Welcome to Justanswer.com, my name is Dustin.
I'm sorry to hear about the issue you are having, I will do my best to help you resolve it.
That fault normally indicates a failure of the internal logic board.. But sometimes, its a sign of a paper jam or debris inside the machine.. So just to be thorough, lets run through these steps completely.
If that doesnt get rid of the error.. Make sure you unplug the machine from power and then leave it unplugged for five minutes, t hen hold power while you are plugging it back in.. Does that clear the error?
If not, the logic board sells ( if you can find it ) for normally 69.99 and above.. You can get a new WF3620 for about the same price, with a warranty
However, if your epson is u nder one year old we can get epson to replace it for free.
I hope the information above helped you repair the problem, or at least helped you figure out the best way to move forward.
I strive to provide great service, and greatly appreciate a 5 star rating clicked and submitted when you are satisfied.. I always answer follow up questions.
Senior Technician and Network Switching Systems Operator / Maintainer.