ISO 14230-2:2013

ISO 14230-2:2013 specifies data link layer services tailored to meet the
requirements of UART-based vehicle communication systems on K-Line as specified
in ISO 14230-1. It has been defined in accordance with the diagnostic services
established in ISO 14229-1 and ISO 15031-5, but is not limited to use with them,
and is also compatible with most other communication needs for in-vehicle
networks. The protocol specifies an unconfirmed communication.
The diagnostic communication over K-Line (DoK-Line) protocol supports the
standardized service primitive interface as specified in ISO 14229-2.
ISO 14230-2:2013 provides the data link layer services to support different
application layer implementations like:

  enhanced vehicle diagnostics (emissions-related system diagnostics beyond
  legislated functionality, non-emissions-related system diagnostics);
  emissions-related OBD as specified in ISO 15031, SAE J1979-DA, and SAE
  J2012-DA.
In addition, ISO 14230-2:2013 clarifies the differences in initialization for
K-line protocols defined in ISO 9141 and ISO 14230. This is important since a
server supports only one of the protocols mentioned above and the client has to
handle the coexistence of all protocols during the protocol-determination
procedure.