DPF Problem: 2.0 TDI BPW A4

Hello,
I have an A4 where the engine block was replaced due to a piston failure.
After the engine replacement, the regeneration indicator came on.
While driving on the highway, it suddenly turned off. However, after driving on a country road, it would always start up again immediately.
After that, I replaced the DPF and reset the ash value to 0.
During a stretch of highway driving, the warning light came on again.
A few kilometers further on, the indicator light started flashing, and the engine went into emergency mode. During this highway drive, I noticed that the coolant temperature repeatedly dropped. Consequently, I had the thermostat replaced.

Now, here's the problem:

Code:

-------------------------------------------------------------------------------- --------------------------------------------------------------------------------                 Adresse 01: Motorelektronik       Labeldatei: DRV\03G-906-016-BPW.lbl    Steuergerät-Teilenummer: 03G 906 016 KN    HW: 03G 906 016 KN   Bauteil und/oder Version: R4 2,0L EDC G000SG  9794                  Codierung: 0000072             Betriebsnummer: WSC 46493 XXX                       VCID: 79F56EE760 XXX 1 Fehler gefunden: 008194 - Partikelfilter Bank 1                P2002 - 000 - Fehlfunktion - Warnleuchte EIN              Freeze Frame:                     Fehlerstatus: 11100000                     Fehlerpriorität: 1                     Fehlerhäufigkeit: 1                     Kilometerstand: 279871 km                     Zeitangabe: 0              Freeze Frame:                     Drehzahl: 2184 /min                     Geschwindigkeit: 109.0 km/h                     (keine Einheit): 4.0                     Tastverhältnis: 60.4 %                     (keine Einheit): 168.30                     Temperatur: 10.8°C                     Zeit: 4492.8 s Readiness: 1 1 0 0 0

It's stored in the error memory and cannot be deleted.
What can I do?

I hope someone can help me, thank you in advance.
Best regards, Oliver.

Hi,

I would like to review the following documents.
- Check the plausibility of the temperature sensor readings on the DPF.
- Differential pressure at the particulate filter when the engine is started, with the engine off.
- Differential pressure at the particulate filter when starting the engine, at idle.
- Compare the differential pressure at the particulate filter with the following topic:
I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

Best regards, Rainer.

Hi,

Is it regenerating now with the new thermostat?

Try going on a regenerative ride.
In August, while I was on my way to work during the regeneration cycle, the lamp turned on. It had interrupted the regeneration because the water temperature was too low.
The cause was a broken plastic tab on the thermostat flange, which is the mounting bracket for the thermostat. This tab had become lodged in the open thermostat.
The thermostat was stuck open, and the engine was not reaching its operating temperature. Consequently, no regeneration cycles were occurring. I then performed a regeneration cycle in August, using the auxiliary heater.
That worked. And then I replaced the thermostats.