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Vehicle Speed Signal Circuit between Navigation ECU and Combination Meter [08/2019 - ]: Procedure

  1. CHECK COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) 
    1. Check the output waveform.
      GTY960391Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Combination Meter Assembly)
      1. Remove the combination meter assembly with the connector still connected.
      2. Connect an oscilloscope to terminal J10-19 (+S) and body ground.
      3. Turn the engine switch on (IG).
      4. Turn a wheel slowly.
      5. Check the signal waveform according to the condition(s) in the table below.
        Item Condition
        Measurement terminal J10-19 (+S) - Body ground
        Tool setting 5 V/DIV., 20 ms./DIV.
        Vehicle condition Wheel being rotated

        OK

        The waveform is similar to that shown in the illustration.

        HINT: 

        When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO METER / GAUGE SYSTEM. Refer to  Speed Signal Circuit [08/2019 - ] 

    Result: 

    OK 

    See step  2

  2. INSPECT NAVIGATION ECU (INPUT WAVEFORM) 
    1. Check the input waveform.
      GTY960345Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Navigation ECU)
      1. Remove the navigation ECU with the connector(s) still connected.
      2. Connect an oscilloscope to terminal J153-9 (SPD) and body ground.
      3. Turn the engine switch on (IG).
      4. Turn a wheel slowly.
      5. Check the signal waveform according to the condition(s) in the table below.
        Item Condition
        Measurement terminal J153-9 (SPD) - Body ground
        Tool setting 5 V/DIV., 20 ms./DIV.
        Vehicle condition Wheel being rotated

        OK

        The waveform is similar to that shown in the illustration.

        HINT: 

        When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [08/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR