P0401 - cracked DPF long term damage?

WADVR

Member
Joined
Jun 19, 2014
Location
Carnation, WA
TDI
'12 Jetta TDI
Hello,

I've got a 2012 with a cracked DPF that I was fine with running on till the emissions fix was done but seems that will be a while from now. I monitor my EGTs and is driving me nuts seeing temps above 1200 much of the time I drive as it can't regen and keeps trying. $2500 for a replacement is out of the question but $1300 for a delete pre emissions fix is out too(Malone tune and delete will be ordered immediately after the 'fix' though) Then I question whether they will force me to repair to comply with the emissions fix... Anyone have any input on this issue? I worry that running these temps will cause damage and more issues later.

This issue has me reconsidering just going with a buy back to get it over with and not deal with the issues. Plus the buy back is offered at more than I paid for the car so it's attractive.

Thanks in advance. I did read several threads about this but still wonder about my options.
 

super1

Veteran Member
Joined
Apr 19, 2010
Location
NY
TDI
none
Damn thought you might have been under 80K
Go with the buyback then


Sent from my iPhone using Tapatalk
 

HeyKid55

New member
Joined
Aug 9, 2016
Location
CLAYTON, NC
TDI
2010 Jetta Sportwagen
I have a couple questions about the DPF: Does having a P0401 code mean that your DPF is cracked? Does having a P0401 code make for a load exhaust noise? I have 108k on my 2010 Jetta sportwagen. I have been rethinking my decision to keep it and the emission issue fixed
 

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
I have a couple questions about the DPF: Does having a P0401 code mean that your DPF is cracked? Does having a P0401 code make for a load exhaust noise? I have 108k on my 2010 Jetta sportwagen. I have been rethinking my decision to keep it and the emission issue fixed
There are other things that can cause a P0401, but user oilhammer (works on many of these cars for a living) said he never saw a P0401 for any reason except a cracked DPF>

There is no increase in exhaust noise that I can tell. if you have an exhaust noise, there may be another problem.



for your 2010, do you have the single part DOC/DPF with NSC (NOX cat)?

might turn out that an approved fix includes a replacement for a defective DPF. just have to wait to see the details.

if you have not the patience for waiting, a sell back is ok.
 

WADVR

Member
Joined
Jun 19, 2014
Location
Carnation, WA
TDI
'12 Jetta TDI
P401 is actually a code for the EGR not functioning but the cause for that is usually a plugged/cracked DPF. That and soot on the tail pipe/back of my white car all point to the DPF causing the issue. My car doesn't run any louder than normal but i am experiencing a lot of heat in the engine compartment and under the car from it always trying to regen. In fact in stop and go traffic the air coming out of the vents starts increasing to where I need to turn on the AC to cool it down. Another side effect is lower MPG. Haven't broke 38 since discovering this issue with usual numbers in low 30s. Was 43-48 prior.
 

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
What exactly are you using to monitor the car?




Have you verified all codes reported?

There could be other issues.
 

WADVR

Member
Joined
Jun 19, 2014
Location
Carnation, WA
TDI
'12 Jetta TDI
What exactly are you using to monitor the car?




Have you verified all codes reported?

There could be other issues.
P3 vent guage. It displays the stored code on each start up. The actual check engine light is no longer displaying. I use this guage primarily to monitor EGTs/regens. Car went from a single 10-15min regen per tank to almost always trying to regen almost like the warm up cycle over and over.

Dealer confirmed the code but haven't dug into it further. They said same as I've read about the DPF causing this issue. Was going to live with it until the 'fix' as they also stated my emissions warranty would be extended(then I could fix under warranty). On my latest dealer visit the TDI leaison pretty much said good luck on getting the fix done before 2018 if even then, so I am rethinking this whole ordeal.
 

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
how do your coolant temps look?

It does not make sense to me that the DPF is trying to go to regen all the time.

watching my car, (with a polar fis plus and VCDS), I can see a little more detail on how the temperatures and soot values change during a regeneration cycle.

it takes a bit of time for the regeneration activity to increase the temperature and supply enough air to the DPF to reduce the measured soot load, and the calculated soot decreases after that. at the end of the cycle, the miles, time, and fuel since regeneration resets to 0.

if the car was always trying to get into regen, the calculated soot level would never get to the point where it is decreased, and pretty soon you would have high enough soot levels that the DPF lamp would light.

