Abstract: An automotive diagnostic method including the step of providing an automotive data retrieving tool having a unique tool identifier, wherein the automotive data retrieving tool is configured to retrieve data from a vehicle onboard computer. Information related to a selling retailer associated with the automotive data retrieving tool is received and the unique tool identifier is associated with the selling retailer in a referral server. The method further includes receiving vehicle data from the automotive data retrieving tool, and analyzing the received vehicle data to make a diagnostic assessment, which is communicated along with the unique tool identifier to the referral server. The method additionally includes the step of matching the unique tool identifier communicated with the diagnostic assessment with the associated selling retailer and generating a referral signal including information related to a possible commercial transaction conducted by the selling retailer.