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DTC B1793: Occupant Classification Sensor Power Supply Circuit Malfunction [09/2014 - ]: Procedure

  1. CHECK FOR DTC 
    1. Turn the engine switch on (IG), and wait for at least 60 seconds.
    2. Clear the DTCs (Refer to DTC CHECK / CLEAR [09/2014 - ] ).

      HINT: 

      • First clear the DTCs stored in the occupant detection ECU, and then clear the DTCs stored in the center airbag sensor.
      • Use the Techstream to clear the DTCs of the occupant detection ECU, otherwise the DTCs cannot be cleared.
    3. Turn the engine switch off.
    4. Turn the engine switch on (IG), and wait for at least 60 seconds.
    5. Check for DTCs (Refer to DTC CHECK / CLEAR [09/2014 - ] ).

      OK

      DTC B1793 is not output.

      HINT: 

      DTCs other than DTC B1793 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 [09/2014 - ] )

    Result: 

    NG 

    See step  2

  2. CHECK CONNECTION OF CONNECTOR 
    1. Turn the engine 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 detection ECU and rear occupant classification sensor LH and RH.

      OK

      Connectors are properly connected.

    Result: 

    NG 

    CONNECT CONNECTOR 

    Result: 

    OK 

    See step  3

  3. CHECK CONNECTOR 
    1. Disconnect the connectors from the occupant detection ECU and rear occupant classification sensor LH and RH.
      GTY412673Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check that the connectors (on the occupant detection ECU side and rear occupant classification sensor LH and RH side) are not damaged (Refer to DIAGNOSIS SYSTEM [09/2014 - ] ).

      OK

      Connectors are not deformed or damaged.

      TEXT IN ILLUSTRATION

      *1 Rear Occupant Classification Sensor LH
      *2 Rear Occupant Classification Sensor RH
      *3 Occupant Detection ECU

    Result: 

    NG 

    REPLACE FRONT SEAT INNER BELT ASSEMBLY RH 

    (Refer to REMOVAL [09/2014 - ] )

    Result: 

    OK 

    See step  4

  4. CHECK FRONT SEAT INNER BELT ASSEMBLY RH 
    1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
      GTY528943Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Front Seat Inner Belt Assembly RH *2 Rear Occupant Classification Sensor LH
      *3 Rear Occupant Classification Sensor RH *4 Occupant Detection ECU
      *5 Connector B *6 Connector C
      *7 Connector E - -
      *a Front view of wire harness connector
      (to Occupant Detection ECU)      		 *b Front view of wire harness connector
      (to Rear Occupant Classification Sensor LH)
      *c Front view of wire harness connector
      (to Rear Occupant Classification Sensor RH)      		 - -
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      z13-1 - Body ground Engine switch on (IG) Below 1 V
      z13-2 - Body ground
    4. Turn the engine switch off.
    5. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      z13-1 - 1 Always Below 1 Ω
      z13-2 - 1
      z13-1 - z13-2 Always 1 MΩ or higher
      z13-1 - Body ground
      z13-2 - Body ground

    Result: 

    NG 

    REPLACE FRONT SEAT INNER BELT ASSEMBLY RH 

    (Refer to REMOVAL [09/2014 - ] )

    Result: 

    OK 

    See step  5

  5. CHECK FOR DTC 
    1. Connect the connectors to occupant detection ECU and rear occupant classification sensor LH and RH.
    2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
    3. Turn the engine switch on (IG), and wait for at least 60 seconds.
    4. Clear the DTCs (Refer to DTC CHECK / CLEAR [09/2014 - ] ).

      HINT: 

      • First clear the DTCs stored in the occupant detection ECU, and then clear the DTCs stored in the center airbag sensor.
      • Use the Techstream to clear the DTCs of the occupant detection ECU, otherwise the DTCs cannot be cleared.
    5. Turn the engine switch off.
    6. Turn the engine switch on (IG), and wait for at least 60 seconds.
    7. Check for DTCs (Refer to DTC CHECK / CLEAR [09/2014 - ] ).

      OK

      DTC B1793 is not output.

      HINT: 

      DTCs other than DTC B1793 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 [09/2014 - ] )

    Result: 

    NG 

    See step  6

  6. CHECK OCCUPANT DETECTION ECU 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Replace the occupant detection ECU (Refer to REMOVAL [09/2014 - ] ).

      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. Turn the engine switch on (IG).
    3. Perform the zero point calibration (Refer to INITIALIZATION [09/2014 - ] ).

      OK

      "Zero Point Calibration is complete." is displayed.

    Result: 

    NG 

    See step  10

    Result: 

    OK 

    See step  8

  8. PERFORM SENSITIVITY CHECK 
    1. Perform the sensitivity check (Refer to INITIALIZATION [09/2014 - ] ).

      Standard

      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. Clear the DTCs (Refer to DTC CHECK / CLEAR [09/2014 - ] ).

      HINT: 

      • First clear the DTCs stored in the occupant detection ECU, and then clear the DTCs stored in the center airbag sensor.
      • Use the Techstream to clear the DTCs of the occupant detection ECU, otherwise the DTCs cannot be cleared.
    2. Turn the engine switch off.
    3. Turn the engine switch on (IG), and wait for at least 60 seconds.
    4. Check for DTCs (Refer to DTC CHECK / CLEAR [09/2014 - ] ).

      OK

      DTC B1793 is not output.

      HINT: 

      DTCs other than DTC B1793 may be output at this time, but they are not related to this check.

    Result: 

    OK 

    END (OCCUPANT DETECTION ECU WAS DEFECTIVE) 

    Result: 

    NG 

    See step  10

  10. CHECK FRONT SEAT ADJUSTER ASSEMBLY RH (REAR OCCUPANT CLASSIFICATION SENSOR LH AND RH) 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Replace the front seat adjuster 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 cable to the negative (-) battery terminal, and wait for at least 2 seconds.
    2. Turn the engine switch on (IG).
    3. Perform the zero point calibration (Refer to INITIALIZATION [09/2014 - ] ).

      OK

      "Zero Point Calibration is complete." is displayed.

    Result: 

    NEXT 

    See step  12

  12. PERFORM SENSITIVITY CHECK 
    1. Perform the sensitivity check (Refer to INITIALIZATION [09/2014 - ] ).

      Standard

      27 to 33 kg (59.5 to 72.8 lb)

    Result: 

    NEXT 

    END (FRONT SEAT ADJUSTER ASSEMBLY RH WAS DEFECTIVE) 

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