How long have you had the car and been watching? there are, of course, seasonal variations in MPG, due to temps and fuel formulation.

You might want to get a VCDS interface. cost is not cheap, but less than a car payment.

Having the check engine light go out with the stored codes is not unusual for this condition.

http://forums.tdiclub.com/showpost.php?p=4865545&postcount=1
 
Last edited:

WADVR

Member
Joined
Jun 19, 2014
Location
Carnation, WA
TDI
'12 Jetta TDI
Coolant temps are usually 190ish to a max of 209.

Have had the car and gauge since 2014 (47k miles) I watch everything pretty obsessively. The regens are more of a warm up cycle. Is up and down. Cruising down the freeway and seeing temps in the 1500s for more than 10-15 minutes several times in a single trip 400 mile trip for example is a little disconcerting. When I say they are like the warm up cycle and up and back down I am meaning that as aposed to a true regen where the temps stay above 916° even at idle and top out at 1540° and are in that range regardless unless compression breaking or slowing down in gear where it cuts fueling I am experiencing these temps mixed with low temps as well. It will be running at 1500+ on flat ground and drop to 7-800s and back several times with 5 miles with the longer durations being in the high end. I have even watched the mpg counter to see if there was a coorilation and can see when the fueling cuts, there is no coorilation between load and the temps I am seeing which tells me the computer is trying to regen or do some other task I am not aware of existing. I have not had a single true complete regen cycle since this became evident. The DPF lamp has never came on.

If you think I need to dig a little deeper, I do see your point and will do so as I am just watching the gauges. A VCDS might be a good investment.
 

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
Not saying you need to do any thing specific,

but without seeing the measuring blocks, it is difficult to know for sure.

with a good view of the soot level figures, and miles, time, and distance since regen, with the DPF status (which does not seem to show on some cars), it is much easier to sort out the various regeneration cycles.

The EGT is helpful, and with the increased fan and sometimes speed at idle, can tip you off of an ongoing regen at the end of the cycle, (should you wish to wait a bit before turning off the car to allow EGT to reduce before you cut off oil flow to the turbo), but as you seem to understand, can also be driven by other conditions.

a TDI and a VCDS can add up to a side hobby, if you like that kind of thing.
 

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
http://pics.tdiclub.com/data/500/2016_03_coolant_and_dpf_temp_charts.pdf

I made up some charts from data recorded over a 26 minute drive last march. includes both a de-NOX regen and DPF active regeneration.

(while not reflected in this data, I have also seen deSOX regens that push exhaust temps over 800c)

there are three different exhaust temps recorded. everything is in centigrade, since that is what the car speaks, and is reported by VCDS.
 

SkeeterMark

Veteran Member
Joined
Jan 8, 2013
Location
North Branch, MN
TDI
2013 Jetta TDI 6M
Mine was diagnosed with a cracked DPF by VW several months ago, and I have soot in the tailpipe. I've driven about 15,000 miles since then. I do not see higher EGR temps (monitored with Torque Pro) nor any increase in regens or attempted regens. Coolant temperatures are the same, and so consistent that 192.2 is screen burned into my phone. In fact, if anything, I think it does less. More like pre 23O6 update. My mileage (of which I keep detailed records) has not changed at all. It drives and behaves pretty much the same as it always did except the CEL is on all the time.

I have 120k on the car, need a timing belt, tires, and a DPF. I would like to put off the DPF until there's a fix (if there's a fix) and then do the tune/delete. I have no hesitation in servicing the car by replacing the tires and timing belt. These were costs I had planned on incurring, and would also incur at some point if I get a used vehicle with buyback money of near or equal value. Since I plan on keeping it until the fix, or until the 2018 deadline, it seems prudent to take care of it. I don't see it as wasted money. Probably less than sales taxes on a replacement.

Problem is, there just isn't a car I can replace this one with that would seem decent now. I've grown accustomed to 50 mpg, and I think fuel prices are in for a change soon.

