GMLAN which stands for (General Motor Local Area Network) is an application- and transport-layer protocol using CAN for lower layer services. Transport-layer services include the transmission of multi-CAN-frame messages based on the ISO 15765-2 multi-frame messaging scheme. It was developed and is used primarily by General Motors for in-vehicle communication and diagnostics. GM's Tech2 uses the CANdi (Controller Area Network diagnostic interface) adapter to communicate over GMLAN.
Some software applications that allow interfacing to GMLAN are Intrepid Control Systems, Inc.'s Vehicle Spy 3, Vector's CANoe, Dearborn Group's Hercules, ETAS' ES-1222, ES590, ES715, and ES580 products, ScanTool.net's OBDLink MX and Professional Product Group's CANCapture.