METER / GAUGE SYSTEM Malfunction in Water Temperature Warning Light

DESCRIPTION

In this circuit, the combination meter assembly receives FC Stack coolant temperature signals from the FC control ECU via the CAN communication system. The combination meter assembly displays the FC Stack coolant temperature that is calculated based on the data received from the FC control ECU.

WIRING DIAGRAM

A01MFM4E22
*1 FC control ECU
*2 Combination Meter Assembly
*3 CAN Communication Line

CAUTION / NOTICE / HINT

Note


  • When replacing the combination meter assembly, make sure to replace it with a new one.

  • If there is an open or short in the FC coolant temperature sensor circuit, the FC control ECU stores DTCs. Troubleshoot the FC system.

    Click here

PROCEDURE


  1. CHECK FOR DTC (CAN COMMUNICATION SYSTEM)


    1. Check for DTCs.

      for LHD: Click here

      for RHD: Click here

      OK
      No DTCs are output.
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    GO TO CAN COMMUNICATION SYSTEM Click here

    C

    GO TO CAN COMMUNICATION SYSTEM Click here

    A

  2. CHECK FOR DTC (FC SYSTEM)


    1. Check for DTCs.

      Click here


      Powertrain > FC > Trouble Codes
      OK
      No DTCs are output.
      Result
      Proceed to
      OK
      NG

    NG

    GO TO FC CONTROL SYSTEM Click here

    OK

  3. PERFORM ACTIVE TEST USING GTS (INDICAT. LAMP COOLANT HOT)


    1. Using the GTS, perform the Active Test.

      Click here


      Body Electrical > Combination Meter > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Indicat. Lamp Coolant Hot Water temperature hot warning light OFF or ON -

      Body Electrical > Combination Meter > Active Test
      Tester Display
      Indicat. Lamp Coolant Hot
      OK
      Value selected during Active Test is displayed.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE COMBINATION METER ASSEMBLY Click here

    OK

  4. READ VALUE USING GTS (FC STACK COOLANT TEMPERATURE (FC OUTLET), FC COOLANT TEMPERATURE)


    1. Using the GTS, read the Data List.

      Click here


      Powertrain > FC > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      FC Stack Coolant Temperature (Radiator Outlet) FC coolant temperature Min.: -40°C (-40°F), Max: 215°C (419°F) 50 to 85°C (122 to 185°F): After warming up -

      Body Electrical > Combination Meter > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      FC Coolant Temperature FC Stack coolant temperature Min.: 0°C (0°F), Max.: 127.5°C (261.5°F) 50 to 85°C (122 to 185°F): After warming up -

      Powertrain > FC > Data List
      Tester Display
      FC Stack Coolant Temperature (Radiator Outlet)

      Body Electrical > Combination Meter > Data List
      Tester Display
      FC Coolant Temperature

      Tech Tips


      • When the Data List values of the ECUs match, an internal malfunction of the FC control ECU is suspected.

      • When the Data List values of the ECUs do not match, a signal output error of the FC control ECU or an internal malfunction of the combination meter assembly is suspected.

      OK
      The Data List values of the ECUs do not match.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FC CONTROL ECU Click here

    OK

  5. CHECK COMBINATION METER ASSEMBLY


    1. Replace the combination meter assembly.

      Click here

    2. Check that the operation of the water temperature warning returns to normal.

      OK
      The operation of the water temperature warning returns to normal.
      Result
      Proceed to
      OK
      NG

    OK

    END (COMBINATION METER ASSEMBLY IS DEFECTIVE)

    NG

    REPLACE FC CONTROL ECU Click here