I was browsing through the siennaclub.org forums, and came across this thread. http://www.siennaclub.org/forum/inde...showtopic=8470. This thread points to a lexus forum. Looks like there's hidden programming inside the nav units for nav override, blue tooth, and some other stuff that isn't documented anywhere. Take a look. I'm going to play around with it when I get a chance. Maybe someone can figure out what all this stuff does.
BTW, my unit is from an 05 Solara. From what I've read, this will only work in the newer generation of nav units.