S60 L5-2.4L VIN 64 B5244S6 (2003)
The engine coolant temperature (ECT) sensor checks the temperature of the engine coolant. The temperature of the engine coolant is required so that the
engine control module (ECM) can regulate:
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the injection period
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the idle speed
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the engine cooling fan (FC)
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the ignition advance
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engagement and disengagement of the A/C compressor
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diagnostic functions.
The sensor is a negative temperature coefficient (NTC) type which is supplied with power from the control module (signal) and is grounded in the
control module.
The resistance in the sensor changes depending on the temperature of the coolant. Depending on the resistance in the sensor, voltage (signal) is
transmitted to the engine control module (ECM). The lower the temperature the higher the voltage (high resistance). A high temperature results in low
voltage (low resistance).
The engine coolant temperature (ECT) sensor is located beside the thermostat.
The engine control module (ECM) can diagnose the engine coolant temperature sensor. The sensor value can be read off using VIDA.
Engine cooling fan (FC) control module
The engine cooling fan (FC) cools the coolant, engine compartment and the condenser when the air conditioning (A/C) compressor is running.
The engine control module (ECM) transmits a pulse width modulated (PWM) signal to the engine cooling fan (FC) control module. The control module
then activates the fan at different speeds. The speed of the engine cooling fan (FC) is determined by the engine control module (ECM), depending on the
coolant temperature (based on the signal from the engine coolant temperature (ECT) sensor) and the vehicle speed.
The temperature conditions for engagement of the different engine cooling fan (FC) stages may vary slightly, depending on the engine variant and the
equipment level. The temperature conditions apply when:
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the A/C is off
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no faults are detected by the Engine Control Module (ECM).
There is an internal diagnostic function in the engine cooling fan (FC). This function transmits a signal to the engine control module (ECM) if the fan is
