 5-79.(B) Tire Ply Material:The type of cord and number of
plies in the sidewall and under the tread.
(C) Tire Identication Number (TIN):The Tire
Identication 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.
(D) Maximum Cold Ination Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. SeeCompact Spare Tire
on page 5-91andLoading Your Vehicle on page 4-34.
(E) Tire Ination:The temporary use tire or compact
spare tire should be inated to 60 psi (420 kPa).
For more information on tire pressure and ination
seeInation - Tire Pressure on page 5-67.
(F) Tire Size:A combination of letters and numbers
dene a tire’s width, height, aspect ratio, construction
type and service description. The letter “T” as the
rst character in the tire size means the tire is for
temporary use only.
(G) Tire Performance Criteria Specication
(TPC Spec):Original equipment tires designed to
GM’s specic tire performance criteria have a
TPC specication code molded onto the sidewall.
GM’s TPC specications meet or exceed all federal
safety guidelines. Compact Spare Tire Example
5-61

Tire Size
The following illustration shows an example of a typical
passenger car tire size.
(A) P-Metric Tire:The United States version of a
metric tire sizing system. The letter “P” as the
rst character in the tire size means a passenger
vehicle tire engineered to standards set by the
U. S. Tire and Rim Association.
(B) Tire Width:The three-digit number indicates the
tire section width in millimeters from sidewall to sidewall.(C) Aspect Ratio:A two-digit number that indicates
the tire height-to-width measurements. For example,
if the tire size aspect ratio is “70,” as shown in item “C”
of the illustration, it would mean that the tire’s sidewall
is 70% as high as it is wide.
(D) 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;
and the letter “B” means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:These characters represent
the load range and speed rating of the tire. The load
index represents the load carry capacity a tire is certied
to carry. The load index can range from 1 to 279.
The speed rating is the maximum speed a tire is certied
to carry a load. Speed ratings range from “A” to “Z”.
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Run-Flat Tires (CTS-V)
If your vehicle has run-at tires, there is no spare tire
and no tire changing equipment. Run-at tires perform
so well without any air that a Tire Pressure Monitor
(TPM) is used to alert you if a tire has lost pressure.
SeeTire Pressure Monitor System (CTS-V) on
page 5-70.
{CAUTION:
When the low tire warning light is displayed on
the instrument panel cluster, your vehicle’s
handling capabilities will be reduced during
severe maneuvers. If you drive too fast, you
could lose control of your vehicle. You or
others could be injured. Don’t drive over
55 mph (90 km/h) when the low tire warning
light is displayed. Drive cautiously and check
your tire pressures as soon as you can.If a tire goes at, you won’t need to stop on the side of
the road to change the tire. You can just keep on
driving. The tire can operate effectively with no air
pressure for up to 65 miles (105 km) at speeds up to
55 mph (90 km/h). The shorter the distance you
drive and the slower the speed, the greater the chance
that the tire will not have to be replaced. When a tire
is lled with air, it provides a cushion between the road
and the wheel. Because you won’t have this cushion
when driving on a deated run-at tire, try to avoid
potholes that could damage your wheel and require
replacement of it.
Some road hazards can damage a tire beyond repair.
This damage could occur even before you’ve driven
on the tire in a deated condition. When a tire has been
damaged, or if you’ve driven any distance on a
run-at tire, check with an authorized run-at tire service
center to determine whether the tire can be repaired
or should be replaced. To maintain your vehicle’s run-at
feature, all replacement tires must be self-supporting
tires. As soon as possible, contact the nearest
authorized GM or run-at servicing facility for inspection
and repair or replacement. To locate the nearest GM
or run-at servicing facility, call Roadside Service.
SeeRoadside Service on page 7-6for details.
5-66

{CAUTION:
Run-at tires are constructed differently than
other tires and could explode during improper
service. You or others could be injured or
killed if you attempt to repair, replace,
dismount, or mount a run-at tire. Let only an
authorized run-at service center repair,
replace, dismount and mount run-at tires.
The valve stems on your run-at tires have sensors that
are part of the Tire Pressure Monitor System (TPMS).
These sensors contain batteries which are designed
to last for 10 years under normal driving conditions.
See your dealer if you ever need to have a wheel
replaced, or if the sensors ever need replacement.
Notice:Using liquid sealants can damage the tire
valves and tire pressure monitor sensors in your
run-at tires. This damage would not be covered
by warranty. Don’t use liquid sealants in your
run-at tires.
Ination - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under-ination or over-ination is all right. It is not.
If your tires do not have enough air (under-ination),
you can get the following:
Too much exing
Too much heat
Tire overloading
Premature or irregular wear
Poor handling
Reduced fuel economy
If your tires have too much air (over-ination),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazards
5-67

The Tire and Loading Information label (tire information
placard) is attached, to either, the center pillar near the
driver’s door latch post or on the rear edge of the driver’s
side rear passenger door. The label shows the size of
your vehicle’s original tires and the correct ination
pressure for your vehicle’s tires when they are cold.
SeeInation - Tire Pressure on page 5-67andLoading
Your Vehicle on page 4-34for additional information.
Your vehicle’s TPM system can alert you about a low tire
pressure condition but it does not replace normal tire
maintenance. SeeTire Inspection and Rotation on
page 5-72andTires on page 5-58.
Each TPM sensor has a unique identication code that
is matched to one of the four tire positions on your
vehicle. Any time you rotate your vehicle’s tires
or replace one or more TPM sensors, the identication
codes will need to be matched to the new tire and
wheel position. The TPM matching process is performed
in a specic sequence and time limit. See your dealer
for service.Notice:Do not use a tire sealant if your vehicle
is equipped with Tire Pressure Monitors.
The liquid sealant can damage the tire pressure
monitor sensors.
The TPM system operates on a radio frequency subject
to Federal Communications Commission (FCC) Rules
and with Industry and Science Canada.
This device complies with Part 15 of the FCC Rules
and with RSS-210 of Industry and Science Canada.
Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(2) this device must accept any interference received
including interference that may cause undesired
operation of the device.
Changes or modications to this system by other than
an authorized service facility could void authorization to
use this equipment.
5-71

