Coolant Temperature Gauge

The temperature gauge is an analog device that is located in the instrument cluster. The Vehicle Control Module (VCM) or Powertrain Control Module (PCM) uses class 2 serial data communications in order to inform the instrument cluster of the engine coolant temperature. The instrument cluster operates the temperature gauge in order to appropriately display the engine coolant temperature. The PCM/VCM determines the coolant temperature by measuring the signal voltage from a variable resistance sensor in the engine coolant jacket with the ignition switch in the RUN position. The sensor changes resistance with coolant temperature. As coolant temperature increases, the resistance of the sensor decreases. The coolant temperature gauge displays temperatures of 37.8°C (100°F), 98.9°C (210°F), and 126.7°C (260°F). The CHECK GAUGES indicator will be ON if the engine coolant temperature is too high. The Engine Coolant Temperature Sensor (ECT) is located in the thermostat housing on the 2.2 L engine. The ECT of the 4.3 L engine is located on the left side of the cylinder head.