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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System - Diagnostic Codes (6 Of 7) >> Airbag System >> DTC B1656: Seat Belt Buckle Switch (LH) [12/2019 - 11/2023] >> Procedure

DTC B1656: Seat Belt Buckle Switch (LH) [12/2019 - 11/2023]: Procedure

  1. CHECK CONNECTION OF CONNECTORS 
    1. Turn the ignition switch off.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

    3. Check that the connectors are properly connected to the airbag sensor assembly and front seat inner belt assembly LH.

      OK

      The connectors are properly connected.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    OK 

    See step  2

  2. CHECK CONNECTORS 
    1. Disconnect the connectors from the airbag sensor assembly and front seat inner belt assembly LH.
    2. Check that the terminals of the connectors are not deformed or damaged.

      OK

      The terminals are not deformed or damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 2 FLOOR WIRE OR FRONT SEAT INNER BELT ASSEMBLY LH 

    Result: 

    OK 

    See step  3

  3. CHECK NO. 2 FLOOR WIRE 
    1. Connect the cable to the negative (-) auxiliary battery terminal.
      GTY883394Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire
      *4 Service Wire
      *a Front view of wire harness connector
      (to Airbag Sensor Assembly)
      *b Front view of wire harness connector
      (to Front Seat Inner Belt Assembly LH)
    2. Turn the ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      M70-2 (LBE+) - Body ground Ignition switch ON Below 1 V
      M70-1 (LBE-) - Body ground Ignition switch ON Below 1 V
    4. Turn the ignition switch off.
    5. Disconnect the cable from the negative (-) auxiliary battery terminal.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

    6. Using a service wire, connect terminals 28 (LBE+) and 27 (LBE-) of connector B.
      NOTE:

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

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      M70-2 (LBE+) - M70-1 (LBE-) 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
      M70-2 (LBE+) - M70-1 (LBE-) Always 1 MΩ or higher
      M70-2 (LBE+) - Body ground Always 1 MΩ or higher
      M70-1 (LBE-) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 2 FLOOR WIRE 

    Result: 

    OK 

    See step  4

  4. CHECK DTC 
    1. Connect the connectors to the airbag sensor assembly and front seat inner belt assembly LH.
      GTY447346Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
    2. Connect the cable to the negative (-) auxiliary battery terminal.
    3. Turn the ignition switch to ON, and wait for at least 60 seconds.
    4. Clear the DTCs stored in memory.

      Body Electrical > SRS Airbag > Clear DTCs 

    5. Turn the ignition switch off.
    6. Turn the ignition switch to ON, and wait for at least 60 seconds.
    7. Check for DTCs.

      Body Electrical > SRS Airbag > Trouble Codes 

      OK

      DTC B1656 is not output.

      HINT: 

      Codes other than DTC B1656 may be output at this time, but they are not related to this check.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

    Result: 

    NG 

    See step  5

  5. CHECK FRONT SEAT INNER BELT ASSEMBLY LH 
    1. Turn the ignition switch off.
      GTY447346Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

    3. Replace the front seat inner belt assembly LH with a known good one.

      Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

      HINT: 

      Perform the following inspection using known good parts from another vehicle if possible.

    4. Connect the cable to the negative (-) auxiliary battery terminal.
    5. Turn the ignition switch to ON, and wait for at least 60 seconds.
    6. Clear the DTCs stored in memory.

      Body Electrical > SRS Airbag > Clear DTCs 

    7. Turn the ignition switch off.
    8. Turn the ignition switch to ON, and wait for at least 60 seconds.
    9. Check for DTCs.

      Body Electrical > SRS Airbag > Trouble Codes 

      OK

      DTC B1656 is not output.

      HINT: 

      Codes other than DTC B1656 may be output at this time, but they are not related to this check.

    10. Turn the ignition switch off.
    11. Disconnect the cable from the negative (-) auxiliary battery terminal.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

    12. Restore the front seat inner belt assembly LH that was installed for testing to its original location.

      Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FRONT SEAT INNER BELT ASSEMBLY LH. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    NG 

    REPLACE AIRBAG SENSOR ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

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