The engine coolant temperature sensor is located in the engine water jacket and is a resistive type sender. The sensor supplies the engine coolant temperature to the powertrain control module (PCM) via discrete input. The filtered coolant temperature data is sent from the PCM to the IPC, via class 2 serial data messages. The IPC uses the temperature data received from the PCM and a software program to determine the proper coolant temperature to display. When the IPC receives the coolant temperature via class 2 serial data message, it compares the data to a calibratable look up table for the engine configuration. The coolant temperature is transmitted via class 2 serial data message on a change of 1.5°C (2.7°F) or more.

The IPC determines the proper pointer position on the engine coolant temperature gauge in order to display the relative engine coolant temperature. The engine coolant temperature gauge is labeled C on the left for cold, less than 32°C (90°F) and H on the right for hot, greater than 128°C (262°F). The gauge will be at the center position when the engine coolant is at the nominal temperature, between 88-104°C (190-219°F). The DSPL MODE button on the DIC is used to turn the display ON and OFF. The display will be ON when the speedometer gauge is ON and OFF when the speedometer gauge is OFF.

The engine coolant temperature indicator may only be ON during RUN. The IPC illuminates the engine coolant temperature indicator under the following conditions:

The IPC controls the operation of the engine coolant temperature indicator. The IPC will turn OFF the indicator and message when the engine coolant temperature falls below 125°C (257°F).