LIGHTING SYSTEM, Diagnostic DTC:B243D, B243E

DTC Code DTC Name
B243D Left Low Beam Fan Malfunction
B243E Right Low Beam Fan Malfunction

DESCRIPTION

The No. 1headlight ECU sub-assembly operates the low beam fan to cool the headlight LED unit in order to prevent the headlight LED unit from overheating.

Illuminates the low beam headlights and continuously operates the low beam fan.

The No. 1 headlight ECU sub-assembly monitors the pulse signals from the FANP terminal when the low beam fans are operating.

Tech Tips

If B243D or B243E is output, the No. 1 headlight ECU sub-assembly performs low beam headlight dimming control.

DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from
B243D Left Low Beam Fan Malfunction

    Detection condition:

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


    Malfunction status:

  • Fan speed signals from the low beam fan of less than 1600 rpm are continuously detected


    Malfunction duration:

  • 120 seconds or more

  • Headlight LED unit assembly LH

  • Headlight unit assembly LH

  • No. 1 headlight ECU sub-assembly LH

 No. 1 headlight ECU sub-assembly LH
B243E Right Low Beam Fan Malfunction

    Detection condition:

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


    Malfunction status:

  • Fan speed signals from the low beam fan of less than 1600 rpm are continuously detected


    Malfunction duration:

  • 120 seconds or more

  • Headlight LED unit assembly RH

  • Headlight unit assembly RH

  • No. 1 headlight ECU sub-assembly RH

 No. 1 headlight ECU sub-assembly RH

WIRING DIAGRAM

B0049YIE02

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. 120 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 > HL AutoLeveling > Trouble Codes
      Body Electrical > HL AutoLeveling (Sub) > Trouble Codes
      OK
      DTC B243D and B243E are not output.
      Result
      Result Proceed to
      OK A
      NG (DTC B243D is output) B
      NG (DTC B243E 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. B004ACNC03
      *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
      3 - B-4 (FANB) Always Below 1 Ω
      5 - B-15 (FANP) Always Below 1 Ω
      4 - B-14 (FANG) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT UNIT ASSEMBLY LH Click here

    OK

  3. CHECK NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH


    1. B004AJDC01
      *a

      Component without harness connected

      (Headlight LED Unit Assembly LH)

      Remove the headlight LED unit assembly LH.

      Click here

    2. Connect the No. 1 headlight ECU sub-assembly LH connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3 - 4 Low beam headlights illuminated 4.75 to 5.25 V
      5 - 4
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HEADLIGHT LED UNIT ASSEMBLY LH Click here

    NG

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

  4. CHECK HEADLIGHT UNIT ASSEMBLY RH


    1. B004ACNC03
      *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
      3 - B-4 (FANB) Always Below 1 Ω
      5 - B-15 (FANP) Always Below 1 Ω
      4 - B-14 (FANG) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT UNIT ASSEMBLY RH Click here

    OK

  5. CHECK NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH


    1. B004AJDC01
      *a

      Component without harness connected

      (Headlight LED Unit Assembly RH)

      Remove the headlight LED unit assembly RH.

      Click here

    2. Connect the No. 1 headlight ECU sub-assembly RH connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3 - 4 Low beam headlights illuminated 4.75 to 5.25 V
      5 - 4
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HEADLIGHT LED UNIT ASSEMBLY RH Click here

    NG

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