The Brake pedal sensor is needing to be re calibrated with the body control module. You will need a OBD2 scanner. Cheapest one I found is the NT510 by Foxwell. I got one for 100 bucks on eBay, Mine has all GM products but it can hold six brands, each additional is 60.00 more.
I did this on my torrent, and several equinox, and it reads my Yukon. it;s a good unit and already paid for its self. It does all sorts of things but here is how you do your brake pedal thing.
turn the Key on without starting, the machine will come on, it will read your vin, ID your car. Nopw do this
Manual Selection->It will ID Your car, your configuration and Transmission, agree Yes-> Click Other-> Choose Control Modules->Body control module->Special functions->BPP sensor calibration. Now follow simple instructions that say DO NOT STEP ON THAT PEDAL. 20 seconds tops you will hear the switch in your BCM “CLICK” turn the key back to off , disconnect the OBD2 plug , your brakes work now. and so will everyone’s that you know that ever has this problem. Or you can sell it for more than you bought it for if you like. i am keeping mine.