An open-end spanner will not work without causing a mar to the sleeve nut. Before installing the new sensor spraying a can of DPF Cleaner into the open hole (the one on the rear) is an excellent move to help the dpf break free. The 1st dpf regen after the sensor change now has to be forced with a tester.
How does it work? DPF’s or ‘traps’ simply do that, they catch particles of soot in the exhaust. As with any filter, they must be emptied to allow them to maintain performance. The process of cleaning the filter is known as ‘regeneration’. How long does a DPF last? DPF’s are designed to last in excess of 100 000 miles.
The fact sheet that bmw have made that’s on the Internet of the specs on what’s needed for the dpf to regen is not correct If you have spent many hours on the motorway many years ago fixing problems cars then most will not be able to repair or pinpoint where the problem is as there are many factors that will stop the regen even down to
A blocked DPF will not work correctly, to clear this blockage there are two types of regeneration which are commonly used to remove the build-up of soot. Newer vehicles engage active regeneration, which is the process of removing the accumulated soot from the filter by adding fuel post combustion to increase exhaust gas temperatures and burn
BMW 520d F10 2013 - Diesel Particulate Filter Regeneration - craig-pd130 : I don't know the specifics for BMWs but pretty much all latest-generation diesels with DPFs regenerate both when the pressure sensors indicate the DPF has reached a threshold level of soot, AND on a mileage basis (the latter is a failsafe, really).
2. Throttle valve gets broken. In diesel engine this is used only for smooth engine shutdown, and for the DPF regeneration. No functional throttle valve -> no regeneration. 3. Regular too short driving distance. Engine does not warm up to the 75c degree temperature and the regeneration does not happen. RScS. 146 18 298 125 404 27 432 248 304

how does bmw dpf regeneration work