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:
How to Set Readiness Codes
Malfunction Indicator Lamp (MIL) Indication (In relation to Readiness
Codes)
The vehicle has certain readiness codes that are part of the on-board
diagnostics for the emissions systems. If the ve ...
Maintenance Items Under the Hood
...
Resetting the Clock Settings
INFO button
► Setup ►Other
►Clock Adjustment►Clock Adjustment
Reset all clock settings to the factory defaults.
Select OK under Reset. ...