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
now I don't take the box off any more but instead I just take the metal sheet guide off of the top (there is 4 screws but only take the center 2 screws off to remove as an assembly) Now you can remove the cleaning blade then take it out side to a suitable trash can turn it over and shake all the toner out then clean the cleaning blade and put it back together
I realise this post was some time back but jsut come across it after having repalced teh unit every couple of months. As a point of clarity, does this workaround work on a unit already printing the marks, or as a preventative?
it depends on how many clicks are on it...if the unit is new it will start making marks when it fills up with waist toner (about every two weeks for us) then take it out, apart and empty it but this only works about three or four times then the roller and cleaning blade will start to wear then it will make marks clean or not ...new rollers and cleaning blades are availble but it's not an easy task and if mistakes are made putting back together it kick some hidden error code that gives false fuser unit codes and then you stuck