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Home >> Lexus >> 2022 >> LS 500h RWD >> Repair and Diagnosis >> Accessories & Equipment >> Headlights >> Lighting System (Ext) - Diagnostic Codes (2 Of 2) & Circuit Tests (1 Of 2) >> Lighting System >> DTC B242F: Open in B Power Line [10/2020 - 10/2022] >> Procedure

DTC B242F: Open in B Power Line [10/2020 - 10/2022]: 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 power 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 B242F 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 [10/2020 - 11/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - 10/2022] 

    Result: 

    C 

    See step  12

    Result: 

    B 

    See step  2

  2. READ VALUE USING TECHSTREAM 
    1. Turn the power switch on (IG).
    2. Using the Techstream, read the Data List.

      Refer to DATA LIST / ACTIVE TEST [10/2020 - 10/2023]

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Headlight ECU LH Fuse Headlight ECU sub-assembly LH fuse condition Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display
      Status of Headlight ECU LH Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  3

  3. READ VALUE USING TECHSTREAM 
    1. Turn the power switch on (IG).
    2. Using the Techstream, read the Data List.

      Refer to DATA LIST / ACTIVE TEST [10/2020 - 10/2023]

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Headlight ECU LH Input Signal Headlight ECU sub-assembly LH input OFF or ON OFF: Headlight ECU sub-assembly LH is not input
      ON: Headlight ECU sub-assembly LH is input      		 -

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display
      Headlight ECU LH Input Signal

      OK

      The Data List value displays "ON".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  4

  4. READ VALUE USING TECHSTREAM 
    1. Turn the power switch on (IG).
    2. Using the Techstream, read the Data List.

      Refer to DATA LIST / ACTIVE TEST [10/2020 - 10/2023]

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Headlight ECU LH Output Signal Headlight ECU sub-assembly LH output OFF or ON OFF: Headlight ECU sub-assembly LH has no power supply
      ON: Headlight ECU sub-assembly LH has power supply      		 -

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display
      Headlight ECU LH Output Signal

      OK

      The Data List value displays "ON".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH - BATTERY) 
    1. Disconnect the A31 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
      A31-13 (ECUB) - Body ground Power switch on (IG) 9.5 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2023] 

    Result: 

    NG 

    See step  9

  6. CHECK HEADLIGHT ECU SUB-ASSEMBLY LH 
    1. Disconnect the A31 headlight ECU sub-assembly LH connector.
    2. Turn the power switch off and wait for at least 15 seconds.
    3. Turn the power switch on (IG).
    4. Using the Techstream, read the Data List.

      Refer to DATA LIST / ACTIVE TEST [10/2020 - 10/2023]

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Headlight ECU LH Fuse Headlight ECU sub-assembly LH fuse condition Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display
      Status of Headlight ECU LH Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2023] 

    Result: 

    NG 

    See step  10

  7. CHECK NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Disconnect the instrument panel junction block assembly connector.
      GTY798862Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Instrument Panel Junction Block Assembly)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      5F-19 - Body ground Power switch off 6 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  11

    Result: 

    OK 

    See step  8

  8. CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 
    1. Remove the instrument panel junction block assembly.

      Refer to REMOVAL [10/2020 - 11/2021] , or refer to REMOVAL [11/2021 - 10/2022]

      GTY806029Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Instrument Panel Junction Block Assembly)      		 - -
    2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

      Refer to REMOVAL [10/2020 - 11/2021] , or refer to REMOVAL [11/2021 - 10/2022]

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      5F-19 - A-15 (HRLY) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

  9. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH - NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU) 
    1. Disconnect the A31 headlight ECU sub-assembly LH connector.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
    3. Disconnect the A61 No. 1 semiconductor power integration ECU connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A61-1 (L) - A31-13 (ECUB) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  10. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH - NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU) 
    1. Disconnect the A31 headlight ECU sub-assembly LH connector.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
    3. Disconnect the A61 No. 1 semiconductor power integration ECU connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A61-1 (L) or A31-13 (ECUB) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  11. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU) 
    1. Disconnect the 5F instrument panel junction block assembly connector.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
    3. Disconnect the A61 No. 1 semiconductor power integration ECU connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      5F-19 - A61-15 (-S) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  12. READ VALUE USING TECHSTREAM 
    1. Turn the power switch on (IG).
    2. Using the Techstream, read the Data List.

