Engine Coolant Temperature Gage
WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
The instrument panel cluster (IPC) displays the engine coolant temperature as determined by the powertrain control module (PCM) or the engine control module (ECM) indicating engine coolant temperature. The engine coolant temperature gage defaults to 100°F (38°C) if there is a malfunction in the engine coolant temperature sensor or the IPC detects a loss of class 2 communication with the PCM/ECM.