Scan Tool Data Definitions
Scan Tool Data DefinitionsECT: 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 Powertrain Control Module (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 Command: The fan control (FC) relay is commanded by the PCM. FC Relay 1 displays the command as ON or OFF.
High Coolant Temp. Lamp: The scan tool displays ON or OFF. The state of the CHECK GAGES indicator as commanded by the instrument panel cluster (IPC). The IPC receives a class 2 message from the Body Control Module (BCM) indicating the coolant temperature.
Low Coolant Lamp: The scan tool displays ON or OFF. The state of the Low Coolant indicator as commanded by the IPC. The IPC receives a class 2 message from the RCM indicating the coolant level.