Which feature is included in the SAD (Yanmar Smart Assist Direct) diagnostic functions?

The feature that is included in the SAD (Yanmar Smart Assist Direct) diagnostic functions is the capability to read and erase Diagnostic Trouble Codes (DTCs) from the ECU. This function is crucial for identifying issues within the engine management system. Diagnostic Trouble Codes are standardized codes that indicate a specific problem within the engine's electronic control unit, allowing technicians to perform targeted troubleshooting.

Reading these codes provides insights into the performance of various engine components, while erasing the codes after repairs clears the memory of the ECU, thus ensuring that the technician can monitor the system for any further issues without previous codes interfering. This function is essential for maintaining the efficiency and reliability of machinery, as it enables prompt detection and resolution of faults.

The other options, while they may represent useful diagnostic functions, are not universally recognized as standard features included in the SAD's core diagnostic functionality. Therefore, the emphasis on the ability to read and erase DTCs is what establishes the correctness of the first option in the context of the SAD system's diagnostic capabilities.