I had a flat tire changed on my 2004 Phaeton at the Dealer. Shortly thereafter, I have received 3 interesting monitor messages. They are: 1. Defective Wheel on board, 2. Tire Pressure monitor system fault 3. Tyre flat.
Can anyone tell me what's going on and how much it will cost me?
If you've never changed the TPMS sensors in the wheels, it's probably an indication the batteries are getting weak. These messages are common now on 2004 Touareg and Phaeton, and are normally eliminated by changing the sensors. (Batteries are built-in the sensors and can't be replaced - so it means new sensors.)
Owners who don't want to spend the money for new sensors (around $100 each) will disable the TPMS using VAG-COM, coding the systems to say it isn't installed.
Some of the 2004 TPMS controllers were also replaced to cure some conditions, and sometimes the antenna wiring around a wheel gets damaged, but batteries are getting weak in all 2004s.
The sensors are made by Beru, and last I heard Tire Rack had about the best price.