A diagnostic system includes a host system having a processor, storage media and a user interface including a display screen, and a plurality of support data sources, which may be resident at or remote from the host system. The storage media stores service or maintenance test designations and descriptions. System software responds to user selection of displayed vehicle systems or symptoms to be diagnosed by displaying test designations. Upon user selection of a test designation, the system displays the first page of the test description and simultaneously links to appropriate support data sources and displays pertinent support data on a portion of the display screen. A method includes selecting and displaying test descriptions and, in response to each such display, automatically retrieving and displaying related data from a support data source.