Systems and methods are provided for detecting flow in a mass flow controller (MFC). The position of a gate in the MFC is sensed or otherwise determined to monitor flow through the MFC and to immediately or nearly immediately detect a flow failure. In one embodiment of the present invention, a novel MFC is provided. The MFC includes an orifice, a mass flow control gate, an actuator and a gate position sensor. The actuator moves the control gate to control flow through the orifice. The gate position sensor determines the gate position and/or gate movement to monitor flow and immediately or nearly immediately detect a flow failure. According to one embodiment of the present invention, the gate position sensor includes a transmitter for transmitting a signal and a receiver for receiving the signal such that the receiver provides an indication of the position of the gate based on the signal received. Other embodiments of the gate position sensor are described herein, as well as systems and methods that incorporate the novel MFC within a semiconductor manufacturing process.