This document is regarding the selection of a well suited protocol for the diagnostic purpose in the automotive industry. Various protocols are compared with respect to their parameters like speed, bandwidth, weight and cost effectiveness. Time critical activities require speed for the communication purposes and also for upgrading or reprogramming the ECU. Selecting a perfect protocol for the diagnostic purposes assist in the proper functioning of the vehicle which in turns increases the safety of the occupants.

Keywords : Diagnostic protocol; Automotive communication bus; OBD; UDS;LIN; CAN and Ethernet.