SFI SYSTEM, Diagnostic DTC:P0493,P0494 and P0495

DTC Code DTC Name
P0493 Fan Overspeed
P0494 Fan Speed Low
P0495 Fan Speed High

DESCRIPTION

The cooling fan motor is controlled by the cooling fan ECU. The ECM sends an operation signal, based on the engine coolant temperature and other signals, to the cooling fan ECU to operate the cooling fan motor. The cooling fan motor operates at low speed or high speed depending on the conditions.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0493

Fan Overspeed

Cooling fan signals received by ECM are inconsistent.

  • Cooling fan motor assembly

  • Wire harness or connector

  • Cooling fan ECU

  • ECM

Comes on

DTC stored

P0494

Fan Speed Low

Cooling fan signals received by ECM are inconsistent.

  • Cooling fan motor assembly

  • Wire harness or connector

  • Cooling fan ECU

  • ECM

Comes on

DTC stored

P0495

Fan Speed High

Cooling fan signals received by ECM are inconsistent.

  • Cooling fan motor assembly

  • Wire harness or connector

  • Cooling fan ECU

  • ECM

Comes on

DTC stored

MONITOR DESCRIPTION

These DTCs are stored when a malfunction is detected in the cooling fan control circuit. If the cooling fan operation signal received by the ECM is different from the cooling fan operation signal which was sent to the cooling fan ECU, the ECM will illuminate the MIL and store a DTC.

WIRING DIAGRAM

A330035E01

CAUTION / NOTICE / HINT

Note:

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

PROCEDURE

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0493, P0494 AND/OR P0495)

    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 / Trouble Codes.

    5. Check for DTCs.

      Powertrain > Engine > Trouble Codes

    Result

    Result

    Proceed to

    DTC P0493, P0494 and/or P0495 is output

    A

    DTC P0493, P0494 and/or P0495 and other DTCs are output

    B
    Tip:

    If DTC P0493, P0494 and/or P0495 and P0691 or P0692 are output simultaneously, troubleshoot for DTC P0691 or P0692 first.

    B

    GO TO DTC CHART

    Click here

    A

  2. PERFORM ACTIVE TEST USING GTS (GMV1 CONTROL AND GMV2 CONTROL)

    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 / GMV1 Control.

      Powertrain > Engine > Active Test

      Tester Display

      GMV1 Control

    5. According to the display on the GTS, perform the Active Test and check the operation of the cooling fan motor assembly.

      OK

      The cooling fan motor assembly operates at high speed.

    6. Enter the following menus: Powertrain / Engine / Active Test / GMV2 Control.

      Powertrain > Engine > Active Test

      Tester Display

      GMV2 Control

    7. According to the display on the GTS, perform the Active Test and check the operation of the cooling fan motor assembly.

      OK

      The cooling fan motor assembly operates at low speed.

    Result

    Proceed to

    OK

    NG
    NG

    CHECK TERMINAL VOLTAGE (POWER SOURCE OF COOLING FAN ECU)Click here

    OK

  3. CHECK TERMINAL VOLTAGE (COOLING FAN ECU)

    A340582C01

    *a

    Front view of wire harness connector

    (to Cooling Fan ECU)

    1. Disconnect the cooling fan ECU connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      A47-1 (GMV) - Body ground

      Ignition switch ON

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE COOLING FAN ECUClick here

    NG

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

    1. Disconnect the cooling fan ECU connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A47-1 (GMV) - A35-26 (FANH)

      Always

      Below 1 Ω

      A47-1 (GMV) or A35-26 (FANH) - Body ground and other terminals

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE ECM

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  5. CHECK TERMINAL VOLTAGE (POWER SOURCE OF COOLING FAN ECU)

    A340581C01

    *a

    Front view of wire harness connector

    (to Cooling Fan ECU)

    1. Disconnect the cooling fan ECU connector.

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      A46-2 (BATT) - Body ground

      Always

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  6. INSPECT COOLING FAN MOTOR ASSEMBLY

    1. Inspect the cooling fan motor assembly.

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE COOLING FAN MOTOR ASSEMBLY

    Click here

    OK

  7. CHECK HARNESS AND CONNECTOR (COOLING FAN ECU - COOLING FAN MOTOR ASSEMBLY)

    1. Disconnect the cooling fan ECU connector.

    2. Disconnect the cooling fan motor assembly connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A46-1 (MTR) - A45-2

      Always

      Below 1 Ω

      A46-1 (MTR) or A45-2 - Body ground and other terminals

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. REPLACE COOLING FAN ECU

    1. Replace the cooling fan ECU.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  9. CHECK WHETHER DTC OUTPUT RECURS (DTC P0493, P0494 AND/OR P0495)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.

      Powertrain > Engine > Clear DTCs

    5. Turn the ignition switch off and wait for a few minutes.

    6. Perform the drive test.

    7. Turn the GTS on.

    8. Enter the following menus: Powertrain / Engine / Trouble Codes.

    9. Check for DTCs.

      Powertrain > Engine > Trouble Codes

    Result

    Result

    Proceed to

    DTC P0493, P0494 and/or P0495 is output

    A

    DTCs are not output

    B
    A

    REPLACE ECM

    Click here

    B

    END