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Radiator Fan System: Inspection

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

Diagnosis: 

Radiator main fan and radiator sub fan do not rotate.

  1. CHECK DTC  .
    1. Turn the ignition switch to ON.
    2. Using the Subaru Select Monitor, read all DTCs. Ref. to LAN SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

    Is DTC displayed?

    Yes:  Perform the diagnosis for the displayed DTCs.

    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) (H4DO)>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  8.
  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-5 and F/B fuse No. 23.

    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 POWER SUPPLY TO FAN MOTOR ASSEMBLY (MAIN)  .
    1. Disconnect the connector from the fan motor assembly (main).
    2. Turn the ignition switch to ON.
    3. Measure the voltage between the fan motor assembly (main) connector and chassis ground.

      Connector & terminal 

      (B134) No. 1 (+) - Chassis ground (-):

      (B134) No. 3 (+) - Chassis ground (-):

    Is the voltage 10 V or more? Yes Go to  5.

    No:  Repair the following item.

    • Open circuit in the harness between fuse and fan motor assembly (main) connector
    • Poor contact of coupling connector
  5. CHECK GROUND CIRCUIT OF FAN MOTOR ASSEMBLY (MAIN)  .

    Measure the resistance between the fan motor assembly (main) connector and chassis ground.

    Connector & terminal 

    (B134) No. 4 - Chassis ground:

    Is the resistance less than 5 Ω?

    Yes:  Go to  6.

    No:  Repair the following item.

    • Open circuit in the harness between fan motor assembly (main) connector and chassis ground
    • Poor contact of coupling connector
  6. CHECK HARNESS BETWEEN ECM AND FAN MOTOR ASSEMBLY (MAIN)  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>ENGINE CONTROL MODULE (ECM)>REMOVAL .
    3. Check the open circuit and short circuit between ECM connector and fan motor assembly (main) connector.

      Connector & terminal 

      (B62) No. 19 - (B134) No. 2:

    Is the harness normal?

    Yes:  Go to  7.

    No:  Repair the following item.

    • Open circuit or short circuit between ECM connector and fan motor assembly (main) connector
    • Poor contact of coupling connector
  7. CHECK OUTPUT SIGNAL OF ECM  .
    1. Connect the connector to the fan motor assembly (main).
    2. Turn the ignition switch to ON.
    3. Using the Subaru Select Monitor, select [Radiator Fan Relay] of [Active Test]. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>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 (H4DO)>RADIATOR FAN SYSTEM>RADIATOR FAN CONTROL OUTPUT WAVEFORM .

      Connector & terminal 

      (B62) No. 19 (+) - Chassis ground (-):

    Does a waveform of the output signal occur?

    Yes:  Replace the fan motor assembly (main). Ref. to COOLING (H4DO)>RADIATOR FAN AND FAN MOTOR ASSEMBLY .

    No:  Replace the ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>ENGINE CONTROL MODULE (ECM) .

  8. 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-7 and F/B fuse No. 19.

    Is the fuse OK?

    Yes:  Go to  9.

    No:  Replace the fuse.

    NOTE: If the fuse is blown again, check the system wiring harness.
  9. CHECK POWER SUPPLY TO FAN MOTOR ASSEMBLY (SUB)  .
    1. Disconnect the connector from the fan motor assembly (sub).
    2. Turn the ignition switch to ON.
    3. Measure the voltage between the fan motor assembly (sub) connector and chassis ground.

      Connector & terminal 

      (B135) No. 1 (+) - Chassis ground (-):

      (B135) No. 3 (+) - Chassis ground (-):

    Is the voltage 10 V or more?

    Yes:  Go to  10.

    No:  Repair the following item.

    • Open circuit in the harness between fuse and fan motor assembly (sub) connector
    • Poor contact of coupling connector
  10. CHECK GROUND CIRCUIT OF FAN MOTOR ASSEMBLY (SUB)  .

    Measure the resistance between the fan motor assembly (sub) connector and chassis ground.

    Connector & terminal 

    (B135) No. 4 - Chassis ground:

    Is the resistance less than 5 Ω?

    Yes:  Go to  11.

    No:  Repair the following item.

    • Open circuit in the harness between fan motor assembly (sub) connector and chassis ground
    • Poor contact of coupling connector
  11. CHECK HARNESS BETWEEN ECM AND FAN MOTOR ASSEMBLY (SUB)  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>ENGINE CONTROL MODULE (ECM)>REMOVAL .
    3. Check the open circuit and short circuit between ECM connector and fan motor assembly (sub) connector.

      Connector & terminal 

      (B62) No. 30 - (B135) No. 2:

    Is the harness normal?

    Yes:  Go to  12.

    No:  Repair the following item.

    • Open circuit or short circuit between ECM connector and fan motor assembly (sub) connector
    • Poor contact of coupling connector
  12. CHECK OUTPUT SIGNAL OF ECM  .
    1. Connect the connector to the fan motor assembly (sub).
    2. Turn the ignition switch to ON.
    3. Using the Subaru Select Monitor, select [Radiator Fan Relay] of [Active Test]. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>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 (H4DO)>RADIATOR FAN SYSTEM>RADIATOR FAN CONTROL OUTPUT WAVEFORM .

      Connector & terminal 

      (B62) No. 30 (+) - Chassis ground (-):

    Does a waveform of the output signal occur?

    Yes:  Replace the fan motor assembly (sub). Ref. to COOLING (H4DO)>RADIATOR FAN AND FAN MOTOR ASSEMBLY .

    No:  Replace the ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>ENGINE CONTROL MODULE (ECM) .

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