iRobot Roomba 866
Question about iRobot Roomba 866
What is error 9? It stops after 3 minutes, after running almost in circles, then error 9 occurs.
Error 9 means that the bumper is blocked and does not move freely. Tap the bumper firmly several times to remove any dirt that may be underneath and then press CLEAN to restart.
Source:
http://lmgtfy.com