Navigation without cellular reception?

[mr-dmitry]

you can not search for a new destination, but routing to previous destinations still work as GPS still available. Searching requires access to central server through cellular connection.

It was a previous destination by an exact address that worked an hour before the failure.

 

[WADan]

It was a previous destination by an exact address that worked an hour before the failure.

Then the only explanation is temporary loss of Gps signal?

 

[mr-dmitry]

Then the only explanation is temporary loss of Gps signal?

The current position was precisely correct. The issue lasted for the entire Tioga road that took an hour to drive through.

 

[dolfs]

Based on the fact that your car can show you separate versions for firmware and navigation data I am going to say that the database for the road network is on-board (local). This map contains all road segments (between junctions), and more detailed data for each segment (so you can follow curves etc, speed limits, and more). It does not contain database information on addresses. In other words it cannot geo-locate (convert address to coordinates). So if you have a destination set it has already been geo-located and the navigation (turn-by turn) works properly with just GPS signal and on-board nav data. To enter a new address connectivity is needed as the geo-location is done through a server.
The map display (in all modes), loads tile data from a server as well and that is why you (may) see blank tiles. That may not always be the case as the system may have (pre)cached some tiles around where you are, or are going to be.