The DPFE (differential pressure feedback EGR) sensor is faulty and needs; To be replaced; There is a blockage in the EGR (tube), most likely carbon buildup; The EGR valve is faulty; The EGR valve may not be opening due to a lack of vaccuum

Read the code and live data with an OBD-II scanner; Look for exhaust or vacuum leaks and check the wiring of the sensor or valve; Test the part before replacing it; Fix the cause, clear the code and test-drive

P0401 on Honda Civic FC: Exhaust Gas Recirculation Flow Insufficient Detected

Short answer: P0401 means “Exhaust Gas Recirculation Flow Insufficient Detected”. The car’s computer has found a fault in the Emissions system and turns on the Check engine light (MIL). First check: read the code and live data with an OBD-II scanner.

Standard OBD-II code Same meaning on all cars (SAE J2012). Not checked against this car’s factory manual.

Code: P0401
System: Emissions
Dashboard light: Check engine light (MIL)
Applies to: Generic OBD-II meaning. Not every code is used by this car.
Confidence: medium (generic OBD-II definition, not checked against the factory manual for this car)
Source: obd-codes.com

Symptoms and when it is set

Check engine light on

Likely causes

The DPFE (differential pressure feedback EGR) sensor is faulty and needs
To be replaced
There is a blockage in the EGR (tube), most likely carbon buildup
The EGR valve is faulty
The EGR valve may not be opening due to a lack of vaccuum

What to check, in order

Read the code and live data with an OBD-II scanner
Look for exhaust or vacuum leaks and check the wiring of the sensor or valve
Test the part before replacing it
Fix the cause, clear the code and test-drive

Related on this car

Same code on other cars

← P0354 P0420 →

Clearing the code does not fix the fault. If it comes back, the problem is still there. For brakes, airbags and steering, see a trained mechanic.