P0401 - EGR insufficient flow with Malone stage 2

Hi all:

I brought my TDI to the dealer about 2 months ago for a check engine light. They determined my exhaust flap was stuck open and replaced it under warranty. While there they also flashed my ecu with the latest software release. Everything was great thereafter. About a month ago I had a Malone dealer in NH install malone stage 2 and DSG tune (keeping DPF and EGR). Car dove great till about a week ago I got a check engine light. Dropped it off at the dealer (who I have a good relationship with and are mod friendly). They called me yesterday saying that it is throwing a P0401 code for EGR insuffient flow and indicated that the tune overwrote the latest software release which supposedly helped keep the DPF cleaner. They recommend flashing the ecu (for $100) to resolve the problem but wanted to check with me because they know about he tune. I told them not to flash it and I took the vehicle back. I think the DPF is cracked (have 72k miles) as I'm seeing a lot of soot in the tailpipe.

I called the shop that did the tune and they said they'll check with Mark Malone to see if there was a mistake with the coding that could be causing this issue. I told them to start there. If there is an issue with the code then I'll bring the car back and they can re-flash at no charge. If the code isn't the issue then I want the dealer to flash back to stock so I can see if the issue continues and if so have it remedied under my extended warranty. Once it is remedies I'd want the shop to re-flash my car (depending on the cause of the issue) or I'd want my money back on the engine tune (DSG is fine). I'd only want my money back if the tune is causing the issue and we can't remedy (to be fair).

What are your thoughts? Any considerations? I was considering a delete but I don't want to deal with issues when I go to sell the car

Looks like DPF is a toast. Visit Malone and ask for a tune "with EGR and without DPF".

Alternatively you can ask for warranty DPF replacement (10 years or 100k miles for N.A. region?) and live with the current tune.

Henrick said:

Looks like DPF is a toast. Visit Malone and ask for a tune "with EGR and without DPF".

Alternatively you can ask for warranty DPF replacement (10 years or 100k miles for N.A. region?) and live with the current tune.

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Thanks for your reply. How would the EFR without DPF work? wouldn't the DPF clog over time and restrict the exhaust?

I'd like to drive for the replacement of the DPF which is why I'm thinking I may have to have it flashed back to stock so the the dealer can follow their diagnostic protocol.

If you opt out DPF, you will need to cut it out physically. I am not familiar with N.A. exhaust setup but depending on it, you might weld in a catalytic converter in place of DPF (some vendor here sells them, they are cheap) or a straight pipe if the there already is a cat and is a separate part of DPF.

Cutting the DPF out is a bit healthier for the car - less backpressure for the turbo (longer turbo life), better fuel consumption, less fuel dillution and less your time wasted (no need to drive around the block to "let it finish a regen") and less headache (worries of shutting down the car while in regen, no hassle of repeated DPF failure, etc).

Looks like there is much hassle of replacing the DPF. Flashing it back, replacing DPF and EGR filter (the latter one probably won't be covered by warranty and you'll have to pay for it out of pocket), then flashing the tune back. Flashing the tune back probably will cost you money too.

It's your car, it's your choice. Go either way you feel is the right one.
If this would be me, I'd cut out the DPF and get a tune for DPFless car. Also, I'd ask the tuner to make a "custom map for inspection". This one could be switched on my a secret combination which only you know and would be de-tune the car's power to help reduce the emissions and pass the inspection. This one wouldn't be used for driving, only for inspection. A friend of mine in Germany has got such thing done.

Update - malone came back and said no issue with the code. Going to discuss with my tuning shop my choices

Your dpf is cracked, the soot that's slipping by is clogging your egr. The emissions system has an 8yr/80,000m warranty, or 10/100k in California. That's the only reason you should see soot in your tailpipe. Did you get the stage 2 that deleted the Regen's or the one that kept Regen's? If this was my situation, I would get the dealership to replace the dpf and egr with a new one, then go buy a new downpipe and sell the brand new replacement dpf. Then have Malone ensure your tune has the dpf and egr deleted electronically in the ecu. And never worry about your exhaust ever again, and enjoy the increase in mpg

