Code P0401?

Tiny
BELLEVUE5150
  • MEMBER
  • 2000 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 155,000 MILES
I have already replaced the egr valve and the dpfe sensor, but still can't keep the check eng light off. Code P0401 insufficientegr flow keeps coming back on, and it's getting next to impossible to get it to pass state emmissions. Truck runs great except for the damn light. Please tell me what I can do next. I have 3 months before inspection again. Thank you.
Do you
have the same problem?
Yes
No
Sunday, August 10th, 2008 AT 10:05 AM

76 Replies

Tiny
ASERIOUSHUNTER
  • MEMBER
I have the exact same question/problem/error code on the same vehicle. I have changed the EGR, DPFE, and the EGR Control valve. I have checked all hoses and ports for blockages or buildup. Still have the light on and Ford doesn't know what to do.

HELP!
Was this
answer
helpful?
Yes
No
Monday, August 11th, 2008 AT 5:02 PM
Tiny
JAYDAWG951
  • MEMBER
I have the same problem! Help
Was this
answer
helpful?
Yes
No
Wednesday, November 12th, 2008 AT 12:01 AM
Tiny
BLUELIGHTNIN6
  • EXPERT
It sounds like it may be caused by the intake being clogged up with carbon deposits, thus not letting exhaust gas back through the intake.

I suggest that you remove the intake manifold, then remove the throttle body. Peel off the throttle body gasket and see if the channel, where the EGR gasses flow into the intake manifold, is clogged with carbon build-up.
Was this
answer
helpful?
Yes
No
Wednesday, November 12th, 2008 AT 12:39 AM
Tiny
FRANK1964
  • MEMBER
  • 1999 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 125,000 MILES
I have pulled the throttle body off and cleaned the ports replaced egr valve pressure sensor and solenoid still get service engine light on with the same code p0401 what else can I try.
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:11 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Have you removed the EGR to make sure it isn't plugged with carbon as well as the intake where it mounts?
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:11 AM (Merged)
Tiny
FRANK1964
  • MEMBER
Yes I have egr is brand new pulled intake completely off and cleaned ports out where egr bolts up. Solenoid, and pressure sensor are new too. Is it possible that tube from exhaust is clogged?
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:11 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Yes, it is possible.
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:11 AM (Merged)
Tiny
FRANK1964
  • MEMBER
Sorry it took so long to get back to you I'm going to pull the tube and check it out if not that should I check into the cat. Converter or start checking wires to pressure sensor as well as solenoid.
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:11 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
It would be a good idea to check the converter too. If it is good, then I would start tracing wires.

Joe
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:11 AM (Merged)
Tiny
WM. COGGESHALL
  • MEMBER
  • 1999 FORD F-150
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 105,000 MILES
Check engine light shows code.P0401. Just before the egr valve, is a (?) Pressure sensor, what are the odds that this needs replacing? Thanks, beans
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:14 AM (Merged)
Tiny
OBXAUTOMEDIC
  • EXPERT
There is a seperate code for the sensor. Take the EGR Valve off and Clean it.

Code Definition

P0401 Exhaust Gas Recirculation Flow Insufficient Detected.
Was this
answer
helpful?
Yes
No
+1
Monday, January 11th, 2021 AT 10:14 AM (Merged)
Tiny
MASTERTECHTIM
  • EXPERT
Also alot of times I find that sensor, dpfe fails alot too if cleaning the egr doesnt work. They have updated the part from the metal one to now a plastic one.
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:14 AM (Merged)
Tiny
KEEGNATION
  • MEMBER
  • 1998 FORD F-150
  • 5.4L
  • V8
  • 2WD
  • AUTOMATIC
  • 197,000 MILES
Hi, a few weeks ago I was getting a rough idle, revving on idle and rough acceleration. It came after a bit too long between an oil change. I added oil, but my dipstick showed almost none. My check engine light was giving me p0401, so I swapped my EGR valve, then DPFE and then tested my vacuum solenoid. Everything checked out, and the check engine light turned off, but the rough idle and rough acceleration are still there around 40 mph to 50 mph.

Now, there was an air leak, so I swapped the hose attaching to the throttle body which cured the idle revving with a good looking one from a junk yard, same model. I also cleaned the throttle body, sprayed carburetor cleaner in the EGR tube and shoved wire brushes in the small ports to clean it out. I swapped seven of the eight spark plugs (#4 has a piece of tape stuck to it, and the socket won't seat), and then tested the front four plugs while running to see if wires and coils were still good. They checked out. I put two rounds of fuel injector cleaner into my tank, on separate occasions but it didn't change the outcome. It runs fine while cold, but once it's warm it gives me the roughness.

