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Occupant Classification System (Diagnostic Codes & Symptom Tests): Overview Lexus ES XV40 facelift

Airbag 4 illustrations ~505 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 recorded when a malfunction is detected in the passenger side buckle switch circuit.

DTC No.DTC Detecting ConditionTrouble Area
B1771The occupant classification ECU receives a line short circuit signal, and open circuit signal, a short circuit to ground signal or a 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

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 399

Scheme 399: WIRING DIAGRAM

The seat belt tension sensor circuit consists of the occupant classification ECU and the seat belt tension sensor.

The seat belt tension sensor sends the seat belt tension signal to the occupant classification ECU.

DTC B1773 and B1776 are recorded when a malfunction is detected in the seat belt tension sensor circuit.

DTC No.DTC Detecting ConditionTrouble Area
B1773 B1776The occupant classification ECU receives line short circuit signal, and open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the seat belt tension sensor circuit for 2 seconds. Seat belt tension sensor malfunction Occupant classification ECU malfunctionFront seat wire RH Front seat outer belt assembly RH (Seat belt tension sensor) 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 B1773 and B1776 are output, perform troubleshooting for the DTC.

Scheme 400

Scheme 400: WIRING DIAGRAM

The pressure sensor circuit consists of the occupant classification ECU and the occupant classification sensor.

The occupant classification sensor sends the pressure signal to the occupant classification ECU.

DTC B1774 and B1775 are recorded when a malfunction is detected in the pressure sensor circuit.

DTC No.DTC Detecting ConditionTrouble Area
B1774 B1775The occupant classification ECU receives a line short circuit signal, and open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the pressure sensor circuit for 2 seconds. Occupant classification sensor malfunction Occupant classification ECU malfunctionFront seat wire RH Occupant classification sensor 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 B1774 and B1775 are output, perform troubleshooting for the DTC.

Scheme 401

Scheme 401: WIRING DIAGRAM

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

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

DTC No.DTC Detecting 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 for 2 seconds. Center airbag sensor assembly malfunction Occupant classification ECU malfunctionFloor wire No. 2 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 402

Scheme 402: WIRING DIAGRAM

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

DTC No.DTC Detecting 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.

DTC B1797 is output when the following condition is met

  1. Zero point calibration is performed when the conditions for the calibration are not satisfied.
  1. Zero point calibration has failed.
ItemCondition
DTCNot recorded
Front passenger seat occupantVacant
Front passenger side buckle switchOFF (The seat belt is not fastened)
ECU temperature0 to 46°C (32 to 114.8°F)
Filtered pressure38 to 75 count

CONDITION FOR THE ZERO POINT CALIBRATION

DTC No.DTC Detecting ConditionTrouble Area
B1797Zero point calibration is performed when the conditions for the calibration are not satisfied. Zero point calibration has failed.There is no malfunction if this DTC is not output again after performing occupant classification system zero point calibration. Occupant classification sensor 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 B1797 is output, perform troubleshooting for the DTC.

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) by the passenger airbag ON/OFF indicator.

HINT

Approximately 6 seconds after the engine switch is turned on (IG), 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
Adult is seatedONOFFOFF
Child is seatedOFFONOFF
VacantOFFOFFOFF
Occupant classification system failureOFFONON