NAVIGATION SYSTEM Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter

DESCRIPTION

The stereo component amplifier assembly receives a vehicle speed signal from the combination meter assembly to control the ASL function.

Tech Tips


  • A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter assembly. The signal is changed to a pulse signal at the transistor in the combination meter assembly. Each ECU controls the respective systems based on the pulse signal.

  • If a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems in the diagram below will not operate normally.

WIRING DIAGRAM

A003YUYE01

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)


    1. A003YMQE04
      Text in Illustration
      *a

      Component with harness connected

      (Combination Meter Assembly)

      Check the output waveform.


      1. Remove the combination meter assembly with the connector still connected.

      2. Connect an oscilloscope to terminal H19-40 (+S) and body ground.

      3. Turn the power 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 H19-40 (+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.

        Tech Tips

        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.

    2. Proceed to the next step based on the inspection result.

      Result
      Result Proceed to
      OK (for 10 Speakers) A
      OK (for 13 Speakers) B
      NG C

    B

    INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY Click here

    C

    GO TO METER / GAUGE SYSTEM Click here

    A

  2. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (INPUT WAVEFORM)


    1. A003ZLIE01
      Text in Illustration
      *a

      Component with harness connected

      (Stereo Component Amplifier Assembly)

      Check the input waveform.


      1. Remove the stereo component amplifier assembly with the connector still connected.

      2. Connect an oscilloscope to terminal H58-6 (SPD) and body ground.

      3. Turn the power 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 H58-6 (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.

        Tech Tips

        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.


    NG

    CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - JUNCTION CONNECTOR) Click here

    OK

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

  3. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY


    1. A003V21E09
      Text in Illustration
      *a

      Component with harness connected

      (Stereo Component Amplifier Assembly)

      Check the input waveform.


      1. Remove the stereo component amplifier assembly with the connector still connected.

      2. Connect an oscilloscope to terminal k1-17 (SPD) and body ground.

      3. Turn the power 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 k1-17 (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.

        Tech Tips

        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.


    NG

    CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - JUNCTION CONNECTOR) Click here

    OK

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

  4. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - JUNCTION CONNECTOR)


    1. Disconnect the H58 stereo component amplifier assembly connector (for 10 Speakers).

    2. Disconnect the k1 stereo component amplifier assembly connector (for 13 Speakers).

    3. Disconnect the H117 junction connector.

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

      Standard Resistance
      for 10 Speakers
      Tester Connection Condition Specified Condition
      H58-6 (SPD) - H117-89 Always Below 1 Ω
      for 13 Speakers
      Tester Connection Condition Specified Condition
      k1-17 (SPD) - H117-89 Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - JUNCTION CONNECTOR)

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (JUNCTION CONNECTOR)