Circuit/System Description

Control modules 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 control modules. The control modules 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 module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.

The motor control module and the hybrid powertrain control module are all internal to the starter/generator control module. All circuits to the hybrid powertrain control module are also internal to the starter/generator control module.

Communication diagnostics for the serial data, including control module power and ground as well as the wakeup circuits for the motor control module and the hybrid powertrain control module are all diagnosed from external sources only to the starter/generator control module connector because any circuit fault condition within the starter/generator control module will cause a complete replacement.