jdong

The B8 A4 does not have TPMS sensors per se -- it uses ABS and other existing onboard systems as indirect ways of inferring tire pressure.

But yeah, the "downside" of indirect TPMS is that it basically knows a "normal" and an "abnormal" state, and abnormal can be anything a 2PSI imbalance to a flat tire. The Audi system is not as bad as the 328i's system in my experience in terms of its trigger-happiness, but what you're describing sounds fairly normal.

gunsmoker

I worked for a company over 10 years ago that was developing such sensors that did not require batteries. It was on the RFID principle where you have a static circuit that has a coil which is powered with AC current that induces AC current into a coil that is brought into its field. The second coil is hooked up to the sensor circuit where the voltage gets rectified and used to power the sensor and the transmitter. I never thought that today's sensors might be using batteries, but as we saw, Audi dropped the sensors in 2010, so it's probably not justifiable to install such gizmos if you can get acceptable results without them.

perdido34

There aren't any dedicated sensors (therefore no batteries) in the 2010 or later models.