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Home >> GMC >> 1999 >> Forward Control 7.4 B >> Repair and Diagnosis >> External Pages >> Different car >> Section 367 (Engine Cooling System) >> Diagnostic Information and Procedures >> Scan Tool Data Definitions
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Scan Tool Data Definitions

WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

IPC -Data - Low Coolant Input:  The scan tool displays Active or Inactive. The IPC monitors the engine coolant indicator module. A closed switch, with low coolant level, is displayed as Active.

IPC - Inputs - Coolant Hot Lamp:  The scan tool displays On or Off. The state of the engine coolant temperature indicator as commanded by the IPC.

IPC - Inputs - Low Coolant Lamp:  The scan tool displays On or Off. The state of the low engine coolant level indicator as commanded by the IPC.

PCM - 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 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.

PCM - FC Relay 1 Circuit Status:  The scan tool displays OK or Fault. This parameter indicates the state of the driver circuit for this device.

PCM - FC Relay 1 Command:  The scan tool displays On or Off. This parameter indicates the state of the low speed fan relay driver.

PCM - FC Relay 2 and 3 Circuit Status:  The scan tool displays OK or Fault. This parameter indicates the state of the driver circuit for this device.

PCM - FC Relay 2 and 3 Command:  The scan tool displays On or Off. This parameter indicates the state of the high speed fan relay driver.