TPM: Extra hardware or VAG-tweak?

The tire pressure monitor (TPM) system being offered for $250 on current Audis: Does anyone know what type it is?
1. Direct measurement, with pressure sensor transmitters in the tires,
and a receiver in the car.
2. Indirect, where the wheel speeds are compared via the ABS sensors and the wheel that spins faster is assumed to be the low pressure one.
If it's #2, it may be just software, already loaded in ROM, and ready to enable with VAG tool..
To reply, please remove one letter from each side of "@" Spammers are VERMIN. Please kill them all.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I can't be sure about the most recent cars, but the TPM in my 2003 RS6 is definitely of the first type - quite a bit of hardware is involved!
--
Peter Bell (Note Spamtrap - To reply, replace 'invalid' with 'bellfamily')

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.