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LIGHTING SYSTEM High Beam Headlight Circuit

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DTC Code DTC Name
  High Beam Headlight Circuit
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DESCRIPTION

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

Tip:

When the high beams are turned on, the main body ECU (multiplex network body ECU) activates the headlight solenoid built into the headlight unit to increases the upper illumination area of the discharge bulb.

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WIRING DIAGRAM

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INSPECTION PROCEDURE

Note:

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

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PROCEDURE


  1. Click here

    CHECK OPERATION (LOW BEAM HEADLIGHTS)


    1. Check the operation of the low beam headlights.

      OK
      Low beam headlights operate normally.

  2. Click here

    PERFORM ACTIVE TEST USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the intelligent tester on.

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

    5. Check that the high beam headlights illuminate.

      Table 1. Main Body
      Tester Display Test Part Control Range Diagnostic Note
      Head Light Hi High beam headlights ON/OFF -
      OK
      High beam headlights illuminate.

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    CHECK HARNESS AND CONNECTOR (SHORT IN RELAY-DRIVEN CIRCUIT)

    Tip:

    When a short circuit occurs between the power distributor (engine room junction block assembly) and high beam headlight bulb, a fail-safe function operates to stop the high beam headlights operation.


    1. Remove the H-LP RH HI fuse from the power distributor (engine room junction block assembly).

    2. Turn the light control switch to the head position and turn the dimmer switch to the high position.

    3. Check if the high beam headlight LH illuminates.

    4. Turn the dimmer switch to the low position.

    5. Install the H-LP RH HI fuse and remove the H-LP LH HI fuse.

    6. Turn the dimmer switch to the high position.

    7. Check if the high beam headlight RH illuminates.

      OK
      Either high beam headlight LH or RH illuminates.

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    INSPECT POWER DISTRIBUTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY)


    1. A019LOXE04

      Remove the power distributor (engine room junction block assembly) from the engine room relay block (Click here).

    2. Connect a positive (+) lead from the battery to terminal 3A-1.

    3. Connect a negative (-) lead from the battery to terminal 3C-5 and 3C-17.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3B-1 - Battery negative Always 11 to 14 V
      3B-5 - Battery negative Always 11 to 14 V
      Table 2. Text in Illustration
      *1

      Component without harness connected

      (Power Distributor (Engine Room Junction Block Assembly))

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    CHECK HARNESS AND CONNECTOR (POWER DISTRIBUTOR - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)


    1. A019P32E01

      Disconnect the 3C power distributor (engine room junction block assembly) connector.

    2. Disconnect the 2F instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3C-5 - 2F-20 Always Below 1 Ω
      3C-5 - Body ground Always 10 kΩ or higher
      Table 3. Text in Illustration
      *1

      Front view of wire harness connector

      (to Power Distributor (Engine Room Junction Block Assembly))
      *2

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)

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    INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. A019LKHE01

      Remove the instrument panel junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2F-20 - A-22 (DIM) Always Below 1 Ω
      2F-20 - Body ground Always 10 kΩ or higher
      Table 4. Text in Illustration
      *1

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

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    REPLACE POWER DISTRIBUTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY)Click here

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    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLEClick here

  9. Click here

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

  10. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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    GO TO PROBLEM SYMPTOMS TABLEClick here

  12. Click here

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY