[Tatsfield]

If this is the PSA origin 4 pot diesel engine, PSA used an eolys fluid injection system to initiate carbon particle burn in the DPF when regenerating. So long as the pump and specific electrics keep working, all you have to do is replace the fluid in the reservoir when the system tells you its due. I know on Peugeots with this engine and filter system the countdown is not based on fluid used but on the number of times the fuel filler cap is opened and closed. The only other disadvantage is that the eolys fluid is not cheap, costing from £30 to £40+ per litre. The advantage to the system is that you don't get diesel fuel dilution of the engine lubricating oil when a regeneration is aborted.