Manual Downshifts: Notes
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.
Manual downshift testing is not required for vehicles equipped with Driver Shift Control (DSC). This is done by shifting the gear selector to M on the display and then by using the + and - on the rocker switch on the gear selector. The TCM and shift solenoids will automatically override DSC downshifts to protect the transmission from damage.