P1401: How to Diagnose & Fix — DPFE (Differential Pressure Feedback EGR) Sensor Circuit High Input
5 vehicles · 2 makes · $50-$2,500 repair
How to diagnose and fix P1401: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Ford F-150 · 1997–2004
The Delta Pressure Feedback EGR (DPFE) sensor and the EGR throttle-body spacer passages are a chronic Check-Engine source on 1997-2004 4.2L/4.6L/5.4L trucks. The ceramic DPFE sensor drifts or cracks, and the narrow 90-degree EGR elbow passages carbon up until flow is blocked, setting P0401 (insufficient EGR flow). The result is a rough idle, stumble or stall when coming to a stop, hesitation, and reduced fuel economy. It is frequently misdiagnosed as the EGR valve itself.
Common Symptoms
- Check-engine light with P0401/P0402
- Rough idle and stumble at stops
- Stalling when decelerating to a stop
- Hesitation on light acceleration
- Reduced fuel economy
How to Fix
Test the DPFE sensor voltage and manually apply vacuum to the EGR valve at idle to confirm the valve/passages are clear. Replace the DPFE sensor (inexpensive, ~15-minute job) and clean the carbon-clogged EGR tube/throttle-body spacer passages. Replace cracked vacuum lines and the EGR valve only if proven faulty.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- DPFE / EGR Pressure Feedback Sensor (bolt-mount design)OEMF77Z-9J460-AB (Motorcraft DPFE-15)Cross-refStandard Motor Products VP8, Standard Motor Products VP8T, Wells 5S2049$25–$65
Motorcraft DPFE-15 (Ford F77Z-9J460-AB) is the updated Motorola 1.0-volt silicon design that supersedes the original ceramic sensor, and RockAuto lists it for every engine
- DPFE / EGR Pressure Feedback Sensor (clip-mount design)Cross-refStandard Motor Products VP17, Wells 5S2047, NTK EA0008$22–$32
RockAuto explicitly splits these listings by mounting and by engine VIN: Wells 5S2047 and NTK EA0008 are called out as 'Engine VIN W; clip mount' on the 4.6L, while 5S2049/EA0009 are 'Engine VIN 6 or VIN W; bolt mount'.
Sources for this issue (1)
Ford Freestar · 2004–2007
The Freestar uses Ford's differential pressure feedback EGR system, and it fails in a well-known pattern. The DPFE (EGR pressure feedback) sensor loses accuracy when its diaphragm weakens or moisture contaminates it, so the PCM commands more vacuum to the EGR valve and the engine runs poorly. Separately, the EGR passages under the plastic upper intake carbon up and physically restrict flow. The original DPFE hoses are a high-temperature type that crack or collapse internally from thermal cycling, which produces the same code. Because there are three independent causes, owners commonly replace one part, clear P0401, and have it return within weeks — this is the single most repeated repair loop on these vans.
Common Symptoms
- Check engine light with P0401
- Rough idle or stumble at light throttle
- Hesitation on acceleration
- Failed state emissions test
- Repeat return of the same code after a sensor replacement
How to Fix
Test DPFE voltage, inspect both high-temperature hoses, test the EVR solenoid and clean the intake EGR passages before ordering. The exact sensor, regulator and hose branches could not all be verified as a current purchasable fitment set, so no partial parts-swap link is approved.
Sources for this issue (3)
Porsche Macan · 2014–2018
The EU-market Macan S Diesel (3.0 V6 TDI) is prone to EGR valve faults and diesel particulate filter (DPF) clogging, especially on cars used for short urban journeys that never complete a hot regeneration. EGR electrical faults can also block regen from running, compounding soot buildup. Additionally, the AdBlue (SCR) pipework at the rear of the engine bay splits, leaving crystallized AdBlue residue around the connectors and triggering emissions warnings. These are highly relevant to German/EU diesel owners; this engine was not sold in the US.
Common Symptoms
- DPF / exhaust emissions warning light
- Repeated/failed regeneration cycles
- Reduced power / limp mode
- AdBlue (DEF) warning or low-range message
- Crystallized AdBlue residue at rear of engine bay
- EGR fault warning
How to Fix
Force/complete a DPF regeneration with a sustained ~20-minute high-rpm drive; clean or replace the EGR valve; replace cracked AdBlue lines/connectors and top up DEF. Severe DPF clogging requires forced regen, off-car DPF cleaning, or DPF replacement. Address EGR fault codes promptly so regen can complete. Avoid chronic short-trip use.
Sources for this issue (3)
Ford Crown Victoria · 1996–2011
Ford Escort · 1996–1999
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P1401 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P1401 mean?
P1401 stands for "DPFE (Differential Pressure Feedback EGR) Sensor Circuit High Input." A Ford/Lincoln/Mercury/Mazda manufacturer-specific code. The powertrain control module saw the differential pressure feedback EGR sensor signal above its maximum calibrated value, meaning the reported EGR flow signal is implausibly high. The engine may idle roughly, hesitate, or run hotter, and the vehicle will fail an emissions test. A useful check: on the plastic-bodied DPFE sensors, any at-rest signal voltage above roughly 1.2V points to a failed sensor. Other manufacturers assign P1401 to different faults (Hyundai, for example, uses it for a DMTL/EVAP performance fault), so match the code to the make before buying anything.
What are the most common causes of P1401?
The most common causes of P1401 are: Failed DPFE sensor (a very common wear item on these vehicles), Cracked, collapsed, melted, or disconnected rubber hoses between the DPFE sensor and the EGR tube, Clogged or corroded EGR tube restricting flow, Open or shorted DPFE signal wiring, or a short to voltage, Corroded or oil-saturated DPFE connector, Failed EGR valve, EGR vacuum regulator solenoid, or PCM (rare). The specific cause varies by vehicle.
How much does it cost to fix P1401?
Repair costs for P1401 range from $50 to $2,500, depending on the vehicle and root cause.
Which vehicles are affected by P1401?
Au7o has documented P1401 across 5 vehicle models from 2 manufacturers: Ford, Porsche.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.