LIGHTING SYSTEM Headlight Signal Circuit

DESCRIPTION

The headlight leveling ECU receives low beam headlight on/off state information from the headlight relay to control the headlight beam level control system.

Tech Tips

Before performing troubleshooting of the automatic headlight beam level control system, check that the low beam headlights operate normally.

WIRING DIAGRAM

B007RY0E01

INSPECTION PROCEDURE

Tech Tips

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

PROCEDURE


  1. READ VALUE USING GTS (HEADLIGHT)


    1. Using the GTS, read the Data List Click here.

      HL Auto Leveling
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Headlight Low Beam State Low beam headlight state / ON or OFF

      ON: Low beam headlights on

      OFF: Low beam headlights off

      		 -
      OK
      The display is as specified in the normal condition column.

    NG

    CHECK HARNESS AND CONNECTOR (HEADLIGHT SIGNAL CIRCUIT) Click here

    OK

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

  2. CHECK HARNESS AND CONNECTOR (HEADLIGHT SIGNAL CIRCUIT)


    1. B007VUEE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Headlight Leveling ECU Assembly)

      Disconnect the A39 headlight leveling ECU connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A39-4 (HDLP) - Body ground Headlight dimmer switch off 11 to 14 V
      Headlight dimmer switch head Below 1 V
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    B

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here