Has anyone ever figured out the source of this CEL? I'm getting the EGR Flow Insufficient and I've had it off and on for about 3 years. I've replaced every piece of the EGR system except the tube that runs from the valve to the exhaust manifold. I've even torn my throttle body apart and thoroughly cleaned out the EGR ports inside the TB and the intake. I've also cleaned my IACV, which I don't think would have anything to do with the EGR system. I just bought some MAF cleaner and am going to clean my MAF this weekend.

I've cleared the code a couple times and the CEL always comes back with the same code. It's not always in the same amount of time and it seems to only come back when it's damp outside, but I can't pinpoint that.

I know this issue has been covered before but I don't think I've ever actually seen a difinitive answer to solve this problem. One would think that after three years of staring at my CEL that I would have gotten used to it by now, but it still drives me insane.

 

The code is thrown because not enough exhaust gas is entering the intake. most likely the hose that you haven't replaced is the cause. i'd try cleaning it as well as the two lines going to the dpfe.

 

I'm having the same trouble right now with my 97 4X4 4.6L short box.

It's givin me the P0401 Code (Insufficient Exhaust REcirculation)

I cleaned the throttle body today by hand since you can't use Cleaner on it because of the protective coating.

I did all that, cleared the code, then drove around for a bit and it still came back up.

Tomoroow I will be checking the DPFE lines an cleaning them if necessary, and also removing the throttle body AND throttle body elbow as well and cleaning the elbow, and whatever I can of the intake plenum. If that don't do it I'll be replacing the DPFE sensor.

I also cleaned the EGR valve, and only 2 weeks ago replaced the EGR line itself.

Hopefully some of this info helps. I'll update it tomorrow night, and let ya know if any of that fixed it.

Also I have some loose vacuum lines leading up to the throttle body that need replaced as well. Could be the problem and not the DPFE Sensor.

Good luck

 

I'm starting to wonder if it's vacuum lines also. I've replaced the DPFE, lines for it, EGR valve, I've done it all, except the metal tube. I'm gonna check over all my vacuum lines when it warms up a bit. Let me know how it goes with you and I'll let everyone know if I find an answer too.

 

That pipe going to the exhaust manifold is next on my list. The two lines coming off the DPFE have already been replaced.

 

I would think vacuum line leak is the ports from the Egr to intake are clear. The vacuum is best checked after the engine is at operating temp.
The DPFE sensors are an issue also. I replaced mine with one from advance auto..... Ended up having to get one from the local ford dealer.
You can get a cheap vacuum gage at harbor freight for under 20 bucks.

 

You can see what I found when I removed my throttle body elbow.

The carbon buildup happened where the ports are inside. They are where the EGR line and EGR Valve emissions flow through, or in my case weren't flowing through.

Cleaned it all out, and cleared my codes. Haven't had a CEL since.

 

Hope that helps.

 

I did the same thing yesterday and my TB elbow looked about the same. I cleaned it all out and it seems to be running great. It seems like it's smoother at idle now.