
(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 the speed rating of
a tire. The load range represents the load
carry capacity a tire is certified to carry. The speed
rating is the maximum speed a tire is certified to
carry a load. Speed ratings range from A to Z.
Tire Terminology and De nitions
Air Pressure:The amount of air inside the
tire pressing outward on each square inch of
the tire. Air pressure is expressed in pounds
per square inch (psi) or kilopascal (kPa).
Accessory Weight
:This means the combined
weight of optional accessories. Some examples of
optional accessories are, automatic transmission,
power steering, power brakes, 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 that is
located 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.
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 pounds per square inch (psi)
or kilopascals (kPa) before a tire has built up heat
from driving. SeeInflation - Tire Pressure on
page 5-57.
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.
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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.
SeeTire Pressure Monitor Operation on page 5-60,
for additional information.Federal Communications
Commission (FCC) and Industry
and Science Canada
The Tire Pressure Monitor System (TPMS) operates
on a radio frequency and complies with Part 15 of
the FCC Rules. Operation is subject to the following
two conditions:
1. This device may not cause harmful interference.
2. This device must accept any interference received,
including interference that may cause undesired
operation.
The Tire Pressure Monitor System (TPMS) operates
on a radio frequency and complies with RSS-210
of Industry and Science Canada. Operation is subject
to the following two conditions:
1. This device may not cause interference.
2. This device must accept any interference received,
including interference that may cause undesired
operation of the device.
Changes or modifications to this system by other than
an authorized service facility could void authorization to
use this equipment.
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TPMS Malfunction Light
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 warning
light flashes for about one minute and then stays
on for the remainder of the ignition cycle. The low tire
warning light comes on at each ignition cycle until
the problem is corrected. Some of the conditions that
can cause the malfunction light 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 TPMS malfunction light and DIC
message should go off once you re-install the
road tire containing the TPMS sensor.
•One or more TPMS sensors are missing or
damaged. The TPMS malfunction light should go
off when the TPMS sensors are installed and
the sensor matching process is performed
successfully. See your dealer/retailer for service.
•Replacement tires or wheels do not match your
vehicle’s original equipment tires or wheels. Tires
and wheels other than those recommended for your
vehicle could prevent the TPMS from functioning
properly. SeeBuying New Tires on page 5-64.
•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 it cannot detect or
signal a low tire condition. See your dealer/retailer for
service if the TPMS malfunction light and DIC message
comes on and stays on.
TPMS Sensor Identi cation Codes
Each TPMS sensor has a unique identification code.
Any time you replace one or more of the TPMS sensors,
or rotate the vehicle’s tires, the identification codes
need to be matched to the new tire/wheel position.
The sensors are matched, to the tire/wheel positions,
in the following order: driver side front tire, passenger
side front tire, passenger side rear tire, and driver
side rear tire using a TPMS diagnostic tool. See your
dealer/retailer for service.
Tire Inspection and Rotation
We recommend that you regularly inspect your
vehicle’s tires, including the spare tire, for signs
of wear or damage. SeeWhen It Is Time for
New Tires on page 5-63for more information.
Tires should be rotated every 5,000 to 8,000 miles
(8 000 to 13 000 km). SeePart A: Scheduled
Maintenance Services on page 6-4.
The purpose of a regular tire rotation is to achieve a
uniform wear for all tires on the vehicle. This will
ensure that your vehicle continues to perform most
like it did when the tires were new.
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Uniform Tire Quality Grading
Quality grades can be found where applicable
on the tire sidewall between tread shoulder
and maximum selection width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the Unites 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-type
snow tires, space-saver, or temporary use
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.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 a half (1
1⁄2) 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 significantly 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
specified government test surfaces of asphalt
and concrete. A tire marked C may have
poor traction performance.
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.
5-66