What is ISO 14229-2 about?
ISO 14229-2 is the second part of multiple series that specifies common session layer services and requirements to provide independence between unified diagnostic services (ISO 14229-1) and all transport protocols and network layer services (e.g., ISO 13400-2 DoIP, ISO 15765-2 DoCAN, ISO 10681-2 communication on FlexRay, ISO 14230- 2 DoK-Line, and ISO 20794-3 CXPI).
ISO 14229-2 specifies a common service primitive interface between OSI layer 5 (session) and layer 4 (transport) via so-called service request/indication/confirmation primitives.
Who is ISO 14229-2 for?
ISO 14229-2 on unified diagnostic services of road vehicles is useful for:
- Manufacture of vehicles
- Service provider of UDS
- Diagnostic tester (client)
- Electronic Control Unit (ECU, server) manufacturers
- Transport industry
- Service provider of network layer services
Why should you use ISO 14229-2?
Unified diagnostic services help you to interact with ECU servers in vehicles.
ISO 14229-2 has been established in order to define common requirements for diagnostic
systems, whatever the serial data link is. ISO 14229-2 specifies session layer services that provide you services that are needed to access the functions, i.e., transmission/reception of data and setting of protocol parameters. This helps the users to understand session layer services better.
ISO 14229-2 provides a timing parameter definition that helps you in detecting errors (default session) and to fulfil the timing requirements during the default session and any non-default session.
What’s changed since the last update?
BS ISO 14229-2:2021 supersedes BS ISO 14229‑2:2013, which is withdrawn.
This second edition replaces the first edition (ISO 14229-2:2013), which has been technically revised.
The main changes are as follows:
- Restructuration of the document
- Introduction of requirement numbers and names
- Technical content improvements based on implementation feedback from the automotive industry

