Scan Tool Data Definitions

Scan Tool Data Definitions

Commanded Fan 1 / Commanded Fan 2: Scan tool displays ON or OFF. Represents the powertrain control module (PCM) commanded state of the fan 1 (low Speed) and fan 2 (high speed) control circuits.
ECT: The scan tool displays -40 - 151°C (-40 - 304°F). The Engine Coolant Temperature (ECT) sensor is mounted in the coolant stream. The 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: The scan tool displays OK or Fault. This parameter indicates the state of the driver circuit for this device.
FC Relay 2 and 3: The scan tool displays OK or Fault. This parameter indicates the state of the driver circuit for this device.