AUDIO AND VISUAL 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 meter circuit plate 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 meter circuit plate. The signal is changed to a pulse signal at the transistor in the meter circuit plate. Each ECU controls its respective systems based on this pulse signal.

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

WIRING DIAGRAM

B004OSTE01

PROCEDURE


  1. INSPECT METER CIRCUIT PLATE (OUTPUT WAVEFORM)


    1. Check the output waveform.

      B004QHVC24
      *a

      Component with harness connected

      (Meter Circuit Plate)

      		 - -

      1. Remove the meter circuit plate with the connector(s) still connected.

      2. Connect an oscilloscope to terminal F6-19 (+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 F6-19 (+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.

        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.

      Result
      Proceed to
      OK
      NG

    NG

    GO TO METER / GAUGE SYSTEM Click here

    OK

  2. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (INPUT WAVEFORM)


    1. Check the input waveform.

      B004P5TC12
      *a

      Component with harness connected

      (Stereo Component Amplifier Assembly)

      		 - -

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

      2. Connect an oscilloscope to terminal F61-11 (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 F61-11 (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.

      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    A

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

    C

    CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - NO. 17 JUNCTION CONNECTOR) Click here

    B

  3. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - NO. 11 JUNCTION CONNECTOR)


    1. Disconnect the F61 stereo component amplifier assembly connector.

    2. Disconnect the F79 No. 11 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F61-11 (SPD) - F79-9 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (METER CIRCUIT PLATE - NO. 11 JUNCTION CONNECTOR)


    1. Disconnect the F6 meter circuit plate connector.

    2. Disconnect the F79 No. 11 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F6-19 (+S) - F79-7 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 11 JUNCTION CONNECTOR

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  5. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - NO. 17 JUNCTION CONNECTOR)


    1. Disconnect the F61 stereo component amplifier assembly connector.

    2. Disconnect the F85 No. 17 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F61-11 (SPD) - F85-17 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (METER CIRCUIT PLATE - NO. 17 JUNCTION CONNECTOR)


    1. Disconnect the F6 meter circuit plate connector.

    2. Disconnect the F85 No. 17 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F6-19 (+S) - F85-16 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 17 JUNCTION CONNECTOR

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR