Single Wire CAN is a method of transmitting CAN frames on a single wire medium. Single Wire CAN was developed by General Motors and is used as the communication bus for body, hvac, and other slower speed applications. There are built in methods to allow ECUs on the network to "sleep" and "wake" through what is known as a high voltage wakeup signal.
The Single Wire CAN specifications are GMW3089 and SAE J2411.
VEHICLE SPY SUPPORT FOR SINGLE WIRE CAN
Vehicle Spy has a long history of supporting Single Wire CAN. There is a Vehicle Spy view dedicated to supporting GMLAN Virtual Networks including the High Voltage Wakeup.