NAVIGATION SYSTEM 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 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 following diagram will not operate normally.

WIRING DIAGRAM


  1. for 1AD-FTV

    A01D5B4E01
  2. for 1ND-TV

    A01D3QCE01
  3. for 1NR-FE

    A01D57YE01
  4. for 1ZR-FE, 2ZR-FE

    A01D4UQE01
  5. for 1ZR-FAE

    A01D5HOE01

PROCEDURE


  1. CHECK VEHICLE SIGNAL (OPERATION CHECK)


    1. A01D4VY

      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 value displayed for "SPEED" 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 GTS.
      for Anti-lock Brake System (for Type A): Click here Click here
      for Anti-lock Brake System (for Type B): Click here Click here
      for Vehicle Stability Control System: Click here Click here
      Result
      Proceed to
      OK
      NG

    OK
    NG
  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)


    1. Check the output waveform.

      A01D3U0C01
      *a

      Component with harness connected

      (Combination Meter Assembly)

      - -

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

      2. Connect an oscilloscope to terminal E46-6 (+S) and body ground.

      3. Turn the ignition switch to ON.

      4. Turn a wheel slowly.

      5. Check the signal waveform according to the condition(s) in the table below.

        Item Condition
        Measurement terminal E46-6 (+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.

      Result
      Proceed to
      OK
      NG

    NG
    OK
  3. INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY (INPUT WAVEFORM)


    1. Check the input waveform.

      A01D3Q1C01
      *a

      Component with harness connected

      (Radio and Display Receiver Assembly)

      - -

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

      2. Connect an oscilloscope to terminal E60-17 (SPD) and body ground.

      3. Turn the ignition switch to ON.

      4. Turn a wheel slowly.

      5. Check the signal waveform according to the condition(s) in the table below.

        Item Condition
        Measurement terminal E60-17 (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.

      Result
      Proceed to
      OK
      NG

    OK
    NG
  4. CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)


    1. Disconnect the E60 radio and display receiver assembly connector.

    2. Disconnect the 3D instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E60-17 (SPD) - 3D-19 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG
    OK
  5. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)


    1. Disconnect the E46 combination meter assembly connector.

    2. Disconnect the 3D instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E46-6 (+S) - 3D-38 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK
    NG