The codes refer to a part which has an estimated lifespan, and on our machine, I can recall one for the encoder strip that came up. But it just comes as a numerical code. Since you cannot buy the repair and service parts from Epson anyway, it does no harm to call the 800 number for Epson support and tell them the code you are seeing. They will tell you what it means. The thing is, if you don't have a service call made, at some point the timer will tell the machine to stop operating unless it's reset by the technician.
In our case, the tech came and because we were beyond warranty and I was not going to purchase a service plan, he changed the settings on the machine so that these "preventive maintenance" warnings don't come up. If I have an incipient failure, it will fail, and then I will know about it and have to pay a technician to come repair it.
The machine is designed so that you pay for a service contract every year, in which case you will not be afraid to call for a technician to come for a service call because you've already paid for it.