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Home >> Lexus >> 2021 >> LS 500h RWD >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System (W/O Advanced Park) - Diagnostic Codes (2 Of 3) >> AIRBAG SYSTEM (w/o Advanced Park) >> DTC B165C: 2nd Seat Seat Belt Buckle Switch (LH) [10/2020 - 10/2023] >> Procedure

DTC B165C: 2nd Seat Seat Belt Buckle Switch (LH) [10/2020 - 10/2023]: Procedure

  1. CHECK CONNECTION OF CONNECTORS 
    1. Turn the power switch off.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    3. Check that the connectors are properly connected to the pedestrian detection ECU assembly and rear seat inner belt assembly LH.

      Result

      Proceed to
      The connectors are properly connected
      The connectors are not properly connected

    Result: 

    The connectors are not properly connected 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    The connectors are properly connected 

    See step  2

  2. CHECK CONNECTORS 
    1. Disconnect the connectors from the pedestrian detection ECU assembly and rear seat inner belt assembly LH.
      GTY789788Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Inner Belt Assembly LH
      *2 Pedestrian Detection ECU Assembly
      *3 Rear Seat Wire LH
      *4 Floor Wire
      *5 Instrument Panel Wire
    2. Check that the connectors (on the pedestrian detection ECU assembly side and rear seat inner belt assembly LH side) are not damaged.

      Result

      Proceed to
      The connectors are not deformed or damaged
      The connectors are deformed or damaged

    Result: 

    The connectors are deformed or damaged 

    REPLACE REAR SEAT WIRE LH OR INSTRUMENT PANEL WIRE 

    Result: 

    The connectors are not deformed or damaged 

    See step  3

  3. CHECK REAR SEAT INNER BELT ASSEMBLY LH CIRCUIT 
    1. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
      GTY825836Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Inner Belt Assembly LH
      *2 Pedestrian Detection ECU Assembly
      *3 Rear Seat Wire LH
      *4 Floor Wire
      *5 Instrument Panel Wire
      *6 Service Wire
      *a Front view of wire harness connector
      (to Rear Seat Inner Belt Assembly LH)
      *b Front view of wire harness connector
      (to Pedestrian Detection ECU Assembly)
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      R50-1 - Body ground Power switch on (IG) Below 1 V
      R50-2 - Body ground Power switch on (IG) Below 1 V
    4. Turn the power switch off.
    5. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    6. Using a service wire, connect terminals 14 (LBR-) and 15 (LBR+) of connector B.
      NOTE:

      Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      R50-1 - R50-2 Always Below 1 Ω
    8. Disconnect the service wire from connector B.
    9. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R50-1 - R50-2 Always 1 MΩ or higher
      R50-1 - Body ground Always 1 MΩ or higher
      R50-2 - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  4

  4. CHECK DTC 
    1. Connect the connectors to the pedestrian detection ECU assembly and rear seat inner belt assembly LH.
      GTY783863Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Inner Belt Assembly LH
      *2 Pedestrian Detection ECU Assembly
    2. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
    3. Turn the power switch on (IG), and wait for at least 60 seconds.
    4. Clear the DTCs.

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

      Body Electrical > SRS Airbag > Clear DTCs 

    5. Turn the power switch off.
    6. Turn the power switch on (IG), and wait for at least 60 seconds.
    7. Check for DTCs.

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

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Proceed to
      DTC B165C is not output
      DTC B165C is output

      HINT: 

      Codes other than DTC B165C may be output at this time, but they are not related to this check.

    Result: 

    DTC B165C is not output 

    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]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - 10/2023] 

    Result: 

    DTC B165C is output 

    See step  5

  5. CHECK REAR SEAT INNER BELT ASSEMBLY LH 
    1. Turn the power switch off.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    3. Replace the rear seat inner belt assembly LH.

      for Fixed Seat Type:

      Refer to REMOVAL [10/2020 - 11/2021] , or refer to REMOVAL [11/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]

      for Power Seat:

      Refer to REMOVAL [10/2020 - 11/2021] , or refer to REMOVAL [11/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]

      HINT: 

      Perform the inspection using parts from a normal vehicle if possible.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  6

  6. CHECK DTC 
    1. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
      GTY829194Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Pedestrian Detection ECU Assembly
    2. Turn the power switch on (IG), and wait for at least 60 seconds.
    3. Clear the DTCs.

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

      Body Electrical > SRS Airbag > Clear DTCs 

    4. Turn the power switch off.
    5. Turn the power switch on (IG), and wait for at least 60 seconds.
    6. Check for DTCs.

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

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Proceed to
      DTC B165C is not output
      DTC B165C is output

      HINT: 

      Codes other than DTC B165C may be output at this time, but they are not related to this check.

    Result: 

    DTC B165C is not output 

    END (REAR SEAT INNER BELT ASSEMBLY LH WAS DEFECTIVE) 

    Result: 

    DTC B165C is output 

    REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

  7. CHECK REAR SEAT INNER BELT ASSEMBLY LH CIRCUIT 
    1. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
      GTY823038Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Inner Belt Assembly LH
      *2 Pedestrian Detection ECU Assembly
      *3 Rear Seat Wire LH
      *4 Floor Wire
      *5 Instrument Panel Wire
      *6 Service Wire
      *a Front view of wire harness connector
      (to Rear Seat Wire LH)
      *b Front view of wire harness connector
      (to Pedestrian Detection ECU Assembly)
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      LR 6-1 (LBR+) - Body ground Power switch on (IG) Below 1 V
      LR 6-2 (LBR-) - Body ground Power switch on (IG) Below 1 V
    4. Turn the power switch off.
    5. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    6. Using a service wire, connect terminals 14 (LBR-) and 15 (LBR+) of connector B.
      NOTE:

      Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      LR 6-1 (LBR+) - LR 6-2 (LBR-) Always Below 1 Ω
    8. Disconnect the service wire from connector B.
    9. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      LR 6-1 (LBR+) - LR 6-2 (LBR-) Always 1 MΩ or higher
      LR 6-1 (LBR+) - Body ground Always 1 MΩ or higher
      LR 6-2 (LBR-) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE REAR SEAT WIRE LH 

    Result: 

    OK 

    See step  8

  8. CHECK INSTRUMENT PANEL WIRE 
    1. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
      GTY827616Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Inner Belt Assembly LH
      *2 Pedestrian Detection ECU Assembly
      *3 Rear Seat Wire LH
      *4 Floor Wire
      *5 Instrument Panel Wire
      *6 Service Wire
      *a Front view of wire harness connector
      (to Rear Seat Wire LH)
      *b Front view of wire harness connector
      (to Pedestrian Detection ECU Assembly)
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      GL 1-8 (LBR+) - Body ground Power switch on (IG) Below 1 V
      GL 1-9 (LBR-) - Body ground Power switch on (IG) Below 1 V
    4. Turn the power switch off.
    5. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    6. Using a service wire, connect terminals 14 (LBR-) and 15 (LBR+) of connector B.
      NOTE:

      Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      GL 1-8 (LBR+) - GL 1-9 (LBR-) Always Below 1 Ω
    8. Disconnect the service wire from connector B.
    9. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      GL 1-8 (LBR+) - GL 1-9 (LBR-) Always 1 MΩ or higher
      GL 1-8 (LBR+) - Body ground Always 1 MΩ or higher
      GL 1-9 (LBR-) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FLOOR WIRE 

    Result: 

    NG 

    REPLACE REAR SEAT WIRE LH 

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