Occupant Classification System (Diagnostics - Introduction): Other Lexus ES XV40 facelift

PRECAUTION

Note. Some systems need to be initialized after reconnecting the negative (-) battery terminal. Refer to INITIALIZATION .

1. INSPECTION PROCEDURE FOR VEHICLE INVOLVED IN ACCIDENT Perform zero point calibration and sensitivity check if any of the following conditions apply. The occupant classification ECU is replaced. The passenger airbag ON/OFF indicator indicates OFF when the front passenger seat is not occupied. The vehicle is brought to the workshop for repair due to an accident or a collision.

Scheme 260

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1. GENERAL DESCRIPTION In the occupant classification system, the occupant classification ECU calculates the weight of the front passenger based on a signal from the occupant classification sensor. This system judges the occupant to be a child when it detects a weight of less than 27.3 kg (60 lb), and disables the front passenger side airbag and front passenger side - side airbag. This system is mainly composed of the occupant classification sensor that detects the load on the front passenger seat. The occupant classification ECU controls the system, and the passenger airbag ON/OFF indicator indicates the ON/OFF condition of the front passenger airbag assembly and front passenger side - side airbag assembly.
2. OCCUPANT CLASSIFICATION SENSOR The occupant classification sensor consists of the bladder mat and the pressure sensor. When weight is applied to the bladder mat, the pressure applied through the silicone to the pressure sensor changes. The pressure sensor converts these changes into voltages and transmits them to the occupant classification ECU. The occupant classification sensor is installed between the seat cushion frame and seat cushion pad. The pressure sensor is installed on the seat frame. The pressure sensor detects the pressure applied to the front passenger seat as a seated passenger. The occupant classification ECU determines whether the front passenger side airbag and front passenger side - side airbag are deployed based on signals from the pressure sensor.
3. SEAT BELT TENSION SENSOR The seat belt tension sensor is installed on the front seat outer belt to detect a CRS (Child Restraint System).

REGISTRATION

1. REGISTRATION NOTE: If any DTCs related to the occupant classification ECU are output, troubleshoot those DTCs by referring to the DIAGNOSTIC TROUBLE CODE CHART. When ECU data saving or loading operations cannot be performed, replace the front seat cushion assembly (with occupant classification ECU and occupant classification sensor). HINT: When the occupant classification ECU is replaced, the previous ECU data must be saved in Techstream and loaded into the new ECU by following the flowchart below. Until the data from the previous ECU are loaded into the new occupant classification ECU, these data are not erased even when the tester is turned off. ECU EXCHANGE PROCEDURE (Before Exchange) describes the procedure to save the data in Techstream from the occupant classification ECU which has been installed on the vehicle. ECU EXCHANGE PROCEDURE (After Exchange) describes the procedure to load the data from the previous ECU, stored in Techstream, into the new ECU. Connect Techstream to the DLC3. Turn the engine switch on (IG). Store the occupant classification ECU data in Techstream by following the prompts on the tester screen. HINT: If the ECU data cannot be stored in Techstream, replace the front seat cushion assembly (with occupant classification ECU and occupant classification sensor). Turn the engine switch on (IG). Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds. Replace the occupant classification ECU. Refer to «REMOVAL»(ref-396531-S09726037482011050900000) . Connect the negative (-) terminal cable to the battery. Turn the engine switch on (IG). Load the data from the previous ECU stored in the tester, into the newly installed ECU by following the prompts on the tester screen. Turn the engine switch off. Turn the engine switch on (IG). Clear the DTCs stored in the memory. Refer to «DTC CHECK / CLEAR»(ref-396711-S13118111402011050900000) . HINT: If DTCs are not cleared at this time, past DTCs will remain.

INITIALIZATION

Note. Make sure that the front passenger seat is not occupied before performing the operation.

HINT

Perform the zero point calibration if any of the following conditions is met

1. The occupant classification ECU is replaced.
2. The passenger airbag ON/OFF indicator indicates OFF when the front passenger seat is not occupied.
3. The vehicle is brought to the workshop for repair due to an accident or a collision.

Scheme 263

1. ZERO POINT CALIBRATION Zero point calibration procedures Check that all of the following conditions are met: The vehicle is parked on a flat surface. No objects are placed on the front passenger seat. The front passenger seat belt buckle switch is OFF. Adjust the seat position according to the table below. Adjustment Item Position Slide Direction Rearmost position Reclining Angle Upright position Headrest Height Lowest position Lifter Height Lowest position Connect Techstream to the DLC3. Turn the engine switch on (IG). Enter the following menus: Body Electrical / Occupant Detection / Utility / Zero Point Calibration. Perform the zero point calibration by following the prompts on the tester screen. HINT: Refer to the Techstream operator's manual for further details. If the zero point calibration is performed when the calibration conditions are not satisfied, DTC B1797 is output. If the zero point calibration has failed, DTC B1797 is output. If After Exchange is selected before the previous ECU data are stored in Techstream, the display screen returns to CONDITION SELECT ECU: Occupant Detect. Item Procedure DTC Perform DTC check and repair Write error Replace front seat cushion assembly (with occupant classification ECU and occupant classification sensor) Temperature Check value of Thermistor Temperature Output in ECU DATA LIST Pressure Check value of Filtered Pressure Sensor Output in ECU DATA LIST Crash counter
2. SENSITIVITY CHECK Sensitivity check procedures Turn the engine switch off. Place a weight of 20 kg (44.0 lb) on the front passenger seat. NOTE: Do not allow the weight to come into contact with the seatback when placing it on the seat cushion. Place the weight in the area shown in the illustration. Turn the engine switch on (IG), and wait for at least 6 seconds. Check that the passenger airbag ON/OFF indicator indicates OFF. OK The passenger airbag ON/OFF indicator indicates OFF. Add a weight of 30 kg (66.1 lb) to the front passenger seat (total 50 kg (110.2 lb)). NOTE: Do not allow the weight to come into contact with the seatback when placing it on the seat cushion. Place the weight in the area shown in the illustration. Check that the passenger airbag ON/OFF indicator indicates ON. OK The passenger airbag ON/OFF indicator indicates ON.