I have a 2007 Cayman S and no TPMS on my track wheels. Everytime I switch to the track wheels I get a TPMS warning, it might take 15 minutes before I see it. After shutting the car off, I will get a new warning, also with a similar time delay. As per a previous post there is no pressure indicated on the the screen after the ewarning has been posted. After the initial switch to track wheels, the pressure continues to show until I get the warning.