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Occupant Classification System (Diagnostic Codes): Overview Lexus GS III facelift

Airbag 4 illustrations ~496 words

DESCRIPTION

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

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

DTC No.DTC Detection ConditionTrouble Area
B1771One of following conditions is met: Occupant classification ECU receives line short circuit signal, and 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 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 345

Scheme 345: 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 Detection ConditionTrouble Area
B1773 B1776One of following conditions is met: Occupant classification ECU receives line short circuit signal, and open circuit signal, short circuit to ground signal or short circuit to B+ signal in seat belt tension sensor circuit for 2 seconds Seat belt tension sensor malfunction Occupant classification ECU malfunctionFront seat wire RH Front seat outer belt 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 346

Scheme 346: WIRING DIAGRAM

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

The occupant detection 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 Detection ConditionTrouble Area
B1774 B1775One of following conditions is met: Occupant classification ECU receives line short circuit signal, and open circuit signal, short circuit to ground signal or short circuit to B+ signal in pressure sensor circuit for 2 seconds Occupant detection sensor malfunction Occupant classification ECU malfunctionFront seat wire RH Occupant detection 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 347

Scheme 347: WIRING DIAGRAM

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

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

DTC No.DTC 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 communication circuit for 2 seconds Center airbag sensor malfunction Occupant classification ECU malfunctionFloor wire Front seat wire RH (for Power seat) Occupant classification ECU Center airbag sensor

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 348

Scheme 348: WIRING DIAGRAM

DTC B1795 is recorded 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.

DTC B1797 is output when the following conditions are 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 Detection ConditionTrouble Area
B1797One of following conditions is met: Zero point calibration is performed when conditions for calibration are not satisfied Zero point calibration has failedThere is no malfunction if this DTC is not output again after performing occupant classification system zero point calibration Occupant detection sensor

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 and front seat side airbag 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