I am servicing a customers KM-C2630D and after running a couple of months fine it started giving an error to reset the yellow toner unit. We'd take the toner unit out, shake it and it seemed to help but eventually no longer helps even though the yellow toner is no where near half empty. Now sometimes it says the same thing about black. That, too, is darn near full. I also wonder if there'sanyway to tell it we put new toners in it. The toner yield page says some of the toners are low but we just put all new Kyocera toners in it a couple of months ago.