Does anyone know if there's an episode when Jeremy appears in lyoko?

i do not know

me neither

yes there it is but he doesnt appear on the world of lyoko like odd または ulrich he appears on lyoko buts its a similar copy of the real world he appears in his normal form not in lyoko form

yes

yes jeremy was in the lyoko in 1 of the episodes

Yes. He does go to Lyoko in an episode, but they do not 表示する what he looks like on Lyoko. Only Odd and Ulrich do because they went with him.

i ager whith stewy

Yes there are times when he goes into lyoko but あなた do not get to see what he looks like. I can not tell あなた the episodes he goes in but i know he does.