The Vehicle Identification Number (VIN) is a unique 17-character code used to identify a vehicle. It can be retrieved through different diagnostic protocols. In OBD-II, the VIN is read using Mode 09 PID 02, where the scan tool sends the request 09 02 and the ECU responds with 49 02 followed by the VIN characters distributed across multiple CAN frames. In vehicles that use Unified Diagnostic Services (UDS), the VIN is obtained through the ReadDataByIdentifier (0x22) service by sending the request 22 F1 90, where F190 is the data identifier assigned to the VIN. The ECU then responds with 62 F1 90 followed by the 17 VIN characters. Although both methods provide the same vehicle identification information, the OBD-II service is designed for standardized emissions-related diagnostics and basic vehicle information, while UDS offers a more flexible and advanced structure that allows access to a wider range of data stored in the vehicle's electronic control units. Understanding and analyzing both response formats is essential for modern automotive diagnostics, vehicle identification verification, and the development of diagnostic tools compatible with current vehicle communication networks.
