LIGHTING SYSTEM(for LED Headlight), Diagnostic DTC:B243B, B243C

DTC Code DTC Name
B243B LED Wiring for High Beam LH Circuit
B243C LED Wiring for High Beam RH Circuit

DESCRIPTION

This DTC is output when the headlight ECU sub-assembly receives a high beam output malfunction signal from the headlight unit. The headlight ECU sub-assembly LH outputs DTCs B243B and B243C.

DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from Note
B243B LED Wiring for High Beam LH Circuit High beam LED output line LH malfunction

  • Headlight unit assembly LH

  • Headlight unit LH

  • No. 1 headlight ECU sub-assembly LH

 No. 1 headlight ECU sub-assembly LH -
B243C LED Wiring for High Beam RH Circuit High beam LED output line RH malfunction

  • Headlight unit assembly RH

  • Headlight unit RH

  • No. 1 headlight ECU sub-assembly RH

 No. 1 headlight ECU sub-assembly LH -

WIRING DIAGRAM

B001FO1E01

CAUTION / NOTICE / HINT

Note

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

Click here

PROCEDURE


  1. CHECK FOR DTC


    1. Clear the DTCs.

      Click here

    2. 10 seconds elapse after turning the ignition switch to ON and illuminating the high beam headlights using the light control switch.

    3. Check for DTCs.

      Click here

      OK
      DTC B243B and B243C are not output.
      Result
      Result Proceed to
      OK A
      NG (DTC B243B is output) B
      NG (DTC B243C is output) C

    A

    USE SIMULATION METHOD TO CHECK

    C

    CHECK HEADLIGHT UNIT RH Click here

    B

  2. CHECK HEADLIGHT UNIT LH


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

      Click here

    2. Clear the DTCs.

      Click here

    3. 10 seconds elapse after turning the ignition switch to ON and illuminating the high beam headlights using the light control switch.

    4. Check for DTCs.

      Click here

      Result
      Result Proceed to
      DTC B243B is output A
      DTC B243C is output B

    A

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

    B

  3. CHECK HEADLIGHT UNIT LH


    1. B001HY8C01
      *a

      Front view of wire harness connector

      (to No. 1 Headlight ECU Sub-assembly LH)
      *b

      Front view of wire harness connector

      (to Headlight Unit Assembly LH)

      Remove the headlight unit LH.

      Click here

    2. Remove the headlight 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
      C-8 (HI LED2) - F-1 Always Below 1 Ω
      C-7 (HI LED0) - F-2 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HEADLIGHT UNIT ASSEMBLY LH Click here

    NG

    REPLACE HEADLIGHT UNIT LH Click here

  4. CHECK HEADLIGHT UNIT RH


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

      Click here

    2. Clear the DTCs.

      Click here

    3. 10 seconds elapse after turning the ignition switch to ON and illuminating the high beam headlights using the light control switch.

    4. Check for DTCs.

      Click here

      Result
      Result Proceed to
      DTC B243C is output A
      DTC B243B is output B

    A

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

    B

  5. CHECK HEADLIGHT UNIT RH


    1. B001HY8C01
      *a

      Front view of wire harness connector

      (to No. 1 Headlight ECU Sub-assembly RH)
      *b

      Front view of wire harness connector

      (to Headlight Unit Assembly RH)

      Remove the headlight unit RH.

      Click here

    2. Remove the headlight 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
      C-8 (HI LED2) - F-1 Always Below 1 Ω
      C-7 (HI LED0) - F-2 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HEADLIGHT UNIT ASSEMBLY RH Click here

    NG

    REPLACE HEADLIGHT UNIT RH Click here