Conditions for Setting the DTC

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The ECM detects the fuel temperature and the engine coolant temperature (ECT) are more than 9.75° C (18° F) of each other at start-up.
The IAT has decreased less than 5.25° C (10° F) after the engine has been running more than 400 seconds above 24 km/h (15 mph).