SAE J1939-71 Vehicle Application Layer is the SAE J1939 reference document for the conventions and notations that specify parameter placement in PGN data fields, the conventions for ASCII parameters, and conventions for PGN transmission rates. This document previously contained the majority of the SAE J1939 data parameters and messages for information exchange between the ECU applications connected to the SAE J1939 communications network. The data parameters (SPNs) and messages (PGNs) previously published within this document are now published in SAE J1939DA. The reference figures and reference information for the SPNs and PGNs associated with the SAE J1939-71 document are published in this document. The data parameters (SPNs) and messages (PGNs) associated with this document are applicable to most SAE J1939 applications. There are several SAE J1939-7X documents that collectively define all of the SAE J1939 application layer data parameters and messages. Diagnostic services and some industry specific data parameters and messages are documented within other SAE J1939-7X application layer documents. An ECU may simultaneously use and support data parameters and messages from multiple SAE J1939-7X application layer documents.