Conditions for Setting the DTC
WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. 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).