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, hybrid coolant temperature, engine speed and vehicle speed, and sends the signals to the cooling fan ECU to regulate the cooling fans. The cooling fan ECU controls the cooling fan speed based on the duty ratio signal sent from the ECM. By basing its control on the operating conditions, the ECM can control the fan speed optimally using the cooling fan ECU, achieving both high cooling performance and quietness.

WIRING DIAGRAM

Click here

CAUTION / NOTICE / HINT

PROCEDURE

1. PERFORM ACTIVE TEST USING GTS (Control the Electric Cooling Fan)

   
   

   1. Connect the GTS to the DLC3.

   2. Turn the power switch on (IG).

   3. Turn the GTS on.

   4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Electric Cooling Fan.

   5. Check the operation of the cooling fans while operating them using the GTS.

      
      Powertrain > Engine and ECT > Active Test

      Tester Display
      Control the Electric Cooling Fan

      OK
      Tester Operation Fan Operation ON Cooling fans operate OFF Cooling fans stop

      Result
      Result Proceed to OK A NG (Cooling fans do not operate) B NG (Cooling fans do not stop) C

   6. Turn the power switch off.

   
   

   A

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

   C

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

   B

2. CHECK COOLING FAN SYSTEM

   
   

   1. 

      Disconnect the A35 ECM connector.

   2. Turn the power switch on (IG).

   3. Check the operation of the cooling fans.

      OK
      Cooling fans operate.

   4. Turn the power switch off.

   5. Reconnect the A35 ECM connector.

      Result
      Result OK NG

   
   

   OK

   REPLACE ECM Click here

   NG

3. INSPECT COOLING FAN MOTOR (COOLING FAN MOTOR AND NO. 2 COOLING FAN MOTOR)

   
   

   1. Inspect the cooling fan motor and No. 2 cooling fan motor.

      Click here

      Result
      Result Proceed to OK A NG (Cooling fan motor) B NG (No. 2 cooling fan motor) C

   
   

   B

   REPLACE COOLING FAN MOTOR Click here

   C

   REPLACE NO. 2 COOLING FAN MOTOR Click here

   A

4. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

   
   

   1. Disconnect the q1 cooling fan ECU connector.

   2. Turn the power switch on (IG).

   3. 

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition q1-3 (B) - q1-1 (GND) Power switch on (IG) 11 to 14 V

   4. Turn the power switch off.

   5. Reconnect the q1 cooling fan ECU connector.

      Result
      Result OK NG

   
   

   NG

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

   OK

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

   
   

   1. Disconnect the A35 ECM connector.

   2. Disconnect the q1 cooling fan ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition A35-44 (RFC) or q1-2 (SI) - Body ground Always 10 kΩ or higher

   4. Reconnect the q1 cooling fan ECU connector.

   5. Reconnect the A35 ECM connector.

      Result
      Result OK NG

   
   

   OK

   REPLACE COOLING FAN ECU

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

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

   
   

   1. Disconnect the q1 cooling fan ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition q1-1 (GND) - Body ground Always Below 1 Ω

   3. Reconnect the q1 cooling fan ECU connector.

      Result
      Result OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

7. INSPECT FAN RELAY

   
   

   1. Inspect the FAN relay.

      Click here

      Result
      Result OK NG

   
   

   NG

   REPLACE FAN RELAY

   OK

8. INSPECT NO. 2 ENGINE ROOM RELAY BLOCK (FAN RELAY)

   
   

   1. Remove the FAN relay from the No. 2 engine room relay block.

   2. 

      *1	No. 2 Engine Room Relay Block
      *2	Cooling Fan Relay

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

      Standard Voltage
      Tester Connection Condition Specified Condition 3 (FAN relay holder) - Body ground Always 11 to 14 V

   3. Reinstall the FAN relay.

      Result
      Result OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

9. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - FAN RELAY)

   
   

   1. Disconnect the q1 cooling fan ECU connector.

   2. Remove the FAN relay from the No. 2 engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition q1-3 (B) - 5 (FAN relay holder) Always Below 1 Ω q1-3 (B) or 5 (FAN relay holder) - Body ground Always 10 kΩ or higher

   4. Reinstall the FAN relay.

   5. Reconnect the q1 cooling fan ECU connector.

      Result
      Result OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

10. CHECK HARNESS AND CONNECTOR (FAN RELAY - BODY GROUND)

    
    

    1. Remove the FAN relay from the No. 2 engine room relay block.

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

       Standard Resistance
       Tester Connection Condition Specified Condition 2 (FAN relay) - Body ground Always Below 1 Ω

    3. Reinstall the FAN relay.

       Result
       Result OK NG

    
    

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN RELAY - BODY GROUND)

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

    
    

    1. Disconnect the A35 ECM connector.

    2. Disconnect the q1 cooling fan ECU connector.

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

       Standard Resistance
       Tester Connection Condition Specified Condition A35-44 (RFC) - q1-2 (SI) Always Below 1 Ω

    4. Reconnect the q1 cooling fan ECU connector.

    5. Reconnect the A35 ECM connector.

       Result
       Result OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

    
    

    1. Disconnect the z1 cooling fan motor connector.

    2. 

       *a	Component without harness connected (Cooling Fan Motor)

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

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

    3. Reconnect the z1 cooling fan motor connector.

       Result
       Result OK NG

    
    

    NG

    REPLACE COOLING FAN MOTOR Click here

    OK

13. CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN MOTOR - BODY GROUND)

    
    

    1. Disconnect the z9 No. 2 cooling fan motor connector.

    2. 

       *a	Component without harness connected (No. 2 Cooling Fan Motor)

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

       Standard Resistance
       Tester Connection Condition Specified Condition z9-1 (-) - Body ground Always 10 kΩ or higher

    3. Reconnect the z9 No. 2 cooling fan motor connector.

       Result
       Result OK NG

    
    

    OK

    REPLACE COOLING FAN ECU

    NG

    REPLACE NO. 2 COOLING FAN MOTOR Click here