Chevrolet 2002 Impala Owner's Manual page 332

Tire Inflation Monitor System
(If Equipped)
The tire inflation monitor system can alert you to a large
change in the pressure of one tire. The system "learns"
the pressure at each tire throughout the operating speed
range of your vehicle. The system normally takes
between 45 and 90 minutes of driving to learn the tire
pressures. This time may be longer depending on your
individual driving habits. Learning need not be
accumulated during a single trip. Once learned, the
system will remember the tire pressures until the
system is recalibrated.
After the system has learned tire pressures with properly
inflated tires, the LOW TIRE PRESSURE message
will come on if the pressure in one tire becomes 12 psi
(83 kPa) lower than the other three tires. The tire
inflation monitor system won't alert you if the
pressure in more than one tire is low, if the system
is not properly calibrated, or if the vehicle is moving
faster than 70 mph (110 km/h).
The tire inflation monitor system detects differences
in tire rotation speeds that are caused by changes in
tire pressure. The system can alert you about a low
--
tire but it doesn't replace normal tire maintenance.
See "Tires" in the Index.
When the LOW TIRE PRESSURE message comes on,
you should stop as soon as you can and check all your
tires for damage. (If a tire is flat, see "If a Tire Goes
Flat" in the Index.) Also check the tire pressure in all
four tires as soon as you can. See "Inflation
Pressure" in the Index.
The LOW TIRE PRESSURE message will also be
displayed (while the ignition is on) until you reset
(calibrate) the system.
Don't reset the tire inflation monitor system without
first correcting the cause of the problem and checking
and adjusting the pressure in all four tires. If you reset
the system when the tire pressures are incorrect, the
system will not work properly and may not alert you
when a tire is low.
Any time you adjust a tire's pressure, rotate your tires,
or have one or more tires repaired or replaced, you'll
need to reset (calibrate) the tire inflation monitor
system. You'll also need to reset the system whenever
you buy new tires and whenever the vehicle's battery
has been disconnected.
-
Tire
6-43