Circuit/System Verification
WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
Ignition ON, command the A/T shift lock control solenoid ON and OFF with the scan tool. The gearshift lever should be unlocked when ON and locked in PARK when OFF.