• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

P0401 Code


MorganMcCann

New Member
Joined
Mar 6, 2013
Messages
280
Reaction score
0
Points
0
Location
Saint Clair, MI
Vehicle Year
1999
Make / Model
Ford
Engine Size
3.0L
Transmission
Automatic
I've got a P0401 code recently. The DPFE and EGR are both stock parts. However, upon looking at the EGR tube there is a small dent near the first bend of the tube, but it has been like that for a while because I have not done any work near that tube in months, and I have driven the truck a good deal.
So, should I look into replacing the EGR tube first, or the DPFE?
 


RonD

Official TRS AI
TRS Technical Advisor
Joined
Jun 2, 2012
Messages
25,290
Reaction score
8,290
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
90% of the time P0401 is a failing DPFE sensor, if the stock sensor lasted over 70k miles you have done good.
3rd party DPFE sensors seem to last longer, just FYI, and they are cheaper than OEM.
Make sure the two hoses for the DPFE sensor are clear and "air tight", i.e. no leaks, the DPFE measures the pressure difference between those two hoses, if one is leaking then DPFE data to computer will be off.

The computer can adjust EGR flow thru the pipe, so a dent shouldn't be a problem, leaking or collapsed pipe would be, but not a "dent".
 
Last edited:

adsm08

Senior Master Grease Monkey
Supporting Member
Article Contributor
Ford Technician
TRS 20th Anniversary
Joined
Sep 20, 2009
Messages
34,623
Reaction score
3,613
Points
113
Location
Dillsburg PA
Vehicle Year
1987
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0
Transmission
Manual
2WD / 4WD
4WD
Tire Size
31X10.50X15
The "dent" is supposed to be there. It's a product of bending the tube to it's shape.

Ron is right, the DPFE sensor is likely giving up.

The only other real test is to put vacuum to the EGR valve with the engine at idle and see if you can stall it.
 

MorganMcCann

New Member
Joined
Mar 6, 2013
Messages
280
Reaction score
0
Points
0
Location
Saint Clair, MI
Vehicle Year
1999
Make / Model
Ford
Engine Size
3.0L
Transmission
Automatic
The dent is into the tube about half way. It seemed like it shouldn't be there to me, but it is supposed to be there?
 

bucko

New Member
Joined
Jun 16, 2014
Messages
80
Reaction score
1
Points
0
Vehicle Year
2000
Make / Model
Ford
Transmission
Automatic
I can check my 2000 tonight and let you know if I have this dent you speak of in the same location. If possible, posting a picture helps.
 

MorganMcCann

New Member
Joined
Mar 6, 2013
Messages
280
Reaction score
0
Points
0
Location
Saint Clair, MI
Vehicle Year
1999
Make / Model
Ford
Engine Size
3.0L
Transmission
Automatic
I've been super busy, I'll try to get a picture tonight. Sadly, I don't have a garage so the lighting will not be very good.
 

MorganMcCann

New Member
Joined
Mar 6, 2013
Messages
280
Reaction score
0
Points
0
Location
Saint Clair, MI
Vehicle Year
1999
Make / Model
Ford
Engine Size
3.0L
Transmission
Automatic
On the picture, if you look at the hose from a different angle you can clearly tell that there is no hole, but it is just dented.
 

Attachments

MorganMcCann

New Member
Joined
Mar 6, 2013
Messages
280
Reaction score
0
Points
0
Location
Saint Clair, MI
Vehicle Year
1999
Make / Model
Ford
Engine Size
3.0L
Transmission
Automatic
Just an update, I replaced the DPFE. The DPFE didn't fix the problem. The CEL came back on. I got a vacuum pump from Autozone, and the EGR valve held a constant vacuum with 10lbs and 15lbs, the engine wanted to stall when the EGR was placed under a vacuum. What else could the be? The EGR Vacuum solenoid? I've also heard the vacuum lines to the DPFE can become clogged.
 

Rearanger

Active Member
Joined
Feb 4, 2008
Messages
1,429
Reaction score
23
Points
38
Location
Southeast USA
Vehicle Year
2003
Make / Model
Ford
Transmission
Manual
I've also heard the vacuum lines to the DPFE can become clogged.
Make sure the two hoses for the DPFE sensor are clear and "air tight", i.e. no leaks, the DPFE measures the pressure difference between those two hoses,
Your answer has probably already been given.
 

MorganMcCann

New Member
Joined
Mar 6, 2013
Messages
280
Reaction score
0
Points
0
Location
Saint Clair, MI
Vehicle Year
1999
Make / Model
Ford
Engine Size
3.0L
Transmission
Automatic
I do believe I somehow managed to reverse the hoses. I've drove about 70 miles since flipping them, and I have had no CEL.
 

MorganMcCann

New Member
Joined
Mar 6, 2013
Messages
280
Reaction score
0
Points
0
Location
Saint Clair, MI
Vehicle Year
1999
Make / Model
Ford
Engine Size
3.0L
Transmission
Automatic
Drove it for about 150 miles, no CEL came back on. I'd say it is fixed.
 

RonD

Official TRS AI
TRS Technical Advisor
Joined
Jun 2, 2012
Messages
25,290
Reaction score
8,290
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual

Sponsored Ad


Sponsored Ad

Members online

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Truck of The Month


Kirby N.
March Truck of The Month

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top