Take a look at BM Catalysts diesel particulate filter (DPF) training video that tells you everything you need to know about servicing a DPF.
In order to meet euro emissions standards, vehicle manufacturers fit DPFs as a way of reducing vehicle emissions of particulate matter (soot). Legislation introduced in the UK in February 2014 means it is now illegal to remove a DPF. Vehicles will now be given an automatic MOT failure if found without a DPF where it should be fitted as standard.