LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mazda >> 2021 >> CX-9 Signature >> Repair and Diagnosis (Single Page) >> Engine Mechanical >> Cooling Fan >> Engine Cooling System >> Fan Control Module Inspection
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Fan Control Module Inspection

NOTE:
  • The fan control module cannot be removed as a single unit. If the fan control module is replaced, replace the cooling fan component.
  1. Connect the M-MDS to the DLC-2.
  2. Start and warm up the engine.
  3. Gradually increase the FAN_DUTY value from 0 to the maximum possible M-MDS operation value using the simulation function. (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.5T)] .)
    • Visually verify that the operation speed of the cooling fan conforms to the override drive.
  4. Using the M-MDS, change the operation condition of the A/C while measuring the engine coolant temperature under the following conditions, and verify that the cooling fan operates correctly.
    • Because there is an intake air temperature decrease control setting, the cooling fan may operate when IAT sensor No. 1 detects 60°C {140°F}or more according to conditions other than those mentioned.
    • Because there is an engine protection control setting, the cooling fan may operate when IAT sensor No. 2 detects 70°C {158°F}or more according to conditions other than those mentioned.

    Fan control module No. 1, No. 2 [A/C OFF] 

    FAN CONTROL MODULE NO. 1, NO. 2 (A/C OFF)

    Engine coolant temperature °C {°F} Cooling fan operation status
    less than 98 {208} Off
    more than 100 {212} On
  5. Verify that the PID FAN_DUTY value is a value other than 0 while measuring the vehicle speed under the following conditions using the M-MDS.

    Fan control module No. 1, No. 2 [A/C ON] 

    FAN CONTROL MODULE NO. 1, NO. 2 (A/C ON)

    Vehicle speed (km/h {MPH}) PID FAN_DUTY [%]
    less than 85 {52} value other than 0
    more than 85 {53} 0
  6. If normal operation cannot be verified in Steps 3, 4 and 5, inspect the input signals of the following parts. Replace the cooling fan motor if all the following parts are normal.
    • ECT sensor
    • Refrigerant pressure sensor
    • Battery