AUDIO AND VISUAL SYSTEM Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter

DESCRIPTION

The multi-media module receiver assembly receives a vehicle speed signal from the No. 1 meter ECU 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 No. 1 meter ECU sub-assembly. The signal is changed to a pulse signal at the transistor in the No. 1 meter ECU sub-assembly. Each ECU controls its respective system 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 diagram below will not operate normally.

WIRING DIAGRAM

A01H0U9E53

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK NO. 1 METER ECU SUB-ASSEMBLY (OUTPUT WAVEFORM)


    1. A01GZGPE02
      Text in Illustration
      *a

      Component with harness connected

      (No. 1 Meter ECU Sub-assembly)

      Check the output waveform.


      1. Remove the No. 1 meter ECU sub-assembly with the connector still connected.

      2. Connect an oscilloscope to terminal L124-10 (+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 L124-10 (+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

    CHECK HARNESS AND CONNECTOR (MULTI-MEDIA MODULE RECEIVER ASSEMBLY - NO. 1 METER ECU SUB-ASSEMBLY) Click here

    OK

    GO TO METER / GAUGE SYSTEM Click here

  2. CHECK HARNESS AND CONNECTOR (MULTI-MEDIA MODULE RECEIVER ASSEMBLY - NO. 1 METER ECU SUB-ASSEMBLY)


    1. Disconnect the L164 multi-media module receiver assembly connector.

    2. Disconnect the L124 No. 1 meter ECU sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L164-56 (SPD) - L124-10 (+S) Always Below 1 Ω
      L164-56 (SPD) or L124-10 (+S) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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