I took the SC in for my first service ( 10K ). I tried to activate the NAV on the way to the dealer & I lost my address function again; when I was a few miles from the dealership it became available.

The dealership confirmed that there are definite issues that result from the satelite, atmospheric, etc. so that seems to be the problem so keep the screen up if you have the same problem until the reception is restored.

I also had the dealer program both doors to lock ( in drive ) & unlock ( in park )...so much more convenient for me ( No charge for this service! ).

PS: NO problems with the Bridgestone Run Flat's with 10,700 miles. The dealer recommends that the tires be rotated every oil change.