I have an used D3 unit that I installed on my car. I bought it from a friend so I know for sure it was working fine before.

Now, when I set a destination up and I start driving, wrong waypoint(s) show up on my top left corner of the screen messing up completely the navigation guidance. I reset the unit but it didn't fix the problem. I restored to factory settings with the same result.

If I use the map only without setting up a route it works fine, it shows my position and it is accurate.

 

All parts are original Pioneer and the antenna is mounted on the dashboard in the center at the very bottom of the windshield. The installation was done by a professional.

 

How can I fix the problem? Any help will be much appreciated. Thank you.