Okay, I've got two problems. 1. I've got a spark plug I can't get out because of the tinniest piece of tape in the way from the socket wrench seating properly. This plug is also the one hardest to reach, and I'm at a loss of how to get it out. I found out using a mirror and a specially rigged head lamp. 2. My rough acceleration has turned into check engine light flashing on and off while driving. Today, my engine shut off entirely after driving it to AutoZone and plugging in the obd2 scanner. I am assuming it's check engine light flashing from unburned fuel getting into catalytic converter but I can't solve the misfire problem. Suggestions on what to try next?
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:14 AM (Merged)
Tiny
SCGRANTURISMO
  • EXPERT
Hello,

Can you pull the Direct Trouble Code (DTC) from your Data Link Connector (DLC) for me again, please? When your Malfunction Indicator Lamp (MIL) or "check engine" light is on and flashing, this means that you are having a catalyst damaging event. There are two types of misfires, Misfire A and Misfire B. Misfire B is a small misfire. Yours is a Misfire A, which needs to dealt with immediately. Please get back to me with the DTC, and we will go from there.

Thanks,
Alex
2CarPros
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:14 AM (Merged)
Tiny
KEEGNATION
  • MEMBER
Alex, when I tried to pull the code it stopped registering a code because the engine shut off and I had to restart the battery with a jump start. I don't have a scanner, I've been driving to AutoZone to borrow theirs.
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:14 AM (Merged)
Tiny
KEEGNATION
  • MEMBER
One more thing; I was testing the TPS and I noticed it was giving bad readings so I changed that as well, a brand new one.
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:14 AM (Merged)
Tiny
JORGE S
  • EXPERT
You would need an advance scanner to read mode6 data. Ford is not very good at throwing misfire codes. Mode6 data will tell you which cylinder is actually misfiring. If the AutoZone scan tool can read that data let us know and I can guide you into what you need to read on the misfire monitor to try and pin point the cylinder misfiring.

To me it sounds like you could have a bad coil under load which is very common. Mode6 data will show us if you have a cylinder misfire. Let us know what the scan tool is capable of doing so we can guide you.
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:14 AM (Merged)
Tiny
SCGRANTURISMO
  • EXPERT
Hello again,

Okay, I would recommend not to drive if at all possible. This is a class A misfire and is very serious for the longevity of your engine. To give you a personal experience I own a 1997 Ford Mustang GT. I installed a Vortech V1 supercharger on it and instead of reflashing the ignition and fuel maps of my PCM, I decided to run a fuel management unit. The FMU's work great, as boost increases it squeezes the fuel return line and effectively ups the psi of the fuel rail 10 psi for every lb of boost. The only thing is they depend on a vacuum line to work and if something happens to that vacuum line when you are under boost, your engine will go extremely lean, and "poof", no more engine. Well when doing a third gear pull, at about 135 mph and 5,500 rpm's, the vacuum hose blew off the FMU. My MIL instantly came on and starting flashing with a dead miss. I was able to baby it home four miles away and park it in my garage. A Misfire A, catalyst damaging event. I am not saying this is going to or is what is going on with your engine in any way, but here's what happened to mine. An eighth of my #4 piston was gone, connecting rod torqued and bent with a hairline fracture right done the shaft (Thank God) it stayed together. You could literally look down through the top of my #4 piston at the connecting rod. This is a Misfire A. Yours probably isn't this serious, but it must be fixed or it could wind up like this. You can pick up a basic code reader on Ebay or Amazon for around $20.00. Anyway, please get the code for me. Maybe they can rent you one with a refundable deposit? We can go from there.

Thanks,
Alex
2CarPros
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:14 AM (Merged)
Tiny
WHITESHIRTSAMMY
  • MEMBER
  • 1996 FORD F-150
  • 4.9L
  • V6
  • 4WD
  • MANUAL
  • 144,000 MILES
Does the "Check Engine" light clear itself when correct repairs have been made on a old 1996 obd2 system? I would like to avoid clearing the code manually because then I have to deal with P1000.
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:14 AM (Merged)
Tiny
KEEGNATION
  • MEMBER
Okay, the AutoZone scanner is not capable of showing Mode 6 data. I did find one on Amazon that says it can show ob2 enhanced mode 6. Would you check out this link and make sure I read it right? It's at the bottom of the page

XTUNER AM1011 OBDII/EOBD Plus Car Code Reader OBD2 Scan Tool Engine Code Reader Automotive CAN OBDII Diagnostic Tool Update Online https://www.amazon.com/dp/B07P4337N5/ref=cm_sw_r_cp_apa_i_ozzSCbQB9AYNZ

I think it will arrive the fastest and is the best price for an ob2 with mode 6. Thanks for clarifying JIS001 and Alex.
Was this
answer
helpful?
Yes
No
Monday, January 11th, 2021 AT 10:14 AM (Merged)

Please login or register to post a reply.

Sponsored links