DIAGNOSIS The ER1 error code indicates a communication failure between the main control board and the display/user interface board. This is a common initialization fault.
FIX Perform a hard reset. 1. Unplug the unit from the wall outlet. 2. Wait for 60 seconds. 3. Plug it back in. The error should clear. If ER1 persists, the internal wire harness connecting the boards may be loose. 4. Unplug the unit. 5. Remove the rear access panel (two Phillips-head screws). 6. Check that the white connector on the wire harness is firmly seated in the socket on the main board. Re-seat it if loose.
IF THAT DIDN'T WORK If ER1 returns immediately after the hard reset and the connector is secure, a main board failure is likely. Contact Ninja Customer Service for warranty support or a board replacement.
HEADS UP Do not attempt to run the unit with the ER1 code displayed. It will not function and may cause further electrical issues.