Conditions for Setting the DTC

WARNING: This page is about a different car, the 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

The ECM detects that the ECT is 10°C (18°F) colder than the first modeled ECT.
AND/OR
The ECM detects that the ECT is 11°C (20°F) colder than the second modeled ECT.