LIGHTING SYSTEM Headlight Signal Circuit

DESCRIPTION

The main body ECU receives a headlight low switch information signal from the light control switch, and illuminates the headlight low beam.

WIRING DIAGRAM

A01X5BZE04
A01XA9TE05
A01X122E01

CAUTION / NOTICE / HINT

Note

Inspect the fuses and bulbs for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (HEADLIGHT)


    1. Using the intelligent tester, perform the Active Test Click here.

      Main Body
      Tester Display Test Part Control Range Diagnostic Note
      Headlight Relay Headlight ON or OFF -
      OK
      Headlight low beam turns on/turns off.

    OK

    REPLACE MAIN BODY ECU (COWL SIDE JUNCTION BLOCK LH)

    NG

  2. INSPECT HEADLIGHT RELAY (HEAD LO)


    1. A01WZ2CE29

      Remove the headlight relay from the engine room relay block, junction block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 Battery voltage not applied to terminals 1 and 2 10 kΩ or higher
      Battery voltage applied to terminals 1 and 2 Below 1 Ω

    NG

    REPLACE HEADLIGHT RELAY (HEAD LO)

    OK

  3. CHECK HARNESS AND CONNECTOR (BATTERY - HEADLIGHT RELAY [HEAD LO])


    1. A01X5SYE05
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Headlight Relay [HEAD LO])

      Remove the headlight relay from the engine room relay block, junction block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      Headlight relay terminal 1 - Body ground Always 11 to 14 V
      Headlight relay terminal 5 - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY [HEAD LO] - MAIN BODY ECU [COWL SIDE JUNCTION BLOCK LH])


    1. Remove the headlight relay from the engine room relay block, junction block.

    2. Disconnect the 2B main body ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Headlight relay terminal 2 - 2B-18 Always Below 1 Ω
      Headlight relay terminal 2 - Body ground Always 10 kΩ or higher

    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR