Engine Cooling Fan Control

ENGINE COOLING FAN CONTROL





The Engine Cooling Fan (FC) is controlled by the Engine Control Module (ECM).

The following components affect the control of the Engine Coolant Fan:

^ Engine Speed (RPM) Sensor (1), giving the engine speed.
^ Engine Coolant Temperature (ECT) Sensor (2), giving the engine speed.
^ Speedometer (3), which shows vehicle speed.
^ Dashboard controls (4), for the A/C system (A/C on/off).
^ A/C pressure sensor (5), gives the pressure in the A/C system.

When extra cooling capacity is required the engine control module (ECM) (6) activates fan relay (7) and the engine cooling fan (FC) (8) starts.

The Engine Cooling Fan (FC) is activated if engine coolant temperature (ECT) exceeds normal operating temperature (102°C), or of the temperature inside the engine control module (ECM) exceeds 80°C.

The Engine Cooling Fan (FC) is activated in cars with an A/C system if:

^ The A/C system is on, vehicle speed is low (below 65 km/h) and pressure is above a set limit.
^ The pressure in the A/C system is too high.

When the engine is switched off the engine control module (ECM) can keep the engine coolant fan activated as follows:

^ For 6 minutes if engine load and temperature have been high before it was switched off.
^ For 3 minutes if the fan was running at high speed before the engine was switched off - there is a risk of overheating.

The engine control module (ECM) has two speeds. Low speed is used for normal control. High (full) speed is only used if there is a risk of the engine overheating or if pressure in the A/C system is high.