Seat Belt: Overview Lexus SC II рестайлинг

Scheme 1

1. INSPECT PASSENGER SEAT BELT WARNING LIGHT ASSEMBLY Measure the resistance of the warning light. Standard resistance RESISTANCE SPECIFICATION Tester Connection Specified Condition Tester probe (+) --> Terminal 3 (ACC) Tester probe (-) --> Terminal 5 (PBEW) 1,300 --> Tester probe (+) --> Terminal 5 (PBEW) Tester probe (-) --> Terminal 3 (ACC) 10 kohms or higher If the result is not as specified, replace the passenger seat belt warning light assembly. (Scheme 1): Identifying Passenger Seat Belt Warning Light Connector Terminals

SYSTEM DESCRIPTION

The seat belt tension reducer system is part of the large-scale multiplex communication system. This system features shared communication wiring that reduces the wiring complexity of the communication lines. The first step in any repair is to confirm the proper operation of the communication system. Proceed with troubleshooting after the communication has been verified (see the «MULTIPLEX COMMUNICATION SYSTEM» ).

1. SEAT BELT WARNING SYSTEM DESCRIPTION If a seat belt is not fastened, this system flashes the seat belt warning light or sounds the seat belt warning buzzer as a reminder. Driver seat belt warning light: When the driver seat belt is not fastened with the ignition switch ON, the driver seat belt warning light on the combination meter comes on to inform the driver. The main body ECU detects the driver seat belt status and sends signals to the combination meter using BEAN. Front passenger seat belt warning light: When the passenger seat belt is not fastened with the ignition switch ON and the passenger seat occupied, the seat belt warning light of the front passenger seat belt warning light blinks. The combination meter displays the passenger seat belt status and whether the passenger seat is occupied. Seat belt warning buzzer: When the vehicle is driven at approximately 25 km/h (16 mph) or more while the driver or front passenger seat belt is not being fastened, the seat belt warning buzzer in the combination meter sounds at an interval of 1.2 seconds for 30 seconds.
2. FUNCTION OF MAIN COMPONENT The following functions are available. FUNCTION OF MAIN COMPONENT Components Function Front seat inner belt LH (driver side buckle switch) Informs main body ECU of driver seat belt condition (fastened or unfastened) Front seat inner belt RH (passenger side buckle switch) Informs center airbag sensor of front passenger seat belt condition (fastened or unfastened) Occupant detection sensor Informs center airbag sensor of front passenger seat condition (occupied or unoccupied) Driver seat belt warning light If driver seat belt is unfastened and ignition switch ON, meter ECU flashes seat belt warning light Front passenger seat belt warning light When front passenger seat is occupied and ignition switch ON, if passenger seat belt is unfastened, meter ECU flashes seat belt warning light of front passenger seat belt warning light Seat belt warning buzzer If driver or passenger seat belt is unfastened and ignition switch ON, meter ECU sounds buzzer as reminder
3. SYSTEM OPERATION When the ignition switch is ON, this system detects the condition of the seat belts based on the signals from the front seat inner belt switches (for driver and front passenger side) and the occupant detection sensor (front passenger side only). The occupant detection sensor, which is built into the seat cushion of the front passenger seat, is used to detect whether or not the front passenger seat is occupied.

