Originally Posted by Rolf-Dieter
Exterior I think would be better it would save the cost on the winter set to be so equipped or US delivered cars. Then on the US cars I believe it will pinpoint the actual tire that is low on pressure whereas on Canadian cars one has to check the pressure on each wheel to find out what wheel is low etc.
This is even more difficult (since one cannot see the problem without a pressure gauge) on Canadian cars running with Run-Flat Tires.
Thank you for your answer but on my last BMW(2008 328i) the sensor did not indicate which tire was low in my non-Idrive vehicle. Now I'm told that the M3 will indicate which tire is low whether you have Idrive or not. I'm skeptical because I just had a bad sensor and the system never indicated which TPMS sensor was bad. Which brings me back to my original questions.