Scan Tool Data Definitions

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

ECT: The scan tool displays -40 to +151°C (-40 to +304°F). The Engine Coolant Temperature (ECT) sensor is mounted in the coolant stream. The PCM/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 PCM/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 PCM/ECM interprets the lower voltage as a warm engine.
FC Relay 1 Command: The scan tool displays OK or Fault. This parameter indicates the state of the driver circuit for this device.
FC Relay 2 and 3 Command: The scan tool displays OK or Fault. This parameter indicates the state of the driver circuit for this device.