FORD 2013 Mustang v.2 - Manual (Page 58)

Vehicles Equipped with Intelligent Access Key (Push Button Start)
Note: It is not possible to program the remote start system as a MyKey
on vehicles equipped with intelligent access key (push button start).
Therefore, you should treat the remote start fob as you would any other
admin key. When the vehicle is started using remote start, the system
will stall the engine when you either enter the vehicle or shift the vehicle
into gear. Prior to the engine stall, the vehicle will have administrative
privileges. When you restart the engine, the vehicle will identify the user
as an admin or MyKey driver depending on the settings of the actual key
used to start the vehicle.
Note: For all vehicles, the number of MYKEY(S) PROGRAMMED or
ADMIN KEYS PROGRAMMED that is displayed in the MyKey system
status menus, may include the non-Ford-approved remote start system
as an additional key in the total count. See the Checking system status
section.
For all vehicles with a non-Ford-approved remote start installed, it is
possible to program all “real” keys as MyKeys, in which case, you will
need to use your remote start system to clear all MyKeys (which
removes all restrictions and returns them to admin key status) by doing
the following:
1. Enter the vehicle and close all doors.
2. Remote start the vehicle using your non-Ford-approved remote start
fob.
3. Follow Steps 1-3 in the Clearing all MyKeys section.
58 MyKey
2013 05+ Mustang (197)
Owners Guide gf, 2nd Printing
USA (fus)