I’m at a total loss, I have a 2.0 tdi 150bhp superb. It has lost power a became very smoky, fault code shows 

P0101

Mass air flow (MAF) sensor/volume air flow (VAF) sensor - range/ performance problem

Mass Air Flow (MAF) Sensor Performance

I have replaced the MAF sensor but car still shows the same code after been driven for a short time, I have checked all wiring and it all seems intact and have checked continuity to the ECU and all four wires going to MAF sensor have continuity. Car also shown fault code for glow plugs which I thought may be causing the smoke but after replacing the glow plugs still the same. Any help with this problem or even an idea of where to look next would be much appreciated 

Smoke and lost power suggests an air leak between the turbo and engine inlet manifold. MAF fault occurs because less airflow is measured than the ECU expects. Smoke shouldn't be getting past the DPF though so there may other issues. 

DPF has been deleted from the car, car has ran perfectly up to this point until the MAF sensor failed and a new one was fitted 

Best get it back to whoever deleted the DPF and get them to fix it then. Good luck at MOT time...

On 13/02/2025 at 10:10, D402 said:

Smoke and lost power suggests an air leak between the turbo and engine inlet manifold. MAF fault occurs because less airflow is measured than the ECU expects. 

 

+1 for this, I'd check for air leaks after the maf sensor to the inlet manifold.

Intercooler perhaps?

On 13/02/2025 at 13:44, D402 said:

Best get it back to whoever deleted the DPF and get them to fix it then. Good luck at MOT time...

I’m in Ireland so it’s the NCT and at the moment deleted DPF is still allowed,

would an air leak cause loss of power? Would this cause any other faults to show too?

"allowed" is probably wrong more like "not checked for"...

 

An air leak after the turbo would cause loss of power & smoke. You would have a sudden drop of boost pressure & less air means less fuel before the combustion because Smokey.

 

Small leaks are often difficult to check for because at low/medium air flow there isn't the pressure to force the leak open & as pressure builds the gap will open.

Did you ever find the cause of this by anychance? I'm having the same issue now