I got stage 2 with DPF and EGR intact. Going to spend the $100 to have my dealer re flash my ecu this week. Then drive it until the light comes on and take it back to them for replacement. I need to pass emission inspection in ~45 days (already failed emission once) so hopefully by then I can pass with stock tune. Then will go back and have malone put back on it. Hoping mark doesn't charge me much for a reflash

emerscape said:

I got stage 2 with DPF and EGR intact. Going to spend the $100 to have my dealer re flash my ecu this week. Then drive it until the light comes on and take it back to them for replacement. I need to pass emission inspection in ~45 days (already failed emission once) so hopefully by then I can pass with stock tune. Then will go back and have malone put back on it. Hoping mark doesn't charge me much for a reflash

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We will be fair with you, no worries. I believe it was me that answered your Malone email if memory serves me correctly.

BuzzKen said:

We will be fair with you, no worries. I believe it was me that answered your Malone email if memory serves me correctly.

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Thanks much appreciated!

So quick update. I had an appointment at the dealer this morning to get the car flashed back to stock. I noticed that the check engine light turned off yesterday so when I got to the dealer I asked them to plug their scanner to see if I had readiness and if there were any codes. They did and found that everything except EVAP was ready and said there were no new codes. They suggested that I get the car inspected while I could so I went ahead and took it to the service station that originally inspected it. It passed! So now I'm wondering if I really need to address this issue and what are the consequences if I don't. I don't feel like dealing with the hassle of going back to stock and having to drive all over the place, take it back in, etc. Any thoughts here? Am I damaging the car by continuing to drive it?

Are you still seeing soot in the tailpipe? Thought that you were thinking cracked dpf? What year is your TDI? If you think you still have dpf issues I would try and resolve before the issue pops up again and potentially strands you or something.


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Fantasiamon said:

Are you still seeing soot in the tailpipe? Thought that you were thinking cracked dpf? What year is your TDI? If you think you still have dpf issues I would try and resolve before the issue pops up again and potentially strands you or something.

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^^
This x100!

Don't count on all being ok just because the light turned off.

I had the p0401 code popping in and out for a couple weeks, took it in to my friendly local VW dealer, and found out the DPF had cracked (internally) and the EGR was clogged (115k).

There is actually a physical inspection and testing procedure that VW requires techs to do before warranting the replacement of the system. They need to remove and check for soot in the EGR, etc. I would go back to the dealer and have them check it just to make sure. The tune should have very little to do with the code popping up on your car. Having the dealer flash the stock tune does not seem like it would solve the problem in my opinion. If the DPF and/or EGR is physically broken, programming will not fix it.

I agree 100%. I Think it is BS that they want to flash back to stock first and see what happens but how can I argue with my dealer?

So quick update. I finally gave up and took my car back to the dealer. I had written them a good review on google as they had asked me ( and because I've been happy with them) and said "do me a favor since I just did you a favor, I don't believe that the software is the issue here, please do an inspection of the DPF and EGR so that I don't have to go through the hassle". I got a call mid-morning and they said that the tech said it needs to be reflashed (meaning they didn't do anything). I told them to go ahead with it. I got another call in the afternoon and they said "we have bad news. The tuning software isn't allowing us to overwrite the ECM, you are going to have to take it back to the tuner". I picked up the car later in the afternoon, no charge, and went on my way. Checking my oil this morning I noticed that the engine cover is now broken and rattling.

Questions for you all:

1) Could the malone tune really prevent the dealer from overwriting it? (I didn't think so)
2) Do they take the engine cover off to tune the ecm? If so I'm going to go back and demand a new one.
3) Can the Malone dealer that did my tune put my car back to stock?


Thanks for the help.

Best,

Pete

So quick update. I finally gave up and took my car back to the dealer. I had written them a good review on google as they had asked me ( and because I've been happy with them) and said "do me a favor since I just did you a favor, I don't believe that the software is the issue here, please do an inspection of the DPF and EGR so that I don't have to go through the hassle". I got a call mid-morning and they said that the tech said it needs to be reflashed (meaning they didn't do anything). I told them to go ahead with it. I got another call in the afternoon and they said "we have bad news. The tuning software isn't allowing us to overwrite the ECM, you are going to have to take it back to the tuner". I picked up the car later in the afternoon, no charge, and went on my way. Checking my oil this morning I noticed that the engine cover is now broken and rattling.

