Michael has the correct answer, i.e. AFC = air flow control.

According to Probst
(http://www.bentleypublishers.com/bosch/gfib/gfib.htm) this should
really be called "L-Jetronic with Lambda."

Digijet and Digifant systems are unique-to-VW versions of Bosch
L-Jetronic with Lambda.  One thing I discovered via this list is
absence of cold start injector (I have air cooled).

AFC just appears to be something cooked up by Bentley to distinguish
between the standard Bosch and VW-specific systems.  "Air-flow
control," used generically actually describes any current Bosch fuel
injection system, departing from the D-Jetronic systems (Squareback,
etc.) of the '60s/early '70s that measured manifold pressure instead.