This SAE Recommended Practice is applicable to all light-duty gasoline and diesel passenger vehicles and trucks@ and to heavy-duty gasoline vehicles. Specific applications of this document include diagnostic@ service and repair manuals@ bulletins and updates@ training manuals@ repair dada bases@ underhood emission labels@ and emission certification applications. This document focuses on diagnostic terms applicable to electrical/electronic systems@ and therefore also contains related mechanical terms@ definitions@ abbreviations@ and acronyms. Even though the use and appropriate updating of this document is strongly encouraged@ nothing in this document should be construed as prohibiting the introduction of a term@ abbreviation@ or acronym not covered by this document.