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Home >> Lexus >> 2021 >> GX 460 Luxury >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Lighting System (Exterior) (Diagnostic Codes & Circuit Tests) >> Lighting System >> DTC B2456: Left Headlight ECU Variation Error [08/2019 - ] >> Procedure

DTC B2456: Left Headlight ECU Variation Error [08/2019 - ]: Procedure

  1. 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 / Clear DTCs.
    5. Clear the DTCs.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  2

  2. CHECK FOR 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. Check for DTCs.

      OK

      DTC B2456 is not output.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - 08/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2020 - 08/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2021 - 08/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2022 - ] 

    Result: 

    NG 

    See step  3

  3. CHECK ECM 
    1. Check if the part number of the ECM installed to the vehicle is correct.

      OK

      Part number is correct.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE ECM. Refer to  REMOVAL [08/2015 - ] 

    Result: 

    OK 

    See step  4

  4. CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 
    1. Check if the part number of the main body ECU (multiplex network body ECU) installed to the vehicle is correct.

      OK

      Part number is correct.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

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

    Result: 

    NG 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [08/2019 - ]