DTC    B1785    Front Occupant Classification Sensor LH Collision Detection


DESCRIPTION

DTC B1785 is output when the occupant classification ECU receives a collision detection signal sent by the front occupant classification sensor LH when an accident occurs.
DTC B1785 is also output when the front seat assembly RH is subjected to a strong impact, even if an actual accident does not occur.
However, when the front occupant classification sensor LH outputs a collision detection signal, even if the vehicle is not in a collision, DTC B1785 can be cleared by performing the zero point calibration and sensitivity check.
Therefore, when DTC B1785 is output, first perform the zero point calibration and sensitivity check.

DTC No.
DTC Detecting Condition
Trouble Area
B1785
  1. Front seat assembly RH malfunction
  2. Occupant classification ECU malfunction
  3. Front occupant classification sensor LH detects large load
  1. Occupant classification ECU
  2. Front seat assembly RH (Front occupant classification sensor LH)

WIRING DIAGRAM

Click here.

INSPECTION PROCEDURE

1.PERFORM ZERO POINT CALIBRATION

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to the on position.

  1. Using the Techstream, perform the zero point calibration (Click here).

    OK:
    COMPLETED is displayed.


NG
Go to step 4
OK


2.PERFORM SENSITIVITY CHECK

  1. Using the Techstream, perform the sensitivity check (Click here).

    1. Confirm that nothing is placed on the passenger seat.

    2. Confirm that the beginning sensor reading is within the standard range.

      Standard range:
      -3.2 to 3.2 kg (-7 to 7 lb)

    3. Place a 30 kg (66.14 lb) weight (e.g. a lead mass) onto the front passenger seat.

    4. Confirm that the sensitivity is within the standard range.

      Standard range:
      27 to 33 kg (59.52 to 72.75 lb)

      HINT:
      When performing the sensitivity check, use a solid metal weight (the check result may not be accurate if a liquid weight is used).


NG
Go to step 4
OK


3.CHECK DTC

  1. Turn the ignition switch to the on position.

  1. Clear the DTCs stored in the memory (Click here).

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

  1. Turn the ignition switch to the lock position.

  1. Turn the ignition switch to the on position.

  1. Check the DTCs (Click here).

    OK:
    DTC B1785 is not output.

    HINT:
    Codes other than DTC B1785 may be output at this time, but they are not related to this check.


OK
USE SIMULATION METHOD TO CHECK
NG


4.REPLACE FRONT SEAT ASSEMBLY RH

  1. Turn the ignition switch to the lock position.

  1. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.

  1. Replace the front seat assembly RH (Click here ).

    HINT:
    Perform the inspection using parts from a normal vehicle if possible.

NEXT


5.PERFORM ZERO POINT CALIBRATION

  1. Connect the negative (-) terminal cable to the battery.

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to the on position.

  1. Using the Techstream, perform the zero point calibration (Click here).

    OK:
    COMPLETED is displayed.


NG
Go to step 8
OK


6.PERFORM SENSITIVITY CHECK

  1. Using the Techstream, perform the sensitivity check (Click here).

    1. Confirm that nothing is placed on the passenger seat.

    2. Confirm that the beginning sensor reading is within the standard range.

      Standard range:
      -3.2 to 3.2 kg (-7 to 7 lb)

    3. Place a 30 kg (66.14 lb) weight (e.g. a lead mass) onto the front passenger seat.

    4. Confirm that the sensitivity is within the standard range.

      Standard range:
      27 to 33 kg (59.52 to 72.75 lb)

      HINT:
      When performing the sensitivity check, use a solid metal weight (the check result may not be accurate if a liquid weight is used).


NG
Go to step 8
OK


7.CHECK DTC

  1. Turn the ignition switch to the on position.

  1. Clear the DTCs stored in the memory (Click here).

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

  1. Turn the ignition switch to the lock position.

  1. Turn the ignition switch to the on position.

  1. Check the DTCs (Click here).

    OK:
    DTC B1785 is not output.

    HINT:
    Codes other than DTC B1785 may be output at this time, but they are not related to this check.


OK
USE SIMULATION METHOD TO CHECK
NG


8.REPLACE OCCUPANT CLASSIFICATION ECU

  1. Turn the ignition switch to the lock position.

  1. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.

  1. Replace the occupant classification ECU (Click here).


NEXT


9.PERFORM ZERO POINT CALIBRATION

  1. Connect the negative (-) terminal cable to the battery.

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to the on position.

  1. Using the Techstream, perform the zero point calibration (Click here).

    OK:
    COMPLETED is displayed.

NEXT


10.PERFORM SENSITIVITY CHECK

  1. Using the Techstream, perform the sensitivity check (Click here).

    1. Confirm that nothing is placed on the passenger seat.

    2. Confirm that the beginning sensor reading is within the standard range.

      Standard range:
      -3.2 to 3.2 kg (-7 to 7 lb)

    3. Place a 30 kg (66.14 lb) weight (e.g. a lead mass) onto the front passenger seat.

    4. Confirm that the sensitivity is within the standard range.

      Standard range:
      27 to 33 kg (59.52 to 72.75 lb)

      HINT:
      When performing the sensitivity check, use a solid metal weight (the check result may not be accurate if a liquid weight is used).

NEXT

END