ODX (Opden Diagnostic Data eXchange, ISO 22901-1) is a formal, machine-readable description language for the diagnostic interface of ECUs. Originally developed by the ASAM e.V. association as ASAM MCD-2D, the last state became ISO standard in 2008. ODX was developed to enable a standardized data exchange between automotive, ECU and tool manufacturers. As a side effect, it also makes the flow of information within a company much more efficient.
The ODX specification includes the data model for describing all diagnostic data of a vehicle control unit such as diagnostic error codes, data parameters, identification data, input/output parameters, coding information or communication parameters. It is a mandatory component of a diagnostic stack according to ISO 22900 (modular vehicle communication interface).
All control units support various standardized diagnostic protocols for error analysis and maintenance. In ODX, all these diagnostic interfaces are described uniformly and standardized. A tester (external or even installed in the vehicle) exchanges information with the control units. ODX describes how the data sent by the ECU via UDS protocol must be translated into values readable by humans (and programs).