8 Digit GM Part Number: The scan tool displays an 8 digit alphanumeric number. The part
number of the module.
Coolant Hot Lamp: The scan tool displays ON/OFF. The scan tool displays ON when the
engine coolant is above 260°
Coolant Temperature: The scan tool displays -40°F to 304°F. The scan tool displays
the engine coolant temperature in °F.
ECT: 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 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.
Fans High Speed: The scan tool displays On or Off. The PCM is commanding all three
fan control relays on when the scan tool indicates On. When all fan control
relays are activated, both cooling fans are enabled on high speed.
Fans Low Speed: The scan tool displays On or Off. The PCM is commanding Fan Control
relay 1 On when the scan tool indicates On. When the PCM commands the Fan
Control relay 1 On, both fans are enabled on low speed.
Julian Date of Build: The scan tool displays 0-999. The day of the year that
the module was built.
PROM ID: The scan tool displays 0-9999. The identification number
of the modules internal PROM.
Year Module Built: The scan tool displays a 1990-2020. The production year
the module was manufactured.