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Home >> Lexus >> 2021 >> RX 350 Base, FWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Exterior Lights >> Lighting System (W/O Automatic Headlight Beam Level Control System) - Diagnostic Codes & Circuit Tests >> LIGHTING SYSTEM (w/o Automatic Headlight Beam Level Control System) >> DTC B2430: LED Headlight LH Circuit Malfunction; DTC B2431: LED Headlight RH Circuit Malfunction [09/2015 - 08/2019] >> Procedure
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DTC B2430: LED Headlight LH Circuit Malfunction; DTC B2431: LED Headlight RH Circuit Malfunction [09/2015 - 08/2019]: Procedure

  1. CHECK FOR DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [09/2015 - 08/2019]

      Body Electrical > Main Body > Clear DTCs 

    2. Check for DTCs.

      Refer to DTC CHECK / CLEAR [09/2015 - 08/2019]

      Body Electrical > Main Body > Trouble Codes 

      Result

      Result Proceed to
      Both DTC B2430 and B2431 are not output A
      Both DTC B2430 and B2431 are output B
      Only DTC B2430 or B2431 is output C

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2015 - 08/2016]  Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2016 - 12/2017]  Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2017 - 08/2019] 

    Result: 

    C 

    See step  6

    Result: 

    B 

    See step  2

  2. INSPECT SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Remove the semiconductor pwr integration ECU from the engine room relay block and junction block assembly.

      Refer to REMOVAL [09/2015 - 08/2016] Refer to REMOVAL [08/2016 - 08/2019]

    2. Inspect the semiconductor pwr integration ECU.

      Refer to INSPECTION [09/2015 - ]

      OK

      Semiconductor pwr integration ECU is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [09/2015 - 08/2016]  Refer to  REMOVAL [08/2016 - 08/2019] 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - POWER SOURCE) 
    1. Measure the voltage according to the value(s) in the chart below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      B-1 (BATT) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) 
    1. Disconnect the 2C instrument panel junction block assembly connector.
    2. Measure the resistance according to the value(s) in the chart below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1D-8 - 2C-31 Always Below 1 Ω
      1D-8 or 2C-31 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 
    1. Remove the instrument panel junction block assembly.

      Refer to REMOVAL [09/2015 - 08/2016] Refer to REMOVAL [08/2016 - 08/2019]

    2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
    3. Measure the resistance according to the value(s) in the chart below.
      GTY669019Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Instrument Panel Junction Block Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      2C-31 - MB-15 (HRLY) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2015 - 08/2016]  Refer to  REMOVAL [08/2016 - 08/2019] 

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [09/2015 - 08/2016]  Refer to  REMOVAL [08/2016 - 08/2019] 

  6. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - HEADLIGHT UNIT*3 OR HEADLIGHT ASSEMBLY*4) 
    1. Disconnect the A20*1 or A24*2 headlight unit*3 or headlight assembly*4 connector.
      1. *1: for LH Side
      2. *2: for RH Side
      3. *3: for TMC Made
      4. *4: for TMMC Made
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      FOR LH SIDE (B2430)

      Tester Connection Condition Specified Condition
      A20-5 (LO) - Body ground Light control switch in head position 11 to 14 V
      FOR RH SIDE (B2431)

      Tester Connection Condition Specified Condition
      A24-5 (LO) - Body ground Light control switch in head position 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  14

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (HEADLIGHT UNIT*1 OR HEADLIGHT ASSEMBLY*2 - BODY GROUND) 
    1. *1: for TMC Made
    2. *2: for TMMC Made
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      FOR LH SIDE (B2430)

      Tester Connection Condition Specified Condition
      A20-6 (E) - Body ground Always Below 1 Ω
      FOR RH SIDE (B2431)

      Tester Connection Condition Specified Condition
      A24-6 (E) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (HEADLIGHT UNIT*1 OR HEADLIGHT ASSEMBLY*2 - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) 
    1. *1: for TMC Made
    2. *2: for TMMC Made
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      FOR LH SIDE (B2430)

      Tester Connection Condition Specified Condition
      A20-7 (S) - Body ground Engine switch on (IG), light control switch in head position 11 to 14 V
      FOR RH SIDE (B2431)

