It'll be covered under the 10/100 warranty only if there's an internal
transmission problem. If you've got no check engine lamp and don't notice
any transmission problems, then that's very unlikely.
I'd recommend replacing the pulse generators (input and output speed
sensors) and not reattaching the connector to the little holder on the
Hyundai's got a detailed bulletin about things that can cause this code.
Go to www.hmaservice.com and register for an account. You'll want to see