Question about codes!

Hi....I'm new to the forum. I just bought a 1999 Infinit G20t. Well...my check engine light came on yesterday so I ran the codes...this is what I got from it...."all illusive iacv/aac valve". I was wondering if anyone knew what I need to do to fix that problem. The more specific the better b/c, honestly, I don't know much about cars...lol! Thanks alot!