What does it mean?
P1401 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: DPFE Sensor Circuit High Input .
Symptoms
- MIL on
- Rough idle and hesitation on light acceleration
- Mild surging at a steady cruise
- Stalling on deceleration if the EGR valve is held open
- Increased fuel consumption and an emissions test failure
Likely causes
- Short to voltage on the DPFE signal circuit
- Open sensor ground, which drives the signal reading high
- Failed DPFE sensor stuck at a high output
- Blocked or kinked downstream hose creating a false pressure difference
- Restricted EGR tube or a plugged metering orifice
- Corroded or bridged connector terminals
- Heat damage to the harness near the exhaust
How to fix it
- Read the DPFE voltage with the key on and the engine off and compare it with the specified rest value
- Inspect both hoses for blockage, soot, cracking and correct routing
- Check sensor ground continuity, an open ground alone will push the signal high
- Test the signal wire for a short to the 5 volt reference or to battery voltage
- Clean the EGR tube and the metering orifice if they are restricted
- Replace the DPFE sensor when the circuits check good but the output stays high
- Verify EGR operation and DPFE response in live data during a road test