Action Taken When the DTC Sets

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, and 2010 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0120, P0122, P0123, P0220, P0222, P0223, and P2135 are Type A DTCs.
The control module commands the TAC system to operate in the Reduced Engine Power mode.
A message center or an indicator displays Reduced Engine Power.
Under certain conditions the control module commands the engine OFF.