2011 Discovery 4 HSE 3ltr, Have purchased replacement from Rimmer spare parts 85 pounds with postage, had disconnected filter sensor, cleared code and reattached, so far so good! has not returned. So now have a spare one in the glovebox. So after over $10k spent on the car since September 22 I will be selling and buying a new Skoda Karoq with a 7 yr warranty.Maybe if you say exactly what modell, year and engine is your "Defender 4" as i can't find any diagram for that also what's the exact fault code