SAE J2534-1 defines a standard vehicle network interface that can be used to reprogram emission related control modules. However, there is a need to support vehicles prior to the 2004 model year as well as non-emission related control modules. The SAE J 2534-2 document meets these needs by detailing extensions to an SAE J 2534-1 interface. Together, these extensions provide the framework for a common interface to protect the software investment of the Vehicle OEMs and Scan Tool manufacturers. Only the optional features will be described by this document. Unless otherwise noted it is expected that these features are added to a fully compliant interface adhering to the December 2004 publication of SAE J 2534-1.