DBW
From OpenECU
Drive By Wire, AKA "ETC," Electronic Throttle Control
A system where the throttle (or gas pedal) is not directly tied to the throttle body butterfly valve as in traditional cable throttle systems. Instead, the throttle control creates a signal (typically analog voltage) to be interpreted by the engine management system. The engine management system in turn controls the butterfly valve opening angle via a separate motor and control system.
In the context of OpenECU, many (if not all) Subaru 2.5L turbocharged engines use drive by wire electronic throttle control. Examples include the USDM 2004 and newer WRX STI, USDM World 2006 or newer WRX, and USDM 2004 or newer Legacy GT.
There can be many reasons and uses for such a system, such as torque management, RPM limiting, and control over throttle response.