LIGHTING SYSTEM Vehicle Speed Signal Circuit

DESCRIPTION

The headlight leveling ECU receives the vehicle speed signal from the combination meter.

WIRING DIAGRAM

A01IN24E01

INSPECTION PROCEDURE

Tech Tips

After replacing the headlight leveling ECU, initialization of the ECU is necessary Click here.

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (VEHICLE SPEED)


    1. Using the intelligent tester, read the Data List Click here.

      HL Auto Leveling
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Vehicle Speed Vehicle speed / 0 to 327.67 km/h A value similar to the actual vehicle speed is displayed -
      OK
      The display is as specified in the normal condition column.

    NG

    CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - HEADLIGHT LEVELING ECU ASSEMBLY) Click here

    OK

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

  2. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - HEADLIGHT LEVELING ECU ASSEMBLY)


    1. A01IO3BE06
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Combination Meter Assembly)
      *2

      Front view of wire harness connector

      (to Headlight Leveling ECU Assembly)

      Disconnect the H62 combination meter connector.

    2. Disconnect the A49 headlight leveling ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H62-3 (+S) - A49-16 (SPDR) Always Below 1 Ω
      H62-3 (+S) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK COMBINATION METER ASSEMBLY


    1. A01IQKQE01
      Text in Illustration
      *1

      Component with harness connected

      (Combination Meter Assembly)

      Remove the combination meter with its connector still connected Click here.

    2. Connect an oscilloscope to the combination meter connector.

    3. Check the waveform.

      Measurement Condition
      Item Content
      Terminal No. (Symbol) H62-3 (+S) - Body ground
      Tool setting 5 V/DIV., 20 ms./DIV.
      Condition Vehicle is driven at approximately 20 km/h (12 mph)
      OK
      Waveform is as 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
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    B

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here

    C

    GO TO METER / GAUGE SYSTEM Click here

    A

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here