940.00 Serial communication failure between the controller board and engine board error

Issue description

A 940.00 error occurs when the black toner cartridge encounters a hard stop. 

Solution

Update the printer firmware to the latest version or at least an xxxx. 230.210 firmware level. See the instructions in Firmware Update Instructions

Note:  Since the issue is triggered when the black toner cartridge encounters a hard stop, an empty black toner cartridge meets that condition. Therefore, there is a need to replace the black toner cartridges after upgrading the firmware.​

If the issue persists, then contact customer support. ​