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Occupant Classification System [Diagnostic Codes & Symptom Tests]: Overview Toyota Sienna III

Airbag 8 illustrations ~1413 words

DESCRIPTION

The passenger side buckle switch circuit consists of the occupant classification ECU and the front seat inner belt assembly RH.

DTC B1771 is stored when a malfunction is detected in the passenger side buckle switch circuit.

DTC CodeDTC Detection ConditionTrouble Area
B1771One of following conditions is met: Occupant classification ECU detects line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to +B signal in passenger side buckle switch circuit for 2 seconds Passenger side buckle switch malfunction Occupant classification ECU malfunctionFront seat wire RH Front seat inner belt assembly RH (Passenger side buckle switch) Occupant classification ECU

HINT

  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1771 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTC cannot be read.

Scheme 267

Scheme 267: WIRING DIAGRAM
Scheme 267: WIRING DIAGRAM

The front occupant classification sensor LH circuit consists of the occupant classification ECU and the front occupant classification sensor LH.

DTC B1780 is stored when a malfunction is detected in the front occupant classification sensor LH circuit.

DTC CodeDTC Detection ConditionTrouble Area
B1780One of following conditions is met: Occupant classification ECU receives line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to +B signal in front occupant classification sensor LH circuit for 2 seconds Front occupant classification sensor LH malfunction Occupant classification ECU malfunctionFront seat cushion spring assembly RH (Front occupant classification sensor LH) Front seat wire RH Occupant classification ECU

HINT

  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1780 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTC cannot be read.

Scheme 268

Scheme 268: WIRING DIAGRAM
Scheme 268: WIRING DIAGRAM

The front occupant classification sensor RH circuit consists of the occupant classification ECU and the front occupant classification sensor RH.

DTC B1781 is stored when a malfunction is detected in the front occupant classification sensor RH circuit.

DTC CodeDTC Detection ConditionTrouble Area
B1781One of following conditions is met: Occupant classification ECU receives line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to +B signal in front occupant classification sensor RH circuit for 2 seconds Front occupant classification sensor RH malfunction Occupant classification ECU malfunctionFront seat cushion spring assembly RH (Front occupant classification sensor RH) Front seat wire RH Occupant classification ECU

HINT

  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1781 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTC cannot be read.

Scheme 269

Scheme 269: WIRING DIAGRAM
Scheme 269: WIRING DIAGRAM

The rear occupant classification sensor LH circuit consists of the occupant classification ECU and the rear occupant classification sensor LH.

DTC B1782 is stored when a malfunction is detected in the rear occupant classification sensor LH circuit.

DTC CodeDTC Detection ConditionTrouble Area
B1782One of following conditions is met: Occupant classification ECU receives line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in rear occupant classification sensor LH circuit for 2 seconds Rear occupant classification sensor LH malfunction Occupant classification ECU malfunctionFront seat cushion spring assembly RH (Rear occupant classification sensor LH) Front seat wire RH Occupant classification ECU

HINT

  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1782 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 270

Scheme 270: WIRING DIAGRAM
Scheme 270: WIRING DIAGRAM

The rear occupant classification sensor RH circuit consists of the occupant classification ECU and the rear occupant classification sensor RH.

DTC B1783 is stored when a malfunction is detected in the rear occupant classification sensor RH circuit.

DTC CodeDTC Detection ConditionTrouble Area
B1783One of following conditions is met: Occupant classification ECU receives line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to +B signal in rear occupant classification sensor RH circuit for 2 seconds Rear occupant classification sensor RH malfunction Occupant classification ECU malfunctionFront seat cushion spring assembly RH (Rear occupant classification sensor RH) Front seat wire RH Occupant classification ECU

HINT

  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1783 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 271

Scheme 271: WIRING DIAGRAM
Scheme 271: WIRING DIAGRAM

DTC B1785 is stored when the occupant classification ECU receives a collision detection signal, which is sent by the front occupant classification sensor LH when an accident occurs.

DTC B1785 is also stored when the front seat assembly RH is subjected to a strong impact, even if an actual accident has not occurred.

However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle is not in a collision, DTC B1785 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1785 is stored, first perform the zero point calibration and sensitivity check.

DTC CodeDTC Detection ConditionTrouble Area
B1785Either of following conditions is met: Occupant classification ECU receives collision detection signal, which is sent by front occupant classification sensor LH when accident occurs Front seat assembly RH is subjected to strong impact, even if actual accident has not occurredFront seat cushion spring assembly RH (Front occupant classification sensor LH)

HINT

  1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1785 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

DTC B1786 is stored when the occupant classification ECU receives a collision detection signal, which is sent by the front occupant classification sensor RH when an accident occurs.

DTC B1786 is also stored when the front seat assembly RH is subjected to a strong impact, even if an actual accident has not occurred.

However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle is not in a collision, DTC B1786 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1786 is stored, first perform the zero point calibration and sensitivity check.

