SEAT BELT SYSTEM > Seat Belt Warning System

INSPECTION

TROUBLE SYMPTOM:

• Seat belt warning light does illuminate or it remains illuminating.

• Buzzer does not beep.

STEPCHECKYESNO

1.CHECK BODY INTEGRATED UNIT.

1) Prepare the Subaru Select Monitor kit.

2) Turn the ignition switch to ON (engine OFF) and run the “PC application for Subaru Select Monitor”.

3) Read the data for ignition power supply voltage from Subaru Select Monitor.

Is the voltage 10 V or more?

Check the ignition switch circuit.

2.CHECK BODY INTEGRATED UNIT.

1) Read the data for the driver’s seat belt switch.

2) Buckle and unbuckle the seat belt.

Is ON ← →OFF displayed on the seat belt switch display corresponding to buckling/unbuckling operation?

Except for KA/KC models:
KA/KC models:

3.CHECK HARNESS.

1) Disconnect the battery negative terminal and wait 20 seconds or more.

2) Check for battery short and open circuits, and short to ground between the body integrated unit and buckle switch of the driver’s seat belt.

Connector & terminal
LHD model

(B281) No. 16 — (R8) No. 3:

RHD model

(B281) No. 16 — (R107) No. 3:

Is the harness normal?

Repair the harness.

4.CHECK HARNESS.

Measure the resistance between the buckle switch of the driver’s seat belt and chassis ground.

Connector & terminal
LHD model

(R8) No. 1 — Chassis ground:

RHD model

(R107) No. 1 — Chassis ground:

Is the resistance less than 10 Ω?

Repair the harness.

5.CHECK SEAT BELT BUCKLE SWITCH RH.

1) Insert the tongue plate to the driver’s seat belt buckle.

2) Check for battery short or open circuits between the seat belt switch connectors.

Connector & terminal
LHD model

(R8) No. 1 — (R8) No. 3:

RHD model

(R107) No. 1 — (R107) No. 3:

Is the resistance 1 MΩ or more?

Replace the inner belt assembly.

6.CHECK SEAT BELT BUCKLE SWITCH RH.

1) Separate the driver’s seat belt buckle and tongue plate.

2) Measure the resistance between seat belt switch connector terminals.

Connector & terminal
LHD model

(R8) No. 1 — (R8) No. 3:

RHD model

(R107) No. 1 — (R107) No. 3:

Is the resistance less than 10 Ω?

Replace the body integrated unit.

Replace the inner belt assembly.

7.CHECK BODY INTEGRATED UNIT.

1) Read the data for the passenger’s seat belt switch.

2) Buckle and unbuckle the passenger’s seat belt.

Is ON ← →OFF displayed on the seat belt switch display corresponding to buckling/unbuckling operation?

8.CHECK HARNESS.

1) Disconnect the battery negative terminal and wait 20 seconds or more.

2) Check for battery short and open circuits, and short to ground between the body integrated unit and seat belt buckle switch LH.

Connector & terminal

(B281) No. 26 — (R8) No. 3:

Is the harness normal?

Repair the harness.

9.CHECK HARNESS.

Check for battery short and open circuits, and short to ground between the seat belt buckle switch LH and seated switch.

Connector & terminal

(R8) No. 3 — (R89) No. 2:
(R8) No. 1 — (R89) No. 1:

Is the harness normal?

Repair the harness.

10.CHECK HARNESS.

Measure the resistance between the seated switch and chassis ground.

Connector & terminal

(R89) No. 2 — Chassis ground:
(R89) No. 1 — Chassis ground:

Is the resistance less than 10 Ω?

Repair the harness.

11.CHECK SEAT BELT BUCKLE SWITCH LH.

1) Insert the tongue plate to the passenger’s seat belt buckle.

2) Measure the resistance between connectors of the seat belt buckle switch LH.

Connector & terminal

(R8) No. 1 — (R8) No. 3:

Is the resistance 1 MΩ or more?

Replace the inner belt assembly.

12.CHECK SEAT BELT BUCKLE SWITCH LH.

1) Separate the passenger’s seat belt buckle and tongue plate.

2) Measure the resistance between connector terminals of the seat belt buckle switch LH.

