Self test failure on Y axis length, basic checks seem not to help (mk3s+)
I was having layer shifts on my x axis, so I cleaned and lubricated the rods. Before and after this, I ran the "belt test" calibration option to check if things were fixed. Cleaning and lubricating seemed to fix the x axis, but afterwards, the y axis started reporting an axis length error.
I tried to troubleshoot this and read a number of related posts on this forum. My y axis motor mount was a bit loose, so I tightened that up; I checked that the pulley set screws were correctly positioned and tightened; I checked and adjusted the belt tension; I checked to make sure the bearing mounts weren't overtightened. After all of this, it still reports a length error. When the printer is off, I can freely move the bed through its full range, and there's no apparent hitches. When the self-test starts it reports the y belt tension as 278, within the acceptable range.
Any idea what could be causing this? It seems to be printing okay despite the error, but it makes me uneasy to have that error in the first place.