Radiator Fan System: Inspection

Operating condition: 

Radiator fan operates depending on the radiator fan speed related to engine coolant temperature or the radiator fan speed related to A/C compressor load, whichever is higher as a load condition.

• Radiator fan speed related to engine coolant temperature

  Courtesy of SUBARU OF AMERICA, INC.

  (A)	Radiator fan speed (%)
  (B)	Engine coolant temperature
  (1)	96°C (205°F)
  (2)	98°C (208°F)
  (3)	100°C (212°F)
  (4)	101°C (214°F)

• Radiator fan speed related to A/C compressor load

  Courtesy of SUBARU OF AMERICA, INC.

  (A)	Radiator fan speed (%)
  (B)	A/C compressor refrigerant pressure
  (1)	0.793 MPa (8.09 kg/cm2 , 114.98 psi)
  (3)	2.7 MPa (27.53 kg/cm2 , 391.5 psi)
  (2)	0.999 MPa (10.19 kg/cm2 , 144.85 psi)
  (4)	3.7 MPa (37.73 kg/cm2 , 536.49 psi)

Diagnosis: 

Radiator main fan and radiator sub fan do not rotate under the above operating conditions.

1. CHECK DTC  .

   Read the DTC using Subaru Select Monitor. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>OPERATION .

   Is DTC detected?

   Yes  :

   1. Repair the corresponding system.
   2. Go to  2.

   No:  Go to  2.

2. CHECK RADIATOR MAIN FAN AND RADIATOR SUB FAN OPERATION  .
   1. Using the Subaru Select Monitor, select [Radiator Fan Relay] of [Active Test]. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>ACTIVE TEST .
      NOTE: It is also possible to check the operation of the radiator main fan and radiator sub fan with the mode set to the delivery mode and ignition switch to ON. Ref. to PRE-DELIVERY INSPECTION>PRE-DELIVERY INSPECTION (PDI) PROCEDURE>DELIVERY MODE .
   2. Check the operation of the radiator main fan and radiator sub fan.

   Do the radiator main fan and radiator sub fan rotate with repetitive ON/OFF operation?

   Yes:  Radiator main fan system is normal.

   No  :

   • When the radiator main fan does not rotate, Go to  3.
   • When the radiator sub fan does not rotate, Go to  12.
3. CHECK FUSE  .
   1. Turn the ignition switch to OFF.
      NOTE: If the delivery mode is set, turn the ignition switch to OFF and then exit the delivery mode. Ref. to PRE-DELIVERY INSPECTION>PRE-DELIVERY INSPECTION (PDI) PROCEDURE>DELIVERY MODE .
   2. Check the SBF-11 and F/B fuse No. 8.

   Is the fuse OK?

   Yes:  Go to  4.

   No:  Replace the fuse.

   NOTE: If the fuse is blown again, check the system wiring harness.
4. CHECK MAIN FAN RELAY  .
   1. Remove the main fan relay. Ref. to COOLING (H4DOTC)>RADIATOR FAN RELAY>LOCATION .
   2. Perform unit check for the main fan relay. Ref. to COOLING (H4DOTC)>RADIATOR FAN RELAY>INSPECTION .

   Is the main fan relay OK?

   Yes:  Go to  5.

   No:  Replace the main fan relay. Ref. to COOLING (H4DOTC)>RADIATOR FAN RELAY>LOCATION .

5. CHECK POWER SUPPLY FOR ECM  .
   1. Install the main fan relay. Ref. to COOLING (H4DOTC)>RADIATOR FAN RELAY>LOCATION .
   2. Disconnect the connector from ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ENGINE CONTROL MODULE (ECM)>REMOVAL .
   3. Turn the ignition switch to ON.
   4. Measure the voltage between ECM connector and chassis ground.

      Connector & terminal 

      (B134) No. 46 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes:  Go to  6.

   No:  Repair the power supply line.

6. CHECK POWER SUPPLY FOR RADIATOR FAN CONTROL MODULE (MAIN)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from radiator fan control module (main).
   3. Turn the ignition switch to ON.
   4. Measure the voltage between radiator fan control module (main) connector and chassis ground.

      Connector & terminal 

      (F106) No. 1 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes:  Go to  7.

   No:  Repair the power supply line.

