Scan Tool Data Definitions
WARNING: This page is about a different car, the 2007 Isuzu i-370, 2007 Isuzu i-290, 2007 GMC Canyon, and 2007 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.
- ECT Sensor
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The scan tool displays -39°C to +140°C (-38°F to +284°F). The Engine Coolant Temperature (ECT) sensor is mounted in the coolant stream. The powertrain control module (PCM) applies 5 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the PCM monitors a high signal voltage and interprets it as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases and the PCM interprets the lower voltage as a warm engine.