2007 CHEVROLET IMPALA wheel

Brake Wear
Your vehicle has four-wheel disc brakes.
Disc brake pads have built-in wear indicators that
make a high-pitched warning sound when the
brake pads are worn and new pads are needed.
The sound can come and go or be heard all
the time your vehicle is moving, except when
you are pushing on the brake pedal rmly.
{CAUTION:
The brake wear warning sound means that
soon the brakes will not work well. That
could lead to an accident. When you hear
the brake wear warning sound, have your
vehicle serviced.
Notice:Continuing to drive with worn-out
brake pads could result in costly brake repair.Some driving conditions or climates can cause a
brake squeal when the brakes are rst applied
or lightly applied. This does not mean something
is wrong with the brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated,
inspect brake pads for wear and evenly tighten
wheel nuts in the proper sequence to torque
specications inCapacities and Specications on
page 403.
Brake linings should always be replaced as
complete axle sets.Brake Pedal Travel
See your dealer/retailer if the brake pedal does
not return to normal height, or if there is a
rapid increase in pedal travel. This could be
a sign that brake service might be required.
Brake Adjustment
Every time you apply the brakes, with or without
the vehicle moving, the brakes adjust for wear.
336

Tire Size
The following illustration shows an example of a
typical passenger vehicle tire size.
(A) Passenger (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 60, as
shown in item C of the illustration, it would mean
that the tire’s sidewall is 60 percent 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.
355

How to Check
Use a good quality pocket-type gage to check
tire pressure. You cannot tell if your tires are
properly inated simply by looking at them. Radial
tires may look properly inated even when they
are under-inated. Check the tire’s ination
pressure when the tires are cold. Cold means your
vehicle has been sitting for at least three hours
or driven no more than 1 mile (1.6 km).
Remove the valve cap from the tire valve stem.
Press the tire gage rmly onto the valve to
get a pressure measurement. If the cold tire
ination pressure matches the recommended
pressure on the Tire and Loading Information
label, no further adjustment is necessary. If the
ination pressure is low, add air until you reach the
recommended amount.
If you overll the tire, release air by pushing on
the metal stem in the center of the tire valve.
Re-check the tire pressure with the tire gage.
Be sure to put the valve caps back on the valve
stems. They help prevent leaks by keeping out dirt
and moisture.
Tire Pressure Monitor System
The Tire Pressure Monitor System (TPMS) uses
radio and sensor technology to check tire pressure
levels. If your vehicle has this feature, sensors
are mounted onto each tire and wheel assembly,
except for the spare tire. The TPMS sensors
monitor the air pressure in your vehicle’s tires and
transmit tire pressure readings to a receiver
located in the vehicle.
When a low tire pressure condition is detected,
the TPMS will illuminate the low tire pressure
warning symbol on the instrument panel cluster,
and at the same time a message to check
the pressure in a specic tire will appear on the
Driver Information Center (DIC) display. The
low tire pressure warning symbol on the instrument
panel cluster and the CHECK TIRE PRESSURE
message will appear at each ignition cycle until the
tires are inated to the correct ination pressure.
Using the DIC, tire pressure levels can be
viewed by the driver. For additional information
and details about the DIC operation and displays
seeDIC Operation and Displays on page 191
andDIC Warnings and Messages on page 199.
360

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 ash 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.
A Tire and Loading Information label, attached to
your vehicle, shows the size of your vehicle’s
original equipment tires and the correct ination
pressure for your vehicle’s tires when theyare cold. SeeLoading Your Vehicle on page 277,
for an example of the Tire and Loading
Information label and its location on your vehicle.
Also seeInation - Tire Pressure on page 359.
Your vehicle’s TPMS system can warn you about
a low tire pressure condition but it does not
replace normal tire maintenance. SeeTire
Inspection and Rotation on page 364andTires on
page 351.
Notice:Do not use a tire sealant if your vehicle
has Tire Pressure Monitors. The liquid sealant
can damage the tire pressure monitor sensors.
The TPMS will not function properly if one or more
of the TPMS sensors are missing or inoperable.
If the system detects a missing or inoperable
sensor, an error message SERVICE TIRE
MONITOR SYSTEM will be shown on the DIC
display. If you have replaced a tire/wheel assembly
without transferring the TPMS sensors, the error
message will be displayed. Once you re-install the
TPMS sensors, the error message should go
off. See your GM dealer for service if all TPMS
sensors are installed and the error message
comes on and stays on.
362

