Just purchased Toyota Certified used 2014 Prius V Three with 42K miles. The vehicle location on navigation is off by about 100 yards. Shows my location about 1-2 blocks away from where the car actually is. The navigation directions are totally wrong. DTC interrogation shows codes B15C1 and B157E. Explanation for code B15C1 is "open in GPS antenna". I could not find B157E, except a comment on the web that another owner had both codes and the radio and navigation system had to be replaced to fix it. Anyone else have experience with similar problems and/or same codes? Does it require replacement of head unit? Should it be covered by Certified warranty? Thanks for your help.