DPF emergency regeneration not working

Hello - I'm new here, so sorry if I'm doing everything wrong already. I've already read the introduction and other information - GREAT forum, nothing like MT or similar platforms.

I'm a hobby mechanic from Austria, and I usually repair my Audi A6 4F Avant 2.0 TDI (BRE) from 2007 myself. Now, here's the actual problem:

I bought a used DPF (long story), cleaned it, and installed it. So far, so good... However, the DPF warning light came on after about 100 km, even though I had set the soot level to 10g and calibrated the differential pressure sensor (NEW, 07Z 906 051A) before driving.

After reading the excellent instructions here on how to verschandeln the DPF (unfortunately, AFTER I had already cleaned mine myself), with the important note that you should perform a forced regeneration immediately BEFORE cleaning (to convert soot into ash), I wanted to verschandeln the DPF again and, in order to do so, perform the forced regeneration.

Okay, so I went directly into the MSG, typed in the corresponding login (I think it was 21295), which was also accepted according to VCDS, but unfortunately, the DPF light immediately came on with the extremely valuable message: "See user manual" . This happened while idling, mind you. I tried it a total of 5 times, and I strictly followed all the requirements as described in the instructions (the tank was half full, the oil was even at 90 degrees, the load was 9.9%, etc.). Every time, the same thing: a loud beep with the DPF light!

What am I missing? What could be the reason for this? Unfortunately, I haven't found any clues through searching. Thank you in advance!

It is normal for the DPF light to come on during a forced regeneration.
The manual should state something like: "Please continue driving with sufficient load..."

Best regards, Rainer.

Start the regeneration process and then log the Mass Air Flow (MAF) sensor data with the post-injection active, which should be code 074. Then, start driving and maintain a steady engine speed, for example, using gear 3. You should then be able to see in the MAF data whether or not the post-injection is occurring. Continue driving until the fuel trim value stops decreasing or the post-injection stops. After that, clear the error codes, and it should be resolved.
Most of the time, the light comes on because the DPF has been regenerated (cleaned).

Thanks for the information!!! I wouldn't have thought to drive there. I honestly thought it had to work from the stand. I will definitely report back and let you know if it worked out. But I won't be able to get there until at least the weekend.

But one thing I'm curious about: The new differential pressure sensor has an offset of -7 after calibration. Does that mean something bad?

Best regards!

Not yet. But it only regenerates if everything else is working correctly. So please upload a recent system scan.
Then we'll see what happens next.

The 10g [of something] only make sense if the cleaning was reasonably successful...

matthiasTDI96 wrote:

So please set up a current car scan. Then we'll see what happens next.

I can bring it by the weekend at the earliest! Thanks!

Sure, here's the translation:

"One more question:"
How long do you let your DPF dry after cleaning? In my case, even after hanging it outside (under a roof) for more than 24 hours, water was still coming out. I tried to blow it dry. Is it bad if there's still moisture in it? Or will the exhaust gases from the engine eventually dry it completely?

alm0st.un1que wrote:

One more question: How long do you let your DPF dry after the cleaning process? In my case, even after hanging it outside (under a roof) for more than 24 hours, water still came out. I tried to blow it out. Is it bad if there is still moisture in it? Or will it eventually dry completely due to the exhaust gases from the engine?

The exhaust gases from the engine consist mainly of CO2 and H2O, commonly referred to as "water."
You shouldn't immediately drive at full throttle with a wet DPF, as the boiling water could damage the ceramic core of the DPF. I don't know if it's even possible for the silicon carbide to absorb a significant amount of water.
To be on the safe side, if your DPF is clogged or partially blocked, let the engine idle for a while and start the next journey slowly.

Best regards, Rainer.

Thank you for the detailed explanation! I will do it!

Did you flush it in the wrong direction?

It's possible that, due to the regeneration process not having been completed before cleaning, you may still have a significant amount of ash in the filter.

Normally, you rinse the part, let it drain, and then you can install it. I personally don't understand why some people dry this part in their home oven. As Rainer writes, just install it, start the engine, and after a while, you can drive off. Always assuming that the rinsing direction was opposite to the exhaust direction.

matthiasTDI96 wrote:

Did you flush it against the flow of exhaust gases...?

Yes, I do.

matthiasTDI96 wrote:

Because the regeneration process didn't occur before cleaning, it's possible that you still have a lot of ash in the filter.

That was also my assumption, which is why I brought up the topic of .

matthiasTDI96 wrote:

Normally, you rinse the thing out, let it drain, and then you can install it. I personally don't understand why there are subjects who dry this thing in their home kitchen oven. As Rainer writes: Install it, start the engine, and after a while, drive off. Always assuming that the rinsing direction was against the exhaust direction.

I hope I'm not being addressed here, as I haven't misused any kitchen or oven ! But I did have concerns about the moisture... until Rainer's response!

Greetings!

No, it wasn't directed at you personally, but rather a general statement. The remaining amount of ash is very difficult to estimate. That's why there's also the suggestion (perhaps in this article?) to try using a thin wire to gauge it. I am familiar with the DPF (specifically the flange and shape) on your vehicle. With a Sharan 7N filter, this isn't possible because there is no direct access (it was the only DPF I ever had in my hands). Of course, the amount of soot due to the lack of regeneration poses an obstacle when cleaning. Therefore, it would probably be best to restore the original fill level first.

alm0st.un1que wrote:

But I was already worried about the wetness... until Rainer's answer! Greetings!

You don't have to do that. I just did the last one last Saturday. I blow them out with compressed air and reinstall them immediately. Besides, if there's condensation inside due to operational reasons, it's not a big deal anyway.
Let me quickly outline my usual approach. Maybe it will be helpful for you.
- Perform a regeneration cycle according to the technical article, with a connected laptop so you can monitor its progress. The DPF warning light is not included on all models.
-Let it cool down until you can work on the filter.
Fill the filter with water and dish soap and let it sit overnight. If possible, seal one end of the pipe with a cork from a wine bottle and place the filter upright. Do not use any aggressive chemicals such as carburetor cleaner or similar products. These substances are ineffective against ash and, moreover, most filters have coatings made of precious metals that do not tolerate them well.
- Then, alternately rinse with a pressure washer and compressed air from both sides until only verschandeln water comes out. Don't just do it three times in an automatic car wash and call it good. This requires some patience. I will refrain from using abrasive cleaning tools like wire brushes, as they could crack the ceramic body.
It's not really about using special high-pressure cleaners; it's more about patience.
- Ultimately, extinguish it and leave it standing for another fifteen minutes. Replace the filter and change the ash receptacle. For the 60g filters, I always put in 20g. There has never been a problem with that. And that's all there is to it.

Thanks again for the responses. The regeneration process started as it should after I drove off. It went down to 0.6%! Unfortunately, it took me a while to get back to you because I had to wait two whole weeks for my gaskets to arrive, as Autodoc seems to be experiencing delivery issues lately (they indicate 1-2 days). So the car sat in the garage for two weekends with the intake manifold removed and without any attachments.

Unfortunately, cleaning the DPF was not a solution to my long-term problem, which I will report on separately (low boost pressure). I unfortunately need to start a new thread because, after reading for years, I haven't found a helpful solution yet, and I've already tried so many things that you could easily create a troubleshooting guide from them .