LIGHTING SYSTEM High Beam Headlight Circuit

DESCRIPTION

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

Tech Tips

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.

WIRING DIAGRAM

A01NDRWE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CHECK OPERATION (LOW BEAM HEADLIGHTS)


    1. Check the operation of the low beam headlights.

      OK
      Low beam headlights operate normally.

    NG

    GO TO PROBLEM SYMPTOMS TABLE Click here

    OK

  2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power 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.

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

    NG

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

    OK

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

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

    Tech Tips

    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.

    NG

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

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (SHORT CIRCUIT BETWEEN FUSE AND BULB)

  4. INSPECT POWER DISTRIBUTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY)


    1. A01NFJ6E04
      Text in Illustration
      *1

      Component without harness connected

      (Power Distributor (Engine Room Junction Block Assembly))

      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

    NG

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

    OK

  5. CHECK HARNESS AND CONNECTOR (POWER DISTRIBUTOR - MAIN BODY ECU)


    1. A01NGS0E01
      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 Main Body ECU (Multiplex Network Body ECU))

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

    2. Disconnect the F12 main body ECU (multiplex network body ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3C-5 - F12-2 (DIM) Always Below 1 Ω
      3C-5 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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