Scan Tool Data Definitions

Scan Tool Data Definitions

Coolant Hot Lamp: The scan tool displays ON/OFF. The scan tool displays ON when the engine coolant is above 151°C (260°F).
Coolant Temperature: The scan tool displays -40°C to +151°C (-40°F to +304°F). This data is the coolant temperature the Instrument Cluster is attempting to display on the coolant temperature gauge.
ECT: The scan tool displays -40°C to +151°C (-40°F to +304°F). The Engine Coolant Temperature (ECT) sensor is mounted in the coolant stream. The PCM 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 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 interprets the lower voltage as a warm engine.
FC Relay 1: The scan tool displays OK or Fault. This parameter indicates the state of the driver circuit for this device.