Put new rotors on my 2020 sierra today. Had all the lights on the dash afterwards. Ecs failure, brake system failure, C05B0 code and others. I did not unhook the battery when doing the job.
Here is how I fixed it. I have an obdlink mx+ I use for cloning pcms. I put the truck in brake service mode (thanks YouTube).
Then with the truck off, in service mode (hold start button without pressing brakes till dash turns on)
I connected the obdlink scanner software, selected the brake controller, and was able to clear the c05b0 code. This will not work without it in brake service mode and will not work with engine running.