Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

A short to ground in the run/crank ignition circuit of the run crank relay will cause an open fuse to the ignition switch. DTC B1428 should be current.
A short to ground in the accessory wake-up serial data circuit will cause an open fuse to the ignition switch. DTC U1814 should be current.
The power modes and controls are determined using BCM logic. Comparing the Body Control Module Power Mode data display parameters listed in Circuit/System Verification will determine if there is a power mode fault.