Ford Explorer : How to Troubleshoot the EGR P0401 Trouble Code

This video should help diagnose and fix EGR issues.
https://youtu.be/jZmJ54sDWJQ

P0401 is for EGR low flow P0401 EGR Insufficient flow test what this !

Check your gas cap

OBD-II Trouble Code P0401 - Insufficient EGR Flow

EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor EGR (DPFE). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR. You may notice drivability problems such as pinging (a.k.a. pre-ignition knock) when the engine is under load or the vehicle is at higher speeds. There may also be other symptoms.

A code P0401 most likely means one or more of the following has happened:
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

Check it and keep us updated. Hope this helps (remember to rating this free answer).

PO401--- EGR Flow Insufficient Detected

If all you have is an egr valve replace it

If you have other hoses & sensors coming & going from it,
leave it to a repair shop

P0401 Exhaust Gas Recirculation Flow Insufficient Detected
Remove the EGR valve and clean up passage ways using spray on carburetor/fuel injector cleaner.

p0401 is egr flow insufficiant. check or remove and clean egr and port. and also check the vacuum lines to egr. Insufficient EGR flow frequently is caused by clogged EGR passageways.

This code is an EGR code for insufficient amount of egr. It could be that the egr tube is clogged or the egr itself is bad or there is not enough vacuum to open the egr properly. There is also a sensor called the DPFE(differential pressure feedback egr) is faulty.

PO4O1 (egr fault) I believe this would be OBD-2 on a 2002 model eh?

P0401 = Exhaust Gas Recirculation, insufficient flow.

I would start with testing the EGR valve and checking the source line for a vacuum leak. EGR may need to be cleaned.