– Plugged or damaged EGR tube
– Differential Pressure Feedback Electronic (DPFE) sensor harness is open or shorted
– Differential Pressure Feedback Electronic (DPFE) sensor poor electrical connection
The purpose of the Exhaust Gas Recirculation (EGR) system on youris to limit oxides of nitrogen (NOx) . This is done by redirecting small amounts of exhaust gas back through the upper intake to get mixed in with the air/fuel charge. The resultant diluted air/fuel mixture (i.e., less oxygen per cubic foot) burns cooler and temperatures are reduced accordingly, thereby lowering NOx emissions.
TheDPFE/EGR system is controlled by the Powertrain Control Module ( ). The system employs an EGR Valve, an Electronic Regulator (EVR), and a Delta Pressure Feedback EGR sensor (DPFE).
The DPFE Sensor measures EGR flow across an orifice located inside the special EGR Tube. The orifice is positioned between two hose ports coming off the tube which are connected to the DPFE sensor with special heat-resistant hoses. When the EGR Valve is open, a pressureis created across the orifice ( pressure vs. exhaust pressure). By design, this difference in pressure is measured by the DPFE sensor in terms of voltage. The DPFE voltage signal output to the PCM is directly proportional to the flow of exhaust gas entering the intake manifold.