V10 Rob

Does anyone know how the Tire Pressure Monitoring system works in the S6?

Does it merely monitor the individual wheel speeds and from that deduces a change in wheel diameter, and from that senses the air pressure "change" and alerts you? OR are there actual air pressure sensors strapped inside each wheel and these send RFID signals to the car's CPU?

I am wondering what happens if you wish to replace wheels/tires and how advanced the wheel shops need to be to handle the change.

Thanks, Rob

NeilK

The Audi TPMS is a direct pressure monitoring system with sensors in each wheel. You can google this and find much information on these systems.

ESN

The sensors can be purchased from Tire Rack, which also has a tutorial on their function IIRC.

NvrFollo

Tire Rack wouldn't sell me them unless I was buying wheels from them..

ESN

Hunh. Did you trying going through Gary on the Wheels & Tire forum?

NvrFollo

I have someone who will shut it down w/VagCom 'cause the dealer wont.

MP4.2+6.0

Achtuning is the only place I have found on the web that carries them standalone. They are pricey, and via a dealer much more so (close to 2x apparently). Maybe some of the other on line and other sellers will get with the program pretty soon--these things are being mandated for all cars soon (being phased in now), and they need replacement when battery goes out (Beru says like 6 years).

The picture on their site really gives a nice view of the actual look. They mount inside the valve stem hole, supported just through that mounting point. The big gray plastic part you see in the picture lies flat on the inner center of the wheel behind the valve stem, and the stem screws into the narrow long side of it where you see the bump out along the center right side. I had a wheel changed on a 2006 A8 and they had no problem transferring the sensor--just a single small Torx screw is removed/tightened inside and the valve stem uncrewed/tightened from the outside.

For anything other than late model Audi OEM wheels, be careful with whether the valve stem mounting configuration is correct for the sensors. Presumably all D3 A8 wheels are as should be C6's; I can confirm the OEM RS style used on the C5 RS6 is as well. TireRack's web info says they have been checking into this. Achtuning says all their wheels support the sensors.

Same system used in D3 A8's, except A8's have individidually monitored sensors (as did the allroad). The C6 just monitors them from one location, and doesn't monitor the spare apparently, although it is fitted with a sensor. All current body Audi's use the same frequency sensors in the US AFAIK. Different frequency on older D2's and allroads and in other countries.

I think only A8's for the past few years allow the system to be turned off via MMI (rather than VAG-COM), so for many Audi's it means an error code if you run wheels w/out sensors.

System is nicely documented in TSB 44 06 01 dated June 1, 2006 if you have a Bentley CD manual or online subscription (or you can order the TSB via Dyment).<ul><li><a href="http://shop.achtuning.com/index.asp?PageAction=VIEWPROD&amp;ProdID=822">Sens or picture from on line source</a></li></ul>

MP4.2+6.0

Somewhat more background info. If you poke around, it has a European listing configurator too. From the sensor I have in hand for an A6--the one I test fit to an RS6 OEM wheel--the Audi part number on it is shown as compatible across all kinds of other Audi's and European brands and models. The S cars aren't listed though at all in their configurator. Audi # 4F0 907 275B.<ul><li><a href="http://www.beru.com/english/produkte/tss.php">Beru grad school course here</a></li></ul>