Help needed to solve puzzling P0102 error code

[Hilux Sam]

Hi Everyone,

I'm hoping somebody might be able to help with what is becoming a difficult to solve P0102 error code.  The car is a manual Diesel 2013 SR5 (KUN26R with 1KD-FTV engine) with about 240k on the odometer. I've only had it a few months and recently had it serviced (not by Toyota), it seems to have been pretty well cared for.  Last week I went to start it after a few days of non usage and the engine light came on and after driving about 100m i noticed the VSC off light was also flashing.  It starts fine but has no power when trying to drive it.  I used an OBD2 scanner with the 'car scanner' app which gave me error code P0102 with C1201.  My first thought was rodent damage but cannot find any sign of chewed wires.

I cleaned the MAF sensor, checked for blockages to the air filter intake, replaced the air filter, checked voltage at the sensor connector, insulation on all wires to earth as well as between the wires, continuity (buzzed but didn't measure resistance) from ECU to the sensor, replaced the MAF sensor.  The replacement sensor is OEM bought from a Toyota dealer.   Error codes were cleared after each step but they return immediately.  I also tried disconnecting the battery to clear codes but that made no difference.  I have inspected the air hose on the engine side of the MAF sensor for leaks but it looks good.  It seems to me like the MAF P0102 code is a symptom not cause but don't know to what check next.  

I had a mechanic come and take a look and he said he thought it could be an ECU problem because with the engine running, when he disconnected the connector to the MAF, there was no change to the airflow reading (which he said was zero) and he expected that the ECU would set the Airflow to Max.  He also said it is an hard error being thrown as it appears as soon as the car is started even after having been cleared.  When I use my OCB2 reader to check the sensor value it says 2.6 which never changes, even with the engine off and only the ignition on.  

Can anyone confirm what value I should see for the MAF sensor with it disconnected?

Any ideas on what I should be doing next would be much appreciated.