CFGB mass flow meter - readings are implausible

Hi,

My Passat has recently been giving a fault code for excessively high measured air masses (see Autoscan). The error first appeared about a week ago in the mountains, but the ADAC diagnosed it but didn't clear it. Two days later, the DPF warning light came on, and the filter was "regenerated" through a driving cycle.
The DPF warning light then went out.
After about 800 km of driving on the weekend, the Autoscan error reappeared. The error codes were cleared, and the readiness was also OK (according to the display in VCDS).
Today, the same error reappeared. The DPF warning light came on. The error was cleared again, but the DPF warning light remains on (presumably due to excessive soot loading).
The readiness status indicates "Exhaust Gas Recirculation Fault", but no error is currently displayed in the system.

Can It is possible that the AGR valve is not opening correctly, as the MAF sensor is measuring too much air, so there is obviously a deficiency in the amount of exhaust gases being returned? The error with the MAF sensor seems to occur only (2x) at 100% AGR control, i.e. when the valve is fully open (or am I misinterpreting this?).

Oh, and... the DPF ash loading is specified as 220 ml, so a cleaning is probably needed.

Best regards from Berlin,
olli

[Translating...]

Hallo,

ich tippe entweder auf ein nicht richtig öffnendes AGR Ventil oder die AGR Rohre sind so sehr verkokt und damit im Querschnitt verringert, dass zuwenig Abgase angesaugt werden können.

Viele Grüsse, Rainer