COOLING FAN SYSTEM > Cooling Fan Circuit

for Preparation Click here


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).

INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

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

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

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

  1. 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



B
Go to step 2

C
Go to step 16
A

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

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


    A251766E01

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

  1. Turn the power switch on (IG).

  1. 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

    Text in Illustration 
    *1
    		Engine Room Relay Block

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



NG
Go to step 15
OK


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


    A251767E01

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

  1. 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

    Text in Illustration 
    *1
    		Engine Room Relay Block

  1. 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.

  1. 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

  1. 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.

  1. 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

  1. 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.

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

  1. 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

  1. Reconnect the cooling fan motor connector.

  1. 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.

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

  1. 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

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

  1. 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)


    A251768E01

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

  1. 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

    Text in Illustration 
    *1
    		Engine Room Relay Block

  1. 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.

  1. Disconnect the ECM connector.

  1. 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

  1. Reconnect the ECM connector.

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



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

REPLACE ECM (Click here)  

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.

  1. Disconnect the No. 2 integration relay connector.

  1. 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

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

  1. Reconnect the No. 2 integration relay connector.



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

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.

  1. Disconnect the ECM connector.

  1. 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

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

  1. 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.

  1. Disconnect the cooling fan motor connector.

  1. Turn the power switch on (IG).

  1. 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

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

  1. 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.

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

  1. Turn the power switch on (IG).

  1. 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

  1. Reinstall the FAN No. 3 relay.

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



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

REPLACE ECM (Click here)