Ford Excursion

Dealing With Ford P0401 Code Issues

The Ford EGR Pressure Feedback system is known for persistent P0401 EGR low flow code issues. Bear in mind, low flow can be caused by several issues.

The most common issue is the failure of the EGR Pressure Feedback sensor commonly known as the DPFE sensor. If the diaphragm in the sensor becomes weak or the sensor is contaminated with moisture it can fail to supply the computer with the correct reference voltage. When this occurs, the computer increases the vacuum supply to the EGR valve causing the vehicle to run poorly. When the low flow signal is unable to be corrected by the computer’s adjustment, then the computer sets a P0401 code for EGR flow.EGR system diagram

The other parts that commonly get overlooked are the EGR Valve Regulator (EVR), which is cataloged as an EGR control solenoid, the DPFE hoses, and carbon build-up inside the EGR system. The EVR is responsible for supplying the proper vacuum to the EGR valve. Any resistance in this control circuit or failure of the EVR can cause a P0401 code. The original DPFE hoses are a special high-temperature hose. These hoses can crack or collapse internally over time due to intense thermal cycling that takes place within the EGR system. Replacement hoses are available in pre-cut sections from NAPA.

To prevent a reoccurrence of the PO401 code, NAPA Echlin recommends replacing the EVR and DPFE hoses when replacing the DPFE sensor. To further ensure the repair, also perform a de-carbonization treatment of the EGR system to prevent the re-occurrence of a P0401 code.

Check out all the fuel & emission system parts available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on dealing With Ford P0401 code issues, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Wikimedia Commons.

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