Occupant Classification System (Diagnostic Codes & Symptom Tests): Overview Lexus GS IV

DESCRIPTION

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

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

Troubleshoot DTC B1771 first when DTCs B1771 and B1795 are output simultaneously.

HINT

1. When DTC B1650/32 is stored 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 detection ECU, otherwise the DTCs cannot be read.

Scheme 269

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.

HINT

1. When DTC B1650/32 is stored 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 detection ECU, otherwise the DTCs cannot be read.

Scheme 270

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.

HINT

1. When DTC B1650/32 is stored 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 detection ECU, otherwise the DTCs cannot be read.

Scheme 271

DTC B1787 is stored when the occupant detection 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 adjuster assembly RH is subjected to a strong impact, even if an actual accident has not occurred.

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

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

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 detection ECU, otherwise the DTCs cannot be read.

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

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

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

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

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 detection ECU, otherwise the DTCs cannot be read.

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

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

HINT

1. When DTC B1650/32 is stored 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 detection ECU, otherwise the DTCs cannot be read.

Scheme 272

The occupant classification sensor power supply circuit consists of the occupant detection ECU and rear occupant classification sensor LH and RH.

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

HINT

1. When DTC B1650/32 is stored 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 detection ECU, otherwise the DTCs cannot be read.

Scheme 273

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

HINT

1. When DTC B1650/32 is stored 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 detection ECU, otherwise the DTCs cannot be read.

Scheme 274

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

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

HINT

1. When DTC B1650/32 is stored 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 detection ECU, otherwise the DTCs cannot be read.

During sleep mode, the occupant detection ECU monitors 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.

HINT

1. When DTC B1650/32 is stored 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 detection ECU, otherwise the DTCs cannot be read.

The occupant classification system detects the front passenger seat condition. The system then informs the passenger of the instrument panel passenger airbag assembly, front seat belt pretensioner RH and lower No. 2 instrument panel assembly airbag status (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 the on/off status depending on the conditions listed below.