GM Genuine Parts Equipment Exhaust Gas Recirculation (EGR) Valves are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These valves are an emission control device. EGR valves modulate the flow of exhaust gas into the intake manifold to help reduce nitrogen oxide (NOx) emissions. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).