Circuit/System Description

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Modules connected to the LAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The 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.

A wake up signal circuit (968) is energized by the serial data gateway module (SDGM) to activate the hybrid powertrain control module (HPCM) which is part of the drive motor generator power inverter module (PIM) and the drive motor generator battery control module (BECM) when serial data is required. The SDGM determines that serial data is required when a wake up signal (circuit 5986) is received from the body control module (BCM). The wake up signal (circuit 5986) from the BCM is also connected to the BECM, and the BECM compares the status of both circuits.