The Audi 80-90 B3 (1986-1991) offers a range of advanced features to enhance your driving experience. It includes a self-diagnostic system that monitors engine components and stores fault codes in its memory. You can retrieve these codes using a VAG 1551 diagnostic tester to identify and troubleshoot any issues. Additionally, the device allows you to perform output checks on various components, ensuring their proper functioning. Please note that output checks can only be done with the engine off, and fault memory can only be erased after the output checks are complete.