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Home >> Lexus >> 2023 >> LX 600 Base >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Headlights >> Lighting System (W/O Adaptive High Beam System) - Diagnostic Codes & Circuit Tests >> LIGHTING SYSTEM (w/o Adaptive High Beam System) >> DTC B242C-04: Headlight Control Module (Sub) System Internal Failure; DTC B242D-04: Headlight Control Module (Main) System Internal Failure [12/2021 - ] >> Procedure
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DTC B242C-04: Headlight Control Module (Sub) System Internal Failure; DTC B242D-04: Headlight Control Module (Main) System Internal Failure [12/2021 - ]: Procedure

  1. CLEAR DTC 
    1. Clear the DTCs.

      Body Electrical > Headlight Control > Clear DTCs 

      Body Electrical > Headlight Control (Sub) > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  2

  2. CHECK FOR DTC 

    Pre-procedure1

    1. Turn ignition switch to ON.
    2. Wait for at least maximum 15 minutes.

      Procedure1

    3. Check for DTCs.

      Body Electrical > Headlight Control > Trouble Codes 

      Body Electrical > Headlight Control (Sub) > Trouble Codes 

      Result

      Result Proceed to
      Any Headlight Control DTCs in the table below are output A
      Any Headlight Control (Sub) DTCs in the table below are output B
      No DTCs in the table below are output C
      Malfunction Content System Relevant DTC
      Headlight Control Module (Main) System Internal Failure Headlight Control B242D-04 Headlight Control Module (Main) System Internal Failure
      Headlight Control Module (Sub) System Internal Failure Headlight Control (Sub) B242C-04 Headlight Control Module (Sub) System Internal Failure

      Post-procedure1

    4. None

    Result: 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2021 - ]