I also have this same problem on a 2013 SV. I get the same hum at startup and notice no extra regen with the brake pedal. I bought it to the dealership. They find the codes C1A70 brake control system and C1AA9 pressure sensor. They also tested the pressure sensor and confirm it not working. However they want to replace the ABS control module: actuator assembly for $1600 and possibly also the brake actuator assembly for $2300 (the difference isn't clear). Claiming the pressure sensor is part of the control module. But, I see one pressure sensor on the brake cylinder. Do I really need a 1000+$ part.