Identifier for readable or writable diagnostic data in UDS services such as 0x22/0x2E.

In the UDS/diagnostics world, a DID is a Data Identifier, i.e., a standardized addressed diagnostic data point that can be read, written, or controlled via diagnostic services. In AUTOSAR DCM and in ODX-based diagnostic descriptions, DIDs are used to reference measurement values, states, or configuration data of an ECU uniquely. For logging and diagnostics, DIDs are important because testers and evaluation tools use them to identify and interpret ECU data consistently.