kevin off the top of my head the diesel particulate filter a honeycomb stucture which the walls are made of porous silicon carbide or off set channels are blocked at one end of the channels after combustion diesel particles left over flow into the particulate filter and because of the sealed channels are forced into the walls which are porous the filter contents are burnt off due to post combustion fuel injection once the filter restricts the gas flow the pressure sensor tells the ecu a new filter is needed or a forced regeneration the aditive is mixed in the tank this depends on the amount of fuel in the tank have you can you reset the adaptions? martin