P0401 Code - EGR Air Flow Control Valve

[Sting-Gray Neutral Pres.]

Greetings,

Truck threw a P0401 code at 70k miles. Dealer diagnosed as follows:
"Disconnected the air tube at the inlet port of the EGR Air Flow Control Valve and found it did not open completely with the Ignition on. Replacement EGR valve needed and retest."

This is not covered under warranty (tangential discussion), and the quote is ~$1,500 so I told them I'll do it myself, thanks. Looking at the shop manual for P0401 code, it's pretty clear they made it to Step 7, shown below:

If it the truck had passed Step 7 the diagnostic process then goes to the EGR cooler followed by the "EGR valve". Pretty certain the manual is referring to the high pressure cooler and valve and not the low pressure cooler and valve there. Regardless, my issue was diagnosed at Step 7.

My big concern here though is that there is almost no information out there about the "EGR Air Flow Control Valve" or ANY stories of it being the source of problems. Due to the very similar name as the (high/low) "EGR valve" internet searches are pretty hopeless. In the Engine Performance 3.0L Emissions Controls section of the shop manual I did find a picture and description of it:

And found a part number for it:
Intake Throttle Valve - Mopar (68490035AA)
(notice the different name that Mopar uses)

This thing sits on the intake manifold and and connects to the high pressure EGR diffuser tube (that gets famously gunky).
Here's a purchase link for the part:
https://parts.allmoparparts.com/oem-parts/mopar-intake-throttle-valve-68490035aa

at a discounted price of $500 I'm not too excited to order and install this if it's a red herring for a problem just upstream with the high pressure cooler or the high pressure EGR valve. Or if it simply needs a thorough cleaning. My non-CEL symptoms are reduced boost and a strong exhaust odor.

Any experience out there with resolving this code, replacement of this part, or these symptoms?

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[Sting-Gray Neutral Pres.]

Not able to replicate what the dealer diagnosed; there doesn't appear to be any issues in air flow control valve operation. Angle of camera is slightly misleading, valve is parallel to axis of tube at start and end of video. Any experienced feedback on valve motion in the video is appreciated.

 

[22EcoDs]

No experience but that looks fully functional to me. I assume you've reset the ECU and code persists? Is deleting an optio Can you scope the other egr valve? Scope the intake and see how bad the buildup is?

 

[Rusty PW]

Appears normal.

 

[Sting-Gray Neutral Pres.]

HP EGR tube carbon buildup was pretty severe. May have been a restriction in the tube, hard to say if it was present before I hit it with carb cleaner and stuff moved towards the exit.

Deleting not a good option.
Don’t have a boroscope but it’s time to for me to get one.

 

[Sting-Gray Neutral Pres.]

Well crap.
I cleaned this all up, removed and cleaned the Air Flow Control Valve for good measure, and put it all back together. When I fired it up, it died before catching. Second firing it ran real rough with a light scraping / rough tick noise at engine RPM and a solid air puff noise at shutoff performed very quickly thereafter. After looking for codes or obvious issues I fired it up again and it ran normally, but upon shutdown there was still a light woosh of air. Tried a couple more times, ran rough one other time, but mostly normal; however it always either an air puff or light air hiss noise at each shutoff.

I'm not an expert on engine internals but it the air on shutdown sound does seem to me like a valve isn't seating properly. Could a small mass of carbon that got knocked loose while wiggling out the pipe cause an intake valve to not seat correctly? If so what are my options?

Put a product in to soften things?
Run it hard?
tow/limp it back to the dealer and have them deal with it? (under engine warranty but Jeep won't warranty EGR issues)
Other ideas?

Pretty worried right now about the engine.

 

[22EcoDs]

I think you need a new dealer. If it's under the power train warranty this should be covered, there's a debate to be had that egr should be under emissions which is actually longer.

 

[Sting-Gray Neutral Pres.]

