DIAGNOSIS A small piece of paper, often a corner, is torn off and stuck in the paper path sensors. The most common spot is the duplexer (double-sided print unit) at the rear.
FIX Open the rear door fully. Look for the green duplexer release lever. Pull it toward you and lift the entire duplexer assembly out. Shine a light into the cavity where it was. Look for shreds of paper. Remove any debris with tweezers. Also check the small paper feed rollers at the very back for fragments. Reinstall the duplexer by aligning it and pushing until it clicks.
IF THAT DIDN'T WORK Check the front area. Open the front door and remove the toner cartridge. Look deep inside at the fuser entry. Use a flashlight. A piece can be lodged on the fuser's green entry guide. Power off and unplug before extracting anything near the fuser.
HEADS UP Never pull jammed paper backward against the paper path direction. Always pull it in the direction the arrows inside the printer indicate. Pulling backward tears it and causes this ghost jam.