The lower part of the second BTR houses waste toner. Yours if FULL. Yes that will cause your sesors to fault. So would the amount of paper dust that has also contaminated this unit. This unit looks to be in poor condition and requires a cleaning. I would be embarresed even to show anyone this photo.
We have the same issue
the 2nd btr is easy to take out then with care take the bottom of it off and empty it...I do this when the lines first start showing up
there is still something wrong with the machine however ...it goes through black toner fast and the waist toner box fills up with in a week or two