UDS诊断 19 02 0A

### UDS Diagnostic Service 19 02 0A Protocol Explanation The UDS (Unified Diagnostic Services) diagnostic service identifier `19` corresponds to the **ReadDTCInformation** request, which is used for reading different types of Diagnostic Trouble Codes (DTCs). The subfunction `02` within this service indicates a specific operation related to DTC information retrieval. Specifically, when combined with data record parameter `0A`, it signifies requesting the number of DTCs by status mask[^1]. This particular combination (`19 02 0A`) instructs the ECU (Electronic Control Unit) or another relevant automotive component to provide detailed information about the count of active DTCs based on specified criteria defined in the status mask. #### Example Request and Response Structure For clarity, here’s how such an interaction might look: - **Request**: ```plaintext 19 02 0A ``` - **Response**: A typical positive response would include: ```plaintext 59 02 LL HH ``` Where: - `59`: Positive response SID. - `LL HH`: Two-byte value representing the total number of DTCs matching the provided status mask conditions. In some cases, additional bytes may follow depending upon whether extended data records are included as part of the response payload. ```python def read_dtc_information(status_mask): """ Simulates sending a ReadDTCInformation request using UDS protocol Args: status_mask (int): Status condition filter applied during DTC counting Returns: tuple: Number of DTCs found that match the given status mask """ # Hypothetical function call simulating network communication result = send_uds_request([0x19, 0x02, status_mask]) if not isinstance(result, list) or len(result) != 4: raise ValueError("Invalid response format") dtc_count = (result[2] << 8) | result[3] return dtc_count ```