It's my first time posting here so don't be harsh on me when it comes to any mistakes or spelling because I'm not a native english speaker
Let us begin...Last year (05/2023) I bought my VW Scirocco 2.0 TDI 103 kw/140 bhp (has a Stage1 ECU flash, MY 2009) with approx. 230k km from a good friend of mine. I didn't have any issues, but my friend warned me that he had trouble with regens when it comes to DPF, mainly the car would wait a long time (read kilometers) to do them. He tried a bunch of stuff to make them more frequent such as adding Liqui Moly DPF additive to a full tank and cleaning the said filter manualy, forcing regens etc.
After the purchase, my car did regens around every 500km and in November of 2023 I checked the parameters of the DPF which looked okay, mainly the pressure value which was 2.56 and should be a good indicator of a healthy DPF.
Two months ago, my car showed CEL, fault code p2196 O2 sensor signal stuck rich/signal too high thinking it was just a dirty sensor. My consumption did increase a bit, but only in city driving. I clear the codes, but after a few days the CEL comes back. I didn't have the chance to scan the code immediately, but the CEL went away on its own. After that, the CEL showed itself again and went away on its own again. After that I cleaned my O2 sensor and went to scan the codes because they were stored and this time it showed p2196 and p0401 EGR insufficient flow. At the same time I checked the parameters for my DPF and everything "looked" fine. The main thing was the pressure of the DPF which read the same 2.56 making me a bit suspicious but nothing too worried about. For a few days everything was fine, the car did it's regen and the consumption was a bit less, but 2 days ago, I got another CEL and again it went away. This time, there was only the p0401 code. For the third time, I checked my DPF parameters to find the same pressure value 2.56 (soot and other values were always different, depending of the timing of the regen and soot build-up). I reset the pressure sensor to find it again, showing the same value of 2.56 and it would climb when revving the engine and go back down to 2.56 on idle. Also in the last month, I noticed a bit of soot in my exhaust, barely noticable, but non the less there and present. People have told me that a bit of soot is normal because the soot from DPF needs to go somewhere after the regen.
As of yet, after 2 days, there are no codes, but these things worry me:
1. Is it a faulty pressure sensor showing the same value?
2. A lot of people on other forums say and link the p0401 code to a cracked DPF but with a lot more soot in the exhaust than there's in mine
3. Some people say and link the p2196 and p0401 code to be connected as one influenced the other
4. Approx. 500km distance for a regen (I feel like it doesn't meassure the soot build-up but instead activates the regen when it hits the "500km" mark- only a speculation)
5. Maybe it's something else that I skipped or not noticed but should look for?
Any advice, help, direction/guide on solving my struggles would be deeply appreciated. Sorry for the long thread, but I had a "hunch" that I need to explain every detail and to be as precise as one could be for a good feedback. Thanks!
