LIGHTING SYSTEM High Beam Headlight Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the high beam headlights via the engine room junction block assembly.

WIRING DIAGRAM

A01G646E10

INSPECTION PROCEDURE

Note

If the main body ECU (multiplex network body ECU) is replaced, refer to Service Bulletin.

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Main Body / Active Test.

    5. Check that the high beam headlights illuminate.

      Main Body
      Tester Display Test Part Control Range Diagnostic Note
      Head Light Hi High beam headlights ON/OFF -
      OK
      The high beam headlights illuminate.

    NG

    CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY Click here

    OK

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

  2. CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY


    1. Using a voltmeter, check the signal reading of the engine room junction block assembly Click here.

      OK
      Output signal reading is normal.

    NG

    INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (RESULTS OF SIGNAL READING CHECK) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY POWER SOURCE AND BODY GROUND)


    1. Remove the engine room junction block assembly from the engine room relay block and junction block assembly Click here.

      A01G71KE04
      Text in Illustration
      *a

      Component without engine room junction block assembly connected

      (Engine Room Relay Block and Junction Block Assembly)

      		 - -

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A-1 (BATT) - Body ground Always 11 to 14 V
      B-1 (ALT) - Body ground Always 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1F-3 (GND1) - Body ground Always Below 1 Ω
      1G-4 (GND2) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)


    1. Disconnect the 3D instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1F-5 - 3D-39 Always Below 1 Ω
      3D-39 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Remove the instrument panel junction block assembly Click here.

    2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3D-39 - MB-26 (DIM) Always Below 1 Ω

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    OK

  6. CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY


    1. Replace the engine room junction block assembly with a new or known good one Click here.

    2. Check that the high beam headlights operate normally.

      OK
      The high beam headlights operate normally.

    NG

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

    OK

    END (ENGINE ROOM JUNCTION BLOCK ASSEMBLY WAS DEFECTIVE)