Yeah, but this is the system based on the rotations per meters. Which sucks as it’s not that accurate and only warns you when it’s already very low on air pressure.
The accurate one’s are veeeery expensive.
You mean it guesses how much pressure is lost based on actual rotations of the tire? So a leaky valve or something will not be found?
Yeah, you “set” it when you filled it. Then it knows the rotations to look for. And if it is off by a lot, it warns you.
I’ve no idea what you’re talking about. I don’t set anything, when I add air to the tire the dash monitor reflects it immediately.
Edit: spelling
Depends on the implementation. Some indeed have it like you described, using some of the sensors used by ABS. others use tiny pressure sensors mounted to the inside bit of the valve of the tyre and those are much more accurate. They aren’t that expensive either. Each sensor is about €20 and lasts about 7 years on its battery before it has to be replaced. (On ours, battery is integrated, so not replaceable). If we had bought our car new, it would’ve cost us €15k-20k. Not the most expensive car. :)