Conditions for Setting the DTC
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.
The hybrid powertrain control module detects the hybrid low, 1-2 clutch slip speed is less than 30 RPM for 4.5 seconds, when hybrid low, 1-2 clutch is commanded OFF.