What is Class 2 in GM vehicles that everyone is hearing about lately?
Class 2 or Class B is really a in-vehicle network SAE J1850 protocol that GM has been using for many years. It just a new data protocol that a majority of vehicle computer modules uses, which share the same single data wire through out the vehicle.
Recently GM has now included the driver’s door module, passenger’s door module, rear seat audio controller, vehicle communication interface module or OnStar®, steering wheel audio controls, rear seat entertainment (RSE), CD changer, radio, DVD/Video, amplifier and XM radio as part of Class 2. Since these new modules are part of the audio system and security system, you are now hearing more about Class 2.
Connected to this same data wire is the Body Control Module (BCM), Powertrain Control Module (PCM), Transfer Case Shift Control Module, Heater & A/C controls (HVAC), Inflatable Restraint Sensing and Diagnostic Module, Theft Deterrent Control Module, Memory Seat Module, Drivers Information Center (DIC), Key/Lights/Seatbelt Chimes (most vehicles), Instrument Panel Cluster (IPC), Suspension Control Module, Electronic Brake Control Module (EBCM) and other modules.