Whirring noise from CCU box

My washing machine threw an F11 code last week and I had the MCU board repaired. Now since hooking that up, the washer works very well. The issue now is there is a really annoying noise, that almost sounds like an electrical current, coming from what seems to be the CCU box. It goes all the way through the cycle and everything seems to be working fine, it's just this noise. What could it be?