The differential pressure feedback EGR sensor (Figure 86) 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 two 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 aluminum differential pressure feedback EGR sensor housing for identification (note that the HI signal uses a larger diameter hose). The differential pressure feedback EGR sensor outputs a voltage proportional to the pressure drop across the metering orifice and supplies it to the PCM as EGR flow rate feedback.
TUBE MOUNTED DIFFERENTIAL PRESSURE FEEDBACK EGR SENSOR
The tube mounted differential pressure feedback EGR sensor (Figure 87) is identical in operation as the larger metal or plastic DPFE sensors and uses a 1.0 volt offset. The HI and REF hose connections are marked on the underside of the sensor.