Bought my Prius used a few years ago. Everything looked great and still is working fine, but at the time that I bought it, the navigation system would read the original disc about every 2nd or 3rd time it was inserted in the unit. Over the past few years, of course, the problem just got worse and I finally gave up trying to use it - always getting the "unable to read data" message. My question: is there a way to check thru the display if the problem is actually with the disc or the machine itself? Is there some kind of sequence of buttons to press to obtain this info? I've checked some other posts here and noticed some suggestions that would seem to work on a post-04 model, but, for instance, I have no "navigation" button - and the "map" button just shows the "unable to read data"message. thanks, Rod
