NAVIGATION SYSTEM Vehicle Speed Signal Circuit between Navigation Receiver Assembly and Combination Meter

DESCRIPTION

The navigation receiver assembly receives a vehicle speed signal from the combination meter assembly and information from the navigation antenna assembly, and then adjusts vehicle position.

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 systems 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 diagram below will not operate normally.

WIRING DIAGRAM

A003UYAE01

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK VEHICLE SENSOR (NAVIGATION CHECK MODE)


    1. Enter the "Vehicle Sensors" screen. Refer to Check Navigation Check in Navigation Check Mode Click here.

    2. A003U16

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

      OK
      The readings are almost equal.

    NG

    INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) Click here

    OK

    REPLACE NAVIGATION RECEIVER ASSEMBLY Click here

  2. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM)


    1. A003T12E49
      Text in Illustration
      *a

      Component with harness connected

      (Combination Meter Assembly)

      Check the output waveform.


      1. Remove the combination meter assembly with the connector(s) still connected.

      2. Connect an oscilloscope to terminal E46-36 (+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 E46-36 (+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. CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - COMBINATION METER ASSEMBLY)


    1. Disconnect the E26 navigation receiver assembly connector.

    2. Disconnect the E46 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E26-3 (SPD) - E46-36 (+S) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - NO. 4 JUNCTION BLOCK)


    1. Disconnect the E26 navigation receiver assembly connector.

    2. Disconnect the 4A No. 4 junction block connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E26-3 (SPD) - 4A-20 Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NAVIGATION RECEIVER ASSEMBLY - NO. 4 JUNCTION BLOCK)

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 4 JUNCTION BLOCK)