COOLING FAN SYSTEM Cooling Fan Circuit

DESCRIPTION

The ECM turns on or off the fan relays using signals calculated from the engine coolant temperature, air conditioning switch (on/off), air conditioning refrigerant pressure, engine speed and vehicle speed signals.

The ECM switches the circuit of the cooling fan motors between series and parallel by turning on or off the fan relays in order to control the speed of the cooling fan motors in two steps.

WIRING DIAGRAM

Refer to the System Diagram.

Click here

CAUTION / NOTICE / HINT

PROCEDURE

1. PERFORM ACTIVE TEST USING GTS (CONTROL THE ENGINE 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 / Active Test / Control the Engine Cooling Fan

      
      Powertrain > Engine > Active Test

      Tester Display
      Control the Engine Cooling Fan

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

      OK
      Active Tester Operation Fan Operation HIGH Cooling fans high speed operate LOW Cooling fans low speed operate OFF Cooling fans stop

      Result
      Proceed to OK NG

   
   

   OK

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

   NG

2. CHECK HARNESS AND CONNECTOR (FANL - FANH POWER SOURCE)

   
   

   1. Disconnect the A38 ECM connector.

   2. Turn the power switch on (IG).

   3. 

      *a	Front view of wire harness connector (to ECM)

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

      Standard Voltage
      Tester Connection Condition Specified Condition A38-8 (FANH) - Body ground Power switch on (IG) 11 to 14 V A38-7 (FANL) - Body ground Power switch on (IG) 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   INSPECT COOLING FAN RELAY (FAN NO. 1, FAN NO. 2 AND FAN NO. 3) Click here

   OK

3. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY AND FAN NO. 3 RELAY POWER SOURCE CIRCUIT)

   
   

   1. Remove the FAN NO. 1 relay and FAN NO. 3 relay from the No. 2 relay block.

   2. 

      *1	No. 2 Relay Block
      *2	FAN NO. 1 Relay
      *3	FAN NO. 3 Relay

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

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

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY AND FAN NO. 3 RELAY POWER SOURCE CIRCUIT)

   OK

4. INSPECT COOLING FAN RELAY (FAN NO. 1, FAN NO. 2 AND FAN NO. 3)

   
   

   1. Inspect the FAN NO. 1 relay, FAN NO. 2 relay and FAN NO. 3 relay.

      Click here

      Result
      Result Proceed to OK A NG (FAN NO. 1 relay) B NG (FAN NO. 2 relay) C NG (FAN NO. 3 relay) D

   
   

   B

   REPLACE FAN NO. 1 RELAY

   C

   REPLACE FAN NO. 2 RELAY

   D

   REPLACE FAN NO. 3 RELAY

   A

5. CHECK HARNESS AND CONNECTOR (FAN NO. 2 RELAY - BODY GROUND)

   
   

   1. Remove the FAN NO. 2 relay from the No. 2 relay block.

   2. 

      *1	No. 2 Relay Block
      *2	FAN NO. 2 Relay

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

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

      Result
      Proceed to OK NG

   
   

   NG

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

   OK

6. 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

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

   
   

   1. Disconnect the A4 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 A4-1 - 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

8. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY AND FAN NO. 2 RELAY - COOLING FAN MOTOR RH)

   
   

   1. Disconnect the A4 cooling fan motor RH connector.

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

   3. 

      *1	No. 2 Engine Room Relay Block
      *2	FAN NO. 1 Relay
      *3	FAN NO. 2 Relay

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition A4-2 - 5 (FAN NO. 1 relay) Always Below 1 Ω A4-2 - 4 (FAN NO. 2 relay) Always Below 1 Ω

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition A4-2 or 5 (FAN NO. 1 relay) - Body ground Always 10 kΩ or higher A4-2 or 4 (FAN NO. 2 relay) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY AND FAN NO. 2 RELAY - COOLING FAN MOTOR RH)

   OK

9. 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

10. CHECK HARNESS AND CONNECTOR (FAN NO. 2 RELAY AND FAN NO. 3 RELAY - COOLING FAN MOTOR LH)

    
    

    1. Disconnect the A5 cooling fan motor LH connector.

    2. Remove the FAN NO. 2 relay and FAN NO. 3 relay from the No. 2 engine room relay block.

    3. 

       *1	No. 2 Engine Room Relay Block
       *2	FAN NO. 2 Relay
       *3	FAN NO. 3 Relay

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

       Standard Resistance (Check for Open)
       Tester Connection Condition Specified Condition A5-1 - 3 (FAN NO. 2 relay) Always Below 1 Ω A5-2 - 5 (FAN NO. 3 relay) Always Below 1 Ω

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition A5-1 or 3 (FAN NO. 2 relay) - Body ground Always 10 kΩ or higher A5-2 or 5 (FAN NO. 3 relay) - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 2 RELAY AND FAN NO. 3 RELAY - COOLING FAN MOTOR LH)

    OK

11. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY - FAN NO. 2 RELAY)

    
    

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

    2. 

