Porsche Boxster Owner's Manual page 122

Settings in the on-board computer
Tire pressure function of the on-board
computer
The tire pressure function of the on-board compu-
ter displays the tire pressures (actual pressure)
dependent on temperature in the four wheels. You
can watch the tire pressure rise as the temperature
increases while driving. This display is only for
information.
Under no circumstances should the tire
pressures be changed based on this display.
120
Controls, Instruments
Calling the tire pressure function of the
on-board computer
Push operating lever up or down until the
tire pressure function of the on-board com-
puter appears. (The selection field must be
switched off.)
Pressure info in Tire pressure menu
In accordance with physical principles, the air
pressure changes as the temperature changes.
The tire pressure increases or decreases by
around 1.5 psi (0.1 bar) for every 18°F (10°C )
change in temperature.
The Tire Pressure Monitoring takes this relationship
between tire pressure and temperature into
account.
You can read the tire pressures to be correct-
ed in this display.
The tire pressure to be corrected (refill pressure)
is indicated on the displayed wheel. Example: If
"-1.5 psi (-0.1 bar)" is displayed, 1.5 psi (0.1 bar)
must be added to this tire.
Note
The Tire pressure menu can only be called up when
the vehicle is stationary.
Calling up the "Info pressure" display
Push operating lever forward in order to switch
on the selection field.
Select "TPC" with the operating lever.
Push operating lever forward. The display
changes to the Tire pressure menu.
Select "Info pressure" with the operating lever.
Push operating lever forward.
Note
After the ignition is switched on, it can take up
to approx. 1 minute before all tire pressures are
displayed. Dashes ("-.-") appear instead of the tire
pressures.