Just a note from my experience - as puppies Yorkies may not know that having an "accident" on the floor or carpet is wrong, but as they get older I think they know right from wrong. When my Emmie (who is now 3) was about 1 or 1-1/2 years old she would come to me and scratch on my leg and then sit down and hang her head. I would go looking and sure enough, I would find a puddle or poop!!! From then on, if she came to me like she was trying to tell me something, I would know that she had had an accident. This rarely happens at all now but I know she knows that she has done wrong if and when it happens. She is puddle pad trained because we live in the country and have no fenced back yard, and all the neighbors in the outlying homes have big dogs who roam freely in our area, as well as the coyotes and owls. Now we have a new puppy and are starting all over with the training!!!
Good luck....
Barbara, Emmie and Izzy B.