Conditions for Setting the DTC
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.
The ECM detects that the minimum ECT of 75°C (167°F) has not been met, when the IAT is greater than 10°C (50°F).
OR
The ECM detects that the minimum ECT of 55°C (131°F) has not been met, when the IAT is less than 10°C (50°F).