Brakes Failed problems of the 2017 Chevrolet Volt

Vehicle brakes fail to fully engage intermittently. When slowing down on multiple separate occasions, the brakes work initially, then, the car feels like it's sliding on ice (dry summer roads) then the brakes engage again. The brake peddle generally feels normal at first, then goes soft and sinks. I've taken the vehicle to the dealership on multiple occasions who've stated there's nothing they can do. This is a serious safety concern to just send someone on their way with. I've also been working with general motors. While working with gm, they recommended I take the vehicle to a different dealership for a second opinion. The new dealership found error codes outlining the traction control module is malfunctioning and electrical ground issues exist.