This document is applicable to all light duty gasoline and diesel vehicles (LDV)@ light duty gasoline and diesel trucks (LDT)@ and heavy duty gasoline vehicles (HDGV). Specific applications of this document include service and repair manuals@ training manuals@ repair data bases@ under-hood emission labels@ and emission certification applications. Even though the use and appropriate updating of this document and its companion documents is strongly encouraged@ nothing in these documents should be construed as prohibiting the introduction of a term acronym not covered by these documents.