NOTE: The existence of a TSB does not mean that the manufacturer has acknowledged responsibility for a known problem, nor does it mean that the local dealership is required to fix the problem outlined in the TSB free charge. The TSB is merely documentation of a known issue and proper diagnoses and repair procedure.

The exhaust gas recirculation (EGR) valve has a differential pressure feedback sensor (DPFE). When this sensor goes bad or fails, it can trigger a P1401 and several other related codes (P040# variants, usually) and create a rough idle. The rough idle is caused by improper exhaust gas regulation – either too much or too little exhaust is being recirculated back into the cylinders, and this is interuppting proper combustion.

The recommended repair for a P1401 code is to replace the DPFE sensor with a new one. Ford offers an upgraded DPFE sensor for most models (part number 4U7Z-9J460-AA) that is reportedly higher quality than the factory sensor it replaces.

If replacing the DPFE sensor does not clear the P1401 code, the problem may be in the EGR valve itself. Thus, the next step is to checked, clean, and/or replace the EGR valve along with its input tube.

Author Jason Lancaster is a one-time Ford Focus owner who – fortunately – never had a DPFE sensor problem. Jason is also the founder of, a website that helps consumers navigate buying, selling, and maintaining their vehicles.

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