scope:

This part of ISO 14230 specifies common requirements of diagnostic services which allow a tester to control diagnostic functions in an on-vehicle Electronic Control Unit (for example, electronic fuel injection, automatic gearbox, antilock braking system, etc.) connected on a serial data link embedded in a road vehicle.

It specifies only layer 2 (data link layer). Included are all definitions which are necessary to implement the services (described in ISO 14230-3) on a serial link (described in ISO 14230-1). Also included are some communication services which are needed for communication/session management and a description of error handling.

This part of ISO 14230 does not specify the requirements for the implementation of diagnostic services.

The physical layer may be used as a multiuser-bus, so a kind of arbitration or bus management is necessary. There are several proposals which are not part of this part of ISO 14230. The car manufacturers are responsible for the correct working of bus management.

Communication between ECUs are not part of this part of ISO 14230.

The vehicle diagnostic architecture of this part of ISO 14230 applies (see figure 2) 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.