Pontiac 2005 Grand Prix - Manual (Page 355)

How to Check
Use a good quality pocket-type gage to check tire
pressure. You cannot tell if your tires are properly
inflated simply by looking at them. Radial tires may look
properly inflated even when they are under-inflated.
Check the tire’s inflation 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 firmly onto the valve to get a pressure
measurement. If the cold tire inflation pressure matches
the recommended pressure on the Tire and Loading
Information label, no further adjustment is necessary.
If the inflation pressure is low, add air until you reach
the recommended amount.
If you overfill 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 vehicle has the tire inflation monitor system, that
can alert the driver to a large change in the pressure of
one tire. It 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 does not replace
normal tire maintenance. See Tires on page 5-58.
The system “learns” the pressure at each tire throughout
the operating speed range of the vehicle. The system
normally takes between 45 and 90 minutes of driving to
learn the tire pressures. This time may be longer
depending on 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 reset.
This symbol, along with the
CHECK TIRE PRESSURE
warning message will
appear in the Driver
Information Center (DIC) if
the pressure in one tire
becomes 12 psi (83 kPa)
lower than the other
three tires.
See DIC Warnings and Messages on page 3-69 for
more information.
5-65