1. Turn off the device, open the nozzle cover, and detach the connector (connected to the red harness) on the right.
Refer to the Page 130 of the User Manual.
(Go to Chapter 5 Maintenance → 4.4 Exchanging Nozzle → #3, #4)
2. Check the interior of the connector of the nozzle and the main board to see if there are any impurities.
3. If no impurities are found, reattach the connector.
Push the red harness towards the direction of the connector one to two times to check
whether the connector is properly connected (Do not pull it out)
4. Turn the device back on and check if EC-306 or another Error Code still occurs.