ISO 15031-4:2014规定了一套由车辆提供的标准诊断服务（OBD服务）。ISO 15031-4:2014规定了一套由外部测试设备提供的补充设施，包括故障诊断仪设施。这些设施提供了对任何车辆上所有公共OBD（车载诊断）服务的完整、高效和安全的访问，符合ISO 15031-4:2014。 ISO 15031-4:2014规定 -在装备OBD的车辆和外部测试设备之间建立通信的方法，以及 -由外部测试设备提供的一套诊断服务，以执行ISO 15031？5中定义的服务。 ISO 15031-4:2014不排除在外部测试设备中包含额外的能力或功能。但是，外部测试设备设计师有责任确保此类能力或功能不会对车载诊断系统车辆（可能连接到外部测试设备或外部测试设备本身）产生不利影响。

ISO 15031-4:2014 specifies a set of standard diagnostic services to be provided by vehicles (OBD services). ISO 15031-4:2014 specifies a complementary set of facilities, to be provided by external test equipment, which will include scan tool facilities. These facilities provide complete, efficient, and safe access to all of the public OBD (on-board diagnosis) services on any vehicle, which is compliant with ISO 15031-4:2014. ISO 15031-4:2014 specifies - a means of establishing communications between an OBD-equipped vehicle and external test equipment, and - a set of diagnostic services to be provided by the external test equipment in order to exercise the services defined in ISO 15031？5. ISO 15031-4:2014 does not preclude the inclusion of additional capabilities or functions in external test equipment. However, it is the responsibility of the external test equipment designer to ensure that no such capability or function can adversely affect either an OBD-equipped vehicle, which may be connected to the external test equipment or the external test equipment itself.