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:
System/Device Information
INFO button
► System/Device Information
View database, software, device, and vehicle identification information.
You will need this information when ordering a
map update. ...
CMP Pulse Plate Removal and Installation
Removal
Remove the air cleaner.
Remove the intake manifold chamber.
Disconnect the following engine wire harness connectors, and remove the
wire harness clamps ...
Ignition Switch
Manual transmission models
WARNING
Removing the key from the ignition switch
while driving locks the steering. This can
cause you to lose control of the vehicle.
Remove the key from the ignit ...