Seat Belt Warning System (Diagnostics): Overview Lexus ES XV40 facelift

SYSTEM DESCRIPTION

1. Driver seat belt warning light When the driver seat belt is not fastened with the engine switch on (IG), the driver seat belt warning light on the combination meter assembly comes on to inform the driver. The center airbag assembly detects the driver seat belt status and sends signals to the combination meter assembly using CAN.
2. Passenger seat belt warning light When the passenger seat belt is not fastened with the engine switch on (IG) and the passenger seat occupied, check that the passenger seat belt warning light on the A/C control assembly (* Multi-media module display) blinks. The combination meter assembly displays the passenger seat belt status and whether the passenger seat is occupied. *: with navigation system

DESCRIPTION

When the engine switch is on (IG), the center airbag sensor assembly transmits front seat inner belt state signals to the combination meter assembly through CAN. If the driver seat belt is not fastened, the combination meter assembly blinks the driver seat belt warning light. If the seat belt is fastened, the warning light goes off.

Note. The seat belt warning system uses CAN. Before troubleshooting the seat belt warning system, perform "COMMUNICATION FUNCTION CHECK" by following "HOW TO PROCEED WITH TROUBLESHOOTING" to confirm that the communication systems are normal.

Scheme 66

with Navigation System

The combination meter assembly detects the state of the front passenger seat inner belt assembly when the front passenger seat is occupied with the engine switch on (IG). If the front passenger seat belt is not fastened, the front seat belt warning light on the multi-media module display blinks. If the seat belt is fastened, the warning light goes off.

without Navigation System

The combination meter assembly detects the state of the front passenger seat inner belt assembly when the front passenger seat is occupied with the engine switch on (IG). If the front passenger seat belt is not fastened, the front seat belt warning light on the A/C control assembly blinks. If the seat belt is fastened, the warning light goes off.

Scheme 67

Scheme 68

Scheme 69

1. CHECK FOR DTCs Check for DTCs. Result Result Proceed to No output DTC A Output DTC (CAN communication) B B --> GO TO «CAN COMMUNICATION SYSTEM»(ref-396655-S21766391472011050900000) CAN COMMUNICATION SYSTEM A: Go to next step
2. PERFORM ACTIVE TEST USING TECHSTREAM Operate Techstream according to the steps on the display and select "ACTIVE TEST". Meter Tester Display Test Part Control Range Diagnostic Note P-Belt Remind P-SEAT BELT indicator light OFF / ON Confirm that the vehicle is stopped with the engine idling Result Result Proceed to OK (without navigation system) A OK (with navigation system) B NG C C --> GO TO «METER / GAUGE SYSTEM»(ref-396653-S34394955792011050900000) COMBINATION METER SYSTEM B --> See step 6 A: Go to next step
3. CHECK WIRE HARNESS (A/C CONTROL ASSEMBLY +B) Disconnect the A/C control assembly connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition E3-2 (IG+) - Body ground Engine switch on (IG) 10 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK A/C CONTROL ASSEMBLY Disconnect the A/C control assembly connector. TEXT IN ILLUSTRATION *1 Component without harness connected (A/C Control Assembly) Connect the positive (+) lead to terminal 2 (IG+), and the negative (-) battery lead to terminals 13 (LB/L) and 18 (GND). Check that the seat belt warning light comes on. OK Seat belt warning light comes on. NG --> REPLACE AIR CONDITIONING CONTROL ASSEMBLY OK: Go to next step
5. CHECK WIRE HARNESS (A/C CONTROL ASSEMBLY - COMBINATION METER ASSEMBLY) Disconnect the combination meter assembly and A/C control assembly connectors. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition E19-9 (P/SB) - E3-13 (LB/L) Always Below 1 ohms E19-9 (P/SB) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> GO TO «OCCUPANT CLASSIFICATION SYSTEM»(ref-396711-S01226508292011050900000) OCCUPANT CLASSIFICATION SYSTEM
6. CHECK WIRE HARNESS (MULTI-MEDIA MODULE DISPLAY +B) Disconnect the multi-media module display connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition E62-3 (IG) - Body ground Engine switch on (IG) 10 to 14 V NG --> REPLACE AIR CONDITIONING CONTROL ASSEMBLY OK: Go to next step
7. CHECK MULTI-MEDIA MODULE DISPLAY Disconnect the multi-media module display connector. TEXT IN ILLUSTRATION *1 Component without harness connected (Multi-media Module Display) *2 Component without harness connected (Multi-media Module Display) Connect the positive (+) lead to terminal 3 (IG), and the negative (-) battery lead to terminals 5 (PBEW) and 10 (GND1). Check that the seat belt warning light comes on. OK Seat belt warning light comes on. NG --> REPLACE MULTI-MEDIA MODULE DISPLAY OK: Go to next step
8. CHECK WIRE HARNESS (MULTI-MEDIA MODULE DISPLAY - COMBINATION METER ASSEMBLY) Disconnect the combination meter assembly and multi-media module display connectors. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition E19-9 (P/SB) - E106-5 (PBEW) Always Below 1 ohms E19-9 (P/SB) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> GO TO «OCCUPANT CLASSIFICATION SYSTEM»(ref-396711-S01226508292011050900000) OCCUPANT CLASSIFICATION SYSTEM