System Overview
WARNING: This page is about a different car, the 2012 Ford Pickup, 2012 Ford F550 Super Duty, 2012 Ford F450 Super Duty, and 2012 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Do not use silicone based sprays or lubricants on any components installed onto or around the diesel exhaust system or intake air distribution and filtering system. Silicone reacts with the Nitrogen Oxides (NOx) sensor and may cause permanent damage to the NOx sensor.
The EGR recirculates some of the engine exhaust gases into the engine at a lower temperature. The cooled exhaust gases have a higher heat capacity and contain less oxygen than air, lowering combustion temperatures and reducing the formation of Nitrogen Oxides (NOx).