Scan Tool Data Definitions

Scan Tool Data Definitions

Coolant Temp: The scan tool displays 40° C (40° F) to 140° C (284° F). This parameter is the state of the engine coolant temperature detected by the Instrument Panel Cluster (IPC).
Coolant Temp Sensor: The scan tool displays 0-10 volts. This parameter is the state of the voltage at the coolant temp sensor detected by the IPC.
Coolant Warning Lamp: The scan tool displays On/Off. This parameter is the state of the coolant warning lamp.
ECT: The scan tool displays -40° C to 140° C (-40° F to 284° F). The Engine Coolant Temperature (ECT) sensor is mounted in the coolant stream. The Engine Control Module (ECM) 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 ECM 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 ECM interprets the lower voltage as a warm engine.