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DTC B1780: Front Occupant Classification Sensor LH 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 any 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.
      • Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
    3. Turn the ignition switch off.
    4. Turn the ignition switch to ON, and wait for at least 60 seconds.
    5. Using the Techstream, check for DTCs of the occupant classification ECU (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

      OK

      DTC B1780 is not output.

      HINT: 

      DTCs other than DTC B1780 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 occupant detection sensor LH.

      OK

      Connectors are properly connected.

    Result: 

    NG 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    OK 

    See step  3

  3. CHECK CONNECTOR 
    1. Check that the connectors (on the occupant classification ECU side and front occupant detection sensor LH side) are not damaged (Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [08/2015 - 08/2019] ).

      OK

      Connectors are not deformed or damaged.

    Result: 

    NG 

    REPLACE FRONT SEAT WIRE RH 

    Result: 

    OK 

    See step  4

  4. CHECK FRONT SEAT WIRE RH 
    GTY573948Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the connectors from the occupant classification ECU and the front occupant detection sensor LH.
    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. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      W1-1 (SGD1) - Body ground Ignition switch ON Below 1 V
      W1-7 (SIG1) - Body ground
      W1-11 (SVC1) - Body ground
    5. Turn the ignition switch off.
    6. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    7. Using service wires, connect terminals 1 (SVC1) and 3 (SGD1), and connect terminals 2 (SIG1) and 3 (SGD1) of connector C.
      NOTE:

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

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      W1-7 (SIG1) - W1-1 (SGD1) Always Below 1 Ω
      W1-11 (SVC1) - W1-1 (SGD1)
    9. Disconnect the service wires from connector C.
    10. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      W1-7 (SIG1) - W1-1 (SGD1) Always 1 MΩ or higher
      W1-11 (SVC1) - W1-1 (SGD1)
      W1-1 (SGD1) - Body ground
      W1-7 (SIG1) - Body ground
      W1-11 (SVC1) - Body ground
      W1-7 (SIG1) - W1-11 (SVC1)

    Result: 

    NG 

    REPLACE FRONT SEAT WIRE RH 

    Result: 

    OK 

    See step  5

  5. CHECK FOR DTC 
    1. Connect the connectors to the occupant classification ECU and the front occupant detection sensor LH.
    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 any 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.
      • Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
    5. Turn the ignition switch off.
    6. Turn the ignition switch to ON, and wait for at least 60 seconds.
    7. Using the Techstream, check for DTCs of the occupant classification ECU (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

      OK

      DTC B1780 is not output.

      HINT: 

      DTCs other than DTC B1780 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 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.

    Result: 

    NEXT 

    See step  7

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

    Result: 

    NG 

    See step  10

    Result: 

    OK 

    See step  8

  8. 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: 

    NG 

    See step  10

    Result: 

    OK 

    See step  9

  9. CHECK FOR DTC 
    1. Turn the ignition switch to ON, and wait for at least 60 seconds.
    2. Clear any 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.
      • Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
    3. Turn the ignition switch off.
    4. Turn the ignition switch to ON, and wait for at least 60 seconds.
    5. Using the Techstream, check for DTCs of the occupant classification ECU (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

      OK

      DTC B1780 is not output.

      HINT: 

      DTCs other than DTC B1780 may be output at this time, but they are not related to this check.

    Result: 

    OK 

    END 

    Result: 

    NG 

    See step  10

  10. REPLACE FRONT SEAT ASSEMBLY RH 
    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 assembly RH.

      HINT: 

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

    Result: 

    NEXT 

    See step  11

  11. PERFORM ZERO POINT CALIBRATION 
    1. Connect the Techstream to the DLC3.
    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. Using the Techstream, perform the zero point calibration (Refer to INITIALIZATION [08/2015 - 08/2019] ).

    Result: 

    NEXT 

    See step  12

  12. 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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