       *1	No. 2 Engine Room Relay Block
       *2	FAN NO. 1 Relay
       *3	FAN NO. 2 Relay

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

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

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

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE NO. 2 RELAY BLOCK

12. INSPECT COOLING FAN RELAY (FAN NO. 1, FAN NO. 2 AND FAN NO. 3)

    
    

    1. Inspect the FAN NO. 1 relay, FAN NO. 2 relay and FAN NO. 3 relay.

       Click here

       Result
       Result Proceed to OK A NG (FAN NO. 1 relay) B NG (FAN NO. 2 relay) C NG (FAN NO. 3 relay) D

    
    

    B

    REPLACE FAN NO. 1 RELAY

    C

    REPLACE FAN NO. 2 RELAY

    D

    REPLACE FAN NO. 3 RELAY

    A

13. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY, FAN NO. 2 RELAY AND FAN NO. 3 RELAY POWER SOURCE CIRCUIT)

    
    

    1. Remove the FAN NO. 1 relay, FAN NO. 2 relay and FAN NO. 3 relay from the No. 2 engine room relay block.

    2. 

       *1	No. 2 Engine Room Relay Block
       *2	FAN NO. 1 Relay
       *3	FAN NO. 2 Relay
       *4	FAN NO. 3 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 Always 11 to 14 V 2 (FAN NO. 2 relay) - Body ground Always 11 to 14 V 1 (FAN NO. 3 relay) - Body ground Always 11 to 14 V

       Result
       Proceed to OK NG

    
    

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY, FAN NO. 2 RELAY AND FAN NO. 3 RELAY - ECM)

    NG

14. CHECK HARNESS AND CONNECTOR (FAN NO. 1 RELAY, FAN NO. 2 RELAY AND FAN NO. 3 RELAY - NO. 1 INTEGRATION RELAY)

    
    

    1. Remove the FAN NO. 1 relay, FAN NO. 2 relay and FAN NO. 3 relay from the No. 2 relay block.

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

    3. Disconnect the 1B No. 1 integration relay connector.

    4. 

       *1	No. 2 Relay Block
       *2	FAN NO. 1 Relay
       *3	FAN NO. 2 Relay
       *4	FAN NO. 3 Relay

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

       Standard Resistance (Check for Open)
       Tester Connection Condition Specified Condition 1 (FAN NO. 1 relay) - 1B-4 Always Below 1 Ω 2 (FAN NO. 2 relay) - 1B-4 Always Below 1 Ω 1 (FAN NO. 3 relay) - 1B-4 Always Below 1 Ω

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition 1 (FAN NO. 1 relay) or 1B-4 - Body ground Always 10 kΩ or higher 2 (FAN NO. 2 relay) or 1B-4 - Body ground Always 10 kΩ or higher 1 (FAN NO. 3 relay) or 1B-4 - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FAN NO. 1 RELAY, FAN NO. 2 RELAY AND FAN NO. 3 RELAY - NO. 1 INTEGRATION RELAY)

    OK

15. INSPECT NO. 1 INTEGRATION RELAY (EFI-MAIN RELAY)

    
    

    1. Inspect the No. 1 integration relay.

       Click here

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE NO. 1 INTEGRATION RELAY (EFI-MAIN RELAY)

    OK

16. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY POWER SOURCE CIRCUIT)

    
    

    1. Remove the No. 1 integration relay from the No. 1 engine room relay block.

    2. Disconnect the 1B No. 1 integration relay connector.

    3. 

       *a	Front view of wire harness connector (to No. 1 Integration Relay)

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

       Standard Voltage
       Tester Connection Condition Specified Condition 1B-3 - Body ground Always 11 to 14 V

       Result
       Proceed to OK NG

    
    

    NG

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

    OK

17. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - BODY GROUND)

    
    

    1. Remove the No. 1 integration relay from the No. 1 engine room relay block.

    2. Disconnect the 1B No. 1 integration relay connector.

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

       Standard Resistance
       Tester Connection Condition Specified Condition 1B-5 - Body ground Always Below 1 Ω

       Result
       Proceed to OK NG

    
    

    NG

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

    OK

18. CHECK HARNESS AND CONNECTOR (ECM - NO. 1 INTEGRATION RELAY)

    
    

    1. Disconnect the A38 ECM connector.

    2. Disconnect the 1B No. 1 integration relay connector.

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

       Standard Resistance (Check for Open)
       Tester Connection Condition Specified Condition A38-46 (MREL) - 1B-6 Always Below 1 Ω

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition A38-46 (MREL) or 1B-6 - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - NO. 1 INTEGRATION RELAY)