      Refer to DATA LIST / ACTIVE TEST [10/2020 - 10/2023]

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Headlight ECU RH Fuse Headlight ECU sub-assembly RH fuse condition Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display
      Status of Headlight ECU RH Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  16

    Result: 

    OK 

    See step  13

  13. READ VALUE USING TECHSTREAM 
    1. Turn the power switch on (IG).
    2. Using the Techstream, read the Data List.

      Refer to DATA LIST / ACTIVE TEST [10/2020 - 10/2023]

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Headlight ECU RH Input Signal Headlight ECU sub-assembly RH input OFF or ON OFF: Headlight ECU sub-assembly RH is not input
      ON: Headlight ECU sub-assembly RH is input      		 -

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display
      Headlight ECU RH Input Signal

      OK

      The Data List value displays "ON".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  17

    Result: 

    OK 

    See step  14

  14. READ VALUE USING TECHSTREAM 
    1. Turn the power switch on (IG).
    2. Using the Techstream, read the Data List.

      Refer to DATA LIST / ACTIVE TEST [10/2020 - 10/2023]

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Headlight ECU RH Output Signal Headlight ECU sub-assembly RH output OFF or ON OFF: Headlight ECU sub-assembly RH has no power supply
      ON: Headlight ECU sub-assembly RH has power supply      		 -

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display
      Headlight ECU RH Output Signal

      OK

      The Data List value displays "ON".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

    Result: 

    OK 

    See step  15

  15. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY RH - BATTERY) 
    1. Disconnect the A32 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
      A32-13 (ECUB) - Body ground Power switch on (IG) 9.5 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2023] 

    Result: 

    NG 

    See step  18

  16. CHECK HEADLIGHT ECU SUB-ASSEMBLY RH 
    1. Disconnect the A32 headlight ECU sub-assembly RH connector.
    2. Turn the power switch off and wait for at least 15 seconds.
    3. Turn the power switch on (IG).
    4. Using the Techstream, read the Data List.

      Refer to DATA LIST / ACTIVE TEST [10/2020 - 10/2023]

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Status of Headlight ECU RH Fuse Headlight ECU sub-assembly RH fuse condition Connect or Disconnect Connect: Fuse not shut off
      Disconnect: Fuse shut off      		 -

      Body Electrical > Power Integration No. 1 > Data List 

      Tester Display
      Status of Headlight ECU RH Fuse

      OK

      The Data List value displays "Connect".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2023] 

    Result: 

    NG 

    See step  19

  17. CHECK NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Disconnect the main body ECU (multiplex network body ECU) G12 connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      G12-12 (HRY2) - Body ground Power switch off 6 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

    Result: 

    NG 

    See step  20

  18. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY RH - NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU) 
    1. Disconnect the A32 headlight ECU sub-assembly RH connector.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
    3. Disconnect the A61 No. 1 semiconductor power integration ECU connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A61-2 (HI) - A32-13 (ECUB) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  19. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY RH - NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU) 
    1. Disconnect the A32 headlight ECU sub-assembly RH connector.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
    3. Disconnect the A61 No. 1 semiconductor power integration ECU connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A61-2 (HI) or A32-13 (ECUB) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  20. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] - NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU) 
    1. Disconnect the G12 main body ECU (multiplex network body ECU) connector.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
    3. Disconnect the A61 No. 1 semiconductor power integration ECU connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G12-12 (HRY2) - A61-14 (-S) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 1 SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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