DPF light, Nox Exceed. P2BA6, DPF problem or something else?

[Sadams]

Hi all,

2011 Audi A3 TDI, previously when I bought it I had just about the entire exhaust system replaced, including the DPF, while it was still covered under warranty. Had no improvement until they finally replaced the DPF itself. Haven't had any problems since, that was about 2 years ago and nearly 60,000 miles later.

Ive had a number of issues occur this fall, P2015 intake manifold which I fixed with the DieselGeeks bracket. Some glow plug error and rough starts on particularly cold days (midwest USA) which I'm investigating and not particularly worried about.

I've had this NOX error for a short bit, I've put unfortunately more miles on the car then I've liked with a DTC, probably about 1-2k. So I'm trying to get some more information about what exactly this code stems from and what I can look to target to fix it. My cheap, ****ty, OBD reader has a mention of the cat converter on the DTC page for the NOX error, but there's a DPF light. Is it a problem with the cat? Is it a problem with the DPF? Is it both? Is it neither?

It is important to note, I still have the full EGR system that was replaced under warranty. I am now out of both dealership and diesel gate warranty and I no longer live in an area that requires emissions. Should I go ahead and spend the $2,000 for a delete kit and tuning? Is there any cheaper solutions?

I have attempted regenning, I've put primarily highway miles on it anyways, I've heard (and smelt) what I believe to be multiple DPF regen cycles after stopping the car at the end of long drives. I tend to cruise control above 2k RPM. I commute regularly on open highway and don't live in the city, so it's hard for me to say my driving habits worsen it, but that's up for debate I guess.

 

[MrCypherr]

The 'DPF' light usually comes on when there is a NOx cat fault present. More so like a regen needed. The NOx regen is basically you driving between 40-70 minutes at highway speeds without (or very little) stopping. I believe you need to have VCDS to monitor it via the MVB. I know some people just reset the values for the NOx cat and the fault goes away. Not sure how good that is but to each their own.

With regards to 'losing' a couple parts, It is for sure a good option if you have to replace DPF/NOx/EGR system parts. Its never a good thing to have exhaust soot go back into the intake. Youll gain more smell on the outside of the car and some noise. You can keep your stock muffler which alot of people do. I know some people scrap their old parts to try and make some of the money back but not sure what prices is like down there.

 

[Sadams]

The 'DPF' light usually comes on when there is a NOx cat fault present. More so like a regen needed. The NOx regen is basically you driving between 40-70 minutes at highway speeds without (or very little) stopping. I believe you need to have VCDS to monitor it via the MVB. I know some people just reset the values for the NOx cat and the fault goes away. Not sure how good that is but to each their own.

With regards to 'losing' a couple parts, It is for sure a good option if you have to replace DPF/NOx/EGR system parts. Its never a good thing to have exhaust soot go back into the intake. Youll gain more smell on the outside of the car and some noise. You can keep your stock muffler which alot of people do. I know some people scrap their old parts to try and make some of the money back but not sure what prices is like down there.

MrCypherr,

Thanks for the quick response. I have seen in other forum posts about the same issue discussing the "regeneration needed" error, but I think that's specific to VCDS, which I do not own and have not been able to run a check.

I don't mind added smell or noise. The EGR/DPF delete is ideal in my mind, but it's a pretty hefty upfront cost and a fair amount of work, so I'm looking to see if there's some other methods I can look into in the mean time before pulling the trigger on a full delete, or confirmation from someone smarter than me who can make the call that it's the best solution.

 

[Arrbees]

The 'DPF' light usually comes on when there is a NOx cat fault present. More so like a regen needed. The NOx regen is basically you driving between 40-70 minutes at highway speeds without (or very little) stopping.

This.
The DPF light comes on when the NOx regen is needed but has failed several times due to shutting off the car. If everything is normal you'll likely hear the fan run high in stop and go traffic and turn on and off like a standard DPF regen.
Driving on the highway is generally the fix. The DPF light should go out once the regen has completed. I have had to repeat the process a second time to get the light to stay off before. 40-70 minutes seems excessive in my experience, but if highway speeds in your area are only 50mph then maybe it will take that long.
You should not need a VCDS to do anything but monitor coolant temps, but if you have heard the fans kick on and noticing slightly worse gas mileage than normal it's likely there's no issue since the car is getting up to temp and dumping excess fuel into the exhaust in an attempt to regen.
This should not be a DPF problem. Notice there are more DPF delete threads then there are dead DPF threads. Therefore the DPF is probably somewhat reliable in these cars despite the bad press unless you've logged over 100,000 miles on the vehicle or have been ignoring a CEL for a long time. Then maybe the DPF is an issue.

 

[turbodieseldyke]

They really should have made the DPF light blink green during regens, so people know when it's happening & not have to guess.

 

[oilhammer]

... Therefore the DPF is probably somewhat reliable in these cars despite the bad press unless you've logged over 100,000 miles on the vehicle or have been ignoring a CEL for a long time. Then maybe the DPF is an issue.

Had to laugh at this part.... the only thing reliable about the DPFs in the CJAAs is that they reliably give me work to do. It is January 17th as of this post, and I've already done four so far this year.

The OP will be in the dark without use of a suitable scan tool. As noted already in this thread, the DPF and deNOx catalyst are two different things, although VAG chose to use the same warning lamp for both. There are also issues in cold weather with poor thermostats causing repeated deNOx catalyst regen failures. If the coolant dips below 87C, it will not regen.

 

[MrCypherr]

They really should have made the DPF light blink green during regens, so people know when it's happening & not have to guess.

That would have made too much sense. Even just have something pop up on the dash saying "Regen in progress" Atleast give the people something lol

 

[Arrbees]

Had to laugh at this part.... the only thing reliable about the DPFs in the CJAAs is that they reliably give me work to do. It is January 17th as of this post, and I've already done four so far this year.

The OP will be in the dark without use of a suitable scan tool. As noted already in this thread, the DPF and deNOx catalyst are two different things, although VAG chose to use the same warning lamp for both. There are also issues in cold weather with poor thermostats causing repeated deNOx catalyst regen failures. If the coolant dips below 87C, it will not regen.

Yeah, and I worked for Apple. I'll never buy an iPhone because they were always broken when people contacted me about them.
But yes, if the CEL light is on, a scantool would be best here.

 

[brownnugen]

Bringing this thread back to the top; is there more than one type of regeneration? One for the DPF and a different one for NOx? My DPF light is on, but I have the 2 NOx error codes P2BA6- NOx Emissions Exceeded and P1A58 -regeneration required.

I forced regeneration twice yesterday with VCDS but the codes are still there.

And someone mentioned a smell during regenerations. I never smelt anything when I forced them yesterday but on the last 2 days (while driving), I have intermittently smelled what I can only describe as a freshly lit match in the passenger compartment of the car. Is that what a regen is supposed to smell like?