I had this same problem, I have a 2020 GMC sierra 1500 Elevation. The service brake pad warning came up I brought it to the dealer and was told I had plenty pad left but that the sensor was grounding out and in order to replace it I would have to change my brakes. I just disabled the message. Now at 26,000 miles only I keep hearing a scrapping noise took off the rear calipers and noticed that my outside pad was still had a lot of life in it but the inner pad was totally gone. I think it has something to do with the electronic Parking Brake. Not Happy about this, now I need to by new rotors and brake pads for the rear. Iv had truck that I did not have to replace the brakes till 50,000 miles.