Error 21, Roomba® j Series and Combo 10 Max

Error twenty-one (21) means the robot is experiencing an Internal Communication Error. Press CLEAN to restart the cleaning mission. If the message persists, perform a robot reboot, and test again.

If a reboot does not clear the error, try removing the battery. After ten seconds, reinstall the battery and test the robot again.

If the message persists after rebooting the robot, please contact iRobot Customer Care.

For expedited service, please have the following ready:

• Your robot charged and with you.
• Your robot's Serial number.
• For warranty claims: Proof of purchase (receipt or invoice for purchase from an authorized retailer).