I've been having this issue since day 1. Bought my '19 AT4 back in September. At around 12k miles I was down to 25%-ish. While in for an oil change I pointed it out. Pads checked at basically brand new. The dealer contacted GM. GM told them that it happens from time to time, they don't know why, to just reset the ECBM and it should work itself out. Note: After resetting the ECBM I noticed that the pedal was significantly harder (i.e. like brand new again).
After a little bit, I noticed that the life was in a rapid decline again. This time I kept track. Next time at the dealer I pointed out again. This time I was told that GM is working on a fix but it is not yet available. I was likely told this based on the bulletin posted above. Since I was projected to hit 0% in about 2k miles and was pretty confident GM wasn't going to have a fix in this time, I asked them to reset the ECBM again since I didn't want to be looking at all kinds of warning lights telling me my brakes needed replacement. The dealers solution to this was to just disable the monitoring. (I could have done that).
My concern though is this: With the brake pedal being electronically controlled through the ECBM, is it taking pad life numbers to simulate pedal stiffness of a worn pad? I do notice my pedal feels like a 25% life remaining pedal again. What happens when it hits 0%. Just because it isn't displayed doesn't means there isn't anything being calculated/decided in the background.