Questions for you all:

1) Could the malone tune really prevent the dealer from overwriting it? (I didn't think so)
2) Do they take the engine cover off to tune the ecm? If so I'm going to go back and demand a new one.
3) Can the Malone dealer that did my tune put my car back to stock?


Thanks for the help.

Best,

Pete

Sry to jump in your thread but I have a bone stock 2010 Jetta and I'm getting this code pop up every few days to a week a clear it with my scan gauge and it comes right back.

emerscape said:

So quick update. I finally gave up and took my car back to the dealer. I had written them a good review on google as they had asked me ( and because I've been happy with them) and said "do me a favor since I just did you a favor, I don't believe that the software is the issue here, please do an inspection of the DPF and EGR so that I don't have to go through the hassle". I got a call mid-morning and they said that the tech said it needs to be reflashed (meaning they didn't do anything). I told them to go ahead with it. I got another call in the afternoon and they said "we have bad news. The tuning software isn't allowing us to overwrite the ECM, you are going to have to take it back to the tuner". I picked up the car later in the afternoon, no charge, and went on my way. Checking my oil this morning I noticed that the engine cover is now broken and rattling.
Questions for you all:
1) Could the malone tune really prevent the dealer from overwriting it? (I didn't think so)
2) Do they take the engine cover off to tune the ecm? If so I'm going to go back and demand a new one.
3) Can the Malone dealer that did my tune put my car back to stock?
Thanks for the help.
Best,
Pete

Click to expand...

1)no
2)no, but who knows what they were doing
3)yes

hymato said:

Sry to jump in your thread but I have a bone stock 2010 Jetta and I'm getting this code pop up every few days to a week a clear it with my scan gauge and it comes right back.

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Your dpf is cracked. Wipe your finger on the inside of your exhaust tips and they will be black.

Thanks BuzzKen back to the dealer I go ��

My 2010 Jetta TDI started throwing P0401 (insufficient EGR flow rate) frequently at about 49,000 miles and 5 years of use. Since the 1 year mark I had also been experiencing the P0401 code occasionally on hot days, especially on the highway. I took it to the dealer then, and they told me in 2011 I needed a new DPF and EGR. I was not convinced at the time that this was a practical problem, so I declined the repair then. However, I went back to them recently when I noticed excessive soot in the tailpipes and more persistent P0401 code. The rear oxygen sensor failed and had to be replaced in 2014.

The dealer replaced the DPF and the EGR cooler on warranty. I cleaned the tailpipes, and they have remained fairly clean, with only slight hint of soot. However, I now have P2271 (rear oxygen sensor stuck rich) code that pops up after about 50 miles of highway driving and does not seem to go away by itself. I suspect that the rear oxygen sensors have been fouled by heavy soot burden and relatively low temperatures leading to more accumulation. Dealer suggested that I could replace the rear oxygen sensor at some time in the future. Our state/county does no emissions testing on diesel cars, and from what I can determine, the rear oxygen sensor in the TDI is more of a reporting sensor than than anything actually controlling the engine.

I'm thinking of trying to clean the rear oxygen sensor with a flame. If it works, great. If not, I can replace with a new one and I will have learned something in the process.

Quick update here - took it back to the dealer and spoke with the shop foreman. He said he's seen a lot of times TDIs have their DPFs fail within months of being tuned. Of course he would blame the time but he did agree that the DPF was toast. they quoted me $2700 which will be covered under my extended warranty. I'm having the work done on Monday. Question for you all - should I really worried about the tune possibly ruining my new DPF? I'm assuming based on the number of people on this forum with tunes that this isn't the case but had to ask

From my personal experience, it seems better with the tune. More aggressive driving blows the dpf clean passively as opposed to constant regens. The shortest dpf life seems to be with gentle/hypermiler driving.