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, 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

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 ignition switch to ON.

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

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

   6. Turn the ignition switch to ON.

      Result
      Result Proceed to OK A NG (Cooling fan LH do not operate) B NG (Cooling fan RH do not operate) C NG (Cooling fan LH do not stop) D NG (Cooling fan RH do not stop) E

   
   

   A

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

   C

   CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH POWER SOURCE CIRCUIT) Click here

   D

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

   E

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

   B

2. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH POWER SOURCE CIRCUIT)

   
   

   1. Disconnect the A59 cooling fan motor LH connector.

   2. 

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition A59-1 (+B2) - A59-2 (E2) Always 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR LH POWERSOUR CE CIRCUIT)

   OK

3. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH - NO. 1 INTEGRATION RELAY)

   
   

   1. Disconnect the A59 cooling fan motor LH connector.

   2. Remove the EFI MAIN relay from the No. 1 engine room relay block.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition A59-4 (IGS2) - 1B-4 Always Below 1 Ω

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition A59-4 (IGS2) or 1B-4 - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

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

   OK

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

   
   

   1. Disconnect the A59 cooling fan motor 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 A59-2 (E2) - Body ground Always Below 1 Ω

      Result
      Proceed to OK NG

   
   

   NG

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

   OK

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

   
   

   1. Disconnect the A38 ECM connector.

   2. Disconnect the A59 cooling fan motor 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 A59-3 (SI2) - A38-60 (RFC) Always Below 1 Ω

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition A59-3 (SI2) or A38-60 (RFC) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE COOLING FAN MOTOR LH Click here

   NG

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

6. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH POWER SOURCE CIRCUIT)

   
   

   1. Disconnect the g1 cooling fan motor RH connector.

   2. 

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition g1-1 (+B) - g1-2 (GND) Always 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR RH POWERSOURCE CIRCUIT)

   OK

7. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH - NO. 1 INTEGRATION RELAY)

   
   

   1. Disconnect the g1 cooling fan motor RH connector.

   2. Remove the EFI MAIN relay from the No. 1 engine room relay block.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition g1-4 (IG) - 1B-4 Always Below 1 Ω

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition g1-4 (IG) or 1B-4 - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR RH - NO. 1 INTEGRATION RELAY)

   OK

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

   
   

   1. Disconnect the g1 cooling fan motor 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 g1-2 (GND) - Body ground Always Below 1 Ω

      Result
      Proceed to OK NG

   
   

   NG

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

   OK

9. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR RH - ECM)

   
   

   1. Disconnect the A38 ECM connector.

   2. Disconnect the g1 cooling fan motor 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 g1-3 (SI) - A38-60 (RFC) Always Below 1 Ω

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition g1-3 (SI) or A38-60 (RFC) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE COOLING FAN MOTOR RH Click here

   NG

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

10. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR LH - ECM)

    
    

    1. Disconnect the A38 ECM connector.

    2. Disconnect the A59 cooling fan motor LH connector.

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

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition A38-60 (RFC) - A59-3(SI2) Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE COOLING FAN MOTOR LH Click here

    NG

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

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

    
    

    1. Disconnect the A38 ECM connector.

    2. Disconnect the g1 cooling fan motor RH connector.

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

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition A38-60 (RFC) - g1-3 (SI) Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE COOLING FAN MOTOR RH Click here

    NG

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