The PCV Valve 12204-31040 is a genuine OEM-grade crankcase ventilation valve designed for Lexus and Toyota models, including the RX350, ES350, IS250, Avalon, Camry, and RAV4. This valve plays a critical role in maintaining engine efficiency by regulating the flow of blow-by gases from the crankcase back into the intake manifold, preventing pressure buildup and reducing harmful emissions.