Depending on the length of time the power was interrupted, your system may require GPS initialization.

If initialization is not necessary, the system proceeds directly to the Startup Confirmation screen.
If the system fails to locate a sufficient number of satellites to locate your position within 10 minutes, the following screen is displayed.

If you are experiencing GPS reception problems:
Adjusting the Mirrors
Keep the inside and outside mirrors clean and
adjusted for best visibility.
Adjust the mirrors before you start driving. ...
Dashboard Vent Removal/Installation
Side Vent
Click here for an interactive version of this procedure (driver's,
passenger's).
NOTE: Take care not to scratch the dashboard or its related parts.
Pull the upper portion ( ...
Features
Audio System
For navigation system operation
See Navigation System Manual
...