Range Rover 4.4 TDV8 (448DT), 313 HP, 2011 – Engine power limited / Error code P006A-00 / Mass air flow 12690 g/h
Hello everyone,
I've been searching for the cause of the following error on my Range Rover L322 with the 4.4-liter TDV8 (448DT, 313 HP, 2011) for over four weeks:
Problem:
The engine power is repeatedly limited, error code P006A-00 (mass air flow vs. boost pressure correlation).
What I've done so far:

Replaced the mass air flow sensor
Checked all cables (including under load)
Transferred the mass air flow sensor cable for testing
Reset the control unit
Performed a smoke test

Anomaly in the live data:
Even with the ignition on (engine off), one side shows a fixed air mass value of 12,690 g/h, while the other side is correctly set to 0 g/h.
After starting, the values ​​naturally rise much too high.
My questions:

What could be causing this fixed value?
Could the control unit be defective?

Other observations:
There is a noticeable draft at the air intake on the primary turbo side.
All vacuum actuators have been tested and are working.
The turbochargers have been professionally reconditioned.
The primary turbocharger flap is open approximately 14% at idle.
The secondary turbo flap shows 0% when idle and opens at around 2500 rpm – correct according to live data.

Now it's your turn – I'd appreciate any advice!