Keeping Up the Pressure

The system has been given upgraded wheel sensors for 2009,
which use a new communication technology and larger batteries
Now utilizing Tripper Logic, the sensors transmit their signals only whenever
requested to do so by the control unit, except in the event of a rapid drop in
pressure, which triggers a continuous signal. To efficiently receive s
ignals from the wheel transmitters, the new generation of TPC now uses a central receiver aerial
beneath the floor of the car, replacing the previously used aerials in each wheel arch.
The system can now continue monitoring tire pressures in the other whee
ls even if some of the control units fail. With the new system, battery service life goes from
seven to ten years.

Press release link - http://press.porsche.com/vehicles/09...Long_FINAL.pdf