Conditions for Setting the DTC: P2185
WARNING: This page is about a different car, the 2007 GMC Sierra, 2007 GMC Cab & Chassis Sierra, 2007 Chevrolet Silverado, and 2007 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The ECT sensor 2 temperature is colder than -39°C (-38°F) for more than 60 seconds. This is equal to more than 4.8 volts on the ECT sensor 2 signal circuit, as measured by the ECM.