Sorry, you need to spell out what you mean by ECU has it is a common term for lots of items.

here is the link for the manual:
https://kubota.ca/getmedia/82f4431d-325f-40b3-805c-45f2c62b4f22/B2650%C2%B7B3350%C2%B7B3350SU-OM-EN-6C41063113?ext=.pdf