LIGHTING SYSTEM, Diagnostic DTC:B2439, B243A

DTC Code DTC Name
B2439 Headlamp LH Circuit
B243A Headlamp RH Circuit

DESCRIPTION

This DTC is output when the headlight light control ECU sub-assembly receives an abnormal signal from the headlight unit assembly.

The headlight light control ECU sub-assembly LH (main) outputs DTC B2439 and B243A

DTC No. Detection Item DTC Detection Condition Trouble Area
B2439 Headlamp LH Circuit Headlight light control ECU sub-assembly LH (main) light source malfunction

  • Headlight light control ECU sub-assembly LH (main)

  • Headlight unit assembly LH

  • Headlight housing sub-assembly LH (wire harness assembly)
B243A Headlamp RH Circuit Headlight light control ECU sub-assembly RH (sub) light source malfunction

  • Headlight light control ECU sub-assembly RH (sub)

  • Headlight unit assembly RH

  • Headlight housing sub-assembly RH (wire harness assembly)

WIRING DIAGRAM

B006KXQE02

CAUTION / NOTICE / HINT

Note

After the headlight light control ECU sub-assembly LH (main) is replaced, vehicle information registration and initialization are necessary.

Click here

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  2. CHECK FOR DTC


    1. Turn the engine switch on (IG).

    2. Turn on the headlights using the headlight dimmer switch.

    3. Check for DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Trouble Codes
      Result
      Proceed to
      DTCs B2439 and B243A output does not occur
      DTC B2439 output occurs
      DTC B243A output occurs

    DTCs B2439 and B243A output does not occur

    USE SIMULATION METHOD TO CHECK Click here

    DTC B243A output occurs

    INSPECT HEADLIGHT HOUSING SUB-ASSEMBLY RH (WIRE HARNESS ASSEMBLY) Click here

    DTC B2439 output occurs

  3. INSPECT HEADLIGHT HOUSING SUB-ASSEMBLY LH (WIRE HARNESS ASSEMBLY)


    1. B006LL4E01

      Remove the headlight sub-assembly LH.

      for ALPHARD:

      Click here

      for VELLFIRE:

      Click here

    2. Remove the headlight unit assembly LH from the headlight sub-assembly LH.

      for ALPHARD:

      Click here

      for VELLFIRE:

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B-3 - A-1 Always Below 1 Ω
      B-4 - A-2 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY LH (WIRE HARNESS ASSEMBLY) for ALPHARD: REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY LH (WIRE HARNESS ASSEMBLY) Click here
    REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY LH (WIRE HARNESS ASSEMBLY) for VELLFIRE: REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY LH (WIRE HARNESS ASSEMBLY) Click here

    OK

  4. REPLACE HEADLIGHT UNIT ASSEMBLY LH


    1. Temporarily replace the headlight unit assembly LH with a new or normally functioning one.

      for ALPHARD:

      Click here

      for VELLFIRE:

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  5. CLEAR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  6. CHECK FOR DTC


    1. Turn the engine switch on (IG).

    2. Turn on the headlights using the headlight dimmer switch.

    3. Check for DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Trouble Codes
      Result
      Proceed to
      DTC B2439 output does not occur
      DTC B2439 output occurs

    DTC B2439 output does not occur

    END (HEADLIGHT UNIT ASSEMBLY LH WAS DEFECTIVE)

    DTC B2439 output occurs

    REPLACE HEADLIGHT LIGHT CONTROL ECU SUB-ASSEMBLY LH (MAIN) Click here

  7. INSPECT HEADLIGHT HOUSING SUB-ASSEMBLY RH (WIRE HARNESS ASSEMBLY)


    1. B006LL4E01

      Remove the headlight sub-assembly RH.

      for ALPHARD:

      Click here

      for VELLFIRE:

      Click here

    2. Remove the headlight unit assembly RH from the headlight sub-assembly RH.

      for ALPHARD:

      Click here

      for VELLFIRE:

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B-3 - A-1 Always Below 1 Ω
      B-4 - A-2 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY RH (WIRE HARNESS ASSEMBLY) for ALPHARD: REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY RH (WIRE HARNESS ASSEMBLY) Click here
    REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY RH (WIRE HARNESS ASSEMBLY) for VELLFIRE: REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY RH (WIRE HARNESS ASSEMBLY) Click here

    OK

  8. REPLACE HEADLIGHT UNIT ASSEMBLY RH


    1. Temporarily replace the headlight unit assembly RH with a new or normally functioning one.

      for ALPHARD:

      Click here

      for VELLFIRE:

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  9. CLEAR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  10. CHECK FOR DTC


    1. Turn the engine switch on (IG).

    2. Turn on the headlights using the headlight dimmer switch.

    3. Check for DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Trouble Codes
      Result
      Proceed to
      DTC B243A output does not occur
      DTC B243A output occurs

    DTC B243A output does not occur

    END (HEADLIGHT UNIT ASSEMBLY RH WAS DEFECTIVE)

    DTC B243A output occurs

    REPLACE HEADLIGHT LIGHT CONTROL ECU SUB-ASSEMBLY RH (SUB) Click here