Conditions for Setting the DTC
WARNING: This page is about a different car, the 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The ECM detects that the difference in range between the IAT and the IAT sensor 2 either plus or minus is greater than 20°C (36°F) for greater than 4 seconds continuously or 50 seconds cumulative.