Lexus NX: Front Passenger Side Seat Belt Warning Light Malfunction

Lexus NX Service Manual / Vehicle Interior / Seat Belt / Seat Belt Warning System / Front Passenger Side Seat Belt Warning Light Malfunction

DESCRIPTION

When the power switch is turned on (IG), the occupant detection ECU sends a signal to the airbag ECU assembly to indicate the state of the front seat inner belt assembly RH and also whether the front passenger seat is occupied. The airbag ECU assembly sends those signals to the combination meter assembly via CAN communication. The combination meter assembly illuminates, blinks or turns off the front seat belt warning light on the combination meter assembly in accordance with these signals.

HINT:

The front seat belt warning light on the combination meter assembly is used for both the driver side seat and front passenger side seat.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • The seat belt warning system uses the CAN communication system. First, confirm that there is no malfunction in the CAN communication system. Refer to the How to Proceed with Troubleshooting procedure.

    Click here

  • When replacing the combination meter assembly, make sure to replace it with a new one.
  • After replacing the airbag ECU assembly, refer to initialization.

    Click here

PROCEDURE

1.

CHECK FOR DTC (OCCUPANT CLASSIFICATION SYSTEM)

(a) Clear the DTCs.

Click here

Body Electrical > Occupant Detection > Clear DTCs

(b) Check for DTCs.

Click here

Body Electrical > Occupant Detection > Trouble Codes

OK:

DTCs are not output.

NG

GO TO OCCUPANT CLASSIFICATION SYSTEM

OK

2.

CHECK FOR DTC (AIRBAG SYSTEM)

(a) Clear the DTCs.

Click here

Body Electrical > SRS Airbag > Clear DTCs

(b) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTCs are not output.

NG

GO TO AIRBAG SYSTEM

OK

3.

READ VALUE USING TECHSTREAM (PASSENGER BUCKLE SW)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Occupant Detection / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Occupant Detection > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Passenger Buckle SW

Front passenger side buckle switch

Set, Unset or NG

Unset: Seat belt not fastened

Set: Seat belt fastened

NG: Data is not determined

Perform the inspection while sitting in the front passenger side seat.

Body Electrical > Occupant Detection > Data List

Tester Display

Passenger Buckle SW

Result

Proceed to

Unset or Set is displayed on the Techstream screen according to the front passenger side seat belt condition

A

Unset or Set is not displayed normally on the Techstream screen according to the front passenger side seat belt condition

B

NG is displayed on the Techstream screen

C

B

REPLACE FRONT SEAT INNER BELT ASSEMBLY RH

C

REPLACE OCCUPANT DETECTION ECU

A

4.

READ VALUE USING TECHSTREAM (RIGHT SIDE BUCKLE SW)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / SRS Airbag / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > SRS Airbag > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Right side Buckle SW

Front passenger side buckle switch

Unset, Set or NG

Unset: Seat belt not fastened

Set: Seat belt fastened

NG: Data is not determined

Perform the inspection while sitting in the front passenger side seat.

Body Electrical > SRS Airbag > Data List

Tester Display

Right side Buckle SW

Result

Proceed to

Unset or Set is displayed on the Techstream screen according to the front passenger side seat belt condition

A

  • Unset or Set is not displayed normally on the Techstream screen according to the front passenger side seat belt condition
  • NG is displayed on the Techstream screen

B

A

REPLACE COMBINATION METER ASSEMBLY

B

REPLACE AIRBAG ECU ASSEMBLY

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