Mazda CX-5 Service & Repair Manual: Electrical Fan Control

Mazda CX-5 Service & Repair Manual / Engine / Cooling / Electrical Fan Control

Outline

Through cooling of the radiator and condenser by operation of the cooling fan according to vehicle conditions, engine reliability and cooling performance have been improved.

Block Diagram

Operation

The PCM determines the demand airflow volume by the following conditions.

Operation Pattern


Demand airflow volume	Cooling fan relay		Cooling fan motor
Demand airflow volume	No.1	No.2/No.3	No.1	No.2
No airflow	OFF	OFF	Stop	Stop
Small	ON	OFF	Low-speed	Low-speed
Large	ON	ON	High-speed	High-speed

Engine coolant temperature condition

Controls the PCM output duty ratio according to the engine coolant temperature.
The control temperature while the engine coolant temperature is decreasing is controlled differently than when it is increasing.

A/C operation condition

Controls the demand airflow volume depending on the refrigerant pressure and vehicle speed when the A/C switch is on.


Operation condition	Demand airflow volume
When all of the following conditions are met. Refrigerant pressure: 1.3 MPa {13 kgf/cm2, 189 psi} or less, vehicle speed: 45 km/h {28 mph} or more Refrigerant pressure: 2.2 MPa {22 kgf/cm2, 319 psi} or less, vehicle speed: 85 km/h {53 mph} or more	No airflow
When all of the following conditions are met. Refrigerant pressure: 1.3 MPa {13 kgf/cm2, 189 psi} or less, vehicle speed: 45 km/h {28 mph} or less Refrigerant pressure: 1.3—1.5 MPa {14—15 kgf/cm2, 189—217 psi}, vehicle speed: 85 km/h {53 mph} or less Refrigerant pressure: 1.5—2.2 MPa {16—22 kgf/cm2, 218—319 psi}, vehicle speed: 65—85 km/h {41—52 mph}	Small
When all of the following conditions are met. Refrigerant pressure: 1.5—2.2 MPa {16—22 kgf/cm2, 218—319 psi}, vehicle speed: 65 km/h {40 mph} or less Refrigerant pressure: 2.2 MPa {22 kgf/cm2, 319 psi} or more	Large

After Cooling Control

If the ignition is switched off directly after continuous high engine-load travel, the PCM operates (demand airflow volume: low) the cooling fan for a maximum of 9 minutes when all of the following conditions are met due to the possibility that the engine may not restart as a result of a fuel supply malfunction caused by the high temperature.

Engine coolant temperature: 90°C {194 °F} or more
Accumulated amount of engine heat is extremely large
Driving record for vehicle speed of 25 km/h {16 mph} or more available

Cooling System

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