The CAN di module connects between the Tech 2's diagnostic link cable and the OBD adapter. Once the CAN di module is connected, it can be used on all GM vehicle applications, even those vehicles using other platforms such as OBD I and OBD II An industry change in protocol from OBD II to Controller Area Network (CAN) is ongoing. In order to perform diagnostics on a vehicle that uses the CAN interface, you will need the Tech 2 and a CAN diagnostic interface module. (CAN di Module is included in the Tech 2 Deluxe Kit 3649.).