Genuine OEM Volkswagen Control Unit, part number 03L997009J. This electronic control module is designed for diesel engines, responsible for managing critical engine functions such as fuel injection, ignition timing, and emissions control. It is typically mounted within the engine bay or under the dashboard. The unit has a weight of 1.066 kg. Genuine OEM control units are crucial for ensuring the correct firmware, sensor calibration, and overall system compatibility for reliable engine operation.