Wow! I don't know. I suppose it depends on the individual yorkie. I had Muffin trained to go outside in nice weather and daytime. At night and in bad weather, we had pads in the attached garage. So, it worked out great for her. She wasn't confused by it at all for some reason.
I'm trying to train Kacee the same way except for her I have some pads in the house, too, which I didn't do for Muffin. It seems like she pees a lot more than Muffin ever did as a pup or my memory has faded, but I'm certain she does!