OPERATION CHECK

1. INSPECT DRIVER SEAT BELT WARNING LIGHT Turn the ignition switch ON. When the driver seat belt is not fastened, check that the driver seat belt warning light on the combination meter blinks. When the driver seat belt is fastened, check that the driver seat belt warning seat belt warning light on the combination meter is off.
2. INSPECT PASSENGER SEAT BELT WARNING LIGHT Turn the ignition switch ON. When the front passenger seat belt is not fastened with the passenger seat occupied, check that the front passenger seat belt warning light blinks. When the front passenger seat belt is fastened with the passenger seat occupied, check that the front passenger seat belt warning light is off.
3. INSPECT SEAT BELT WARNING BUZZER HINT: If the buzzer does not sound, the buzzer cancel setting may be set to ON (see «CUSTOMIZE PARAMETERS» ). Turn the ignition switch ON. When the vehicle is driven at approximately 25 km/h (16 mph) or more while the driver or front passenger seat belt is not being fastened, check that the buzzer in the combination meter sounds at an interval of 1.2 seconds for 30 seconds. Check that the buzzer sounds at an interval of 0.4 seconds for 90 seconds. Check that the buzzer stops 2 minutes after the buzzer starts sounding. After the buzzer has stopped, turn the ignition switch OFF and then start the engine again. Drive the vehicle at approximately 25 km/h (16 mph) or more while the driver or front passenger seat belt is not being fastened, and then check that the buzzer sounds again. After the buzzer has stopped, fasten the driver and front passenger seat belts. Drive the vehicle at approximately 25 km/h (16 mph) or more and unfasten the driver or front passenger seat belt, and then check that the buzzer sounds again. After the buzzer has stopped, move the shift lever to the R position, and then move it to the D position. Drive the vehicle at approximately 25 km/h (16 mph) or more, and then check that the buzzer sounds again.

DESCRIPTION

When the ignition switch is ON, the center airbag sensor transmits front seat inner belt state signals to the combination meter through BEAN. If the driver seat belt is not fastened, the combination meter blinks the driver seat belt warning light. If the seat belt is fastened, the warning light goes off.

Scheme 2

1. CHECK FOR DTC Check for DTCs. OK: Multiplex communication system DTC output does not occur. NG: Go to MULTIPLEX COMMUNICATION SYSTEM (See «DTC CHECK / CLEAR» ) OK: Go to next step
2. PERFORM ACTIVE TEST BY INTELLIGENT TESTER (DRIVER SEAT BELT WARNING LIGHT) Operate the intelligent tester according to the steps on the display and select "ACTIVE TEST". Combination meter: ACTIVE TEST DETAIL - COMBINATION METER Tester Display Test Part Control Range D-BELT REMIND* Driver seat belt warning light ON or OFF HINT: *: Confirm that the vehicle is stopped with the engine idling. OK: Driver seat belt warning light can be switched by "ACTIVE TEST". OK: Go to COMBINATION METER ASSEMBLY (See «PROBLEM SYMPTOMS TABLE» ) NG: Go to next step
3. CHECK FRONT SEAT INNER BELT ASSEMBLY LH (Scheme 2): Identifying Front Seat Inner Belt Connector Terminals Disconnect the B12 belt connector. Measure the resistance according to the value(s) in the table below. Standard resistance RESISTANCE SPECIFICATION Tester Connection Switch Condition Specified Condition 1 - 3 Seat belt is fastened Below 1 ohms Seat belt is not fastened 10 kohms or higher NG: REPLACE FRONT SEAT INNER BELT ASSEMBLY LH (See «REMOVAL» ) OK: REPLACE MAIN BODY ECU

The combination meter detects the state of the front seat inner belt RH when the front passenger seat is occupied with the ignition switch ON. If the front passenger seat belt is not fastened, the front passenger seat belt warning light on the front passenger seat belt warning light.

