This application describes apparatuses, systems, and methods that combines specific configurations of a pneumatic actuation system together with a pressure measurement device to allow for measurement of pressure inside isolated subsystems within the system to thereby provide detection of leaks within the system. In certain exemplary embodiments, the apparatus comprises a directional control valve that employs at least one port connectivity configuration that creates at least one isolated fluid subsystem within the overall system. When the valve is in this isolated subsystem configuration, a given mass of fluid (i.e., compressed gas) can neither enter nor leave the subsystem. The leak detection method consists of momentarily placing the valve in this isolated subsystem configuration when switching between standard configurations, and measuring pressure with at least one pressure sensor in the isolated fluid subsystem while in this configuration, where loss of pressure in this configuration indicates existence of a leak.