2016 V40 D4 MAF fault?

[P37tsy]

I have a 2016 V40 D4 with 130K which regularly comes up with the dreaded tortoise and reduce performance message.
When scanned it shows P00BC00 Mass or volume flow A circuit range/performance- air flow too low.
I tried cleaning the MAF but this did not help.
I fitted a new MAF but this did not help
I then removed and cleaned the EGR and cooler which was fairly blocked, but this did not improve it.
I found the inlet manifold pressure sensor was very dirty, so fitted replacement, but this too did not fix it.
Any idea where to go next?

[P37tsy]

Well, I checked the exhaust pressure sensor pipe and it was blocked solid. So I removed the pipe and eventually managed to clear it (with carb cleaner and bicycle brake cable in a drill). Put it back on and the car drives fine with no stuttering but it now comes up with a P047100 Exhaust sensor A circuit range/performance. This fault only shows when reading codes with scanner and doesn't bring up a warning on the dash. I had a new exhaust gas pressure sensor from GSF but this brings up the same fault.
It seems strange that when the pipe was blocked and the sensor would have been reading nothing it didn't bring up this fault, but now it is clear it is.