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Home >> Toyota >> 2018 >> Mirai >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System - Diagnostic Codes (2 Of 3) >> Airbag System >> DTC B1656-38: Seat Belt Buckle Switch LH Circuit Malfunction [06/2015 - ] >> Procedure

DTC B1656-38: Seat Belt Buckle Switch LH Circuit Malfunction [06/2015 - ]: 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 90 seconds.
    3. Check that the connectors are properly connected to the airbag sensor assembly and front seat inner belt assembly LH.

      Result

      Result Proceed to
      Connectors are properly connected A
      Connectors are not properly connected B

    Result: 

    B 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    A 

    See step  2

  2. CHECK CONNECTORS 
    1. Disconnect the connectors from the airbag sensor assembly and front seat inner belt assembly LH.
      GTY383981Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire
    2. Check that the connectors (on the airbag sensor assembly side and front seat inner belt assembly LH side) are not damaged.

      Result

      Result Proceed to
      Connectors are not deformed or damaged A
      Connectors are deformed or damaged B

    Result: 

    B 

    REPLACE NO. 2 FLOOR WIRE 

    Result: 

    A 

    See step  3

  3. CHECK NO. 2 FLOOR WIRE 
    1. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
      GTY601215Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Inner Belt Assembly LH *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire *4 Connector C
      *5 Connector B *6 Service Wire
      *a Front view of wire harness connector
      (to Front Seat Inner Belt Assembly LH)      		 *b Rear view of wire harness connector
      (to Airbag Sensor 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
      P43-2 (LBE+) - Body ground Power switch on (IG) Below 1 V
      P43-1 (LBE-) - 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 90 seconds.
    6. Using a service wire, connect terminals 10 (LBE+) and 18 (LBE-) 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
      P43-2 (LBE+) - P43-1 (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
      P43-2 (LBE+) - P43-1 (LBE-) Always 1 MΩ or higher
      P43-2 (LBE+) - Body ground Always 1 MΩ or higher
      P43-1 (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.
      GTY384366Courtesy 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, 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 [06/2015 - ]

      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 [06/2015 - ]

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Result Proceed to
      DTC B1656/38 is not output A
      DTC B1656/38 is output B

      HINT: 

      Codes other than DTC B1656/38 may be output at this time, but they are not related to this check.

    Result: 

    B 

    USE SIMULATION METHOD TO CHECK. Refer to  DIAGNOSIS SYSTEM [06/2015 - ] 

    Result: 

    A 

    See step  5

  5. REPLACE FRONT 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 90 seconds.
    3. Replace the front seat inner belt assembly LH.

      Refer to REMOVAL [06/2015 - 11/2018] , or refer to REMOVAL [11/2018 - ]

      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.
      GTY384366Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
    2. Turn the power switch on (IG), and wait for at least 60 seconds.
    3. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [06/2015 - ]

      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 [06/2015 - ]

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Result Proceed to
      DTC B1656/38 is not output A
      DTC B1656/38 is output B

      HINT: 

      Codes other than DTC B1656/38 may be output at this time, but they are not related to this check.

    Result: 

    A 

    END (FRONT SEAT INNER BELT ASSEMBLY LH WAS DEFECTIVE) 

    Result: 

    B 

    REPLACE AIRBAG SENSOR ASSEMBLY. Refer to  REMOVAL [06/2015 - 11/2018]  , or refer to  REMOVAL [11/2018 - ] 

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