TPMS Sensor Identication Codes
Each TPMS sensor has a unique identication
code. Any time you replace one or more of
the TPMS sensors or rotate the vehicle’s tires,
the identication codes will need to be matched
to the new tire/wheel position. The sensors
are matched, to the tire/wheel positions, in the
following order: driver’s side front tire, passenger’s
side front tire, passenger’s side rear tire, and
driver’s side rear tire using a TPMS diagnostic
tool. See your GM dealer for service.
The TPMS sensors may also be matched to each
tire/wheel position by increasing or decreasing
the tire’s air pressure. When increasing the tire’s
pressure, do not exceed the maximum ination
pressure indicated on the tire’s sidewall.
You will have two minutes to match each tire
and wheel position. If it takes longer than
two minutes to match any tire and wheel position,
the matching process stops and you will need
to start over.The TPMS matching process is outlined below:
1. Set the parking brake.
2. Turn the ignition switch to RUN with the
engine off.
3. Using the DIC, press the vehicle information
button until the LEARN TIRE POSITIONS
message displays.
4. Press the set/reset button to allow the system
to learn the tire positions. The horn will sound
twice to indicate the receiver is ready, and
the TIRE LEARNING ACTIVE message
will display. The TPMS system is ready for
the sensor matching process to begin.
5. Start with the driver’s side front tire.
6. Remove the valve cap from the tire’s valve
stem. Activate the TPMS sensor by increasing
or decreasing the tire’s air pressure for
ve seconds, or until a horn chirp sounds.
The horn chirp, which may take up to
30 seconds to sound, conrms that the sensor
identication code has been matched to the
tire/wheel position. To decrease the tire’s
air-pressure use the pointed end of the valve
cap, a pencil-style air pressure gage, or a key.
363

7. Proceed to the passenger’s side front tire, and
repeat the procedure in Step 6.
8. Proceed to the passenger’s side rear tire, and
repeat the procedure in Step 6.
9. Proceed to the driver’s side rear tire, and
repeat the procedure in Step 6.
10. After hearing the conrming horn chirp for the
driver’s side rear tire, the tire learning process
ends. Turn the ignition switch to OFF.
11. Set all four tires to the recommended air
pressure level as indicated on the Tire
and Loading Information label.
12. Put the valve caps back on the valve stems.
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 modications to this system by other
than an authorized service facility could void
authorization to use this equipment.
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 366andWheel
Replacement on page 371for 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 408for scheduled rotation
intervals.
364

When rotating your tires, always use the correct
rotation pattern shown here.
Do not include the compact spare tire in your
tire rotation.
After the tires have been rotated, adjust the front
and rear ination pressures as shown on the Tire
and Loading Information label. SeeInation - Tire
Pressure on page 359andLoading Your Vehicle on
page 277.Reset the Tire Pressure Monitor System. See
“TPMS Sensor Identication Codes” under
Tire Pressure Monitor System on page 360.
Make certain that all wheel nuts are properly
tightened. See “Wheel Nut Torque” under
Capacities and Specications on page 403.
{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after time. The wheel could
come off and cause an accident. When
you change a wheel, remove any rust or
dirt from places where the wheel attaches
to the vehicle. In an emergency, you can
use a cloth or a paper towel to do this;
but be sure to use a scraper or wire brush
later, if needed, to get all the rust or dirt
off. SeeChanging a Flat Tire on page 374.
365

{CAUTION:
Mixing tires could cause you to lose
control while driving. If you mix tires of
different sizes, brands, or types (radial
and bias-belted tires), the vehicle may not
handle properly, and you could have a
crash. Using tires of different sizes,
brands, or types may also cause damage
to your vehicle. Be sure to use the correct
size, brand, and type of tires on all
wheels. It is all right to drive with your
compact spare temporarily, as it was
developed for use on your vehicle.
SeeCompact Spare Tire on page 385.
{CAUTION:
If you use bias-ply tires on your vehicle,
the wheel rim anges could develop
cracks after many miles of driving. A tire
and/or wheel could fail suddenly, causing
a crash. Use only radial-ply tires with the
wheels on your vehicle.
If you must replace your vehicle’s tires with those
that do not have a TPC Spec number, make
sure they are the same size, load range, speed
rating, and construction type (radial and
bias-belted tires) as your vehicle’s original tires.
367