T2i has F00

[bunnymommy]

How would I be able to fix this? I don't know how it happened!

[jrhoffman75]

Your camera isn't recognizing a lens. Check that your lens is fully installed and/or check that contacts are clean.

[ebiggs1]

F00 usually means there's no contact with a lens or the lens has no built in chip. Is it a real Canon lens or an after market? This happens quite often with off-brand lenses.

Otherwise make sure the little spring loaded contacts are all "springing".  

[hernhombeecaryb]

There are still lenses on the market that are made for manual focus. If this lens is new to you that may be the case.