Battery Voltage 1: The scan tool displays 0-12 volts of
battery voltage at the BCM.
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 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, FC Relay 2 Command: The
scan tool displays On or Off. This parameter indicates the state of the driver circuit
for this device.