Connector & terminal

(R8) No. 1 — (R8) No. 3:

Is the resistance less than 10 Ω?

Replace the inner belt assembly.

13.CHECK SEATED SWITCH.

1) Disconnect the seated switch connector.

2) Place a weight on the passenger’s seat (seated switch turns ON).

3) Measure the resistance between seated switch connector terminals.

Connector & terminal

(R89) No. 1 — (R89) No. 2:

Is the resistance less than 10 Ω?

Replace the seated switch.

14.CHECK SEATED SWITCH.

1) Remove the weight from the passenger’s seat (seated switch turns OFF).

2) Measure the resistance between seated switch connector terminals.

Connector & terminal

(R89) No. 1 — (R89) No. 2:

Is the resistance 1 MΩ or more?

Replace the body integrated unit.

Replace the seated switch.

15.CHECK SEAT BELT WARNING LIGHT (DRIVER’S SEAT).

1) Separate the driver’s and the passenger’s seats belt buckles and tongue plates.

2) Buckle and unbuckle the driver’s seat belt.

Does the seat belt warning light in the combination meter illuminate ← →go out corresponding to buckling/unbuckling?

16.CHECK COMBINATION METER.

1) Turn the ignition switch to OFF.

2) Turn the ignition switch to ON again.

Does seat belt warning light illuminate with combination meter initialization?

Check the combination meter.

17.CHECK DTC.

Read the DTC using Subaru Select Monitor.

Is any CAN-related body system DTC detected?

Check the CAN system according to the DTC.

Replace the body integrated unit or the combination meter. Or replace both. There could be a transmission problem from the body integrated unit, or a receiving problem in the combination meter.

18.CHECK SEAT BELT WARNING LIGHT (PASSENGER’S SEAT).

1) Separate the driver’s and the passenger’s seats belt buckles and tongue plates.

2) Sit in the passenger’s seat.

3) Buckle and unbuckle the passenger’s seat belt.

Does the passenger’s seat belt warning light in the clock illuminate ← →go out corresponding to buckling/unbuckling?

19.CHECK HARNESS.

Check for battery short and open circuits, and short to ground between the body integrated unit and clock.

Connector & terminal

(i84) No. 25 — (i59) No. 2:

Is the harness normal?

Repair the harness.

20.CHECK CLOCK.

Measure the power supply voltage to the clock.

Connector & terminal

(i59) No. 8 (+) — Chassis ground (−):
(i59) No. 9 (+) — Chassis ground (−):

Is the voltage 10 V or more?

Check the harness and fuse.

21.CHECK SEAT BELT WARNING LIGHT (PASSENGER’S SEAT).

1) Disconnect the connector of body integrated unit.

2) Short the clock connector terminals and chassis ground.

Connector & terminal

(i59) No. 2 — Chassis ground:

Does the warning light in the clock illuminate?

Replace the body integrated unit since an external circuit or internal system fault is suspected as the cause.

Replace the clock.

22.CHECK SEAT BELT WARNING LIGHT.

1) Separate the driver’s and the passenger’s seats belt buckles and tongue plates.

2) Start the engine, and set the vehicle speed at 20 km/h (12 MPH) or more.

Does the seat belt warning light repeatedly flash (5 sec) ← →go out (1 sec)?

23.CHECK BODY INTEGRATED UNIT.

Read the DTC of body integrated unit using Subaru Select Monitor.

Is DTC U1223 detected?

Check the following items.

• LAN SYSTEM

• VDC

• ABS

24.CHECK BODY INTEGRATED UNIT.

Read the ‘front wheel speed’ data of the body integrated unit.

Does the data display 999.9 km/h?

Check the following items.

• LAN SYSTEM

• VDC

• ABS

25.CHECK BODY INTEGRATED UNIT.

Read the ‘front wheel speed’ data of the body integrated unit.

Does the data display the wheel speed data correctly?

Replace the body integrated unit.

Check the following items.

• LAN SYSTEM

• VDC

• ABS

26.CHECK ALARM AND BUZZER.

Connect the driver’s seat belt.

Does the seat belt warning light go out and buzzer sound stop?

System is normal. Temporary poor contact.

27.CHECK COMBINATION METER.

Perform the self-diagnosis of combination meter.

Did the buzzer sound?

Replace the combination meter.