This part of ISO 14230 specifies the requirements for the Keyword Protocol 2000 data link on which one or several on-vehicle Electronic Control Units are connected to an off-board tester in order to perform diagnostic functions.
This part of ISO 14230 specifies the requirements of the implementation of the Diagnostic Services specified in ISO 14229, including

-  byte-encoding and hexadecimal values for the service identifiers;
-  byte-encoding for the parameters of the diagnostic service requests and responses;
-  hexadecimal values for the standard parameters.

The vehicle environment to which this part of ISO 14230 applies may consist of a single tester that may be temporarily connected to the on-vehicle diagnostic data link and several on-vehicle Electronic Control Units connected directly or indirectly.