DTC CodeDTC Detection ConditionTrouble Area
B1786Either of following conditions is met: Occupant classification ECU receives collision detection signal, which is sent by front occupant classification sensor RH when accident occurs Front seat assembly RH is subjected to strong impact, even if actual accident has not occurredFront seat cushion spring assembly RH (Front occupant classification sensor RH)

HINT

  1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1786 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

DTC B1787 is stored when the occupant classification ECU receives a collision detection signal, which is sent by the rear occupant classification sensor LH when an accident occurs.

DTC B1787 is also stored when the front seat assembly RH is subjected to a strong impact, even if an actual accident has not occurred.

However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle is not in a collision, DTC B1787 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1787 is stored, first perform the zero point calibration and sensitivity check.

DTC CodeDTC Detection ConditionTrouble Area
B1787Either of following conditions is met: Occupant classification ECU receives collision detection signal, which is sent by rear occupant classification sensor LH when accident occurs Front seat assembly RH is subjected to strong impact, even if actual accident has not occurredFront seat cushion spring assembly RH (Rear occupant classification sensor LH)

HINT

  1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1787 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

DTC B1788 is stored when the occupant classification ECU receives a collision detection signal, which is sent by the occupant classification sensor rear RH when an accident occurs.

DTC B1788 is also stored when the front seat assembly RH is subjected to a strong impact, even if an actual accident has not occurred.

However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle is not in a collision, DTC B1788 can be cleared by conducting the zero point calibration and sensitivity check.

Therefore, if DTC B1788 is stored, first perform the zero point calibration and sensitivity check.

DTC CodeDTC Detection ConditionTrouble Area
B1788Either of following conditions is met: Occupant classification ECU receives collision detection signal, which is sent by occupant classification sensor rear RH when accident occurs Front seat assembly RH is subjected to strong impact, even if actual accident has not occurredFront seat cushion spring assembly RH (Rear occupant classification sensor RH)

HINT

  1. When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1788 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

The center airbag sensor assembly communication circuit consists of the occupant classification ECU and the center airbag sensor assembly.

DTC B1790 is stored when a malfunction is detected in the center airbag sensor assembly communication circuit.

DTC CodeDTC Detection ConditionTrouble Area
B1790One of following conditions is met: Occupant classification ECU receives line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to +B signal in center airbag sensor assembly communication circuit for 2 seconds Center airbag sensor assembly malfunction Occupant classification ECU malfunctionNo. 2 floor wire Front seat wire RH Occupant classification ECU Center airbag sensor assembly

HINT

  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1790 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 272

Scheme 272: WIRING DIAGRAM
Scheme 272: WIRING DIAGRAM

The occupant classification sensor power supply circuit consists of the occupant classification ECU and the occupant classification sensors.

DTC B1793 is stored when a malfunction is detected in the occupant classification sensor power supply circuit.

DTC CodeDTC Detection ConditionTrouble Area
B1793One of following conditions is met: Occupant classification ECU receives line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to +B signal in occupant classification sensor power supply circuit for 2 seconds Open circuit in occupant classification sensor wire harness Occupant classification ECU malfunctionFront seat cushion spring assembly RH (Occupant classification sensors) Front seat wire RH

HINT

  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1793 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 273

Scheme 273: WIRING DIAGRAM
Scheme 273: WIRING DIAGRAM

DTC B1794 is stored when a malfunction is detected in the occupant classification ECU.

DTC CodeDTC Detection ConditionTrouble Area
B1794One of following conditions is met: Occupant classification ECU circuit malfunction Occupant classification ECU malfunction Occupant classification ECU receives short circuit to ground signal in passenger side buckle switch circuit for 2 secondsFront seat wire RH Harness or connector Occupant classification ECU

HINT

  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1794 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

Scheme 274

Scheme 274: WIRING DIAGRAM
Scheme 274: WIRING DIAGRAM

DTC B1795 is stored when a malfunction is detected in the occupant classification ECU.

Troubleshoot DTC B1771 first when both DTCs B1771 and B1795 are present.

DTC CodeDTC Detection ConditionTrouble Area
B1795Occupant classification ECU malfunctionOccupant classification ECU

HINT

  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1795 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

During sleep mode, the occupant classification ECU monitors the condition of each sensor while the ignition switch is off. In this mode, if the occupant classification ECU detects an internal malfunction, DTC B1796 is stored.

DTC CodeDTC Detection ConditionTrouble Area
B1796Occupant classification ECU malfunctionOccupant classification ECU

HINT

  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1796 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

The occupant classification system detects the front passenger seat condition. It then informs a passenger of the front passenger airbag assembly and front seat side airbag assembly condition (activated/not activated) with the passenger airbag ON/OFF indicator.

HINT

Approximately 6 seconds after the ignition switch is turned ON, the passenger airbag ON/OFF indicator will be on/off depending on the conditions listed below.

Front Passenger Seat ConditionPassenger Airbag ON/OFF IndicatorSRS Warning Light
ON IndicatorOFF Indicator
VacantOFFOFFOFF
Adult is seated.ONOFFOFF
Child is seated.OFFONOFF
Child restraint system is set.OFFONOFF
Occupant classification system failureOFFONON

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