I think you need a new dealer. If it's under the power train warranty this should be covered, there's a debate to be had that egr should be under emissions which is actually longer.

It's not the dealer, it's Jeep. Service advisor said the corporate computer system tells them if coverage applies to a repair, and encouraged me to take it up with Jeep Cares, which I did. Outcome of that is here, with a larger thread about warrantable emissions items:
https://www.jeepgladiatorforum.com/forum/threads/dpf-code-engine-light-at-55k.101393/post-1629738

That's the related tangent mentioned my first post. Any thoughts on engine running condition?

 

[22EcoDs]

can you isolate the wooshing sound to the intake or exhaust? The variable vane turbo on shutdown could just be opening up. Id listen from an unfiltered airbox, then the exhaust side... see where it is more prominent. I suppose carbon could have gotten stuck, in that case running to operating temp should free it up. Mine will make a puff sometimes on shutdown.

 

[Sting-Gray Neutral Pres.]

Update on this. I purchased a boroscope and checked out the main part of the air intake as best I could. A fair amount of carbon buildup in there but no obvious concerns or blockages. Reset the ECU and drove it hard, ran like a top so I think it was just a bit of loose carbon flushing through the intake tract.

However, I kept it close to home and after about 50 miles of driving over a week or so the CEL and P0401 code came back (which my Tazer refuses to show, I had to buy a separate code reader). Of course my backup vehicle then promptly broke down too so I had to deal with that first but now I'm back to the Jeep. The blockage is deeper and the shop repair manual says next step is the high pressure EGR cooler and the final step is the high pressure EGR valve. I've lost trust in the dealership since they said it was the air flow control valve and that clearly was not the case. Jeep has told me EGR is not covered under warranty so it looks like I'll be undertaking an R&R of these components myself.

 

[Sting-Gray Neutral Pres.]

Follow up and hopefully final update that will help others.
After talking with the dealership some more it was apparent there diesel tech was describing things just incorrectly enough to sow confusion, which Stellantis is doing everyone no favors by labeling multiple major emissions parts with similar names, and sometimes multiple names for the same part. And different part numbers for the same part

Even though my first line of this thread was a direct quote, the tech had always intended to replace the high pressure EGR cooler and high pressure EGR valve, which is exactly what they did. I carefully considered doing this myself and concluded it wasn't worth my time and the risk and gladly paid the shop to do it. Pre-tax cost was about $1300, $723.00 of which was for the parts. That part value actually helped me confirm the intended repair prior to the fix.

For anyone that gets this code and is going down this path, here are a few things to consider.

• If having a dealership repair, this is not covered under existing warranties past 50k for pre-2024 diesels. I imagine the 2024 and newer revision of the UFC (see link in post #8 for more info) will cover EGR on diesels much longer.
• If having a dealership repair, verify that they are replacing part number CSNDVB11AA. This is critical. It is a "kit" that includes both the high pressure EGR cooler and high pressure EGR valve, and it costs $723.00 MSRP. This is actually a really good price compared to the individual component costs, and is likely due to a Gen II Ecodiesel recall. This part is also superseded by part # CSNDVB11AB and possibly one more. I have only verified the first part number, which is still sold.
• If you want to do this yourself:
  • You can find this part for ~$300 online.
  • You will also need these parts, minus the intake gasket, but including a few brass nuts which I didn't add to this cart.
  • 
    
    
  • watch this how-to video for guidance:
  • buy the half-moon wrenches discussed in the video, there are some nasty bolts to deal with.
  • The video, while great, is for a RAM 1500. The Gladiator/Wrangler have a coolant pipe for the cabin heater directly in the way that should be removed for better access. This will require draining the coolant, which was one more obstacle for me but may viewed as an additional coolant maintenance opportunity by others (replacing coolant in these is an involved, separately researched subject).
  • Removing the battery and battery tray may also help access, but I think it could be done without.

Good luck out there, and I hope my endless research and attempts at penny-pinching help save some effort or money for others.

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