Differential Pressure Feedback Exhaust Gas Recirculation (EGR) (DPFE) Sensor
WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 2006 Mercury Mountaineer, 2006 Mercury Monterey, 2006 Mercury Montego, 2006 Mercury Milan, and 2006 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
The DPFE sensor is a ceramic, capacitive-type pressure transducer that monitors the differential pressure across a metering orifice located in the orifice tube assembly. The differential pressure feedback sensor receives this signal through 2 hoses referred to as the downstream pressure hose (REF SIGNAL) and upstream pressure hose (HI SIGNAL). The HI and REF hose connections are marked on the DPFE sensor housing for identification (note that the HI signal uses a larger diameter hose). The DPFE sensor outputs a voltage proportional to the pressure drop across the metering orifice and supplies it to the powertrain control module (PCM) as EGR flow rate feedback.