D5 P0100 MAF circuit warning
 

After an air filter change, my V60 D5 is reporting the above error. I have an OBD dongle and can read the codes and sensor values via Torque Pro, but the symptoms are very confusing.
The MAF reading is a constant 255 g/s even when the sensor is disconnected and I know it is not the MAF sensor because I have tested a new one. The engine is running normally, no performance issues or excessive consumption etc. The air fuel ratio is 1:29 at idle and drops down for power as I would expect. The turbo boost seems normal up to a max of 1.6 bar. Apart from clearing the code I am not sure what is causing the problem.
I have read some threads on EGR valves and forced regeneration, but can anyone help me diagnose this?

Sounds like a wiring issue so check the plug with ignition on for good grounds and lives with a multimeter.

MAF connector voltages
 

I have inspected the connectors and cleaned them as much as possible. I have taken voltage readings of the connector (engine off, ignition on) with the MAF disconnected (it is almost impossible to take readings with it connected without stripping wires).

PIN Voltage
1 0.00
2 0.04
3 5.02
4 4.50

I have looked at the wiring diagram but I do not know where these wires should terminate (I assume the ECU somewhere). Can anyone help me diagnose this fault? :confused:

Incidentally (may be related!), the battery is low after not many miles during lockdown. Could this be affecting the MAF reading? :thinking2:

Hi, by any chance you figure out, what was causing this problem, because i have identical (P0100 and low battery) on my V60 D3.
thanks