7. CHECK HARNESS BETWEEN ECM AND RADIATOR FAN CONTROL MODULE (MAIN)  .
   1. Turn the ignition switch to OFF.
   2. Measure the resistance between ECM connector and radiator fan control module (main) connector.

      Connector & terminal 

      (B134) No. 59 - (F106) No. 2:

   Is the resistance less than 1 Ω?

   Yes:  Go to  8.

   No:  Repair the open circuit of harness between ECM connector and radiator fan control module (main) connector.

8. CHECK GROUND CIRCUIT FOR RADIATOR FAN CONTROL MODULE (MAIN)  .

   Measure the resistance between radiator fan control module (main) connector and chassis ground.

   Connector & terminal 

   (F106) No. 3 - Chassis ground:

   Is the resistance less than 5 Ω?

   Yes:  Go to  9.

   No:  Repair the open circuit of harness between radiator fan control module (main) connector and chassis ground.

9. CHECK MAIN FAN MOTOR  .
   1. Disconnect the connector from the main fan motor.
   2. Apply battery voltage to the main fan motor.
      1. Connect the battery positive terminal to the main fan motor terminal No. 1.
      2. Connect the battery negative terminal to the main fan motor terminal No. 2.

   Does the main fan motor rotate?

   Yes:  Go to  10.

   No:  Replace the main fan motor. Ref. to COOLING (H4DOTC)>RADIATOR FAN AND FAN MOTOR ASSEMBLY .

10. CHECK HARNESS BETWEEN RADIATOR FAN CONTROL MODULE (MAIN) AND MAIN FAN MOTOR  .
    1. Disconnect the connector from radiator fan control module (main).
    2. Measure the resistance between radiator fan control module (main) connector and main fan motor connector.

       Connector & terminal 

       (F17) No. 1 - (F50) No. 2:

       (F17) No. 2 - (F50) No. 1:

    Is the resistance less than 1 Ω?

    Yes:  Go to  11.

    No:  Repair the open circuit in harness between radiator fan control module (main) connector and main fan motor connector.

11. CHECK OUTPUT SIGNAL OF ECM  .
    1. Connect the connector to radiator fan control module (main) and main fan motor.
    2. Turn the ignition switch to ON.
    3. Using the Subaru Select Monitor, select [Radiator Fan Relay] of [Active Test]. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>ACTIVE TEST .
       NOTE: It is also possible to check the output signal of ECM with the mode set to the delivery mode and ignition switch to ON. Ref. to PRE-DELIVERY INSPECTION>PRE-DELIVERY INSPECTION (PDI) PROCEDURE>DELIVERY MODE .
    4. Read the output signal waveform using an oscilloscope. Ref. to COOLING (H4DOTC)>RADIATOR FAN SYSTEM>RADIATOR FAN CONTROL OUTPUT WAVEFORM .

       Connector & terminal 

       (B134) No. 59 (+) - Chassis ground (-):

    Does a waveform of the output signal occur?

    Yes:  Replace the radiator fan control module (main). Ref. to COOLING (H4DOTC)>RADIATOR FAN CONTROL UNIT .

    No:  Replace the ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ENGINE CONTROL MODULE (ECM) .

12. CHECK FUSE  .
    1. Turn the ignition switch to OFF.
       NOTE: If the delivery mode is set, turn the ignition switch to OFF and then exit the delivery mode. Ref. to PRE-DELIVERY INSPECTION>PRE-DELIVERY INSPECTION (PDI) PROCEDURE>DELIVERY MODE .
    2. Check the SBF-12 and F/B fuse No. 8.

    Is the fuse OK?

    Yes:  Go to  13.

    No:  Replace the fuse.

    NOTE: If the fuse is blown again, check the system wiring harness.
13. CHECK SUB FAN RELAY  .
    1. Remove the sub fan relay. Ref. to COOLING (H4DOTC)>RADIATOR FAN RELAY>LOCATION .
    2. Perform unit check for the sub fan relay. Ref. to COOLING (H4DOTC)>RADIATOR FAN RELAY>INSPECTION .

    Is the sub fan relay OK?

    Yes:  Go to  14.

    No:  Replace the sub fan relay. Ref. to COOLING (H4DOTC)>RADIATOR FAN RELAY>LOCATION .

