Help diagnosing MAF related fault, 2.0tdi BKD black smoke!


Registered User
Hey guys, having an issue with my 2.0tdi sportback (140 BKD engine), basically for a while it has been excessively producing black smoke out of the back, even at low speeds its producing an embarrassing amount of smoke. I scanned the car on VCDS and got the following fault code:

1 Fault Found:

16485 - Mass Air Flow Sensor (G70): Implausible Signal
P0101 - 000 - -
Freeze Frame:
RPM: 1260 /min
Torque: 0.0 Nm
Speed: 67.0 km/h
Load: 0.0 %
Duty Cycle: 96.8 %
Bin. Bits: 00101011
Mass Air / Rev.: 250.0 mg/str
Mass Air / Rev.: 600.0 mg/str

I changed the MAF sensor for a brand new Bosch one and for a while I thought the issue was resolved (it was smoking a lot less, although still smoking) but alas this morning the same fault code has come back. The code disappears for a few days after its been cleared but always comes back with the EML.

I should mention I've also changed one of the very small breather pipes that comes out of the odd looking plastic sphere by the engine bay as it had a little leak (sorry for my lack of terminology but it basically just seemed to be used to build pressure) but same issue.

Any advice on where to go from here would be much appreciated as I'm totally stuck!


Registered User
Had the same embarrassing black smoke recently even when not accelerating on the same engine.

Can you hear a boost leak? Mine turned out to be a split intercooler.