Genuine OEM BMW Lambda Oxygen Sensor, part number 13628593852. This sensor measures the oxygen content in the exhaust gases, providing critical data to the engine control unit (ECU) for optimizing the air-fuel ratio. Proper functioning of the oxygen sensor is essential for efficient fuel combustion, reduced emissions, and optimal engine performance. It is typically installed in the exhaust manifold or pipe. Genuine OEM oxygen sensors are calibrated to precise standards, ensuring accurate readings and long-term reliability.