Modern vehicle diagnostic systems allow scan tools to communicate with Electronic Control Units (ECUs) to retrieve vehicle information, including Diagnostic Trouble Codes (DTCs). In Smart vehicles and other Mercedes-Benz platforms, communication is often based on CAN networks and proprietary implementations derived from KWP2000 and UDS protocols. Understanding how to interpret diagnostic requests related to DTC reading and how to generate valid ECU responses is essential for developing simulators, testing tools, and validation environments. Furthermore, analyzing diagnostic frames helps identify message structures, fault status information, and the way scan tools display DTCs to technicians. This knowledge improves troubleshooting efficiency and provides a deeper understanding of vehicle electronic diagnostic systems.
