The main purpose of this Recommended Practice is to verify that vehicles are capable of communicating a minimum subset of information, in accordance with the diagnostic test services specified in SAE J1979: E/E Diagnostic Test Modes, or the equivalent document ISO 15031-5: Communication Between Vehicle and External Equipment for Emissions-Related Diagnostics - Part 5: Emissions-related diagnostic services. Any software meeting these specifications will utilize the vehicle interface that is defined in SAE J2534, Recommended Practice for Pass-Thru Vehicle Programming.