Circuit/System Verification
WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
With the scan tool installed, ignition ON and the engine OFF, observe the Battery Positive Voltage parameter in the EBCM data list. The reading should be between 9-17 volts.