Major car issues, why would previous owner have gotten the DPF remapped?

I don't think the DPF would have been remapped rather it was removed and the ECU remapped to compensate for the missing DPF.

Are you sure its P2409? Thats to do with a poor fitting fuel cap that prevents the fuel evaporation system from functioning, but usually only on petrol cars.

But if its the 1.6 you have, the DPF is fairly simple design. You have a large honeycomb system that simply traps soot in the exhaust and this DPF filter has a pressure sensor connected across the filterto measure the difference in pressures. Once this pressure exceeds a certain level it triggers a regeneration (engine ECU changes fuelling to massively increase exhaust temp to burn off the soot). If it cant regen and the pressure goes too high, it triggers a fault code.

If its remapped and the filter is blocked, check to see if the DPF element is there via a flexible borescope or by any tell tale signs that it was removed. One easy method I seen is a 1" hole drilled right though the DPF and welded back. This 1" welded hole can be spotted from the top or bottom of the DPF. It appears that this 1" hole allows the differential pressure sensor to still see a filter restriction within tolerance and the error code wont be triggered so no remap is required.

Edit, if you look at this picture you can see the DPF and the small tubes coming out the side for a pressure sensor and how drilling a hole the whole way through the filter will clear the filter permanently

mullingar wrote: »

Are you sure its P2409? Thats to do with a poor fitting fuel cap that prevents the fuel evaporation system from functioning, but usually only on petrol cars.

But if its the 1.6 you have, the DPF is fairly simple design. You have a large honeycomb system that simply traps soot in the exhaust and this DPF filter has a pressure sensor connected across the filterto measure the difference in pressures. Once this pressure exceeds a certain level it triggers a regeneration (engine ECU changes fuelling to massively increase exhaust temp to burn off the soot). If it cant regen and the pressure goes too high, it triggers a fault code.

If its remapped and the filter is blocked, check to see if the DPF element is there via a flexible borescope or by any tell tale signs that it was removed. One easy method I seen is a 1" hole drilled right though the DPF and welded back. This 1" welded hole can be spotted from the top or bottom of the DPF. It appears that this 1" hole allows the differential pressure sensor to still see a filter restriction within tolerance and the error code wont be triggered so no remap is required.

Edit, if you look at this picture you can see the DPF and the small tubes coming out the side for a pressure sensor and how drilling a hole the whole way through the filter will clear the filter permanently

Great post.

Have a read of this page from the Workshop manual on the function of this fuel door switch in the Focus Diesel. The code could match unintentionally to a petrol evaporate system

http://workshop-manuals.com/ford/focus_2004.75_07.2004/mechanical_repairs/3_powertrain/303_engine/303-04f_fuel_charging_and_controls_1.6l_duratorq-tdci_(dv)_diesel/description_and_operation/fuel_charging_and_controls_vehicles_with_diesel_particulate_filter_(dpf)/

Fair play mullingar, users like you make this forum.