Ok, so I have this new RS6 and it supposedly has a tire pressure monitor....so how do you ( or do you ) "see" or display the pressures? Or does it just warn you ... I don't see anything in the owners manual that expalins any of this. Thanks !

European ones have it as an option I think.

Thanks - that explains the mystery!

regular basis.

It would strike me that the tire pressure sensor shouldn't cause a leak.

I wonder if my wife's A8L will have the same issue...

Last summer I did start losing air through the TPM valve stems, but through autumn/winter/spring I've not noticed any appreciable loss. I wonder if there's a certain temperature point at which they lose air - different expansion/contraction rates of the different metal compound used?

Another thing to watch out for - don't replace the plastic valve caps with metal ones. I did (the shop lost the grey plastic ones and put standard black ones on and they looked awful) and now after a while they've become stuck on. My business partner's car went into the shop because he couldn't get them off and they broke one of the stems trying. Mine has two stuck which I expect will have the same problem when I need to get them off next. The metal compound seems to react badly with metal caps, which I now assume must be designed for standard brass/rubber stems.

in the middle of summer (January) we get 40 Degree C max (104 F)with 35 (95 F) average.

I use Nitrogen in my tyres.

As for the metal valve cap, I also use these, but have had no problem with them being stuck.

during winter, so it may not be an issue for you.