Circuit/System Description

Devices connected to the powertrain high speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver device as an availability indication of the transmitter device. Each message contains the identification number of the transmitter device.

This diagnostic is used to check the loss of communication with hybrid powertrain control module on high speed GMLAN bus. The battery energy control module supervises a periodic serial data message to check the communication status of the hybrid powertrain control module. If this message is not received within 3 seconds, then this DTC is set.