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Home >> Lexus >> 2021 >> LS 500 Base, RWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Exterior Lights >> Lighting System (Ext) - Diagnostic Codes (2 Of 3) >> Lighting System >> DTC B242E: Open in IG Circuit [10/2022 - 10/2023] >> Procedure

DTC B242E: Open in IG Circuit [10/2022 - 10/2023]: Procedure

  1. CHECK FOR DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [10/2020 - 10/2023]

      Body Electrical > AFS > Clear DTCs 

      Body Electrical > AFS (Sub) > Clear DTCs 

    2. Turn the engine switch on (IG) and wait for at least 10 seconds or more.
    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [10/2020 - 10/2023]

      Body Electrical > AFS > Trouble Codes 

      Body Electrical > AFS (Sub) > Trouble Codes 

      OK

      DTC B242E is not output.

      Result

      Result Proceed to
      OK A
      NG (DTC output from headlight ECU sub-assembly LH) B
      NG (DTC output from headlight ECU sub-assembly RH) C

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - 10/2023] 

    Result: 

    C 

    See step  3

    Result: 

    B 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH - BATTERY AND BODY GROUND) 
    1. Disconnect the A121 headlight ECU sub-assembly LH connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A121-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A121-12 (GND) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH. Refer to  REMOVAL [10/2020 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  3. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY RH - BATTERY AND BODY GROUND) 
    1. Disconnect the A122 headlight ECU sub-assembly RH connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A122-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A122-12 (GND) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH. Refer to  REMOVAL [10/2020 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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