2011 Hyundai Santa Fe Question: Any one know this Combustion chamber clogged w/carbon. chemical cleaning needed

check engine lite came on-still in warranty. dealer said "actuator for butterlies that run thru intake manifold" broke due to "combustion chamber clogged w/carbon" they will warranty replace actuator, but i must pay for "chemical cleaning of combustion chamber" car has 38K miles, 2 yrs old. Never had that issue on my 10 yr old toyota w/150K miles. is the dealer telling me something legit or blowing smoke up ...