Parece que a ranger 2.2 diesel inibe a regeneração do catatilsador quando P0420 presente, levando a obstrução do dpf
It seem s that dpf regeneration is stopped If p0420 code is present. Its a fact?
yes, ECU believes that your cat converter is in a atate that it cannot work effectively enough.
But such questions should be asked in forums for your car, not here.