It should clear after the battery is unhooked, or probably after a number of restarts.  I don't think it will derate unless the fault condition actually exists...ie if you fix the problem it should go back to full power even if the check engine stays on for a while before it resets. 

Bern has all the good manuals where he works, I imagine he looked it up there, but I wouldn't be surprised if the codes could be found online....lol, I guess they definitely can now, on NAT!