Cooling Fan Motor Control

ECM controls the A/C auto amplifier and cooling fan motor. At this time, the reference revolution of the cooling fan motor is controlled by a PWN signal from ECM.

The cooling fan motor operates according to the duty cycle of PWM signal from ECM as follows.

• 10%: Cooling fan motor OFF
• 20% Cooling fan motor ON (minimum speeds)
• 90%: Cooling fan motor ON (maximum speeds)

When abnormal control occurs, the cooling fan motor operates at the maximum speed.

Cooling Fan Operation After Engine Stop 

If coolant temperature or engine oil temperature (calculated from reference temperature) is outside the threshold when the key is turned OFF, the fan motor is activated for 5 minutes at the maximum. At this time, the duty cycle of PWM signal is 40% at the maximum. If the battery voltage level is too low, the fan motor is not activated.