14. CHECK POWER SUPPLY FOR ECM  .
    1. Install the sub fan relay. Ref. to COOLING (H4DOTC)>RADIATOR FAN RELAY>LOCATION .
    2. Disconnect the connector from ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ENGINE CONTROL MODULE (ECM)>REMOVAL .
    3. Turn the ignition switch to ON.
    4. Measure the voltage between ECM connector and chassis ground.

       Connector & terminal 

       (B134) No. 45 (+) - Chassis ground (-):

    Is the voltage 10 V or more?

    Yes:  Go to  15.

    No:  Repair the power supply line.

15. CHECK POWER SUPPLY FOR RADIATOR FAN CONTROL MODULE (SUB)  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from radiator fan control module (sub).
    3. Turn the ignition switch to ON.
    4. Measure the voltage between radiator fan control module (sub) connector and chassis ground.

       Connector & terminal 

       (F22) No. 1 (+) - Chassis ground (-):

    Is the voltage 10 V or more?

    Yes:  Go to  16.

    No:  Repair the power supply line.

16. CHECK HARNESS BETWEEN ECM AND RADIATOR FAN CONTROL MODULE (SUB)  .
    1. Turn the ignition switch to OFF.
    2. Measure the resistance between ECM connector and radiator fan control module (sub) connector.

       Connector & terminal 

       (B134) No. 27 - (F22) No. 2:

    Is the resistance less than 1 Ω?

    Yes:  Go to  17.

    No:  Repair the open circuit of harness between ECM connector and radiator fan control module (sub) connector.

17. CHECK GROUND CIRCUIT FOR RADIATOR FAN CONTROL MODULE (SUB)  .

    Measure the resistance between radiator fan control module (sub) connector and chassis ground.

    Connector & terminal 

    (F22) No. 3 - Chassis ground:

    Is the resistance less than 5 Ω?

    Yes:  Go to  18.

    No:  Repair the open circuit of harness between radiator fan control module (sub) connector and chassis ground.

18. CHECK SUB FAN MOTOR  .
    1. Disconnect the connector from the sub fan motor.
    2. Apply battery voltage to the sub fan motor.
       1. Connect the battery positive terminal to the sub fan motor terminal No. 1.
       2. Connect the battery negative terminal to the sub fan motor terminal No. 2.

    Does the sub fan motor rotate?

    Yes:  Go to  19.

    No:  Replace the sub fan motor. Ref. to COOLING (H4DOTC)>RADIATOR FAN AND FAN MOTOR ASSEMBLY .

19. CHECK HARNESS BETWEEN RADIATOR FAN CONTROL MODULE (SUB) AND SUB FAN MOTOR  .
    1. Disconnect the connector from radiator fan control module (sub).
    2. Measure the resistance between radiator fan control module (sub) connector and sub fan motor connector.

       Connector & terminal 

       (F16) No. 1 - (F51) No. 2:

       (F16) No. 2 - (F51) No. 1:

    Is the resistance less than 1 Ω?

    Yes:  Go to  20.

    No:  Repair the open circuit in harness between radiator fan control module (sub) connector and sub fan motor connector.

20. CHECK OUTPUT SIGNAL OF ECM  .
    1. Connect the connector to the radiator fan control module (sub) and the sub fan motor.
    2. Turn the ignition switch to ON.
    3. Using the Subaru Select Monitor, select [Radiator Fan Relay] of [Active Test]. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>ACTIVE TEST .
       NOTE: It is also possible to check the output signal of ECM with the mode set to the delivery mode and ignition switch to ON. Ref. to PRE-DELIVERY INSPECTION>PRE-DELIVERY INSPECTION (PDI) PROCEDURE>DELIVERY MODE .
    4. Read the output signal waveform using an oscilloscope. Ref. to COOLING (H4DOTC)>RADIATOR FAN SYSTEM>RADIATOR FAN CONTROL OUTPUT WAVEFORM .

       Connector & terminal 

       (B134) No. 27 (+) - Chassis ground (-):

    Does a waveform of the output signal occur?

    Yes:  Replace the radiator fan control module (sub). Ref. to COOLING (H4DOTC)>RADIATOR FAN CONTROL UNIT .

    No:  Replace the ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ENGINE CONTROL MODULE (ECM) .