COOLING FAN SYSTEM Cooling Fan Circuit

DESCRIPTION

The ECM turns the fan relays on or off 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 the fan relays on or off in order to control the speed of the cooling fan motors in two steps.

WIRING DIAGRAM

Refer to System Diagram Click here.

CAUTION / NOTICE / HINT

PROCEDURE

1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE ELECTRIC COOLING FAN)

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the power switch on (IG).

   3. Turn the tester 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 tester.

      OK
      Tester Operation Specified Condition ON Fans operate OFF Fans do not operate

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

   
   

   A

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

   C

   INSPECT FAN NO. 1 RELAY Click here

   B

2. INSPECT ENGINE ROOM RELAY BLOCK (FAN NO. 1, FAN NO. 2 OR FAN NO. 3 RELAY VOLTAGE)

   
   
   1. 

      Text in Illustration

      *1	Engine Room Relay Block

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

   2. Turn the power switch on (IG).

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

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

   4. Reinstall the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay.

   
   

   NG

   CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - NO. 2 INTEGRATION RELAY) Click here

   OK

3. INSPECT ENGINE ROOM RELAY BLOCK (FAN NO. 1 RELAY AND FAN NO. 3 RELAY VOLTAGE)

   
   
   1. 

      Text in Illustration

      *1	Engine Room Relay Block

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

   2. 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 5 (FAN No. 3 relay) - Body ground Always 11 to 14 V

   3. Reinstall the FAN No. 1 relay and FAN No. 3 relay.

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (AUXILIARY BATTERY - ENGINE ROOM RELAY BLOCK)

   OK

4. INSPECT FAN NO. 1 RELAY

   
   

   1. Inspect the FAN No. 1 relay Click here.

   
   

   NG

   REPLACE FAN NO. 1 RELAY

   OK

5. INSPECT FAN NO. 2 RELAY

   
   

   1. Inspect the FAN No. 2 relay Click here.

   
   

   NG

   REPLACE FAN NO. 2 RELAY

   OK

6. INSPECT FAN NO. 3 RELAY

   
   

   1. Inspect the FAN No. 3 relay Click here.

   
   

   NG

   REPLACE FAN NO. 3 RELAY

   OK

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

   
   

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

   2. 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

   3. Reinstall the FAN No. 2 relay.

   
   

   NG

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

   OK

8. INSPECT COOLING FAN MOTOR

   
   

   1. Inspect the cooling fan motor Click here.

   
   

   NG

   REPLACE COOLING FAN MOTOR Click here

   OK

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

   
   

   1. Disconnect the cooling fan motor connector.

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

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

   3. Reconnect the cooling fan motor connector.

   
   

   NG

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

   OK

10. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)

    
    

    1. Disconnect the cooling fan motor connector.

    2. Remove the FAN No. 1 relay and FAN No. 2 relay from the 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 A5-2 - 5 (FAN No. 1 relay) Always Below 1 Ω A5-2 - 4 (FAN No. 2 relay) Always Below 1 Ω

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition A5-2 or 5 (FAN No. 1 relay) or 4 (FAN No. 2 relay) - Body ground Always 10 kΩ or higher

    4. Reconnect the cooling fan motor connector.

    5. Reinstall the FAN No. 1 relay and FAN No. 2 relay.

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)

    OK

11. INSPECT NO. 2 COOLING FAN MOTOR

    
    

    1. Inspect the No. 2 cooling fan motor Click here.

    
    

    NG

    REPLACE NO. 2 COOLING FAN MOTOR Click here

    OK

12. CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)

    
    

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

    2. Remove the FAN No. 2 relay and FAN No. 3 relay from the 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 A6-1 - 3 (FAN No. 2 relay) Always Below 1 Ω A6-2 - 3 (FAN No. 3 relay) Always Below 1 Ω

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition A6-1 or 3 (FAN No. 2 relay) - Body ground Always 10 kΩ or higher A6-2 or 3 (FAN No. 3 relay) - Body ground Always 10 kΩ or higher

    4. Reconnect the No. 2 cooling fan motor connector.

    5. Reinstall the FAN No. 2 relay and FAN No. 3 relay.

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 2 COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)

    OK

13. INSPECT ENGINE ROOM RELAY BLOCK (FAN NO. 1 RELAY - FAN NO. 2 RELAY)

    
    
    1. 