      Tester Connection Condition Specified Condition
      A24-7 (S) - Body ground Engine switch on (IG), light control switch in head position 11 to 14 V

      Result

      Result Proceed to
      OK (DTC B2430 is output) A
      OK (DTC B2431 is output) B
      NG C

    Result: 

    B 

    See step  11

    Result: 

    C 

    See step  13

    Result: 

    A 

    See step  9

  9. CHECK HEADLIGHT UNIT LH 
    1. Interchange the headlight unit LH with RH and connect the connectors to them.

      Refer to DISASSEMBLY [09/2015 - 08/2019]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  10

  10. CHECK FOR DTC 
    1. Check for DTCs.

      Refer to DTC CHECK / CLEAR [09/2015 - 08/2019]

      Body Electrical > Main Body > Trouble Codes 

      Result

      Result Proceed to
      DTC B2430 is output A
      DTC B2431 is output (for TMC Made) B
      DTC B2431 is output (for TMMC Made) C

    Result: 

    A 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2015 - 08/2016]  Refer to  REMOVAL [08/2016 - 08/2019] 

    Result: 

    B 

    REPLACE HEADLIGHT UNIT LH. Refer to  DISASSEMBLY [09/2015 - 08/2019] 

    Result: 

    C 

    REPLACE HEADLIGHT ASSEMBLY LH. Refer to  REMOVAL [09/2015 - 08/2016]  Refer to  REMOVAL [08/2016 - 08/2019] 

  11. CHECK HEADLIGHT UNIT RH 
    1. Interchange the headlight unit RH with LH and connect the connectors to them.

      Refer to DISASSEMBLY [09/2015 - 08/2019]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  12

  12. CHECK FOR DTC 
    1. Check for DTCs.

      Refer to DTC CHECK / CLEAR [09/2015 - 08/2019]

      Body Electrical > Main Body > Trouble Codes 

      Result

      Result Proceed to
      DTC B2431 is output A
      DTC B2430 is output (for TMC Made) B
      DTC B2430 is output (for TMMC Made) C

    Result: 

    A 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2015 - 08/2016]  Refer to  REMOVAL [08/2016 - 08/2019] 

    Result: 

    B 

    REPLACE HEADLIGHT UNIT RH. Refer to  DISASSEMBLY [09/2015 - 08/2019] 

    Result: 

    C 

    REPLACE HEADLIGHT ASSEMBLY RH. Refer to  REMOVAL [09/2015 - 08/2016]  Refer to  REMOVAL [08/2016 - 08/2019] 

  13. CHECK HARNESS AND CONNECTOR (HEADLIGHT UNIT*1 OR HEADLIGHT ASSEMBLY*2 - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) 
    1. *1: for TMC Made
    2. *2: for TMMC Made
    1. Disconnect the J8 main body ECU (multiplex network body ECU) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      FOR LH SIDE (B2430)

      Tester Connection Condition Specified Condition
      A20-7 (S) - J8-16 (LLEW) Always Below 1 Ω
      A20-7 (S) or J8-16 (LLEW) - Body ground Always 10 kΩ or higher
      FOR RH SIDE (B2431)

      Tester Connection Condition Specified Condition
      A24-7 (S) - J8-3 (RLEW) Always Below 1 Ω
      A24-7 (S) or J8-3 (RLEW) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2015 - 08/2016]  Refer to  REMOVAL [08/2016 - 08/2019] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  14. INSPECT SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Remove the semiconductor pwr integration ECU from the engine room relay block and junction block assembly.

      Refer to REMOVAL [09/2015 - 08/2016] Refer to REMOVAL [08/2016 - 08/2019]

    2. Inspect the semiconductor pwr integration ECU.

      Refer to INSPECTION [09/2015 - ]

      OK

      Semiconductor pwr integration ECU is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (HEADLIGHT ASSEMBLY - SEMICONDUCTOR PWR INTEGRATION ECU) 

    Result: 

    NG 

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [09/2015 - 08/2016]  Refer to  REMOVAL [08/2016 - 08/2019] 

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