Circuit/System Description
WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) monitors the state of charge (SOC) of the 12V electrical system. If the BCM senses that the 12V current draw was greater than 2 amps and the SOC at key-on is 30 percent lower than it was when the engine was last running, DTC B1527 00 will set.