2002 Ford Windstar Engine cod PO401

  • 6 CYL
  • 2WD
  • 124,000 MILES
On mine 2002 Windstar engine lite is comes on.I did check with OBD-2 It Is PO 401. The engine runs not bed
but the light stays on. Some time when it shifts it like driving on the bumpy road, I fill the van scheiks. Please some body tell me what to do.
Thank You
Do you
have the same problem?
Wednesday, February 25th, 2009 AT 11:55 PM

1 Reply

P0401 Insufficient EGR Flow

What does that mean?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.

SymptomsYou 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.

CausesA 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
Possible SolutionsIn fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.

Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
Clean out the EGR valve and/or tubing to remove deposits
Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
Replace the DPFE sensor (with a good quality / OEM one)
Replace the EGR valve
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Thursday, February 26th, 2009 AT 12:02 AM

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