2.5 TDI V6 AKE Misfire: Spritzbeginnregelung 27-00 Fix

Hello, I hope someone can help me. I have an Audi A4 2.5 TDI V6 AKE Quattro.
The car suddenly jerks or stutters under load (when the accelerator pedal is pressed more than 50%). The jerking feels like a lack of fuel.

Error read: 0550 Injection start control 27-00, implausible signal.
Filling the tank completely didn't help.

The return lines were replaced, regardless of the issue that occurred four weeks ago.
I have done some research:
Air in the fuel system (how do you check for it?).
VP44 pump failure (allegedly replaced by the previous owner 40,000 km ago, and it appears to be the case visually, as seen when the return lines were replaced).
Injection start within the standard range, from 14.8° advance to 2° retard, which is acceptable.
Defective pump in the tank (which would mean the error would disappear when the tank is full, but it doesn't?).
LMM? Or can I rule that out?

Thank you in advance for your help.

[Translating...]

Autoscan?