ISO 27145-3:20 12定义了ISO 14229-1中规定的统一诊断服务（UDS）子集的实现。诊断服务用于传达ISO 27145-2中定义的诊断数据。 统一诊断服务的子集源自全球统一车载诊断全球技术法规（WWH-OBD GTR）中规定的要求。ISO 27145-3:20 12中定义的公共消息集独立于底层传输、网络、数据链路和物理层。ISO 27145-3:20 12没有规定车载网络架构的任何要求。 ISO 27145-3:20 12与ISO 14229-1兼容，包括支持SAE J1979-DA和SAE J2012-DA WWH-OBD数据集的规定。 ISO 27145-3:20 12旨在与ISO 27145-4一起使用，ISO 27145-4是协议初始化的入口点，基于两个不同的数据链路:·通过控制器局域网(DoCAN)进行诊断通信，ISO 15765？1、ISO 15765？2、ISO 15765？4; ·通过互联网协议（DoIP）进行诊断通信，ISO 13400（所有部分）。 ISO 27145-3:20 12包括满足多个地区、车辆类型、车型年份和发动机类型的OBD法规所需的功能。对于某些地区来说，这些法规尚未最终确定，预计未来会发生变化。ISO 27145-3:20 12不试图解释法规，也不包括所包含的诊断服务和数据参数对各种车辆应用的适用性。ISO 27145-3:20 12的用户旨在验证其每个条款对特定车辆、发动机、车型年份和地区的适用性。

ISO 27145-3:2012 defines the implementation of a subset of unified diagnostic services (UDS) specified in ISO 14229-1. The diagnostic services are used to communicate the diagnostic data defined in ISO 27145-2. The subset of unified diagnostic services derives from the requirements stated in the World-Wide Harmonized On-Board Diagnostic Global Technical Regulations (WWH-OBD GTR). The common message set defined in ISO 27145-3:2012 is independent of the underlying transport, network, data link and physical layer. ISO 27145-3:2012 does not specify any requirements for the in-vehicle network architecture. ISO 27145-3:2012 is compatible with ISO 14229-1 and includes provisions to support the data set of SAE J1979-DA and SAE J2012-DA WWH-OBD. ISO 27145-3:2012 is intended for use with ISO 27145-4, which is the entry point for the protocol initialization and is based on two different data links:

• · Diagnostic communication over Controller Area Network (DoCAN), ISO 15765？1, ISO 15765？2, ISO 15765？4;
• · Diagnostic communication over Internet Protocol (DoIP), ISO 13400 (all parts).

ISO 27145-3:2012 includes capabilities required to satisfy OBD regulations for multiple regions, vehicle types, model years, and engine types. Those regulations are not yet final for some regions and are expected to change in the future. ISO 27145-3:2012 does not attempt to interpret the regulations and does not include applicability of the included diagnostic services and data parameters for various vehicle applications. It is intended that users of ISO 27145-3:2012 verify the applicability of each of its clauses for a specific vehicle, engine, model year and region.