NAVIGATION SYSTEM(for Radio and Display 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. A005B6BE02
      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

    GO TO METER / GAUGE SYSTEM Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - COMBINATION METER SUB-ASSEMBLY)


    1. Disconnect the L31 stereo component amplifier assembly connector.

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L31-11 (SPD) - L27-15 (+S) Always Below 1 Ω

    OK

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

    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
      Tester Connection Condition Specified Condition
      L31-11 (SPD) - L70-21*1 Always Below 1 Ω
      L31-11 (SPD) - L70-11*2 Always Below 1 Ω

      • *1: for LHD

      • *2: for RHD


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    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
      Tester Connection Condition Specified Condition
      L27-15 (+S) - L70-32*1 Always Below 1 Ω
      L27-15 (+S) - L70-31*2 Always Below 1 Ω

      • *1: for LHD

      • *2: for RHD


    OK

    REPLACE JUNCTION CONNECTOR

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR