The exhaust gas recirculation, or EGR, valve plays a key role in reducing unwanted engine emissions and engine knock. The EGR valve is typically housed on the intake manifold and permits a measured amount of exhaust gasses back into the engine. If a faulty valve is not replaced, it can cause major damage to the engine requiring very costly repairs. You can promote environmental welfare and good automotive health by making sure that the EGR system has a working BMW EGR Valve installed.