Genuine OEM Audi Electronic Control Unit, part number 09S927158BD. This electronic control unit is responsible for managing the operation of the 8-speed automatic transmission. It is marked as number 1 in the provided diagram. The unit has dimensions of 0.156m x 0.125m x 0.035m and weighs 0.342 kg. Genuine OEM electronic control units ensure correct firmware and sensor calibration for optimal transmission performance.