I have a Skoda Octavia Mk3 (essentially a VW mechanically) which started to give false warnings about loss of tyre pressure after about 60k miles.
It used to work well, and correctly warned me when a slow puncture had reduced the pressure in one tyre from 36 to 28 psi.
But now it is giving random false warnings on one or the other rear tyre, sometimes twice in one day, sometimes once a week. There is never anything actually wrong with the tyre pressures. I check them and make minor adjustments once a week, and reset the detector system.
The detection system is the passive kind. There are no actual pressure sensors but the system uses the wheel rotation speed (off the ABS sensors) to determine if one is turning consistently faster than the others.
I asked at my garage. They said that if the fault is in the ABS sensor(s) there would be other warnings coming up. I asked them to clean the ABS sensors on the rear wheels. They said they can't because they are integral with the hub and so are inaccessible.
Does anyone know of any cause or how to fix it?