Faulty DPFE sensor (internal short or contamination); Short to voltage on the DPFE signal circuit (VREF or sensor output wire chafed against a power wire); Damaged or corroded DPFE sensor connector pins or terminals; PCM internal fault causing incorrect reference voltage; Exhaust backpressure issues or blocked EGR passages that skew sensor readings; Wiring harness damage from heat or vibration near the EGR tube

DTC codes / Ford codes / P1401

P1401 · FordDifferential Pressure Feedback Electronic Sensor Circuit High Voltage

P1401 on Ford vehicles means the powertrain control module (PCM) has detected a high-voltage condition on the differential pressure feedback electronic (DPFE) sensor circuit. The DPFE sensor measures the pressure difference across the exhaust gas recirculation (EGR) valve, and a high signal voltage tells the PCM that the sensor output is above the expected range, often due to a wiring short to voltage or a failed sensor.

SystemPowertrain

Code typeFord specific

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Slight rough idle or hesitation during acceleration in some cases
Reduced fuel economy if the EGR system is disabled by the PCM
Failed emissions test due to the EGR monitor not completing
In rare cases, a noticeable ping or spark knock under load if EGR flow is affected

Common causes, most likely first

Faulty DPFE sensor (internal short or contamination)
Short to voltage on the DPFE signal circuit (VREF or sensor output wire chafed against a power wire)
Damaged or corroded DPFE sensor connector pins or terminals
PCM internal fault causing incorrect reference voltage
Exhaust backpressure issues or blocked EGR passages that skew sensor readings
Wiring harness damage from heat or vibration near the EGR tube

How to diagnose and fix it

Inspect the DPFE sensor connector and wiring for chafing, corrosion, or loose pins, and repair as needed
Measure reference voltage at the DPFE sensor connector with the key on, engine off, and compare to specification
Backprobe the DPFE signal wire and check for a short to voltage with a multimeter while wiggling the harness
Test the DPFE sensor output voltage with a vacuum pump applied to the sensor ports and compare to expected values
Replace the DPFE sensor if it fails the voltage or vacuum test
Clear the diagnostic trouble codes and perform a road test to verify the repair and confirm the EGR monitor runs
If the code returns, check for intermittent wiring faults or a faulty PCM

DPFE sensor circuit high voltage pitfalls

A common misdiagnosis is replacing the DPFE sensor when the real problem is a shorted reference voltage wire in the harness, so always check the circuit before condemning the sensor.
The DPFE sensor on Ford vehicles is heated and can be contaminated by exhaust condensation or carbon, causing high voltage readings that mimic a circuit fault.
A stuck-open EGR valve can cause excessive flow and a high DPFE signal, but it often sets related codes like P0401 or P0402 alongside P1401.
Some aftermarket DPFE sensors have incorrect calibration and can set P1401 even when the circuit is good, so use a quality OEM-style replacement.
The PCM may set P1401 if the sensor signal voltage exceeds 4.5 volts for a calibrated time, which can happen intermittently due to heat-related wiring issues.

Can I keep driving with P1401?

You can usually continue driving with P1401 because the EGR system is disabled and the engine runs in a default mode, but avoid long trips or heavy loads until repaired to prevent potential engine knock or emissions issues.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.