Jun 27 2011
Recently heard of someone who was driving along (not in a Mazda, as far as I know) and a message lit up "Please pull over - you have a puncture in your rear nearside tyre." "Cobblers!" thought the driver "Car feels fine to me!" However, after a while he decided to stop and look. Sure enough - puncture, rear N/S tyre.
He did not have any kind of tyre pressure monitoring system fitted, but apparently on his car, the wheel rotation sensors are continually monitored by the control unit, and if it notes one wheel consistently beginning to rotate very slightly faster than the others over a period of time, it works out that the rolling radius has decreased slightly, almost certainly indicating a slow puncture.
OK, not as sensitive, as certain or as swift-to-act as a tyre-pressure sensing sytem, but simple, elegant and cheap since it uses existing sensors and just processes already-available information intelligently.
Maybe I'm just out-of-touch and this is old hat, but I was impressed.