I have the same problem on my 2019 Silverado. It’s a daily trifecta of “service brake pad monitor” to “Brake Failure” then limp mode. Brakes are fine but something is triggering it. Dealership just says $1200 to replace pads and rotors. This 2019 has not been anything close to other Chevrolets I have owned. It’s also sad that you have to complain to get a dealership to react rather than old fashioned customer service. From what I’m reading, 2019’s are junk from brakes to the transmission.