Abstract: The present invention, in one aspect, includes a diaphragm assembly for being connected between an engine exhaust path and an engine electronic control unit to transmit changes in exhaust gas pressure from the exhaust path to the control unit. In an exemplary embodiment, the diaphragm assembly includes a diaphragm housing and a diaphragm positioned in the housing and separating a first chamber and a second chamber. The first chamber is configured to be in flow communication with the exhaust path and the second chamber is configured to be in flow communication with the engine control unit. The diaphragm housing, in the exemplary embodiment, includes a first housing member and a second housing member. An inner surface of the first housing member also is a side wall of the first chamber, and the inner surface has a conical shape to facilitate drainage of water from the first chamber. Also, the first chamber has a first volume and said second chamber has a second volume.