Tire Pressure Monitor System - Chevrolet 2008 TrailBlazer Owner's Manual

If your vehicle has P255/50R20 104V size tires installed
on the rear axle, they will require inflation pressure
adjustment when driving your vehicle at speeds above 99
mph (160 km/h). Set the cold inflation pressure, for the
rear tires only, to the maximum inflation pressure shown
on the tire sidewall, or 38 psi (262 kPa), whichever is
lower. See the example following. When you end this
high-speed driving, return the tires to the cold tire inflation
pressure shown on the Tire and Loading Information
label. See Loading Your Vehicle on page 4-35.
Example:
You will find the maximum load and inflation pressure
molded on the tire's sidewall, in small letters, near
the rim flange. It will read something like this: Maximum
load 690 kg (1521 lbs) 300 kPa (44 psi) Max. Press.
For this example, you would set the inflation pressure for
high-speed driving at 38 psi (262 kPa).
The inflation pressure for the front tires should be set to
the cold tire inflation pressure shown on the Tire and
Loading Information label.
Racing or other competitive driving may affect the
warranty coverage of your vehicle. See your warranty
booklet for more information.

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 vehicle's
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 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.
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