AUDIO AND VISUAL SYSTEM Vehicle Speed Signal Circuit between Stereo Component Amplifier and Combination Meter

DESCRIPTION

This circuit is necessary for the ASL (Auto Sound Leveliser) built into the stereo component amplifier. Speed signals are received from the combination meter and used for the ASL.

The ASL function automatically adjusts the sound data in order to enable hearing the clear audio sound even when vehicle noise increases (as vehicle noise increases, the volume is turned up etc.).

Tech Tips


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

  • If a short occurs in an ECU, all systems in the diagram below will not operate normally.

WIRING DIAGRAM

A015ZA8E01

INSPECTION PROCEDURE

PROCEDURE


  1. OPERATION OF SPEEDOMETER


    1. Drive the vehicle and check if the function of the speedometer on the combination meter is normal.

      OK
      Actual vehicle speed and the speed indicated on the speedometer are the same.

      Tech Tips

      The vehicle speed sensor is functioning normally when the indication on the speedometer is normal.


    NG

    GO TO METER / GAUGE SYSTEM Click here

    OK

  2. INSPECT STEREO COMPONENT AMPLIFIER


    1. A0163BKE03

      Disconnect the stereo component amplifier connector.

    2. Measure the voltage.


      1. Jack up either one of the drive wheels.

      2. Move the shift lever to N.

      3. Turn the engine switch on (IG).

      4. Measure the voltage between terminal SPD of the stereo component amplifier and body ground when the drive wheels are turned slowly.

        A015YK8E01
        OK
        Voltage pulses as shown in the illustration.

    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER - STEREO COMPONENT AMPLIFIER) Click here

    OK

    REPLACE STEREO COMPONENT AMPLIFIER Click here

  3. CHECK HARNESS AND CONNECTOR (COMBINATION METER - STEREO COMPONENT AMPLIFIER)


    1. A0163BKE03

      Disconnect the stereo component amplifier connector and combination meter connector.

    2. A0163BKE04

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      P30-11 (SPD) - J34-5 (+S) Engine switch off Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - STEREO COMPONENT AMPLIFIER)


    1. A0163BKE03

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      P30-11 (SPD) - Body ground Engine switch off 10 kΩ or higher

      Tech Tips

      If the resistance between terminal SPD and body ground is less than 10 kΩ, there may be a short in a wire harness, connector, or an ECU that is connected to the SPD signal wire.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR OR CHECK EACH ECU

    OK

    REPLACE COMBINATION METER Click here