Conditions for Setting the DTC
WARNING: This page is about a different car, the 2004 Suzuki Swift + and 2004 Chevrolet Aveo. However, it is still accessible from the selected car via links, so may be relevant.
The ECM detects the actual ECT difference of 0.3-51°C (32.5-124°F) of the calculated ECT for a time of 100-600 seconds, which the amount of time depends on the start-up coolant temperature.