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Occupant Classification System (Diagnostic Codes & Symptom Tests): Overview Lexus CT I

Airbag 8 illustrations ~1278 words

DESCRIPTION

The passenger side buckle switch circuit consists of the occupant detection 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 detection 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 detection ECU malfunctionFront seat wire RH Front seat inner belt assembly RH (Passenger side buckle switch) Occupant detection ECU

HINT

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

Scheme 334

Scheme 334: WIRING DIAGRAM

The front occupant classification sensor LH circuit consists of the occupant detection 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 detection 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 cushion spring assembly (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 detection ECU. When DTC B1780 is output, perform troubleshooting for the DTC.

Scheme 335

Scheme 335: WIRING DIAGRAM

The front occupant classification sensor RH circuit consists of the occupant detection 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 detection 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 cushion spring assembly (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 detection ECU. When DTC B1781 is output, perform troubleshooting for the DTC.

Scheme 336

Scheme 336: WIRING DIAGRAM

The rear occupant classification sensor LH circuit consists of the occupant detection 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 detection 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 cushion spring assembly (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 detection ECU. When DTC B1782 is output, perform troubleshooting for the DTC.

Scheme 337

Scheme 337: WIRING DIAGRAM

The rear occupant classification sensor RH circuit consists of the occupant detection 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 Detecting ConditionTrouble Area
B1783The occupant detection 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 cushion spring assembly (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 detection ECU. When DTC B1783 is output, perform troubleshooting for the DTC.

Scheme 338

Scheme 338: WIRING DIAGRAM

DTC B1785 is stored when the occupant detection 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 detection 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 cushion spring assembly malfunctionFront seat cushion spring assembly (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 detection ECU. When DTC B1785 is output, perform troubleshooting for the DTC.

DTC B1786 is stored when the occupant detection 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 detection 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 cushion spring assembly malfunctionFront seat cushion spring assembly (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 detection ECU. When DTC B1786 is output, perform troubleshooting for the DTC.

DTC B1787 is stored when the occupant detection 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 detection 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 cushion spring assembly malfunctionFront seat cushion spring assembly (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 detection ECU. When DTC B1787 is output, perform troubleshooting for the DTC.

DTC B1788 is stored when the occupant detection 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 detection ECU outputs a collision detection signal and sets DTC B1788, the DTC can be cleared by performing the 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 cushion spring assembly malfunctionFront seat cushion spring assembly (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 detection ECU. When DTC B1788 is output, perform troubleshooting for the DTC.

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

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

DTC No.DTC Detection ConditionTrouble Area
B1790The occupant detection 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 airbag sensor assembly communication circuit. Occupant detection ECU malfunction Airbag sensor assembly malfunctionNo. 2 floor wire Front seat wire RH Occupant detection ECU 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 detection ECU. When DTC B1790 is output, perform troubleshooting for the DTC.

Scheme 339

Scheme 339: WIRING DIAGRAM

The occupant classification sensor power supply circuit consists of the occupant detection 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 detection 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. Front occupant classification sensor LH malfunction Front occupant classification sensor RH malfunction Rear occupant classification sensor LH malfunction Rear occupant classification sensor RH malfunctionFront seat wire RH Front seat cushion spring assembly (4 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 detection ECU. When DTC B1793 is output, perform troubleshooting for the DTC.

Scheme 340

Scheme 340: WIRING DIAGRAM

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

DTC No.DTC Detections ConditionsTrouble Areas
B1794The occupant detection ECU receives an open circuit signal in the occupant detection ECU auxiliary battery positive line. Occupant detection ECU malfunctionAuxiliary battery ECU-B fuse Wire harness Occupant detection ECU

HINT

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

Scheme 341

Scheme 341: WIRING DIAGRAM

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

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

HINT

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

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

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

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

HINT

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

The occupant classification system detects the front passenger seat condition. It then displays the front passenger airbag, front passenger side knee airbag and front seat belt pretensioner RH condition (activated/not activated) using 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 installed.OFFONOFF
Occupant classification system failureOFFONON