Originally Posted by JAJ
My i-drive says I'm due in 8000 miles. That said, I'm running relatively new RS19's.
It's clear the brake sensor doesn't measure brake wear, the accelerometer measures how hard you stop, then guesses at how much wear the brakes are getting.
To the best of my knowledge, the brake sensor is a binary switch. It comes on when the pad wears out to the degree that a ground loop is broken. So you might be correct in that the system is using some other data stream to guess at what's left.