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:
Instruments and Controls
This section gives information about the controls and displays that contribute
to the daily operation of your vehicle. All the essential controls are within easy
reach. ...
Gauges
TripMeter
This meter shows the number of miles (U.S.) or kilometers (Canada) driven since
you last reset it.
There are two trip meters: Trip A and Trip B. Switch between these displays by
pres ...
USB Commands
USB play
USB play track # (#: 1 to 30)
USB skip forward
USB skip back
USB track random*
USB track repeat*
USB track scan*
USB folder up
USB folder down
USB folder random*
USB folder repeat*
...