LIGHTING SYSTEM, Diagnostic DTC:B2439, B243A

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

DESCRIPTION

The No. 1 headlight ECU sub-assembly supplies internally boosted voltage to the LED so that the current supplied to the LED is always maintained at a constant value.

These DTCs are also output when the No. 1 headlight ECU sub-assembly detects malfunctions while monitoring the applied voltage.

DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from
B2439 Headlight LH Circuit

    Detection condition:

  • Engine switch on (IG), low beam headlights illuminated


    Malfunction status:

  • LED (LED) malfunction

  • Open/short in LED (LEG) circuit


    Malfunction duration:

  • 10 seconds or more

  • Headlight unit assembly LH

  • Headlight LED unit assembly LH

  • No. 1 headlight ECU sub-assembly LH

 No. 1 headlight ECU sub-assembly LH
B243A Headlight RH Circuit

    Detection condition:

  • Engine switch on (IG), low beam headlights illuminated


    Malfunction status:

  • LED (LED) malfunction

  • Open/short in LED (LEG) circuit


    Malfunction duration:

  • 10 seconds or more

  • Headlight unit assembly RH

  • Headlight LED unit assembly RH

  • No. 1 headlight ECU sub-assembly RH

 No. 1 headlight ECU sub-assembly RH

WIRING DIAGRAM

B000V80E01
*a Lo / Hi Beam
*b Headlight LED Unit Assembly
*c Headlight Unit Assembly
*d No. 1 Headlight ECU Sub-assembly

CAUTION / NOTICE / HINT

Note

If the No. 1 headlight ECU sub-assembly LH has been replaced, it is necessary to synchronize the vehicle information.

Click here

PROCEDURE


  1. CHECK FOR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Clear DTCs
      Body Electrical > HL AutoLeveling (Sub) > Clear DTCs

    2. 10 seconds elapse after turning the engine switch on (IG) and illuminating the low beam headlights using the light control switch.

    3. Check for DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Trouble Codes
      Body Electrical > HL AutoLeveling (Sub) > Trouble Codes
      OK
      DTC B2439 and B243A are not output.
      Result
      Result Proceed to
      OK A
      NG (DTC B2439 is output) B
      NG (DTC B243A is output) C

    A

    USE SIMULATION METHOD TO CHECK Click here

    C

    CHECK HEADLIGHT UNIT ASSEMBLY RH Click here

    B

  2. CHECK HEADLIGHT UNIT ASSEMBLY LH


    1. Interchange the headlight unit assembly LH with RH and connect the connectors to them.

      Click here

    2. Clear the DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Clear DTCs
      Body Electrical > HL AutoLeveling (Sub) > Clear DTCs

    3. 10 seconds elapse after turning the engine switch on (IG) and illuminating the low beam headlights using the light control switch.

    4. Check for DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Trouble Codes
      Body Electrical > HL AutoLeveling (Sub) > Trouble Codes
      Result
      Result Proceed to
      DTC B2439 is output A
      DTC B243A is output B

    A

    REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH Click here

    B

  3. CHECK HEADLIGHT UNIT ASSEMBLY LH


    1. B000XJ5C02
      *a

      Component without harness connected

      (Headlight LED Unit Assembly LH)
      *b

      Component without harness connected

      (No. 1 Headlight ECU Sub-assembly LH)

      Remove the headlight unit assembly LH.

      Click here

    2. Remove the headlight LED unit assembly LH.

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 - B-2 (LO LED2) Always Below 1 Ω
      1 - B-3 (LO LED1) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HEADLIGHT LED UNIT ASSEMBLY LH Click here

    NG

    REPLACE HEADLIGHT UNIT ASSEMBLY LH Click here

  4. CHECK HEADLIGHT UNIT ASSEMBLY RH


    1. Interchange the headlight unit assembly RH with LH and connect the connectors to them.

      Click here

    2. Clear the DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Clear DTCs
      Body Electrical > HL AutoLeveling (Sub) > Clear DTCs

    3. 10 seconds elapse after turning the engine switch on (IG) and illuminating the low beam headlights using the light control switch.

    4. Check for DTCs.

      Click here


      Body Electrical > HL AutoLeveling > Trouble Codes
      Body Electrical > HL AutoLeveling (Sub) > Trouble Codes
      Result
      Result Proceed to
      DTC B243A is output A
      DTC B2439 is output B

    A

    REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH Click here

    B

  5. CHECK HEADLIGHT UNIT ASSEMBLY RH


    1. B000XJ5C02
      *a

      Component without harness connected

      (Headlight LED Unit Assembly RH)
      *b

      Component without harness connected

      (No. 1 Headlight ECU Sub-assembly RH)

      Remove the headlight unit assembly RH.

      Click here

    2. Remove the headlight LED unit assembly RH.

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 - B-2 (LO LED2) Always Below 1 Ω
      1 - B-3 (LO LED1) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HEADLIGHT LED UNIT ASSEMBLY RH Click here

    NG

    REPLACE HEADLIGHT UNIT ASSEMBLY RH Click here