I am concerned about the cracked DPF. I don't know if I can drive it for nearly 2 more years this way if the fix is a long way out there, or until I have to sell it back if they announce there is no fix. For now, it seems fine. I imagine it will start running poorly if it becomes an issue, and at that point I might opt for buy back.
 
Last edited:

n1das

TDIClub Enthusiast, Veteran Member
Joined
Jun 11, 2002
Location
Nashua, NH, USA
TDI
2014 BMW 535xd ///M-Sport, 2012 BMW X5 Xdrive35d, former 3x TDI owner
The P0401 code is for "EGR malfunction - insufficient flow". The LP EGR path has a filter in the path from exhaust back to the intake and this eventually gets clogged up from soot getting past the (cracked) DPF and restricts flow.

The LP EGR circuit takes exhaust downstream from the DPF so that it's clean exhaust being recirculated. The filter (listed as a TUBE) cleans up anything left over in the exhaust before injecting the flow into the intake path upstream of the intercooler. Note that this is different from the HP EGR path which usually takes exhaust from the exhaust manifold ahead of the turbo and injects into the intake path downstream from the intercooler.



With a cracked DPF you have some soot getting past the DPF and it slowly clogs up the EGR filter ("TUBE") in the LP EGR path. Flow in the LP EGR path eventually gets restricted enough to trigger the P0401 code for insufficient flow.

The only issue I see with driving with a cracked DPF and P0401 code is you will have the P0401 code continuously and some soot in the exhaust pipes. Given the issues with EGR and the dreaded intake clogging particularly with older TDIs, the filter clogging up effectively reduces the amount of LP EGR, equivalent to blocking off the LP EGR. It doesn't affect the HP EGR path at all. If your state doesn't require the car to pass an OBD-II scan for state inspection and you don't mind a perpetual P0401 code then you are good to go. If your state requires passing an OBD-II scan then you'll have to fix it somehow.

I had a cracked DPF and P0401 code in my 2010 JSW TDI back in 2012, starting around 70k miles. At the time I didn't know the DPF was cracked and replaced just the LP EGR filter ("TUBE") since I knew the DPF wasn't clogged up and power and MPGs were all normal. That cleared the P0401 code long enough for me to get thru an OBD-II scan to pass NH state inspection. The P0401 code came back about a week later as the new filter was getting clogged up. I drove it that way until I sold the car in 2013 at only 102k miles.

Fear not, if you don't have to pass an OBD-II scan in your state then you can safely continue driving with a P0401 code.

Good luck.
 
Last edited:

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
one more note is that if you drive with the MIL lit, you want to check once in a while to see if there are additional codes that could be more of an immediate issue.
 

pdq import repair

Veteran Member
Joined
Nov 6, 2016
Location
idaho
TDI
09 Jetta
I have driven mine with a cracked DPF now for about 15K miles. Drives and acts entirely normal, just soot in the tailpipe.
 

SkeeterMark

Veteran Member
Joined
Jan 8, 2013
Location
North Branch, MN
TDI
2013 Jetta TDI 6M
I do check for additional codes once in a while. So far, so good, so I'll bypass any repairs and drive on, just as I have been.

Thanks for the info.
 

SkeeterMark

Veteran Member
Joined
Jan 8, 2013
Location
North Branch, MN
TDI
2013 Jetta TDI 6M
Now, it turns out, I do NOT have a cracked DPF. I just had my timing belt done and my guru said that is not the problem. Says a regen and driving it hard for 1/2 hour will clear my error code.
So the dealer performed their diagnosis for $275 and recommended a $2400 repair to the DPF and EGR for something that was not the problem. hmmmm. Almost fraudulent.
 

bennybmn

Veteran Member
Joined
Mar 17, 2012
Location
Long Island, NY
TDI
(Formerly) '11 Jetta 6 speed, Alltrack 6MT
My CEL has been off and on now for a month or so... Seems to come on as the weather gets warmer. but it turned off today oddly, and it's over 40.
 

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
perhaps the borderline P0401 error is related to the winter/summer fuel, vs weather.

