NAVIGATION SYSTEM(for Navigation Receiver Type) 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 sub-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 sub-assembly. The signal is changed to a pulse signal at the transistor in the combination meter sub-assembly. 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

A005DK6E01

PROCEDURE


  1. INSPECT COMBINATION METER SUB-ASSEMBLY (OUTPUT WAVEFORM)


    1. A005B5WE01
      Text in Illustration
      *a

      Component with harness connected

      (Combination Meter Sub-assembly)

      Check the output waveform.


      1. Remove the combination meter sub-assembly with the connector(s) still connected.

      2. Connect an oscilloscope to terminal L27-15 (+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 L27-15 (+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.


    NG
    OK
  2. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY (INPUT WAVEFORM)


    1. A005ACYE01
      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(s) still connected.

      2. Connect an oscilloscope to terminal L31-11 (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 L31-11 (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.


    OK
    NG
  3. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - JUNCTION CONNECTOR)


    1. Disconnect the L31 stereo component amplifier assembly connector.

    2. Disconnect the L70 junction connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      L31-11 (SPD) - L70-21 Always Below 1 Ω
      for RHD
      Tester Connection Condition Specified Condition
      L31-11 (SPD) - L70-11 Always Below 1 Ω

    NG
    OK
  4. CHECK HARNESS AND CONNECTOR (COMBINATION METER SUB-ASSEMBLY - JUNCTION CONNECTOR)


    1. Disconnect the L27 combination meter sub-assembly connector.

    2. Disconnect the L70 junction connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      L27-15 (+S) - L70-32 Always Below 1 Ω
      for RHD
      Tester Connection Condition Specified Condition
      L27-15 (+S) - L70-31 Always Below 1 Ω

    OK
    NG