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Home >> Lexus >> 2021 >> RX 350 Base, AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Exterior Lights >> Lighting System (W/ Automatic Headlight Beam Level Control System) - Diagnostic Codes >> LIGHTING SYSTEM (w/ Automatic Headlight Beam Level Control System) >> DTC B2439: Headlight LH Circuit; DTC B243A: Headlight RH Circuit [08/2019 - ] >> Procedure
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DTC B2439: Headlight LH Circuit; DTC B243A: Headlight RH Circuit [08/2019 - ]: Procedure

  1. CONFIRM MODEL 
    1. Choose the model to be inspected.

      Result

      Result Proceed to
      for Multiple Beam Headlight A
      for Single Beam Headlight B

    Result: 

    B 

    See step  10

    Result: 

    A 

    See step  2

  2. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / AFS / Trouble Codes.
    5. Clear the DTCs.

      Body Electrical > AFS > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  3

  3. CHECK FOR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Operate the light control switch to turn on the low beam headlights and wait 10 seconds or more.
    4. Turn the Techstream on.
    5. Enter the following menus: Body Electrical / AFS / Trouble Codes.
    6. Check for DTCs.

      Body Electrical > AFS > 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

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - ] 

    Result: 

    C 

    See step  7

    Result: 

    B 

    See step  4

  4. CHECK HEADLIGHT UNIT LH 
    1. Interchange the headlight unit LH with RH and connect the connectors.

      Refer to DISASSEMBLY [08/2019 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  5

  5. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / AFS / Trouble Codes.
    5. Clear the DTCs.

      Body Electrical > AFS > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  6

  6. CHECK FOR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Operate the light control switch to turn on the low beam headlights and wait 10 seconds or more.
    4. Turn the Techstream on.
    5. Enter the following menus: Body Electrical / AFS / Trouble Codes.
    6. Check for DTCs.

      Body Electrical > AFS > Trouble Codes 

      Result

      Result Proceed to
      DTC B2439 is output A
      DTC B243A is output (for TMC Made) B
      DTC B243A is output (for TMMC Made) C

    Result: 

    A 

    REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    B 

    REPLACE HEADLIGHT UNIT LH. Refer to  DISASSEMBLY [08/2019 - ] 

    Result: 

    C 

    REPLACE HEADLIGHT ASSEMBLY LH. Refer to  REMOVAL [08/2019 - ] 

  7. CHECK HEADLIGHT UNIT RH 
    1. Interchange the headlight unit RH with LH and connect the connectors.

      Refer to DISASSEMBLY [08/2019 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  8. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / AFS / Trouble Codes.
    5. Clear the DTCs.

      Body Electrical > AFS > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  9

  9. CHECK FOR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Operate the light control switch to turn on the low beam headlights and wait 10 seconds or more.
    4. Turn the Techstream on.
    5. Enter the following menus: Body Electrical / AFS / Trouble Codes.
    6. Check for DTCs.

      Body Electrical > AFS > Trouble Codes 

      Result

      Result Proceed to
      DTC B243A is output A
      DTC B2439 is output (for TMC Made) B
      DTC B2439 is output (for TMMC Made) C

    Result: 

    A 

    REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    B 

    REPLACE HEADLIGHT UNIT RH. Refer to  DISASSEMBLY [08/2019 - ] 

    Result: 

    C 

    REPLACE HEADLIGHT ASSEMBLY RH. Refer to  REMOVAL [08/2019 - ] 

  10. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / HL Auto Leveling / Trouble Codes.
    5. Clear the DTCs.

      Body Electrical > HL Auto Leveling > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  11

  11. CHECK FOR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Operate the light control switch to turn on the low beam headlights and wait 10 seconds or more.
    4. Turn the Techstream on.
    5. Enter the following menus: Body Electrical / HL Auto Leveling / Trouble Codes.
    6. Check for DTCs.

      Body Electrical > HL Auto Leveling > 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

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - ] 

    Result: 

    C 

    See step  15

    Result: 

    B 

    See step  12

  12. CHECK HEADLIGHT UNIT LH 
    1. Interchange the headlight unit LH with RH and connect the connectors.

      Refer to DISASSEMBLY [08/2019 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  13

  13. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / HL Auto Leveling / Trouble Codes.
    5. Clear the DTCs.

      Body Electrical > HL Auto Leveling > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  14

  14. CHECK FOR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Operate the light control switch to turn on the low beam headlights and wait 10 seconds or more.
    4. Turn the Techstream on.
    5. Enter the following menus: Body Electrical / HL Auto Leveling / Trouble Codes.
    6. Check for DTCs.

      Body Electrical > HL Auto Leveling > Trouble Codes 

      Result

      Result Proceed to
      DTC B2439 is output A
      DTC B243A is output (for TMC Made) B
      DTC B243A is output (for TMMC Made) C

    Result: 

    A 

    REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    B 

    REPLACE HEADLIGHT UNIT LH. Refer to  DISASSEMBLY [08/2019 - ] 

    Result: 

    C 

    REPLACE HEADLIGHT ASSEMBLY LH. Refer to  REMOVAL [08/2019 - ] 

  15. CHECK HEADLIGHT UNIT RH 
    1. Interchange the headlight unit RH with LH and connect the connectors.

      Refer to DISASSEMBLY [08/2019 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  16

  16. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / HL Auto Leveling / Trouble Codes.
    5. Clear the DTCs.

      Body Electrical > HL Auto Leveling > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  17

  17. CHECK FOR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Operate the light control switch to turn on the low beam headlights and wait 10 seconds or more.
    4. Turn the Techstream on.
    5. Enter the following menus: Body Electrical / HL Auto Leveling / Trouble Codes.
    6. Check for DTCs.

      Body Electrical > HL Auto Leveling > Trouble Codes 

      Result

      Result Proceed to
      DTC B243A is output A
      DTC B2439 is output (for TMC Made) B
      DTC B2439 is output (for TMMC Made) C

    Result: 

    A 

    REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH. Refer to  REMOVAL [08/2019 - ] 

    Result: 

    B 

    REPLACE HEADLIGHT UNIT RH. Refer to  DISASSEMBLY [08/2019 - ] 

    Result: 

    C 

    REPLACE HEADLIGHT ASSEMBLY RH. Refer to  REMOVAL [08/2019 - ] 

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