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 light failure indicator sensor detects a LO beam malfunction and outputs a malfunction signal to the AFS ECU via the headlight shade ECU.

DTC Code DTC Detection Condition Trouble Area
B2439 Malfunction in headlight assembly LH (light source)

  • Headlight assembly LH

  • Headlight shade ECU*1

  • Headlight light control ECU sub-assembly (for LO/HI beam)*2

  • Headlight LED unit assembly LH (for LO/ HI beam)*2

  • AFS ECU

  • Harness or connector
B243A Malfunction in headlight assembly RH (light source)

  • Headlight assembly RH

  • Headlight shade ECU*1

  • Headlight light control ECU sub-assembly (for LO/HI beam)*2

  • Headlight LED unit assembly RH (for LO/ HI beam)*2

  • AFS ECU

  • Harness or connector

WIRING DIAGRAM

A001CW2E04
A0019YTE02

CAUTION / NOTICE / HINT

Note

Check if DTC B2440 or B2441 is output. If output, refer to the following procedures Click here.

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTC Click here.


    NEXT

  2. CHECK HEADLIGHT ASSEMBLY (OPERATION)


    1. Check that the low beam headlights turns on normally when the headlight dimmer switch is operated.

      OK
      The low beam headlights turns on normally.

    NG

    PROCEED TO "LO-beam Headlight does not Illuminate" Click here

    OK

  3. CHECK HEADLIGHT TYPE


    1. Check headlight type.

      Result
      Result Proceed to
      for HID Headlight A
      for LED Headlight B

    B

    CHECK HARNESS AND CONNECTOR (AFS ECU - HEADLIGHT) Click here

    A

  4. CHECK FOR DTC


    1. Turn the engine switch on (IG).

    2. Turn on the low beam headlight by operating the headlight dimmer switch.

    3. Check for DTC Click here.

      OK
      DTC B2439 or B243A output does not occur

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

  5. CHECK HEADLIGHT SHADE ECU


    1. Temporarily replace the headlight shade ECU with a new or normally functioning one Click here.

    2. Turn the engine switch on (IG).

    3. Turn on the low beam headlight by operating the headlight dimmer switch.

    4. Check for DTC Click here.

      OK
      DTC B2439 or B243A output does not occur

    OK

    END (HEADLIGHT SHADE ECU WAS DEFECTIVE)

    NG

  6. CHECK HEADLIGHT ASSEMBLY


    1. Temporarily replace the headlight with a new or normally functioning one Click here.

    2. Turn the engine switch on (IG).

    3. Turn on the high beam headlight by operating the headlight dimmer switch.

    4. Check for DTC Click here.

      OK
      DTC B2439 or B243A output does not occur

    OK

    END (HEADLIGHT WAS DEFECTIVE)

    NG

    REPLACE AFS ECU Click here

  7. CHECK HARNESS AND CONNECTOR (AFS ECU - HEADLIGHT)

    A001AWJE03

    1. Disconnect the A37 AFS ECU connector.

    2. Disconnect the B1*1 or B11*2 headlight connector.


      • *1: for LH

      • *2: for RH

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

      Standard Resistance
      for LH
      Tester Connection Condition Specified Condition
      A37-6 (INL) - B1-20 (S) Always Below 1 Ω
      A37-6 (INL) - Body ground Always 10 kΩ or higher
      for RH
      Tester Connection Condition Specified Condition
      A37-7 (INR) - B11-20 (S) Always Below 1 Ω
      A37-7 (INR) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK FOR DTC


    1. Turn the engine switch on (IG).

    2. Turn on the high beam headlight by operating the headlight dimmer switch.

    3. Check for DTC Click here.

      OK
      DTC B2439 or B243A output does not occur

    NG

    INSPECT HEADLIGHT ASSEMBLY Click here

    OK

  9. CHECK FOR DTC


    1. Turn the engine switch on (IG).

    2. Turn on the low beam headlight by operating the headlight dimmer switch.

    3. Check for DTC Click here.

      OK
      DTC B2439 or B243A output does not occur

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

    REPLACE HEADLIGHT LIGHT CONTROL ECU SUB-ASSEMBLY (FOR LO/HI BEAM) Click here

  10. INSPECT HEADLIGHT ASSEMBLY


    1. Remove the headlight Click here.

      A001DRBE03
      *1 Front view of wire harness connector: (to Headlight Light Control ECU [for LO/HI Beam])
      *2 Front view of wire harness connector: (to Headlight LED Unit [for LO/HI Beam])
      *3 Connector color: White
      *4 Connector color: Black

    2. Disconnect the headlight light control ECU (for LO/HI beam) connector Click here.

    3. Disconnect the headlight LED unit (for LO/HI beam) connector Click here.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (MD2) - A-2 Always Below 1 Ω
      3 (LO) - A-1 Always Below 1 Ω
      1 (HI) - B-2 Always Below 1 Ω
      8 (MD1) - B-1 Always Below 1 Ω

    NG

    REPLACE HEADLIGHT ASSEMBLY Click here

    OK

  11. INSPECT HEADLIGHT ASSEMBLY


    1. A001BFKE03
      *1 Component without harness connected: (Headlight)
      *2 Front view of wire harness connector: (to Headlight Light Control ECU [for LO/HI Beam])
      *3 PO

      Remove the headlight Click here.

    2. Disconnect the headlight light control ECU (for LO/HI beam) connector Click here.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      20 (S) - 11 (PO) Always Below 1 Ω

    NG

    REPLACE HEADLIGHT ASSEMBLY Click here

    OK

  12. CHECK HEADLIGHT LIGHT CONTROL ECU SUB-ASSEMBLY (FOR LO/HI BEAM)


    1. Temporarily replace the headlight light control ECU (for LO/HI beam) with a new or normally functioning one Click here.

    2. Turn the engine switch on (IG).

    3. Turn on the high beam headlight by operating the headlight dimmer switch.

    4. Check for DTC Click here.

      OK
      DTC B2439 or B243A output does not occur

    OK

    END (HEADLIGHT LIGHT CONTROL ECU (FOR LO/HI BEAM) WAS DEFECTIVE)

    NG

  13. CHECK HEADLIGHT LED UNIT ASSEMBLY (FOR LO/HI BEAM)


    1. Temporarily replace the headlight LED unit (for LO/HI beam) with a new or normally functioning one Click here.

    2. Turn the engine switch on (IG).

    3. Turn on the high beam headlight by operating the headlight dimmer switch.

    4. Check for DTC Click here.

      OK
      DTC B2439 or B243A output does not occur

    OK

    END (HEADLIGHT LED UNIT [FOR LO/HI BEAM] WAS DEFECTIVE)

    NG

    REPLACE AFS ECU Click here