I'd try a new transponder chip or at least try t erase all keys and start again by resetting CIM.

Had a diesel Vectra in yesterday that had a used pump fitted to it, for some strange reason (may be normal but i'm not sure it is) the pump wouldn't recode as it thought the CIM wasn't programmed either.

I programmed the as CIM & ECM installed which isn't always a good thing to do but it started eventually.

thanks
lee