       Text in Illustration

       *1	Engine Room Relay Block

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

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

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

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

    3. Reinstall the FAN No. 1 relay and FAN No. 2 relay.

    
    

    NG

    REPLACE ENGINE ROOM RELAY BLOCK

    OK

14. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - ECM)

    
    

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

    2. Disconnect the ECM connector.

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

       Standard Resistance (Check for Open)
       Tester Connection Condition Specified Condition 2 (FAN No. 2 relay) - A60-22 (FANH) Always Below 1 Ω 2 (FAN No. 3 relay) - A60-21 (FANL) Always Below 1 Ω

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition 2 (FAN No. 2 relay) or A60-22 (FANH) - Body ground Always 10 kΩ or higher 2 (FAN No. 3 relay) or A60-21 (FANL) - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reinstall the FAN No. 2 relay and FAN No. 3 relay.

    
    

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM RELAY BLOCK - ECM)

15. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - NO. 2 INTEGRATION RELAY)

    
    

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

    2. Disconnect the No. 2 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 1 (FAN No. 1 relay) - 1B-4 Always Below 1 Ω 1 (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 1 (FAN No. 2 relay) or 1 (FAN No. 3 relay) or 1B-4 - Body ground Always 10 kΩ or higher

    4. Reinstall the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay.

    5. Reconnect the No. 2 integration relay connector.

       Result
       Result Proceed to OK (for 2ZR-FXE (w/ EGR system)) A NG B OK (for 2ZR-FXE (w/o EGR system)) C

    
    

    A

    CHECK ECM POWER SOURCE CIRCUIT Click here

    B

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM RELAY BLOCK - NO. 2 INTEGRATION RELAY)

    C

    CHECK ECM POWER SOURCE CIRCUIT Click here

16. INSPECT FAN NO. 1 RELAY

    
    

    1. Inspect the FAN No. 1 relay Click here.

    
    

    NG

    REPLACE FAN NO. 1 RELAY

    OK

17. INSPECT FAN NO. 3 RELAY

    
    

    1. Inspect the FAN No. 3 relay Click here.

    
    

    NG

    REPLACE FAN NO. 3 RELAY

    OK

18. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - ECM)

    
    

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

    2. Disconnect the ECM connector.

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

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition 2 (FAN No. 1 relay) or 2 (FAN No. 2 relay) or A60-22 (FANH) - Body ground Always 10 kΩ or higher 2 (FAN No. 3 relay) or A60-21 (FANL) - Body ground Always 10 kΩ or higher

    4. Reinstall the FAN No. 1 relay, FAN No. 2 relay and FAN No. 3 relay.

    5. Reconnect the ECM connector.

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM RELAY BLOCK - ECM)

    OK

19. CHECK HARNESS AND CONNECTOR (COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)

    
    

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

    2. Disconnect the cooling fan motor connector.

    3. Turn the power switch on (IG).

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

       Standard Voltage
       Tester Connection Switch Condition Specified Condition A5-2 - Body ground Power switch on (IG) 11 to 14 V

    5. Reinstall the FAN No. 1 and FAN No. 2 relay.

    6. Reconnect the cooling fan motor connector.

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)

    OK

20. CHECK HARNESS AND CONNECTOR (NO. 2 COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)

    
    

    1. Remove the FAN No. 3 relay from the engine room relay block.

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

    3. Turn the power switch on (IG).

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

       Standard Voltage
       Tester Connection Switch Condition Specified Condition A6-2 - Body ground Power switch on (IG) 11 to 14 V

    5. Reinstall the FAN No. 3 relay.

    6. Reconnect the No. 2 cooling fan motor connector.

    
    

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 2 COOLING FAN MOTOR - ENGINE ROOM RELAY BLOCK)