This SAE Recommended Practice describes a standardized interface that connects between a standard personal computer (PC) and vehicle. The purpose of this interface is to enable the reprogramming of emission-related control modules, in 2004 and later model year vehicles. The interface shall consist of the necessary hardware and/or software to support the requirements defined in this document. It is expected that vehicle manufacturers will provide the software application that will control the pass-thru interface, to perform the actual reprogramming. The goal of this document is to ensure that reprogramming software from any vehicle manufacturer is compatible with interface supplied by any tool manufacturer. A common interface for all vehicle manufacturers reduces the tool costs for aftermarket garages, while allowing each vehicle manufacturer to control the programming sequence for the electronic control units (ECUs) in their vehicles.