I got a 'failure' or other issue with the TPM on my new '09 c4s : I just switched the summer wheels and tires to winter snows on Porsche rims. The system is functioning because the 'process complete' did show. BUT :

1) I set the tire type in the TPM menu to Winter tyres
2) System says process complete
3) Tire indicator lights up in speedo and flashed for about 2 minute (driving at =60 mph, tires warm). Display says TPM in learning mode Pressure monitoring inactive.
4) Then the tire symbol stays lit steady.
5) A couple of minutes later, the TPM learning message disappears, and a red exclamation comes on, with the tire symbol steady.
6) The display now reads TPM inactive. Message screen also says the same thing.

Note that my c4s cpu does not ask for the wheel size; the summers are 19" and the winters 18". Both are in perfect shape. I put over two hundred fifty miles on the car after setting up learn mode the first time. I also tried it four additional times and checked / filled the tires. I tried changing the Load; no affect.

Any ideas ? All 911's need this system working. Maybe the batteries of the transmitters are the issue ? Are these readily available ?

Thanks in advance for the feedback !

 

It turns out that the TPM sensors operate at different frequencies. My 19" summers have '09 units but my snows, which are on '09 18" OEM wheels had '07 sensors installed because I was driving an '07 c4 when I got them. I got the new '09 sensors from Damon @ TireRack, (great deal) and my local Porsche dealer did the replacement and re-mount for a great price.

Happy snowfalls are ahead ! I've driven through three squalls already this Fall.