General Motors GMLAN

What is GMLAN? It is General Motors new Serial Communication Protocol that has been introduced in a couple of 2004 vehicles. These vehicles still use the Class2 protocol for engine management and will have a gate way between it and GMLAN. The next couple of years Class2 protocol will be replaced by GMLAN. The GMLAN is based off the Controller Area Network (CAN) protocol. GMLAN is a reliable and cost effective way to send data between different Electronic Control Units (ECU’s) in the vehicle.

GMLAN supports 3 different speed buses.
• Low Speed - Uses Single Wire (refered to as Single Wire CAN or SWCAN). Used in security, doorlocks/windows and other low speed non-Real Time data.
• Mid Speed -
• High Speed - Uses Two Wire twisted pair. Primarily used for Powertrain and Chassis Devices as well as Anti Lock Brakes.