This computer module is a genuine OEM part for your 2005 Saturn Ion. It is a direct replacement for your vehicle's ECU, PCM, and ECM. The module is manufactured by GM and has a part number of 12589999. This item is perfect for anyone looking to replace their faulty ECU, PCM, or ECM. It is compatible with a variety of part numbers, including 19369984 and 12600889. The item is made in the United States and is a genuine OEM part. Buy with confidence knowing that you are getting a high-quality product that will fit your vehicle perfectly.