Abstract: A diagnostic system and method for testing the operation of a rotary flow device, such as a turbine or compressor of a turbocharger with a variable-geometry mechanism, such as adjustable vanes, is provided. The system includes a flow generator configured to provide a flow of gas through the device, a power source configured to adjust a position of the variable vanes or other variable-geometry mechanism of the device, and a controller configured to selectively control the adjustment of the position of the vanes. The controller and power source can be configured to actuate the variable vanes to at least one predetermined position so that an operational condition of the device can be determined according to the flow of air through the device. For example, the system can detect the operation of a valve or other adjustment device that controls the position of the vanes. Further, the system can monitor the flow of gas through the device to detect the configuration and operability of the vanes.