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Occupant Classification System (Diagnostic Codes): Overview Lexus HS I

Airbag 8 illustrations ~1279 words

DESCRIPTION

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

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

DTC No.DTC Detection ConditionTrouble Area
B1771The occupant classification ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the passenger side buckle switch circuit. 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

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1771 is output, perform troubleshooting for the DTC.

Scheme 32

Scheme 32: WIRING DIAGRAM

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

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

DTC No.DTC Detection ConditionTrouble Area
B1780The occupant classification ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the front occupant classification sensor LH circuit. Front occupant classification sensor LH malfunctionFront seat wire RH Front seat assembly RH (Front occupant classification sensor LH)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1780 is output, perform troubleshooting for the DTC.

Scheme 33

Scheme 33: WIRING DIAGRAM

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

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

DTC No.DTC Detection ConditionTrouble Area
B1781The occupant classification ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the front occupant classification sensor RH circuit. Front occupant classification sensor RH malfunctionFront seat wire RH Front seat assembly RH (Front occupant classification sensor RH)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1781 is output, perform troubleshooting for the DTC.

Scheme 34

Scheme 34: WIRING DIAGRAM

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

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

DTC No.DTC Detection ConditionTrouble Area
B1782The occupant classification ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the rear occupant classification sensor LH circuit. Rear occupant classification sensor LH malfunctionFront seat wire RH Front seat assembly RH (Rear occupant classification sensor LH)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1782 is output, perform troubleshooting for the DTC.

Scheme 35

Scheme 35: WIRING DIAGRAM

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

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

DTC No.DTC Detection ConditionTrouble Area
B1783The occupant classification ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the rear occupant classification sensor RH circuit. Rear occupant classification sensor RH malfunctionFront seat wire RH Front seat assembly RH (Rear occupant classification sensor RH)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1783 is output, perform troubleshooting for the DTC.

Scheme 36

Scheme 36: WIRING DIAGRAM

DTC B1785 is stored when the occupant classification ECU receives a collision detection signal sent by the front occupant classification sensor LH if 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 does not occur.

If the vehicle is not in a collision, but the occupant classification ECU outputs a collision detection signal and sets DTC B1785, the DTC can be cleared by performing Zero Point Calibration and Sensitivity Check.

Therefore, if DTC B1785 is output, first perform Zero Point Calibration and Sensitivity Check.

DTC No.DTC Detection ConditionTrouble Area
B1785Front occupant classification sensor LH sensed large load Front seat assembly RH malfunctionFront seat assembly RH (Front occupant classification sensor LH)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1785 is output, perform troubleshooting for the DTC.

DTC B1786 is stored when the occupant classification ECU receives a collision detection signal sent by the front occupant classification sensor RH if 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 does not occur.

If the vehicle is not in a collision, but the occupant classification ECU outputs a collision detection signal and sets DTC B1786, the DTC can be cleared by performing Zero Point Calibration and Sensitivity Check.

Therefore, if DTC B1786 is output, first perform Zero Point Calibration and Sensitivity Check.

DTC No.DTC Detection ConditionTrouble Area
B1786Front occupant classification sensor RH sensed large load Front seat assembly RH malfunctionFront seat assembly RH (Front occupant classification sensor RH)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1786 is output, perform troubleshooting for the DTC.

DTC B1787 is stored when the occupant classification ECU receives a collision detection signal sent by the rear occupant classification sensor LH if 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 does not occur.

If the vehicle is not in a collision, but the occupant classification ECU outputs a collision detection signal and sets DTC B1787, the DTC can be cleared by performing Zero Point Calibration and Sensitivity Check.

Therefore, if DTC B1787 is output, first perform Zero Point Calibration and Sensitivity Check.

DTC No.DTC Detection ConditionTrouble Area
B1787Rear occupant classification sensor LH sensed large load Front seat assembly RH malfunctionFront seat assembly RH (Rear occupant classification sensor LH)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1787 is output, perform troubleshooting for the DTC.

DTC B1788 is stored when the occupant classification ECU receives a collision detection signal sent by the rear occupant classification sensor RH if 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 does not occur.

If the vehicle is not in a collision, but the occupant classification ECU outputs a collision detection signal and sets DTC B1788, the DTC can be cleared by performing Zero Point Calibration and Sensitivity Check.

Therefore, if DTC B1788 is output, first perform Zero Point Calibration and Sensitivity Check.

DTC No.DTC Detection ConditionTrouble Area
B1788Rear occupant classification sensor RH sensed large load Front seat assembly RH malfunctionFront seat assembly RH (Rear occupant classification sensor RH)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1788 is output, perform troubleshooting for the DTC.

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

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

DTC No.DTC Detection ConditionTrouble Area
B1790The occupant classification ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the center airbag sensor assembly communication circuit. Occupant classification ECU malfunction Center airbag sensor assembly malfunctionNo. 2 floor wire Front seat wire RH Occupant classification ECU Center airbag sensor assembly

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1790 is output, perform troubleshooting for the DTC.

Scheme 37

Scheme 37: WIRING DIAGRAM

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

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

DTC No.DTC Detection ConditionTrouble Area
B1793The occupant classification ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the occupant classification sensor power supply circuit. Occupant classification sensors malfunctionFront seat wire RH Front seat assembly RH (Occupant classification sensors)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1793 is output, perform troubleshooting for the DTC.

Scheme 38

Scheme 38: WIRING DIAGRAM

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

DTC No.DTC Detection ConditionTrouble Areas
B1794The occupant classification ECU receives an open circuit signal in the occupant classification ECU battery positive line. Occupant classification ECU malfunctionAuxiliary battery ECU-B fuse Wire harness Occupant classification ECU

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1794 is output, perform troubleshooting for the DTC.

Scheme 39

Scheme 39: WIRING DIAGRAM

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

DTC No.DTC Detection ConditionTrouble Area
B1795Occupant classification ECU malfunctionOccupant classification ECU

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1795 is output, perform troubleshooting for the DTC.

In sleep mode, the occupant classification ECU reads the condition of each sensor while the power switch is off.

In this mode, if occupant classification ECU detects an internal malfunction, DTC B1796 is stored.

DTC No.DTC Detection ConditionTrouble Area
B1796Occupant classification ECU malfunctionOccupant classification ECU

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1796 is output, perform troubleshooting for the DTC.

The occupant classification system detects the front passenger seat condition. It then informs the front passenger airbag, front passenger side knee airbag and front seat belt pretensioner RH condition (activated/not activated) with the passenger airbag ON/OFF indicator.

HINT

Approximately 6 seconds after the power switch is turned on (IG), the passenger airbag ON/OFF indicator will indicate 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

See also:
REMOVAL