LIGHTING SYSTEM Headlight Signal Circuit

DESCRIPTION

The headlight leveling ECU receives the 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

A01IT9ZE03

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (HEADLIGHT)


    1. Using the intelligent tester, 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 RELAY [H-LP] - HEADLIGHT LEVELING ECU ASSEMBLY) Click here

    OK

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

  2. CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY [H-LP] - HEADLIGHT LEVELING ECU ASSEMBLY)

    A01IRYEE28
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Headlight Leveling ECU Assembly)

    1. Disconnect the A49 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
      A49-3 (B2) - Body ground Light control switch off 11 to 14 V
      Light control switch head Below 1 V
      Result
      Result Proceed to
      NG A
      OK (for LHD) B
      OK (for RHD) C

    B

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here

    C

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here

    A

    REPAIR OR REPLACE HARNESS OR CONNECTOR