You can reset the TPM system when stationary, which presumably simply clears the fault condition. The TPM system then starts monitoring all wheels afresh... I have done this a few times in the last couple of years and have to say the system has been pretty good at catchng deflating tyres!
As Deano says there is no direct monitoring of tyre pressure, just the effect of tyre deflation on the wheel speed as measured by ABS. In other words the car has to be in motion for a soggy tyre to be detected.
