Yesterday I got a flat tire. I noticed because the car was handling
strangely. I never got a warning signal. My car is a 09 Cooper S with
run flats and should have TPMS's. I stopped at a gas station and
it had no pressure at all...!! Why didnt I get a warning signal? Has
anyone heard of this before

 

Maybe the sensors were set for zero pressure?

Had you ever reset them?

 

Sounds like your system is not working at all. For the last couple of weeks, I've been getting a warning light but all of my tires have the same pressure. I tried to reset it but it won't. Sounds like we are both having TPMS problems of a different kind.

 

Just remember in resetting you MUST drive the car for a while after the reset and the car will notify you when the reset is complete. Many people forget the driving part of the reset procedure.

 

I filled the flat tire to the same pressure as the rest and then reset the computer. My tire went completely flat again without sending any signal.
Seems I will need to take it to my dealer. Thanks for helping..!!