I have a 04 gx 470, nav/ml, with the vaistech ipod adapter. I had the vaistech installed about a month ago, and some time after that my nav lost its "gps" signal (you know the little icon right underneath the compass in the upper left corner of the screen in "map" mode...). It just disappeared one day...

Now, the nav system gets lost all the time. Although you can "recalibrate" your position and direction, it simply does not work for long periods of time. Eventually it will start wandering off on its own way. For example, a drive from LA to San Diego resulted in the nav system thinking I was about 30 miles northwest of Catalina Island, apparently operating the vehicle in stealth-submarine mode Quite annoying to be sure.

So, before I haul this into the dealer again to take a look -- and they will no doubt charge me a squillion dollars to fix it -- is there anything on the system diagnostic-wise I can look at to get an idea of the problem?

I considered that perhaps the vaistech screwed up the gps on the nav somehow, but I am skeptical of that as I can find nobody else on the forums with a similar problem. So I'm thinking that it's a separate issue.

I had this same problem. It ended up the Vais iPod adapter was causing the problem. I posted the issue on the Vais forum and got this reply from the administrator:

"We have had this problem back in January of 2006, in about 500 units.
Our factory installed a wrong component on the board that was causing this problem. If you bought your unit around that time, then you need to send it back for repair."


I got my ipod adapter in September of 06 but swapped it out for a new one and the problem is fixed. Its been working fine for the last 8 months.

That is odd because I bought one a year and half later (May 07); you would think that these would be gone by now, or that they would have been recalled. But I guess it's possible. At any rate I'm dealing with vaistech now on this to see if they can help.