ECT: The scan tool displays -40 to +151°C (-40 to +304°F). The engine coolant temperature (ECT) sensor is mounted in the coolant stream. The powertrain control module (PCM) or engine control module (ECM) applies 5 volts to the ECT sensor signal circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold and the internal resistance is high, the PCM or ECM monitors a high signal voltage and interprets it as a cold engine. As the sensor warms and the internal resistance decreases, the voltage signal decreases and the PCM or ECM interprets the lower voltage as a warm engine.

F C 1, F C 2 Command: The scan tool displays On or Off. This parameter indicates the state of the driver circuit for this device.

Low Coolant Level, Switch Inputs: The scan tool displays YES or NO, determined by the state of the low coolant level switch.