how to test if ots motor control or main

Hi. I have attached the tech sheet to your unit. The E5E error code is a communication error between the main board and the speed board. It says to check wiring between them. If wiring is good replace the main board. IF that does not take care of the issue replace the speed board.  There is not a way to determine which boars is at fault with a communication error.  Attached is links for both parts