ISO 15031-1:2001 Road vehicles — Communication between vehicle and external equipment for emissions related diagnostics — Part 1: General information. ISO 15031-2 ISO/PRF TR 15031-2:2004 Road vehicles — Communication between vehicle and external equipment for emissions related diagnostics — Part 2: Terms, definitions, abbreviations and acronyms. ISO 15031-3 ISO 15031-3:2004 Road vehicles — Communication between vehicle and external equipment for emissions related diagnostics — Part 3: Diagnostic connector and related electrical circuits, specification and use. SAE J1939-13 SAE J1939-13: Off-Board Diagnostic Connector. ISO 15031-4 ISO DIS 15031-4.3:2004 Road vehicles — Communication between vehicle and external equipment for emissions related diagnostics — Part 4: External test equipment. SAE J1939-73 SAE J1939-73: Application Layer — Diagnostics.