Displayed Coolant Temp: The scan tool displays -39°C to
+140°C (-38°F to +284°F). This is the actual indication of the displayed
coolant temperature.
ECT: 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.
High Speed Fan Relay: The scan tool displays On and Off. It
represents the commanded state of the high speed cooling fan relay as commanded by
the PCM.
Low Speed Fan Relay: The scan tool displays On and Off. It represents
the commanded state of the low speed cooling fan relay as commanded by the PCM.
Monitored Coolant Temp: The scan tool displays -39°C to
+140°C (-38°F to +284°F). This is the actual coolant temperature as received
from the powertrain control module (PCM).