Scan Tool Data Definitions

Scan Tool Data Definitions
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).