Diesel particulate filters are not so much ‘repaired’ as cleaned. During their everyday operation, DPF’s do not have moving parts, so there is nothing to repair as such.
It is the build up of fine soot that is the result of the combustion process of diesel fuel that can cause problems if the vehicle fails to regenerate properly. The process of regeneration is regularly completed in most diesel engine vehicles, but it is dependent on the DPF reaching a temperature of around 600 degree Celsius in order to burn off and clear out the build up of soot in the DPF. If the DPF does not get to this temperature because it is subject to short city journeys for the majority of the time, then the build up of soot may require the DPF to undergo a forced regeneration which will need to be done in a vehicle garage using specialist equipment. An engine warning light on the vehicle is likely to illuminate, to warn you that the build-up of soot requires attention, at that point the car should be taken on an extended journey, holding about 3500 revs for about twenty minutes to try and clear soot from the DPF without breaking the speed limit.