GM Service Manual Online
For 1990-2009 cars only
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.