COOLING FAN SYSTEM Cooling Fan Circuit

DTC Code DTC Name
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

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CAUTION / NOTICE / HINT

Note:

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

PROCEDURE

  1. PERFORM ACTIVE TEST USING TECHSTREAM (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

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    C

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

    B

  2. CHECK COOLING FAN SYSTEM

    1. A326548N04

      Disconnect the A52 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 A52 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

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    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. A268366C39

      *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 A52 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

      A52-44 (RFC) or q1-2 (SI) - Body ground

      Always

      10 kΩ or higher

    4. Reconnect the q1 cooling fan ECU connector.

    5. Reconnect the A52 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 NO.1 RELAY

    1. Inspect the FAN NO.1 relay.

      Click here

    Result

    Result

    OK

    NG
    NG

    REPLACE FAN NO.1 RELAY

    OK

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

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

    2. A362783C01

      *1

      FAN NO.1 Relay

      *a

      No. 2 Engine Room Relay Block

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      3 (FAN NO.1 relay holder) - Body ground

      Always

      11 to 14 V

    3. Reinstall the FAN NO.1 relay.

    Result

    Result

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - FAN NO.1 RELAY)

    1. Disconnect the q1 cooling fan ECU connector.

    2. Remove the FAN NO.1 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 NO.1 relay holder)

      Always

      Below 1 Ω

      q1-3 (B) or 5 (FAN NO.1 relay holder) - Body ground

      Always

      10 kΩ or higher

    4. Reinstall the FAN NO.1 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 NO.1 RELAY - BODY GROUND)

    1. Remove the FAN NO.1 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 NO.1 relay) - Body ground

      Always

      Below 1 Ω

    3. Reinstall the FAN NO.1 relay.

    Result

    Result

    OK

    NG
    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    NG

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

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

    1. Disconnect the A52 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

      A52-44 (RFC) - q1-2 (SI)

      Always

      Below 1 Ω

    4. Reconnect the q1 cooling fan ECU connector.

    5. Reconnect the A52 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 z15 cooling fan motor connector.

    2. A255683C52

      *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

      z15-1 (-) - Body ground

      Always

      10 kΩ or higher

    3. Reconnect the z15 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 z14 No. 2 cooling fan motor connector.

    2. A362784C02

      *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

      z14-1 (-) - Body ground

      Always

      10 kΩ or higher

    3. Reconnect the z14 No. 2 cooling fan motor connector.

    Result

    Result

    OK

    NG
    OK

    REPLACE COOLING FAN ECU

    NG

    REPLACE NO. 2 COOLING FAN MOTOR

    Click here