LIGHTING SYSTEM Headlight Signal Circuit

DESCRIPTION

The headlight leveling ECU receives the low beam headlight on/off state information from the headlight dimmer switch 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

A01J6WEE03

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 (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 DIMMER SWITCH ASSEMBLY - HEADLIGHT LEVELING ECU ASSEMBLY AND BODY GROUND) Click here

    OK

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

  2. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER SWITCH ASSEMBLY - HEADLIGHT LEVELING ECU ASSEMBLY AND BODY GROUND)


    1. Disconnect the C29 headlight dimmer switch connector.

    2. Disconnect the H17 headlight leveling ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      C29-20 (H) - H17-3 (B2) Always Below 1 Ω
      C29-12 (EL) - Body ground Always Below 1 Ω
      H17-3 (B2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY


    1. A01J5B4E30

      Remove the headlight dimmer switch Click here.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      20 (H) - 12 (EL) Headlight dimmer switch head Below 1 Ω
      Headlight dimmer switch off 10 kΩ or higher

    NG

    REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY Click here

    OK

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here