ECT -- Range: -40°C to +150°C (-40°F to +302°F): The PCM applies 5.0 volts to the ECT sensor circuit. The
sensor is a thermistor which changes internal resistance as the engine temperature
changes. When the sensor is cold (internal resistance high), the PCM senses a high
signal voltage and interprets the voltage 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.
Displayed Coolant Temperature -- Range: 32-127°C (89-260°F): This data is the coolant temperature the Instrument Cluster is attempting
to display on the coolant temperature gauge. This data may differ from the monitored
coolant temperature for a period of time due to filtering. The data may also differ
from the monitored coolant temperature when coolant temperature is not in the range
of 71-127°C (160-260°F) since the display is limited to these
values. If a class 2 communication failure occurs, this data will be at the
minimum value of 32°C (89°F).
Monitored Coolant Temperature -- Range: 40-215°C (40-419°F): This data is the clusters measurement of the engine coolant temperature
as provided by the PCM on the class 2 serial data line.