Coolant Temperature
WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The DIC receives serial data messages from the BCM requesting the display of the coolant temperature. The coolant temperature is sent to the BCM as determined by the PCM/ECM via a serial data message.