P0401 Check engine code

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Jul 8, 2002 | 09:28 AM

cinnpass

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Joined: Oct 2001

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P0401 Check engine code

I am getting a P0401 engine code "Exhaust Gas Recirculation Flow Insufficient Detected". Where do I start and what do I need to check to diagnose what is causing the problem?

Jul 8, 2002 | 11:48 AM

ckrichard

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Joined: Mar 2002

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From: Conroe, TX

P0401 Check engine code

Replace the EGR valve.

Chris

P.S try calling your local ford dealership they will probility have a cheaper price than autozone.

Jul 8, 2002 | 08:57 PM

DHH

Junior User

Joined: May 2002

Posts: 65

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From: Plymouth USA

P0401 Check engine code

According to the 1996 Ford PCED manual the following could cause this code.
-EGR valve stuck closed or iced
-EGR valve diaphragm leaks
-EGR valve or flow path restricted
-EGR vacuum hose off, plugged or leaks
-VPWR circuit open to EGR vacuum regulator (EGR V.R.) solenoid
-EVR circuit to PCM open
-EVR circuit to PCM shorted to PWR
-Differential Pressure Feedback EGR (D.P.F. EGR)sensor pressure hoses both off
-D.P.F. EGR sensor hoses reversed
-D.P.F. EGR sensor VREF circuit open
-Downstream pressure hose off
-Downstream pressure hose plugged
-Damaged orifice tube assembly
-Damaged EGR V.R. solenoid
-Damaged D.P.F. EGR sensor
-Damaged PCM

As you can see there are a number of possibilities that could cause your problem. It is more than likely the EGR valve, but at least now you have some things to check. Hope this helps.

Jul 8, 2002 | 11:14 PM

nightri1

Freshman User

Joined: Nov 2000

Posts: 44

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From: USA

P0401 Check engine code

Hey guys I have a similar problem too. Just had a guy at Autozone download the fault codes from my 96 Explorer 4.0. He got three, two for the EGR, low flow and too much flow, and the third was "catalyst ineffecient." I have a new EGR on order at Ford and will pick it up in the morning. My question is; would the bad EGR cause the fault about the catalyst? This character said it was not uncommon for the catalyst to be bad with 138K on the odometer. Can't wait to price that at Ford. Or perhaps could it be bad sensors before and after the catalyst?
Thanks for helping.

Jul 10, 2002 | 11:33 AM

ranger9496

New User

Joined: Jun 2002

Posts: 4

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From: Springfield US

P0401 Check engine code

I just went through this same problem. I first replaced hoses to the DPFE sensor (no luck). Next, I checked the EGR valve for vacuum (5-6 psi)OK then took if off to see if it was clean (no blockages), again it was OK. I was getting voltage readings from the DPFE sensor outside of that shown in the manual so I replaced the sensor. Seems to have worked. I replaced the sensor several weeks ago and erased the code and it has not come back. Good luck.