Scan Tool Data Definitions

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

Coolant Temperature: The scan tool displays -40°C to +151°C (-40°F to +304°F). This data is the coolant temperature the Instrument Cluster is attempting to display on the coolant temperature gage.

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 Command: The scan tool displays On or Off. This parameter indicates the state of the driver circuit for this device.

FC Relay 2 and 3 Command: The scan tool displays On or Off. This parameter indicates the state of the driver circuit for this device.

Coolant Level Input: The scan tool displays OK or Low. If the ground circuit opens, the scan tool will display Low.

Fig 1: Diagnostic Trouble Code (DTC) List

Courtesy of GENERAL MOTORS CORP.