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:
Guidance Prompts
INFO button
► Setup
Set the number of guidance prompts before you get to the guidance point.
Select an option.
The following options are available:
To replay voice guidance, select VOI ...
ODS Unit Replacement
Removal
Do the battery terminal disconnection procedure,
then wait at least 3 minutes before starting work.
Disconnect the passenger's side airbag harness 2P connector. ...