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Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 9 (Engine Controls And Fuel - 2.5L (LCV) - Diagnostic Information And Procedures (1 Of 2)) >> Diagnostic Information and Procedures >> DTC P0128 or P01F0 >> Circuit/System Description

Circuit/System Description

WARNING: This page is about a different variant/trim than selected.

For an overview of the component/system, refer to: Cooling System Description and Operation (LCV, LGX) .

Circuit Description
Signal The control module input circuit has an internal resistance connected to 5 V.
Low Reference Grounded through the control module.
Component Description
B34 Engine Coolant Temperature Sensor The sensor is a negative temperature coefficient thermistor. As the temperature of the air, fluid, or metal increases, the resistance of the sensor decreases, varying the voltage on the signal circuit.
K20 Engine Control Module The control module contains a microprocessor used to process input data to control outputs.
The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.

The engine control module (ECM) monitors the temperature of the engine coolant for engine control and as an enabling criteria for some diagnostics. The amount of heat an engine generates is proportional to the amount of air that enters the engine. The ECM monitors this amount of air to calculate a theoretical engine coolant temperature (ECT). The ECM uses the calculated temperature to determine the following: