COOLING FAN SYSTEM Cooling Fan Circuit

DESCRIPTION

The ECM calculates an appropriate cooling fan speed based on the engine coolant temperature, air conditioning switch condition, refrigerant pressure, engine speed and vehicle speed. The cooling fan ECUs control each cooling fan speed based on the duty cycle calculated by the ECM. By optimally controlling the cooling fan speed via the cooling fan ECUs based on the conditions of the vehicle, the ECM can achieve both high cooling performance and quietness.

WIRING DIAGRAM

Refer to the System Diagram.

Click here

CAUTION / NOTICE / HINT

PROCEDURE

1. PERFORM ACTIVE TEST USING GTS (CONTROL THE ENGINE COOLING FAN DUTY RATIO)

   
   

   1. Connect the GTS to the DLC3.

   2. Turn the engine switch on (IG).

   3. Turn the GTS on.

   4. Enter the following menus: Powertrain / Engine / Active Test / Control the Engine Cooling Fan Duty Ratio.

      
      Powertrain > Engine > Active Test

      Tester Display
      Control the Engine Cooling Fan Duty Ratio

   5. Perform the Active Test according to the display on the GTS.

      OK
      Active Test Operation Fan Operation 30 - 100% Cooling fans operate 0% Cooling fans stop

      Result
      Result Proceed to OK A NG (Fan LH does not operate) B NG (Fan RH does not operate) C NG (Fan LH does not stop) D NG (Fan RH does not stop) E

   
   

   A

   PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

   C

   CHECK COOLING FAN SYSTEM (FAN RH) Click here

   D

   CHECK HARNESS AND CONNECTOR (COOLING FAN ECU LH - ECM) Click here

   E

   CHECK HARNESS AND CONNECTOR (COOLING FAN ECU RH - ECM) Click here

   B

2. CHECK COOLING FAN SYSTEM (FAN LH)

   
   

   1. Disconnect the A46 ECM connector.

   2. Turn the engine switch on (IG).

   3. Check the operation of the cooling fan LH.

      OK
      The cooling fan LH operates.

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE ECM Click here

   NG

3. INSPECT COOLING FAN MOTOR LH

   
   

   1. Inspect the cooling fan motor LH.

      Click here

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE COOLING FAN MOTOR LH Click here

   OK

4. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU LH POWER SOURCE)

   
   

   1. Disconnect the A5 cooling fan ECU LH connector.

   2. Turn the engine switch on (IG).

   3. 

      *a	Front view of wire harness connector (to Cooling Fan ECU LH)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition A5-1 (+B1) - A5-3 (E1) Engine switch on (IG) 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   CHECK HARNESS AND CONNECTOR (COOLING FAN ECU LH - BODY GROUND) Click here

   OK

5. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU LH AND COOLING FAN ECU RH - ECM)

   
   

   1. Disconnect the A46 ECM connector.

   2. Disconnect the A5 cooling fan ECU LH connector.

   3. Disconnect the A6 cooling fan ECU RH connector.

   4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition A5-2 (SI), A6-2 (SI2) or A46-60 (RFC) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE COOLING FAN ECU LH

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU LH AND COOLING FAN ECU RH - ECM)

6. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU LH - BODY GROUND)

   
   

   1. Disconnect the A5 cooling fan ECU LH connector.

   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition A5-3 (E1) - Body ground Always Below 1 Ω

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU LH - BODY GROUND)

   OK

7. INSPECT FAN NO. 1 RELAY

   
   

   1. Inspect the FAN NO. 1 relay.

      Click here

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE FAN NO. 1 RELAY

   OK

8. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY POWER SOURCE CIRCUIT)

   
   

   1. Remove the FAN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

   2. Turn the engine switch on (IG).

   3. 

      *1	No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2	FAN NO. 1 Relay

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition 1 (FAN NO. 1 relay) - Body ground Engine switch on (IG) 11 to 14 V 3 (FAN NO. 1 relay) - Body ground Always 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY POWER SOURCE CIRCUIT)

   OK

9. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU LH - FAN NO. 1 RELAY)

   
   

   1. Disconnect the A5 cooling fan ECU LH connector.

   2. Remove the FAN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

   3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition A5-1 (+B1) - 5 (FAN NO. 1 relay) Always Below 1 Ω

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition A5-1 (+B1) or 5 (FAN NO. 1 relay) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY - BODY GROUND)

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU LH - FAN NO. 1 RELAY)

10. CHECK COOLING FAN SYSTEM (FAN RH)

    
    

    1. Disconnect the A46 ECM connector.

    2. Turn the engine switch on (IG).

    3. Check the operation of the cooling fan RH.

       OK
       The cooling fan RH operates.

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE ECM Click here

    NG

11. INSPECT COOLING FAN MOTOR RH

    
    

    1. Inspect the cooling fan motor RH.

       Click here

       Result
       Proceed to OK NG

    
    

    NG

    REPLACE COOLING FAN MOTOR RH Click here

    OK

12. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU RH POWER SOURCE)

    
    

    1. Disconnect the A6 cooling fan ECU RH connector.

    2. Turn the engine switch on (IG).

    3. 

       *a	Front view of wire harness connector (to Cooling Fan ECU RH)

       Measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection Condition Specified Condition A6-1 (+B2) - A6-3 (E2) Engine switch on (IG) 11 to 14 V

       Result
       Proceed to OK NG

    
    

    NG

    CHECK HARNESS AND CONNECTOR (COOLING FAN ECU RH - BODY GROUND) Click here

    OK

13. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU LH AND COOLING FAN ECU RH - ECM)

    
    

    1. Disconnect the A46 ECM connector.

    2. Disconnect the A5 cooling fan ECU LH connector.

    3. Disconnect the A6 cooling fan ECU RH connector.

    4. Measure the resistance according to the value(s) in the table below.

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition A5-2 (SI), A6-2 (SI2) or A46-60 (RFC) - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE COOLING FAN ECU RH

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU LH AND COOLING FAN ECU RH - ECM)

14. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU RH - BODY GROUND)

    
    

    1. Disconnect the A6 cooling fan ECU RH connector.

    2. Measure the resistance according to the value(s) in the table below.

       Standard Resistance (Check for Open)
       Tester Connection Condition Specified Condition A6-3 (E2) - Body ground Always Below 1 Ω

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU RH - BODY GROUND)

    OK

15. INSPECT FAN NO. 2 RELAY

    
    

    1. Inspect the FAN NO. 2 relay.

       Click here

       Result
       Proceed to OK NG

    
    

    NG

    REPLACE FAN NO. 2 RELAY

    OK

16. CHECK HARNESS AND CONNECTOR (FAN NO. 2 RELAY POWER SOURCE CIRCUIT)

    
    

    1. Remove the FAN NO. 2 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

    2. Turn the engine switch on (IG).

    3. 

       *1	No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
       *2	FAN NO. 2 Relay

       Measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection Condition Specified Condition 1 (FAN NO. 2 relay) - Body ground Engine switch on (IG) 11 to 14 V 3 (FAN NO. 2 relay) - Body ground Always 11 to 14 V

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 2 RELAY POWER SOURCE CIRCUIT)

    OK

17. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU RH - FAN NO. 2 RELAY)

    
    

    1. Disconnect the A6 cooling fan ECU RH connector.

    2. Remove the FAN NO. 2 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

    3. Measure the resistance according to the value(s) in the table below.

       Standard Resistance (Check for Open)
       Tester Connection Condition Specified Condition A6-1 (+B2) - 5 (FAN NO. 2 relay) Always Below 1 Ω

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition A6-1 (+B2) or 5 (FAN NO. 2 relay) - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 2 RELAY - BODY GROUND)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU RH - FAN NO. 2 RELAY)

18. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU LH - ECM)

    
    

    1. Disconnect the A46 ECM connector.

    2. Disconnect the A5 cooling fan ECU LH connector.

    3. Measure the resistance according to the value(s) in the table below.

       Standard Resistance (Check for Open)
       Tester Connection Condition Specified Condition A5-2 (SI) - A46-60 (RFC) Always Below 1 Ω

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU LH - ECM)

    OK

19. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH - BODY GROUND)

    
    

    1. Disconnect the z1 cooling fan motor LH connector.

    2. 

       *a	Component without harness connected (Cooling Fan Motor LH)

       Measure the resistance according to the value(s) in the table below.

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition z1-1 (-) - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE COOLING FAN ECU LH

    NG

    REPLACE COOLING FAN MOTOR LH Click here

20. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU RH - ECM)

    
    

    1. Disconnect the A46 ECM connector.

    2. Disconnect the A6 cooling fan ECU RH connector.

    3. Measure the resistance according to the value(s) in the table below.

       Standard Resistance (Check for Open)
       Tester Connection Condition Specified Condition A6-2 (SI2) - A46-60 (RFC) Always Below 1 Ω

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN ECU RH - ECM)

    OK

21. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH - BODY GROUND)

    
    

    1. Disconnect the z10 cooling fan motor RH connector.

    2. 

       *a	Component without harness connected (Cooling Fan Motor RH)

       Measure the resistance according to the value(s) in the table below.

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition z10-1 (-) - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE COOLING FAN ECU RH

    NG

    REPLACE COOLING FAN MOTOR RH Click here