(probably some of each.)


Edit: I caught a couple new P0401 errors yesterday. same fuel, warmer weather.
 
Last edited:

zuulmusic

Member
Joined
May 5, 2017
Location
US aye
TDI
mkvi
I have a similar issue on my 2011 Golf TDI (almost 90K mi, no mods).
I've had P0401 pop up intermittently the past few months and getting more frequent. Also most of the time more recently I have a very rough idle, cold but also after warming up. occasionally there is no rough idle at all. In the colder months sometimes I could barely get it started, and similar rough idle thereafter. There is still full power when accelerating. There is some soot in the tailpipe but I only now started looking.

I'm wondering if I could possibly damage things to the point where I can't eventually take it to the buyback appointment. I want to hold onto it for awhile first!
 

GetMore

Veteran Member
Joined
Apr 10, 2003
Location
Patterson, New York
TDI
1997 Passat TDI, 2010 Jetta Sportwagen
Hard starting might be "frozen intercooler". You haven't given us a location or the temps it happens at, so we can only guess, but do a search and see if it matches.
I don't think dpf or egr filter issues cause rough idle, so that might be something completely different.

As long as it moves under it's own power, and isn't limping along, you should not have issues with the turn-in. If it breaks beyond that you will be screwed.
 

zuulmusic

Member
Joined
May 5, 2017
Location
US aye
TDI
mkvi
So I want to take it on a 1000 mile road trip soon, but I still have the occasional rough idle and code on and off. Even if it is a cracked DPF, can I do so much damage that it won't run (clog up?) after a long trip?

The hard starts were mostly early spring here (Cleveland) about 40F. Has done it recently above 50F but not much now.
 

tdi54

Veteran Member
Joined
Dec 19, 2010
Location
California
TDI
1981 Rabbit Diesel(sold), 2009 Jetta TDI MT(sold)2010 Jetta TDI MT, 2015 Jetta TDI SEL, DSG, 99 Ford F 350 PSD Dually, 2016 BMW X5 xDrive35d, 2016 535d
I have been driving with cracked dpf for a while now. To get the MIL light off, I removed the filter media in the low pressure egr filter [you need to take it to an exhaust shop to get it cut to remove filter and weld it back] and since then the car is driving with no issues, no MIL light just sooty exhaust pipe, which I couldn't care less about it.
 

zuulmusic

Member
Joined
May 5, 2017
Location
US aye
TDI
mkvi
I have been driving with cracked dpf for a while now. To get the MIL light off, I removed the filter media in the low pressure egr filter [you need to take it to an exhaust shop to get it cut to remove filter and weld it back] and since then the car is driving with no issues, no MIL light just sooty exhaust pipe, which I couldn't care less about it.
Not worried about soot going into engine?
 

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
The engine already gets some soot from the high pressure EGR loop.

the problem with gutting the low pressure EGR is more in the intake side of the turbo (my guess) which is designed to only see well-filtered air. (and the screened and cooled low pressure EGR exhaust gasses)
 

tdi54

Veteran Member
Joined
Dec 19, 2010
Location
California
TDI
1981 Rabbit Diesel(sold), 2009 Jetta TDI MT(sold)2010 Jetta TDI MT, 2015 Jetta TDI SEL, DSG, 99 Ford F 350 PSD Dually, 2016 BMW X5 xDrive35d, 2016 535d
the problem with gutting the low pressure EGR is more in the intake side of the turbo (my guess) which is designed to only see well-filtered air. (and the screened and cooled low pressure EGR exhaust gasses)

I think the gases are still cooled but you might be right on the intake side of the turbo, at this point I am not sure if there will be long term damage.
I have put over 10K with this set up and have not seen any performance or fuel economy issues. I guess time will tell.
 

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
Agreed.

the VW folks put the screen/filter there for some reason.

(I have on theory that it is really there to detect a failed DPF. and that improvement in this capability is why a new LP EGR filter is part of the "fix" as described in the court docs... to do a better job of detecting failed DPFs. I have a further wild ass guess that discussion on who covers which part for how long is being discussed, and delaying approval of the "fix")
 
Top