LIGHTING SYSTEM, Diagnostic DTC:B2439, B243A

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

DESCRIPTION

The 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 headlight ECU sub-assembly detects malfunctions while monitoring the applied voltage.

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

    Detection condition:

  • Power 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 LH

  • Headlight unit assembly LH

  • Headlight ECU sub-assembly LH

 Headlight ECU sub-assembly LH -
B243A Headlight RH Circuit

    Detection condition:

  • Power 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 RH

  • Headlight unit assembly RH

  • Headlight ECU sub-assembly RH

 Headlight ECU sub-assembly RH -

WIRING DIAGRAM

B004WATE06
*a Lo / Hi Beam
*b Headlight Unit
*c Headlight Unit Assembly
*d Headlight ECU Sub-assembly

CAUTION / NOTICE / HINT

Note

If the headlight ECU sub-assembly LH has been replaced, it is necessary to synchronize the vehicle information and initialize the headlight ECU sub-assembly LH.

Click here

PROCEDURE


  1. CHECK FOR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > AFS > Clear DTCs
      Body Electrical > AFS (Sub) > Clear DTCs

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

    3. Check for DTCs.

      Click here


      Body Electrical > AFS > Trouble Codes
      Body Electrical > AFS (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 > AFS > Clear DTCs

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

    4. Check for DTCs.

      Click here


      Body Electrical > AFS > Trouble Codes
      OK
      DTC B2439 is not output.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH Click here

    OK

  3. CHECK HEADLIGHT UNIT ASSEMBLY LH


    1. B004WG8C01
      *a

      Component without harness connected

      (Headlight ECU Sub-assembly LH)
      *b

      Component without harness connected

      (Headlight Unit LH)

      Remove the headlight unit LH.

      Click here

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

      Standard Resistance
      Tester Connection Wiring Color Condition Specified Condition
      B-2 - F-1 V Always Below 1 Ω
      B-3 - F-2 B Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HEADLIGHT UNIT LH Click here

    NG

    REPLACE HEADLIGHT HOUSING SUB-ASSEMBLY LH (WIRE HARNESS) 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 > AFS (Sub) > Clear DTCs

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

    4. Check for DTCs.

      Click here


      Body Electrical > AFS (Sub) > Trouble Codes
      OK
      DTC B243A is not output.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH Click here

    OK

  5. CHECK HEADLIGHT UNIT ASSEMBLY RH


    1. B004WG8C01
      *a

      Component without harness connected

      (Headlight ECU Sub-assembly RH)
      *b

      Component without harness connected

      (Headlight Unit RH)

      Remove the headlight unit RH.

      Click here

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

      Standard Resistance
      Tester Connection Wiring Color Condition Specified Condition
      B-2 - F-1 V Always Below 1 Ω
      B-3 - F-2 B Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HEADLIGHT UNIT RH Click here

    NG

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