Circuit Description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
All vehicle modules monitor system voltage. The system voltage message is sent to other modules via Class 2 message. When the system voltage is above the specified range DTC B1328 shall set within the affected module.