A method is provided for enhancing service diagnostics for root cause analysis of an identified problem in a vehicle. Service repair data of previously serviced vehicles is obtained from a memory storage device. The service data is compiled based on a service repair history for each vehicle. Each vehicle within the compiled service data having at least two service repairs performed within a predetermined period of time is identified. Combinations of parts serviced during each service repair are identified. A count is determined that indicates the number of times each combination appears in the compiled service data. The combinations having counts greater than a predetermined threshold are identified. A determination is made whether any of the combinations having counts greater than the predetermined threshold are present in the structural taxonomy database. A functional taxonomy database is updated by assigning the selected combinations to the function taxonomy database not present in the structural taxonomy database.