NAVIGATION SYSTEM (for Radio and Display Type) 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


  1. for 2AR-FE

    B000NO5E01
  2. for 2GR-FE

    B000M8ZE01

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK VEHICLE SIGNAL (OPERATION CHECK)


    1. B000IMV

      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
    OK
  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)


    1. B000KN3E08
      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 I18-9 (+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 I18-9 (+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
    OK
  3. CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - COMBINATION METER ASSEMBLY)


    1. Disconnect the I155 radio and display receiver assembly connector.

    2. Disconnect the I18 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I155-17 (SPD) - I18-9 (+S) Always Below 1 Ω

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


    1. Disconnect the I155 radio and display receiver assembly connector.

    2. Disconnect the I124 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I155-17 (SPD) - I124-17 Always Below 1 Ω

    NG
    OK