A Lambda Sensor, also known as an oxygen sensor, is a device used in vehicles to measure the amount of oxygen in the exhaust gases. This information helps the engine control unit (ECU) adjust the air-fuel mixture for optimal combustion, improving fuel efficiency and reducing emissions. Typically located in the exhaust system, the Lambda Sensor plays a crucial role in meeting environmental regulations. By providing real-time data, it helps ensure that the engine operates efficiently, which can lead to better performance and lower fuel costs for drivers.