AUDIO AND VISUAL SYSTEM (w/ Multi-display) Vehicle Speed Signal Circuit between Radio Receiver and Combination Meter

DESCRIPTION


Tech Tips


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

A01NLPME01

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK VEHICLE SIGNAL (OPERATION CHECK)


    1. A01NMES

      Enter the "Vehicle Signal Check Mode" screen. Refer to Check Vehicle Signal Check Mode in Operation Check Click here.

    2. While driving the vehicle, compare the "SPEED" indicator to the reading on the speedometer. Check if these readings are almost equal.

      Tech Tips

      The combination meter assembly receives the vehicle speed signal from the skid control ECU via CAN communication. Therefore, perform the following inspection referring to values on the Data List of the skid control ECU because it is the source of the vehicle speed signal.

      OK
      Vehicle speed displayed on the "Vehicle Signal Check Mode" screen is almost the same as the actual vehicle speed measured using the intelligent tester (See page Click here).

    NG

    INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) Click here

    OK

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

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)


    1. A01NLV1E01
      Text in Illustration
      *a

      Component with harness connected

      (Combination Meter Assembly)

      Check the output waveform.


      1. Remove the combination meter assembly with the connector still connected.

      2. Connect an oscilloscope to terminal F15-3 (+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 F15-3 (+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

  3. INSPECT RADIO RECEIVER ASSEMBLY (INPUT WAVEFORM)


    1. A01NMEXE21
      Text in Illustration
      *a

      Component with harness connected

      (Radio Receiver Assembly)

      Check the input waveform.


      1. Remove the radio receiver assembly with the connector still connected.

      2. Connect an oscilloscope to terminal G37-17 (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 G37-17 (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.


    NG

    CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - JUNCTION CONNECTOR) Click here

    OK

    REPLACE RADIO RECEIVER ASSEMBLY Click here

  4. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - JUNCTION CONNECTOR)


    1. Disconnect the G37 radio receiver assembly connector.

    2. Disconnect the F93 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G37-17 (SPD) - F93-47 Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (RADIO RECEIVER ASSEMBLY - JUNCTION CONNECTOR)

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (JUNCTION CONNECTOR)