How are EGR Pressure Feedback Sensor issues diagnosed?
When incorrect exhaust gas recirculation (EGR) flow rates are noted by the engine control module (ECM), the technician will connect a diagnostic scanner so he or she may understand why the ECM has reported this fault. While reading the readings of the various sensors, the technician may notice that the DPFE (pressure sensor) is reading out of its manufacturer specified range. The technician will then back-probe the signal voltage to ensure the sensor is reporting the voltage read by the ECM, otherwise the ECM could have failed. If the signal voltage is identical to that read by the ECM, and the reference voltage is correct, the sensor will need to be replaced.
How are EGR Pressure Feedback Sensors replaced?
Replacing the sensor in most American made vehicles will require two rubber or composite rubber hoses to be removed from the sensor and metal lines from the EGR tube or exhaust manifold. Afterwards, the sensor will be disconnected from its electronic connector, the hoses will be replaced as needed, and the new sensor will be installed. Some models may have the sensor installed with a fastener or clip, and this is a simple matter of removing installation hardware and replacing it for the new sensor.
RepairPal Recommendations for EGR Pressure Feedback Sensor issues
If the rubber hoses leading to the sensor are cracked, leaking, or otherwise in disrepair, replace them to determine if that is the cause of on EGR leak. In some situations, this may be the case. Also, replace the sensor only after determining it is performing outside of its set parameters, not before. Replacing the sensor without cause may lead to unnecessary financial and time costs.
What to look out for when dealing with EGR Pressure Feedback Sensor issues
The EGR system is nearly as hot as the exhaust system, especially if the engine has been running under heavy load or high engine speed. Wait at least thirty minutes to one hour before servicing the system, or just ensure the metal tubes, rubber hoses, and sensor are cool to the touch before proceeding. Some systems will use a sensor that screws into the EGR tube, so ensure you understand which type you have, where it is located, and how it is serviced and tested before attempting diagnosis or replacement.