I've had the same problem for many months on Mazda 2.2 diesel 2016 GJ. The car has been driving as normal but the SCBS code was coming up together with traction control light. I learnt on the way that this is the way Mazda 6 tells you there is a problem and you need to plug in to a computer for diagnostic. My error code was P0101 - Air Flow, Air Mass Meter.
Since I developed the problem I had:
- MAF sensor replaced with a genuine Mazda one (£250 - I wouldn't go with a non-genuine tbh)
- Manifold cleaned up
- MAP sensor cleaned up and checked
- EGR cooler cleaned up and checked
- all pipes/connectors checked up
- oil and filters replaced (twice in the space of 5k miles)
- strainer cleaned up
I also learnt that Mazda 6 requires injector washers change as the copper ones worn and may cause a lot of various problems.
Copper washers were replaced with steel ones (genuine Mazda part)
During the change my mechanic found out that injector number 2 was seized.
He couldn't do it with manual tools as he would risk damaging the plastic cover of the engine, which would cost a lot to replace.
I found Dan from Diesel Matters (UK) who specialises in that sort of work who just got it out this morning with a set of very specialist tools. The seized injector was already worn too so we had to change it (£340)
Now I need to flush the engine to get as much carbon built up out as possible and replace oil/filter again and clean the strainer.
I hope that this work will be enough and that the MAF sensor issues was only some sort of side effect of the injector issue.
But time will tell!