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DTC B1771: Passenger Side Buckle Switch Circuit Malfunction [08/2015 - 08/2019]: Procedure

  1. CHECK FOR DTC 
    1. Turn the ignition switch to ON, and wait for at least 60 seconds.
    2. Clear the DTCs stored in the memory (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

      HINT: 

      First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

    3. Turn the ignition switch off.
    4. Turn the ignition switch to ON, and wait for at least 60 seconds.
    5. Check for DTCs (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

      OK

      DTC B1771 is not output.

      HINT: 

      Codes other than DTC B1771 may be output at this time, but they are not related to this check.

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK 

    (Refer to DIAGNOSIS SYSTEM [08/2015 - 08/2017] , or refer to DIAGNOSIS SYSTEM [08/2017 - 08/2019] )

    Result: 

    NG 

    See step  2

  2. CHECK CONNECTION OF CONNECTOR 
    1. Turn the ignition switch off.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Check that the connectors are properly connected to the occupant classification ECU and the front seat inner belt RH.

      OK

      Connectors are properly connected.

    Result: 

    NG 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    OK 

    See step  3

  3. CHECK CONNECTOR 
    1. Disconnect the connectors from the occupant classification ECU and the front seat inner belt RH.
    2. Check that the connectors (on the occupant classification ECU side and front seat inner belt RH side) are not damaged (Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [08/2015 - 08/2019] ).

      OK

      Connectors are not deformed or damaged.

      HINT: 

      If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

      RESULT

      Result Proceed to
      OK A
      NG (w/ Power seat) B
      NG (w/ Manual seat) C

    Result: 

    B 

    REPLACE FRONT SEAT WIRE RH 

    Result: 

    C 

    REPLACE NO. 2 FLOOR WIRE 

    Result: 

    A 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (OCCUPANT CLASSIFICATION ECU - FRONT SEAT INNER BELT RH) 
    GTY552221Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
    2. Turn the ignition switch to ON, and wait for at least 60 seconds.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      FOR POWER SEAT

      Tester Connection Switch Condition Specified Condition
      W6-9 (BSW) - Body ground Ignition switch ON Below 1 V
      W6-5 (BGND) - Body ground
      FOR MANUAL SEAT

      Tester Connection Switch Condition Specified Condition
      P14-9 (BSW) - Body ground Ignition switch ON Below 1 V
      P14-5 (BGND) - Body ground
    4. Turn the ignition switch off.
    5. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    6. Using a service wire, connect terminals 1 (RBE-) and 2 (RBE+) of connector C.
      NOTE:

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

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

      Standard Resistance

      FOR POWER SEAT

      Tester Connection Condition Specified Condition
      W6-9 (BSW) - W6-5 (BGND) Always Below 1 Ω
      FOR MANUAL SEAT

      Tester Connection Condition Specified Condition
      P14-9 (BSW) - P14-5 (BGND) Always Below 1 Ω
    8. Disconnect the service wire from connector C.
    9. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      FOR POWER SEAT

      Tester Connection Condition Specified Condition
      W6-9 (BSW) - Body ground Always 1 MΩ or higher
      W6-5 (BGND) - Body ground
      W6-9 (BSW) - W6-5 (BGND)
      FOR MANUAL SEAT

      Tester Connection Condition Specified Condition
      P14-9 (BSW) - Body ground Always 1 MΩ or higher
      P14-5 (BGND) - Body ground
      P14-9 (BSW) - P14-5 (BGND)
      RESULT

      Result Proceed to
      OK A
      NG (w/ Power seat) B
      NG (w/ Manual seat) C

    Result: 

    B 

    REPLACE FRONT SEAT WIRE RH 

    Result: 

    C 

    REPLACE NO. 2 FLOOR WIRE 

    Result: 

    A 

    See step  5

  5. CHECK FOR DTC 
    1. Connect the connectors to the occupant classification ECU and the front seat inner belt RH.
    2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
    3. Turn the ignition switch to ON, and wait for at least 60 seconds.
    4. Clear the DTCs stored in the memory (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

      HINT: 

      First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

    5. Turn the ignition switch off.
    6. Turn the ignition switch to ON, and wait for at least 60 seconds.
    7. Check for DTCs (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

      OK

      DTC B1771 is not output.

      HINT: 

      Codes other than DTC B1771 may be output at this time, but they are not related to this check.

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK 

    (Refer to DIAGNOSIS SYSTEM [08/2015 - 08/2017] , or refer to DIAGNOSIS SYSTEM [08/2017 - 08/2019] )

    Result: 

    NG 

    See step  6

  6. REPLACE FRONT SEAT INNER BELT ASSEMBLY RH (PASSENGER SIDE BUCKLE SWITCH) 
    1. Turn the ignition switch off.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Replace the front seat inner belt RH (Refer to REMOVAL [08/2015 - 08/2017] , or refer to REMOVAL [08/2017 - 08/2019] ).

      HINT: 

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

    4. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

    Result: 

    NEXT 

    See step  7

  7. CHECK FOR DTC 
    1. Turn the ignition switch to ON, and wait for at least 60 seconds.
    2. Clear the DTCs stored in the memory (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

      HINT: 

      First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

    3. Turn the ignition switch off.
    4. Turn the ignition switch to ON, and wait for at least 60 seconds.
    5. Check for DTCs (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

      OK

      DTC B1771 is not output.

      HINT: 

      Codes other than DTC B1771 may be output at this time, but they are not related to this check.

    Result: 

    OK 

    END 

    Result: 

    NG 

    See step  8

  8. REPLACE OCCUPANT CLASSIFICATION ECU 
    1. Turn the ignition switch off.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Replace the occupant classification ECU.

      HINT: 

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

    4. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
    5. Turn the ignition switch to ON, and wait for at least 60 seconds.
    6. Clear the DTCs stored in the memory (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

      HINT: 

      If the DTCs are not cleared at this time, past DTCs will remain.

    Result: 

    NEXT 

    See step  9

  9. PERFORM ZERO POINT CALIBRATION 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON, and wait for at least 60 seconds.
    3. Using the Techstream, perform the zero point calibration (Refer to INITIALIZATION [08/2015 - 08/2019] ).

    Result: 

    NEXT 

    See step  10

  10. PERFORM SENSITIVITY CHECK 
    1. Using the Techstream, perform the sensitivity check (Refer to INITIALIZATION [08/2015 - 08/2019] ).

      Standard range

      27 to 33 kg (59.5 to 72.8 lb)

    Result: 

    NEXT 

    END 

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