Code P0401...
#1
07-20-2005, 10:14 PM
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Code P0401...
Hi all,
I'm trying to diagnose a problem with a P0401 code...
Ok, here is what it says for the code...
---
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I'm trying to diagnose a problem with a P0401 code...
Ok, here is what it says for the code...
---
P0401 - EGR Flow Insufficient Detected
The EGR system is monitored during steady state driving conditions while the EGR is commanded on. The test fails when the signal from the DPF EGR sensor indicates that EGR flow is less than the desired minimum.
Possible Causes
Vacuum Supply
EGR valve stuck closed
EGR valve leaks vacuum
EGR flow path restricted
EGRVR circuit shorted to PWR
VREF open to DPF EGR SENSOR
DPF EGR sensor downstream hose off or plugged
EGRVR circuit open to PCM
VPWR open to EGRVR solenoid
DPF EGR sensor hoses both off
DPF EGR sensor hoses reversed
Damaged EGR orifice tube
Damaged EGRVR solenoid
Damaged PCM
Diagnostic Aides
Perform KOER selftest and look for DTC P1408 as an indication of a hard fault. If P1408 is not present, look for contamination, restrictions, leaks, and intermittents.
---
Now, I have changed the EGR and PVC valves and neither of those helped a bit as after getting them installed and clearing the code it showed back up later that same day. Considering the code info and the fact that it isn't the EGR itself does anyone know if a bad Catalytic Converter could cause this code?
As we speak I need to install a new catalytic converter and just haven't had the time to do it. The EGR and PVC valves were very simple however after talking to a few people I hear their may be some welding needed to get the CAT replaced.
Also, prior to the P0401 code I was getting some severe misfire and ended up changing the spark plugs and wires which made things really good for a while. Some months after the spark plug job this code started showing up. I was just going over all of these codes...
...and did a search for "cata" and came across the P0420 a few codes down and noticed that it says severe misfire could cause catalyst damage. Is the "catalyst" the same as the catalytic converter? If so I guess it's safe to say this was a result of the bad spark plugs and wires then?
Hmmm, but could the bad catalyst be the cause of this code I'm getting?
TIA!
So, a few questions from above...
1) Does anyone know what else could be causing the P0401 code? Again, it's not the EGR or PVC valves as they have been changed.
2) Are catalyst and catalytic converter the same things? Ok, nevermind #2 -- I found this answer in the FAQ 
3) Is it possible that a damaged catalyst could be the cause of the P0401 code?
Last edited by tb40nd; 07-20-2005 at 11:12 PM.
#2
07-20-2005, 10:28 PM
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#3
07-20-2005, 11:15 PM
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Yes, I found that much... any help on the questions 1 or 3? I found the answer to #2 in the FAQ a little bit ago.
1) Does anyone know what else could be causing the P0401 code? Again, it's not the EGR or PVC valves as they have been changed.
3) Is it possible that a damaged catalyst could be the cause of the P0401 code?
#4
07-20-2005, 11:35 PM
If you have a 5.4 engine, replace your DPFE sensor. Your done. Its part number EGR155 from Oreillys and YES it is a Motorcraft OE sensor disguised in a Borg Warner box - the SAME Exact sensor that is $100 at the dealer. Its about $44 at Oreilly.
If you have a 4.6 engine, replace the DPFE sensor and also pull off the throttle body and unclog the EGR ports.
If you have a 4.6 engine, replace the DPFE sensor and also pull off the throttle body and unclog the EGR ports.
#5
07-20-2005, 11:44 PM
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schweeeet!
from the sounds of it you've been down this road already? i'm sure hoping so!
btw, my apologies as i forgot to add that i have the 4.6L / W model engine.
hey, are there any HOW TO'S for replacing the DPFE sensor? pics?
i'll do a search as well, TIA!
see sig for truck info... 1998 Expedition, 4.6L, 4x4
from the sounds of it you've been down this road already? i'm sure hoping so!
btw, my apologies as i forgot to add that i have the 4.6L / W model engine.
hey, are there any HOW TO'S for replacing the DPFE sensor? pics?
i'll do a search as well, TIA!
see sig for truck info... 1998 Expedition, 4.6L, 4x4
Last edited by tb40nd; 07-21-2005 at 12:17 AM.
#6
07-21-2005, 03:25 AM
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#7
07-29-2005, 08:41 PM
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#8
07-29-2005, 08:47 PM
#9
07-30-2005, 12:55 AM
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Originally Posted by fcmazz
tb40nd,
so was this the fix on the 4.6L . I have the exact same problem. Took it in today, changed egr and selenoid and darn light just came on again. Did you get yours fixed?
Thanks
so was this the fix on the 4.6L . I have the exact same problem. Took it in today, changed egr and selenoid and darn light just came on again. Did you get yours fixed?
Thanks
you can clean the ports without removing the TB - i'm no where near close to being a mechanic and it was super easy to do.
my egr ports were TOTALLY clogged - its running sooooo much better now. haven't had even a hint of a code since i put it all back together.
good luck and post back if you need further assistance - everyone here has been great!
#10
07-30-2005, 07:42 AM
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To my knowledge, every single 4.6 in the '97 and '98 will clog the egr ports,
usually around 100,000, give or take. Like clockwork.
I cleaned mine around 127,000 in March 2004, and now have 156,000.
It's acting the same way now. I wonder if the heavy driving might have
clogged them again. No code yet. I'll dive in one of these days and look.
usually around 100,000, give or take. Like clockwork.
I cleaned mine around 127,000 in March 2004, and now have 156,000.
It's acting the same way now. I wonder if the heavy driving might have
clogged them again. No code yet. I'll dive in one of these days and look.
#11
07-30-2005, 08:26 AM
Like clock work, every three days the same type thread comes up, P0401. Thats amazing. same symptoms and all. must be a big problem out there. Mine had 108,000 miles on it took it apart and there was not much in htere cleaned it all up anyway runs better. Replaced the DPFE sensor just to be on the safe side. I wish they had a Orillys arounf here, could only get it from ford 108.00$$. NAPA said they could special order one for 79.00$ but it was a ten day turnaround. No one else carried or could order it.
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#13
07-30-2005, 02:50 PM
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Originally Posted by fcmazz
tb40nd
Appreciate the reply. Will try this and keep in touch here.
Thanks again
FCMAZZ
Appreciate the reply. Will try this and keep in touch here.
Thanks again
FCMAZZ
hey, in the second sentence where i said...
"you can clean the ports without removing the TB..."
...i meant to say YOU CAN'T CLEAN the ports without removing the TB. sorry about that and hopefully it didn't slow you down any.
God Bless!
#14
07-30-2005, 10:31 PM
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