Ice Possible
WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The IPC illuminates the ICE POSSIBLE message in the driver information center (DIC) when the outside air temperature drops below 4°C (39°F). The IPC receives a class 2 message from the body control module (BCM) indicating the outside air temperature.