Scan Tool Data Definitions

WARNING: This page is about a different car, the 2002 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.

ECT: The scan tool displays -40°C to +150°C (-40°F to +302°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.

FC Relay 1 Command: The scan tool displays ON or OFF. This parameter indicates the PCM commanded state of the low speed cooling fans.

FC Relay 2 and S/P Command: The scan tool displays ON or OFF. This parameter indicates the PCM commanded state of the high speed cooling fans.

Low Coolant Level: Displays On or OFF. The status of the discrete engine coolant level switch signal. The instrument cluster uses this input to determine display of the CHECK COOLANT LEVEL message on the DIC.