The DELPHI Lambda zonde, part number ES20678-12B1, is a critical sensor for modern engine management systems. It measures the amount of oxygen in the exhaust gases, providing vital data to the engine control unit (ECU). By accurately monitoring oxygen levels, the Lambda zonde allows the ECU to precisely adjust the air-fuel mixture. This precise control is essential for maximizing combustion efficiency, reducing harmful emissions, and improving overall fuel economy. A properly functioning Lambda zonde contributes significantly to your vehicle's environmental compliance and running costs. Crafted with DELPHI's commitment to quality, this Lambda zonde is built to withstand the harsh conditions of the exhaust system. Its robust construction ensures durability and consistent performance over its service life. Replacing a faulty Lambda zonde can resolve issues such as poor fuel economy, rough idling, and check engine lights.