hchampion

I recently replaced my 2007 ES350 navigation system with one from a salvage yard. It seems to work but after about 10 miles or so, the position indicator on the screen is about 2 miles off. After a while the navigation system completely loses its way. Question. Does the different unit need to be calibrated or adjusted in some way. (I have ran the new tire calibration with no change in behavior) Would a trip to the dealer to reprogram Help?