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:
Installation
Hold the gearbox housing using a C-clamp (A) and wooden blocks (B) to a
workbench as shown. Do not clamp the cylinder part of the gearbox housing in
a vise.
...
Pairing from Phone Setup
PHONE button
► Phone Setup
Use the Phone setup screen to pair an additional Bluetooth-compatible phone
if a
phone has been previously paired to the system.
1. Select Add/Select a Phone ...
Map Scale Commands
Display north up
Display heading up
Display zoom in
Display zoom out
Display (specify scale):
1/20 mile (80 m) scale
1/8 mile (200 m) scale
1/4 mile (400 m) scale
1/2 mile (800 m) scale
1 mil ...