Scheme 3

Scheme 4

1. CHECK FOR DTC Check for DTCs. Result: RESULT REFERENCE Result Proceed to DTC output does not occur A Multiplex communication system DTC output occurs B Airbag system DTC output occurs C Occupant classification system DTC output occurs D B: Go to MULTIPLEX COMMUNICATION SYSTEM (See «DTC CHECK / CLEAR» ) C: Go to AIRBAG SYSTEM (See «DATA LIST / ACTIVE TEST» ) D: Go to OCCUPANT CLASSIFICATION SYSTEM (See «DIAGNOSTIC TROUBLE CODE CHART» ) A: Go to next step
2. INSPECT FUSE (P-IG, RADIO NO. 2) Remove the P-IG fuse from the passenger side junction block. Measure the resistance according to the value(s) in the table below. Standard resistance RESISTANCE SPECIFICATION Tester Connection Condition Specified Condition P-IG fuse Always Below 1 ohms NG: REPLACE FUSE OK: Go to next step
3. PERFORM ACTIVE TEST BY INTELLIGENT TESTER (FRONT PASSENGER SEAT BELT WARNING LIGHT) Operate the intelligent tester according to the steps on the display and select "ACTIVE TEST". Combination meter: ACTIVE TEST DETAIL - COMBINATION METER Tester Display Test Part Control Range P-BELT REMIND* Front passenger seat belt warning light ON or OFF HINT: *: Confirm that the vehicle is stopped with the engine idling. OK: Front passenger seat belt warning light condition can be switched by "ACTIVE TEST". NG: Go to step 6 OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (PASSENGER SEAT BELT WARNING LIGHT COMBINATION METER, BATTERY AND BODY GROUND) (Scheme 3): Identifying Passenger Seat Belt Warning Light And Combination Meter Connector Terminals Disconnect the F17 light connector. Disconnect the C8 meter connector. Measure the resistance and voltage according to the value(s) in the table below. Standard resistance RESISTANCE SPECIFICATION Tester Connection Condition Specified Condition F17-5 (PBEW) - C8-10 (PBLT) Always Below 1 ohms F17-6 (GND) - Body ground F17-5 (PBEW) or C8-10 (PBLT) - Body ground 10 kohms or higher Standard voltage VOLTAGE SPECIFICATION Tester Connection Condition Specified Condition F17-3 (LAPB) - Body ground Ignition switch ON 11 to 14 V NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK PASSENGER SEAT BELT WARNING LIGHT ASSEMBLY (Scheme 4): Identifying Passenger Seat Belt Warning Light Connector Terminals Disconnect the F17 light connector. Connect the positive (+) lead to terminal 3 (LAPB), and the negative (-) battery lead to terminals 5 (PBEW) and 6 (GND). Check that the seat belt warning light comes on. OK: Seat belt warning light comes on. NG: REPLACE PASSENGER SEAT BELT WARNING LIGHT ASSEMBLY OK: REPLACE COMBINATION METER ASSEMBLY (See «REMOVAL» )
6. REPLACE FRONT SEAT INNER BELT ASSEMBLY RH Temporarily replace the front seat inner belt RH with a new or normally functioning one (see «REMOVAL» ).
7. CHECK PASSENGER SEAT BELT WARNING LIGHT Check the passenger seat belt warning light function (see «OPERATION CHECK» ). OK: Passenger seat belt warning light operates normally. NG: REPLACE COMBINATION METER ASSEMBLY (See «REMOVAL» ) OK: END (FRONT SEAT INNER BELT RH IS DEFECTIVE)

1. SEAT BELT WARNING SYSTEM DESCRIPTION If a seat belt is not fastened, this system flashes the seat belt warning light or sounds the seat belt warning buzzer as a reminder. Driver seat belt warning light: When the driver seat belt is not fastened with the ignition switch ON, the driver seat belt warning light on the combination meter comes on to inform the driver. The main body ECU detects the driver seat belt status and send signals to the combination meter using BEAN. Front passenger seat belt warning light: When the passenger seat belt is not fastened with the ignition switch ON and the passenger seat occupied, the front passenger seat belt warning light on the passenger seat belt warning light blinks. The combination meter displays the passenger seat belt status and whether the passenger seat is occupied. Seat belt warning buzzer: When the vehicle is driven at approximately 25 km/h (16 mph) or more while the driver or front passenger seat belt is not being fastened, the seat belt warning buzzer in the combination meter sounds at an interval of 1.2 seconds for 30 seconds.
2. FUNCTION OF MAIN COMPONENT The following functions are available. FUNCTION OF MAIN COMPONENT Component Function Front seat inner belt LH (driver side buckle switch) Informs main body ECU of driver seat belt condition (fastened or unfastened) Front seat inner belt RH (passenger side buckle switch) Informs center airbag sensor of front passenger seat belt condition (fastened or unfastened) Occupant detection sensor Informs center airbag sensor of front passenger seat condition (occupied or unoccupied) Driver seat belt warning light If driver seat belt is unfastened and ignition switch ON, meter ECU flashes seat belt warning light as reminder Front passenger seat belt warning light When front passenger seat is occupied and ignition switch ON, if passenger seat belt is unfastened, meter ECU flashes seat belt warning light as reminder Seat belt warning buzzer If driver or passenger seat belt is unfastened and ignition switch is ON, meter ECU sounds buzzer as reminder.
3. SYSTEM OPERATION When the ignition switch is ON, this system detects the condition of the seat belts based on the signals from the front seat inner belt switches (for driver and front passenger side) and the occupant detection sensor (front passenger side only). The occupant detection sensor, which is built into the seat cushion of the front passenger seat, is used to detect whether or not the front passenger seat is occupied.

