LIGHTING SYSTEM Low Beam Headlight Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the low beam headlights.

WIRING DIAGRAM

A001S5TE02

CAUTION / NOTICE / HINT

Note


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

  • Before replacing the main body ECU (multiplex network body ECU), refer to Service Bulletin.

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS (HEADLIGHT RELAY)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch to on (IG).

    3. Turn the GTS on.

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

    5. Check that the relay operates.


      Body Electrical > Main Body > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Headlight Relay Low beam headlights ON or OFF -

      Body Electrical > Main Body > Active Test
      Tester Display
      Headlight Relay
      OK
      Headlight relay operates. (Low beam headlights illuminate.)
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

  2. INSPECT NO. 1 INTEGRATION RELAY (H-LP LH RELAY, H-LP RH RELAY)


    1. Remove the No. 1 integration relay from the No. 1 engine room relay block.

      Click here

    2. Inspect the No. 1 integration relay.

      Click here

      OK
      No. 1 integration relay is normal.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 1 INTEGRATION RELAY Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - AUXILIARY BATTERY)


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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      1A-5 - Body ground Power switch off 11 to 14 V
      1B-8 - Body ground Power switch off 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - HEADLIGHT ASSEMBLY LH AND HEADLIGHT ASSEMBLY RH AND BODY GROUND)


    1. Disconnect the A9 headlight assembly LH connector.

    2. Disconnect the A28 headlight assembly RH connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1B-1 - A9-2 (LO) Always Below 1 Ω
      1A-12 - A28-2 (LO) Always Below 1 Ω
      A9-1 (E) - Body ground Always Below 1 Ω
      A28-1 (E) - Body ground Always Below 1 Ω
      1B-1 - Body ground Always 10 kΩ or higher
      1A-12 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - INSTRUMENT PANEL JUNCTION BLOCK)


    1. Disconnect the 3F 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
      1A-11 - 3F-31 Always Below 1 Ω
      1B-2 - 3F-31 Always Below 1 Ω
      1A-11 or 3F-31 - Body ground Always 10 kΩ or higher
      1B-2 or 3F-31 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Remove the instrument panel junction block assembly.

      for LHD: Click here

      for RHD: 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.

      A001OS6C07
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      3F-31 - MB-15 (HRLY) Always Below 1 Ω
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG (for LHD) C
      NG (for RHD) D

    A

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

    B

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

    C

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    D

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here