Tire Inspection and Rotation
Tires should be rotated every 5,000 to 8,000 miles
(8 000 to 13 000 km).
Any time you notice unusual wear, rotate your tires as
soon as possible and check wheel alignment. Also
check for damaged tires or wheels. SeeWhen It Is Time
for New Tires on page 5-73andWheel Replacement
on page 5-77for more information.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The rst rotation
is the most important. SeeScheduled Maintenance
on page 6-4, for scheduled rotation intervals.When rotating your tires, always use the correct rotation
pattern shown here.
Do not include the compact spare tire, If your vehicle
has one, in the tire rotation.
After the tires have been rotated, adjust the front and
rear ination pressures as shown on the Tire and
Loading Information label.
If your vehicle has run-at tires, the Tire Pressure
Monitor (TPM) system will need to have the sensors
reset after a tire rotation is performed. A special tool is
needed to reset the sensor identication codes.
See your dealer for service.
5-72

Buying New Tires
To nd out what kind and size of tires your vehicle
needs, look at the tire and loading information label.
For more information about this label and its location on
your vehicle, seeLoading Your Vehicle on page 4-34.
The tires installed on your vehicle when it was new had a
Tire Performance Criteria Specication (TPC Spec)
number on each tire’s sidewall. When you get new tires,
GM recommends that you get tires with that same TPC
Spec number. That way your vehicle will continue to have
tires that are designed to give proper endurance,
handling, speed rating, load range, traction, ride, tire
pressure monitoring system performance and other
things during normal service on your vehicle. If your tires
have an all-season tread design, the TPC number will be
followed by an “MS” (for mud and snow).Whenever you replace your tires with those not having
a TPC Spec number, make sure they are the same
size, load range, speed rating and construction
type (bias, bias-belted or radial) as your original tires.
Winter tires with the same speed rating as your original
equipment tires may not be available for H, V, W,
and ZR speed rated tires. If you choose snow tires with
a lower speed rating, never exceed the tire’s maximum
speed capability.
If you replace your vehicle’s tires with those not having
a TPC spec number, the tire pressure monitoring
system may give an inaccurate low pressure warning.
Non-TPC Spec tires may give a low pressure warning
that is higher or lower than the proper warning level you
would get with TPC Spec numbered tires.
5-74

Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specied government test course.
For example, a tire graded 150 would wear one and
a half (1.5) times as well on the government course as
a tire graded 100. The relative performance of tires
depends upon the actual conditions of their use,
however, and may depart signicantly from the norm
due to variations in driving habits, service practices and
differences in road characteristics and climate.
Traction – AA, A, B, C
The traction grades, from highest to lowest, are AA, A,
B, and C. Those grades represent the tire’s ability
to stop on wet pavement as measured under controlled
conditions on specied government test surfaces of
asphalt and concrete. A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.
Temperature – A, B, C
The temperature grades are A (the highest), B, and C,
representing the tire’s resistance to the generation
of heat and its ability to dissipate heat when tested
under controlled conditions on a specied indoor
laboratory test wheel. Sustained high temperature can
cause the material of the tire to degenerate and
reduce tire life, and excessive temperature can lead to
sudden tire failure. The grade C corresponds to a
level of performance which all passenger car tires must
meet under the Federal Motor Vehicle Safety Standard
No. 109. Grades B and A represent higher levels of
performance on the laboratory test wheel than the
minimum required by law.
Warning: The temperature grade for this tire is
established for a tire that is properly inated and not
overloaded. Excessive speed, underination, or
excessive loading, either separately or in combination,
can cause heat buildup and possible tire failure.
5-76

Run-Flat Tires (CTS-V)
If your vehicle has run-at tires, there is no spare tire
and no tire changing equipment. Run-at tires can
operate effectively with no air pressure for a limited
distance and speed. These tires perform so well without
any air pressure that a Tire Pressure Monitor (TPM)
is used to alert you when there is a low tire condition.
{CAUTION:
When the low tire warning light is displayed on
the instrument panel cluster, your vehicle’s
handling capabilities will be reduced during
severe maneuvers. If you drive too fast, you
could lose control of your vehicle. You or
others could be injured. Don’t drive over
55 mph (90 km/h) when the low tire warning
light is displayed. Drive cautiously and check
your tire pressures as soon as you can.SeeRun-Flat Tires (CTS-V) on page 5-66andTire
Pressure Monitor System (CTS-V) on page 5-70,
for additional information.
{CAUTION:
Special tools and procedures are required to
service a run-at tire. If these special tools and
procedures aren’t used you or others could be
injured and your vehicle could be damaged.
Always be sure the proper tools and
procedures, as described in the service
manual, are used.
To order a service manual seeService Publications
Ordering Information on page 7-11.
5-80