1. INSPECT DRIVER SEAT BELT WARNING LIGHT Turn the ignition switch ON. When the driver seat belt is not fastened, check that the driver seat belt warning light on the combination meter blinks. When the driver seat belt is fastened, check that the driver seat belt warning seat belt warning light on the combination meter is off.
2. INSPECT PASSENGER SEAT BELT WARNING LIGHT Turn the ignition switch ON. When the front passenger seat belt is not fastened with the passenger seat occupied, check that the front passenger seat belt warning light blinks. When the front passenger seat belt is fastened with the passenger seat occupied, check that the front passenger seat belt warning light is off.
3. INSPECT SEAT BELT WARNING BUZZER If the buzzer does not sound, the buzzer cancel setting may be set to ON (see «CUSTOMIZE PARAMETERS» ). Turn the ignition switch ON. When the vehicle is driven at approximately 25 km/h (16 mph) or more while the driver or front passenger seat belt is not being fastened, check that the buzzer in the combination meter sounds at an interval of 1.2 seconds for 30 seconds. Check that the buzzer sounds at an interval of 0.4 seconds for 90 seconds. Check that the buzzer stops 2 minutes after the buzzer starts sounding. After the buzzer has stopped, turn the ignition switch OFF and then start the engine again. Drive the vehicle at approximately 25 km/h (16 mph) or more while the driver or front passenger seat belt is not being fastened, and then check that the buzzer sounds again. After the buzzer has stopped, fasten the driver and front passenger seat belts. Drive the vehicle at approximately 25 km/h (16 mph) or more and unfasten the driver or front passenger seat belt, and then check that the buzzer sounds again. After the buzzer has stopped, move the shift lever to the R position, and then move it to the D position. Drive the vehicle at approximately 25 km/h (16 mph) or more, and then check that the buzzer sounds again.

When the ignition switch is ON, the center airbag sensor transmits front seat inner belt state signals to the combination meter through BEAN. If the driver seat belt is not fastened, the combination meter blinks the driver seat belt warning light. If the seat belt is fastened, the warning light goes off.

Scheme 5

1. CHECK FOR DTC Check for DTCs. OK: Multiplex communication system DTC output does not occur. NG: Go to MULTIPLEX COMMUNICATION SYSTEM (See «DTC CHECK / CLEAR» ) OK: Go to next step
2. PERFORM ACTIVE TEST BY INTELLIGENT TESTER (DRIVER SEAT BELT WARNING LIGHT) Operate the intelligent tester according to the steps on the display and select "ACTIVE TEST". Combination meter: ACTIVE TEST DETAIL - COMBINATION METER Tester Display Test Part Control Range D-BELT REMIND* Driver seat belt warning light ON or OFF HINT: *: Confirm that the vehicle is stopped with the engine idling. OK: Driver seat belt warning light can be switched by "ACTIVE TEST". OK: Go to COMBINATION METER ASSEMBLY (See «PROBLEM SYMPTOMS TABLE» ) NG: Go to next step
3. CHECK FRONT SEAT INNER BELT ASSEMBLY LH (Scheme 5): Identifying Front Seat Inner Belt Connector Terminals Disconnect the B12 belt connector. Measure the resistance according to the value(s) in the table below. Standard resistance RESISTANCE SPECIFICATION Tester Connection Switch Condition Specified Condition 1 - 3 Seat belt Is fastened Below 1 ohms Seat belt is not fastened 10 kohms or higher NG: REPLACE FRONT SEAT INNER BELT ASSEMBLY LH (See «REMOVAL» ) OK: REPLACE MAIN BODY ECU

The combination meter detects the state of the front seat inner belt RH when the front passenger seat is occupied with the ignition switch ON. If the front passenger seat belt is not fastened, the front passenger seat belt warning light on the passenger seat belt warning light.

