Circuit/System Verification
WARNING: This page is about a different car, the 2014 GMC Yukon XL 1500, 2014 GMC Yukon, 2014 Chevrolet Tahoe, and 2014 Chevrolet Suburban 1500. However, it is still accessible from the selected car via links, so may be relevant.
Key ON, engine OFF. The TCCM runs a 2 second bulb test on all indicators of the TCSCS at key ON.