NAVIGATION SYSTEM, Diagnostic DTC:B15C2

DTC Code DTC Name
B15C2 Speed Signal Malfunction

DESCRIPTION

The navigation ECU sub-assembly receives a vehicle speed signal from the meter circuit plate and information from the navigation antenna assembly, and then adjusts the vehicle position.

The navigation ECU sub-assembly stores this DTC when the difference between the speed information that the navigation antenna assembly receives and the SPD pulse received from the meter circuit plate becomes large.

Tech Tips


  • A voltage of 12 V or 5 V is output from each ECU and then input to the meter circuit plate. The signal is changed to a pulse signal at the transistor in the meter circuit plate. 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.

DTC No. DTC Detection Condition Trouble Area
B15C2 A difference between the GPS speed and SPD pulse is detected.

  • Navigation ECU sub-assembly

  • Meter circuit plate

  • Harness or connector

  • Junction connector

WIRING DIAGRAM

A005AM2E04

PROCEDURE


  1. CHECK VEHICLE SENSOR (OPERATION CHECK)


    1. A005AVZ

      Enter the "Vehicle Sensors" screen. Refer to Check GPS & Vehicle Sensors 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 meter circuit plate 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 Sensors" screen is almost the same as the actual vehicle speed measured using the GTS (See page Click here).

    OK

    REPLACE NAVIGATION ECU SUB-ASSEMBLY Click here

    NG

  2. INSPECT METER CIRCUIT PLATE (OUTPUT WAVEFORM)


    1. A005A98E01
      Text in Illustration
      *a

      Component with harness connected

      (Meter Circuit Plate)

      Check the output waveform.


      1. Remove the meter circuit plate with the connector(s) still connected.

      2. Connect an oscilloscope to terminal L27-15 (+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 L27-15 (+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 NAVIGATION ECU SUB-ASSEMBLY (INPUT WAVEFORM)


    1. Check the input waveform.

      A005DCME01

      1. Remove the navigation ECU sub-assembly with the connector(s) still connected.

      2. Connect an oscilloscope to terminal L38-17 (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 L38-17 (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.

        Text in Illustration
        *a

        Component with harness connected

        (Navigation ECU Sub-assembly)

    OK

    REPLACE NAVIGATION ECU SUB-ASSEMBLY Click here

    NG

  4. CHECK HARNESS AND CONNECTOR (NAVIGATION ECU SUB-ASSEMBLY - JUNCTION CONNECTOR)


    1. Disconnect the L38 navigation ECU assembly connector.

    2. Disconnect the L70 junction connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      L38-17 (SPD) - L70-3 Always Below 1 Ω
      for RHD
      Tester Connection Condition Specified Condition
      L38-17 (SPD) - L70-12 Always Below 1 Ω

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (JUNCTION CONNECTOR)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NAVIGATION ECU SUB-ASSEMBLY - JUNCTION CONNECTOR)