[Richyroos]

I cant answer your question about DIS or INPA, but a good rule of thumb test is to disconnect the MAF as you have done, but you need to drive the car with it disconnected, and see if the car drives any differently, if it drives much better the MAF is knackered - if is much the same it is probably perfectly OK.

When it is unplugged the ECU recognises that, and substitutes a set of stored preset values to run the engine, and should run pretty well. Therefore if the car runs worse with it connected, you have a faulty MAF! They seem to lead a hard life, as it is a fairly common failure point, Ive had to buy one on my 140,000 mile 530D. Don't be tempted to buy a copy part - they don't work! You must use Bosch - you can source them fairly easily, far cheaper than Mr BMW's parts bin.

 

[Richyroos]

Your best bet would be to have the car checked on a diagnostic machine, it could be a different sensor that is setting the regens to run - there are several!

A good BMW specialist should be able to diagnose what the fault is quite quickly, as would a main dealer of course - but at rather higher cost!! Have you had any DPF warnings on the dash? perhaps the DPF is heavily sooted up, and the regens that are taking place, are only having a limited cleaning effect. Some have gone to Terraclean to have the DPF chemically cleaned, not especially cheap to have done, but people report good results of the process afterwards.

My driving is not ideal for the DPF, so I use the odd tin of Cataclean DPF cleaner in the fuel, which seems to help my car show sensible DPF backpressure figures. Mine regens every month or so usually.