This International Standard specifies common requirements of diagnostic services which allow a diagnostic tester to control diagnostic functions in an on-vehicle electronic control unit (e.g. electronic fuel injection, automatic gearbox, anti-lock braking system, etc.) connected on a serial data link embedded in a road vehicle.
It specifies generic services which allow the diagnostic tester to stop or to resume non-diagnostic message transmission on the data link.
This International Standard does not apply to non-diagnostic message transmission, nor to use of the communication data link between two electronic control units.
This International Standard neither specifies implementation requirements, numerical values of services and parameters, nor requirements for the communication services.
The vehicle diagnostic architecture of this International Standard applies to
— a single tester that may be temporarily or permanently connected to the on-vehicle diagnostic data link, and
— several on-vehicle electronic control units connected directly or indirectly.
In vehicle 1, the ECUs are connected over an internal data link and indirectly connected to the diagnostic data link through a gateway. This standard applies to the diagnostic communications over the diagnostic data link; the diagnostic communications over the internal data link may conform to this standard or to another protocol.
In vehicle 2, the ECUs are directly connected to the diagnostic data link.