456 fault code P1625

I sure hope someone can help me with this. I recently replaced the right cylinder head on 456 gta bad guides smoking very badly. Every thing went right together with no problems but now I have a fault code P1625 and no Ferrari info to decipher it. Any insight would be greatly appreciated I am at my wits end, the car runs really well and I think the guys at Norwoods did an excellent job on the head work just need to get this code cleared