[1.6 HDI 187kkm FAP 109KM] - Risk of particle filter clogging: see handbook

The most likely cause is a FAP/DPF that is at end of life or loaded with ash, often made worse by many short trips and interrupted regenerations, even if the current differential pressure still looks acceptable [#16825692][#16826218][#16829266] One reply notes that these engines can start showing the warning around 180,000 km, and that an efficient filter should show about 3–7 mbar at idle and up to about 200 mbar under load; if the readings are zero or clearly wrong, the pressure sensor, its hoses, or the filter itself should be checked with a manometer [#16826618][#16829266] The thread starter later found that the warning disappeared only after removing, washing and drying the FAP, then telling the ECU that a new filter was installed, without replacing the pressure sensor [#16911566] So the practical fix is to verify the sensor/hoses first, but if the filter has high ash loading or the car has had many failed regenerations, clean or replace the FAP and reset the filter counter in the ECU [#16826218][#16911566]