Genuine OEM Volkswagen Engine Control Unit, part number 5NA906259H550. This unit is responsible for managing all engine operations, including fuel injection, ignition timing, and emissions control. It is typically located within the engine bay or passenger compartment. The unit weighs approximately 0.92 kg and measures 0.19m x 0.18m x 0.04m. Genuine OEM ECUs are essential for ensuring the correct firmware and sensor calibration, which is critical for reliable engine performance and longevity.