Scheme 6

Scheme 7

1. CHECK FOR DTC Check for DTCs. Result: RESULT REFERENCE Result Proceed to DTC output does not occur A Multiplex communication system DTC output occurs B Airbag system DTC output occurs C B: Go to MULTIPLEX COMMUNICATION SYSTEM (See «DTC CHECK / CLEAR» ) C: Go to AIRBAG SYSTEM (See «DATA LIST / ACTIVE TEST» ) A: Go to next step
2. INSPECT FUSE Remove the P-IG fuse from the passenger side junction block. Measure the resistance according to the value(s) in the table below. Standard resistance RESISTANCE SPECIFICATION Tester Connection Condition Specified Condition P-IG fuse Always Below 1 ohms NG: REPLACE FUSE OK: Go to next step
3. PERFORM ACTIVE TEST BY INTELLIGENT TESTER (FRONT PASSENGER SEAT BELT WARNING LIGHT) Operate the intelligent tester according to the steps on the display and select "ACTIVE TEST". Combination meter: ACTIVE TEST DETAIL - COMBINATION METER Tester Display Test Part Control Range P-BELT REMIND* Front passenger seat belt warning light ON or OFF HINT: *: Confirm that the vehicle is stopped with the engine idling. OK: Front passenger seat belt warning light condition can be switched by "ACTIVE TEST". NG: Go to step 6 OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (PASSENGER SEAT BELT WARNING LIGHT COMBINATION METER, BATTERY AND BODY GROUND) (Scheme 6): Identifying Passenger Seat Belt Warning Light And Combination Meter Connector Terminals Disconnect the F13 light connector. Disconnect the C8 meter connector. Measure the voltage and resistance according to the value(s) in the table below. Standard resistance RESISTANCE SPECIFICATION Tester Connection Condition Specified Condition F13-5 - C8-10 (PBLT) Always Below 1 ohms F13-3 - Body ground 10 kohms or higher F13-5 or C8-10 (PBLT) -Body ground Standard voltage VOLTAGE SPECIFICATION Tester Connection Condition Specified Condition F13-3 - Body ground Always 11 to 14 V NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK PASSENGER SEAT BELT WARNING LIGHT ASSEMBLY (Scheme 7): Identifying Passenger Seat Belt Warning Light Connector Terminals Disconnect the F13 light connector. Measure the resistance according to the value(s) in the table below. Standard resistance RESISTANCE SPECIFICATION Tester Connection Condition Specified Condition Tester probe (+) --> Terminal 3 Tester probe (-) --> Terminal 5 Always 1,300 ohms Tester probe (+) --> Terminal 5 Tester probe (-) -4 Terminal 3 10 kohms or higher Connect the positive (+) lead to terminal 3 and the negative (-) lead to terminals 5. Check that the seat belt warning light comes on. OK: Seat belt warning light comes on. NG: REPLACE PASSENGER SEAT BELT WARNING LIGHT ASSEMBLY OK: REPLACE COMBINATION METER ASSEMBLY (See «REMOVAL» )
6. REPLACE FRONT SEAT INNER BELT ASSEMBLY RH Temporarily replace the front seat inner belt RH with a new or normally functioning one (see «REMOVAL» ).
7. CHECK PASSENGER SEAT BELT WARNING LIGHT Check the passenger seat belt warning light function (see «OPERATION CHECK» ). OK: Passenger seat belt warning light operates normally. NG: REPLACE COMBINATION METER ASSEMBLY (See «REMOVAL» ) OK: END (FRONT SEAT INNER BELT RH IS DEFECTIVE)

Identifying Front Seat Inner Belt Assembly Components With Torque Specifications. Scheme 8

See also:
• DISASSEMBLY