Circuit/System Verification
WARNING: This page is about a different car, the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
Start and idle the engine. Using the scan tool output controls command the 1-2 SS ON and OFF. Observing the 1-2 Sol. CKT Status parameter on the scan tool, ensure that the parameter shows OK.