Abstract: A vehicle audio system is tested during vehicle assembly by a computer controlled system coupled to a vehicle data bus via a diagnostic connector. Radio settings are controlled via the data bus. RF signals bearing preset tones are generated according to computer command via an encoder and RF generator and coupled to the audio antenna base. A microphone in the vehicle detects tones from the speakers and a decoder analyzes the tones to determine whether a tone is correct. Certain speakers are selected for test by adjustment of Fade and Balance controls to check speaker connections. AM and FM SEEK function are checked to verify radio circuits and antenna connections.