After a wonderful experience with the Nav unit in a friend's 2010 Prius 4, I just purchased a used 2011 Prius 4 with 50K mi. for just that purpose. Unfortunately, I'm finding the Nav system is totally unusable. It couldn't even direct me home from the grocery store today - 2 miles away from home (which is correctly programmed in). It must be a sporadic problem because I tested the system several times near the dealership and it worked like a charm. The dealership wants to install a new disc for $200. I'm willing to do so if it will fix the problem, but the problems are so severe that I'm wondering if it's more than a software issue. Today it kept repeating the same instructions no matter which direction I turned.
