Circuit/System Verification
WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Ignition ON, observe the scan tool Hybrid Battery 1-20 parameters. Each reading should be between 13-19 Volts, and all readings should be within 1.5 Volts of each other.