Circuit/System Verification
WARNING: This page is about a different car, the 2006 Chevrolet Monte Carlo and 2006 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
Use the scan tool to observe the HS Comm. Cmd. parameter in the BCM data list/outputs with the driver door open and key out of the ignition, and with the ignition in the RUN position. The reading should match the normal range of the typical scan tool data above.
If all parameters are all correct and the DTC is current, replace the BCM.