Coolant Temp Warning Indicator

The IPC illuminates the TEMP indicator (thermometer icon) when the Powertrain Control Module (PCM) determines that the coolant temperature is more than 262°F (128°C). The Instrument Panel Cluster (IPC) receives a discrete input from the PCM requesting illumination. The IPC performs the displays test at the start of each ignition cycle. The TEMP indicator will illuminate during this test.
The vehicle also has a temperature gauge that shows the engine coolant temperature. If the gauge pointer moves into the Red area, the engine is too hot. This reading indicates the same thing as the warning light. The IPC displays the engine coolant temperature as determined by the PCM. The IPC receives a class 2 message from the PCM indicating the engine coolant temperature. The engine coolant temperature gage defaults to "C" (cold) or below if the PCM detects a malfunction in the engine coolant temperature sensor circuit and if the IPC detects a loss of class 2 communications with the PCM.