I had a really long multi-filament print in progress and woke up to find the print had stopped as was reporting TR2852. The QR code solution sent me on a wild goose chase of tearing down the extruder etc. While preparing to shut down and go to work cleaning out the extruder, I noticed my poop chute had backed up into the machine.
I emptied the poop chute and was able to restart the print in progress and all is right with the world.
Short answer check you poop chute first.