can an ez command controller program 4 digit codes?
No, is the answer.
The following link will go the the Bachmann EZ Command page. There are more links at the bottom of that page that gives all information.
http://www.bachmanntrains.com/home-usa/ezcommand_2010.php (http://www.bachmanntrains.com/home-usa/ezcommand_2010.php)
kent-
The EZCommand system doesn't actually work with either a two- or a four-digit loco
number. It just assigns (well, the operator assigns) each loco to one of the ten buttons
in the middle the command station. Of course, you can always put the locomotives'
numbers on the card next to the buttons which would simulate assigning the locomotives'
cab numbers.
-- D