I my case... I was having issues with the filament not loading from the MMU2S to the Hotend Extruder motor. I was able to load to the MMU2S everytime... But, not into the selector assembly. After hours of checking over my work and looking online... I ended up talking with tech support and they sent me to this link. This link applies to i3 MK3s MMU2S but, the concept is the same for older version of i3s. https://help.prusa3d.com/article/wprwem ... alibration
. Go to your main menu - Support - Sensor Info. You should see FINDA, Pinda and IR. All of these should be be 0 "IF" you do not have any filament loaded. If any of them are showing 1. Then you need to address that until it say 0. Then test it with a piece of filament it should change from 0 to 1 and back once you remove the filament. This does not apply to PINDA! Because that is the sensor for your hotend height to the metal sheet. But, you can trigger this with someone metal just to know that its working. So, once you follow the directions from the link for the IR on the hotend extruder... the same concept applys to FINDA for the MMU2s. Both of these will effect your printer from loading and unloading correctly. I hope this helps.