Some GM vehicles started using Class 2 Serial Data network system in 1995, which was also the phasein year for ODB II. Since then, Class 2 is becoming GMs predominant network system. Modules on this network system share information and each one can transmit and receive messages. gm class 2 serial data voltage U1301 Chevrolet High Voltage On Class 2 Serial Data Circuit When the module detects one of the following conditions on the class 2 serial data circuit for approximately 3 seconds, the setting of all other class 2 serial communication DTCs is inhibited and a DTC will set.
Class 2 data bus shorted Posted to Technical Tips Forum on 23 Replies This system, and possibly the issues, are likely old news to many of you, but it was my first time getting a broken data bus on a GM. gm class 2 serial data voltage
In addition to this, Node Alive messages are transmitted by each module on the class 2 serial data circuit about once every 2 seconds. When the module detects one of the following conditions on the class 2 serial data circuit for approximately 3 seconds, the setting of all other class 2 serial communication DTCs is inhibited and a DTC will set. Since we are talking GM Class 2 serial data bus protocol here, it is normal to find 1. 2 to 1. 8 volts to be the engine idling voltage of Pin 2 when measured against Pin 5 using a voltmeter. However at KOEO for GM vehicles, expect a normal voltage of 5 volts. General Motors Computerized Vehicle Control Systems: A Short History serial data line. This was a single circuit that was referenced to ground and was shared to a certain pin on each module. To prevent collisions of data and to establish a vehicles used class 2 data explicitly and others had two buses, one for class 2 data and gm class 2 serial data voltage Voltage supplied to the module is in the normal operating voltage range; vehicle power mode required serial data communication to occur, then the PCM did not detect any valid messages on the Class 2 serial data circuit, and voltage level detected on the Class 2 serial data circuit remained in a continuous high state for 3 seconds. A Closer Look at Vehicle Data Communications T hrough the years weve come to depend on the infor module through a serial data line. Star Network Serial data lines wire circuit that replaced the class 2 data circuits on many GM vehicles (Figure 4). The GM low speed LAN is Here is a list of data streams that GM uses today; Class 2 The data link connector (DLC) allows a scan tool to communicate with the class 2 serial data the signal voltage on the data line remains high (usually 5 The Class 2 serial data circuit is provided at pin 2 of the DLC.