Error 2 clean the brushes

My roomba moves for about a minute then says I need to clean the brushes. The brushes are clean. I’ve replaced all brushes and battery several times. I recently took the whole thing apart because of this error. I cleaned the fuzz around the motor and other places. I can’t tell if the brushes are spinning while it’s moving although it does sound different than normal. I thought this was because I cleaned around the motor. I can find parts on Amazon. Should I replace the green housing that the brushes sit in or should I replace the round sensor in the housing?