SEAT BELT SYSTEM > Seat Belt Warning System

INSPECTION

CAUTION:

• Before diagnosing the airbag system, always turn the ignition switch to OFF, disconnect the battery ground cable, and then wait for 60 seconds or more.

• When replacing the airbag module, seat belt pretensioner, roll connector, control module, or sensors, reconnect the replacement part and check that the warning light operates normally.

• When inspecting the airbag main harness, disconnect the airbag module connectors of the driver’s and passenger’s seats for safety.

• Before inspecting the airbag rear harness, disconnect the side airbag module connectors, curtain airbag module connectors, seat belt pretensioner connectors and lap seat belt pretensioner connectors to ensure safety.

TROUBLE SYMPTOM:

• Seat belt warning light does not illuminate or it remains illuminating.

• Buzzer does not beep.

STEPCHECKYESNO

1.CHECK CURRENT DATA.

1) Prepare the Subaru Select Monitor kit.

2) Run the “PC application for Subaru Select Monitor”.

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

4) Turn the ignition switch ON ←→ OFF.

Does the voltage change between 9 V or higher ←→ less than 1.5 V, matching the ignition switch ON ←→ OFF operation?

Check the ignition switch circuit.

2.CHECK FUNCTION.

1) Disconnect the driver’s seat belt.

2) Turn the ignition switch to ON.

3) Check the display of the seat belt warning light in the combination meter.

4) Fasten and detach the seat belt buckle.

Does the seat belt warning light illuminate ←→ turn off according to the seat belt buckle operation?

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

3.CHECK FUNCTION.

1) Sit in the passenger’s seat and disconnect the passenger’s seat belt.

2) Turn the ignition switch to ON.

3) Check the display of the seat belt warning light in the clock.

4) Fasten and detach the seat belt buckle.

Does the seat belt warning light illuminate ←→ turn off according to the seat belt buckle operation?

4.CHECK FUNCTION.

1) Disconnect the driver’s seat belt.

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

3) Check if the seat belt warning light and warning buzzer sounds.

Does the seat belt warning light keep blinking for 5 seconds and ON for 1 second, and does the buzzer sound?

System is normal.

5.CHECK CURRENT DATA.

1) Select “Current Data Display” and display the data of “Driver’s seat belt SW input”.

2) Fasten and detach the driver’s side seat belt buckle, and read the data of the seat belt switch.

Does the seat belt switch display turn ON ←→ OFF according to the operation of the seat belt buckle?

6.CHECK HARNESS.

1) Turn the ignition switch to OFF.

2) Disconnect the connector of body integrated unit.

3) Disconnect the connector of the driver’s seat belt buckle switch.

4) Check for a short circuit to battery, open circuit or short circuit to ground between the body integrated unit and the driver’s seat belt buckle switch.

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.

7.CHECK HARNESS.

Measure the resistance between the driver’s seat belt buckle switch 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.

8.CHECK DRIVER’S SEAT BELT BUCKLE SWITCH.

Measure the resistance between the connector terminals of the driver’s seat belt switch when the driver’s seat belt is fastened and detached.

Connector & terminal

LHD model

(R8) No. 1 — (R8) No. 3:

RHD model

(R107) No. 1 — (R107) No. 3:

Is the resistance when the belt is fastened 1 MΩ or more, and less than 10 Ω when the belt is detached?

Replace the body integrated unit.

Replace the driver’s side inner belt assembly.

9.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.

10.CHECK COMBINATION METER.

Perform the self-diagnosis of combination meter.

At the start of combination meter self diagnosis, did the buzzer sound and the seat belt warning light illuminate?

Replace the body integrated unit or the combination meter. Or replace both. It may be due to the transmission failure of the body integrated unit or the reception failure of the combination meter.

Replace the combination meter.

11.CHECK CURRENT DATA.

1) Sit in the passenger’s seat.

2) Select “Current Data Display” and display the data of “P seat belt SW input ”.

3) Fasten and detach the passenger’s side seat belt buckle, and read the data of the seat belt switch.

Does the seat belt switch display turn ON ←→ OFF according to the operation of the seat belt buckle?

12.CHECK HARNESS.

1) Turn the ignition switch to OFF.

2) Disconnect the connector of body integrated unit.

3) Disconnect the connector of the passenger’s seat belt buckle switch.

4) Check for a short circuit to battery, open circuit or short circuit to ground between the body integrated unit and the passenger’s seat belt buckle switch.

Connector & terminal

(B281) No. 26 — (R8) No. 3:

Is the harness normal?

Repair the harness.

13.CHECK HARNESS.

1) Disconnect the connector of seating switch.

2) Check for a short circuit to battery, open circuit or short circuit to ground between the seating switch and the passenger’s seat belt buckle switch.

Connector & terminal

(R8) No. 3 — (R89) No. 2:

(R8) No. 1 — (R89) No. 1:

Is the harness normal?

Repair the harness.

14.CHECK HARNESS.

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

Connector & terminal

(R8) No. 1 — Chassis ground:

Is the resistance less than 10 Ω?

Repair the harness.

15.CHECK PASSENGER’S SEAT BELT BUCKLE SWITCH.

Measure the resistance between the connector terminals of the passenger’s seat belt switch when the passenger’s seat belt is fastened and detached.

Connector & terminal

(R8) No. 1 — (R8) No. 3:

Is the resistance when the belt is fastened 1 MΩ or more, and less than 10 Ω when the belt is detached?

Replace the passenger’s side inner belt assembly.

16.CHECK SEATING SWITCH.

Measure the resistance between connector terminals of the seating switch.

Connector & terminal

(R89) No. 1 — (R89) No. 2:

Is the resistance 1 MΩ or more when the seat is not occupied, and less than 10 Ω when occupied?

Replace the body integrated unit.

Replace the seating switch.

17.CHECK HARNESS.

1) Disconnect the clock connector.

2) Turn the ignition switch to ON.

3) Measure the power supply voltage of the clock.

Connector & terminal

(i59) No. 8 (+) — Chassis ground (−):

Is the voltage 10 V or more?

Repair the harness.

18.CHECK HARNESS.

1) Turn the ignition switch to OFF.

2) Disconnect the connector of body integrated unit.

3) 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.

19.CHECK CLOCK.

1) Connect the clock connector.

2) Turn the ignition switch to ON.

3) Use an appropriate wiring harness to create a short between the body integrated unit and clock.

Connector & terminal

(i84) No. 25 — Chassis ground:
(i59) No. 2 — Chassis ground:

Does passenger’s seat belt warning light in the clock illuminate?

Replace the body integrated unit.

Replace the clock.

20.CHECK DTC.

Read the DTCs for all systems using the Subaru Select Monitor.

Is a DTC detected?

Perform a check according to the DTC.

21.CHECK CURRENT DATA.

Select “Current Data Display” and read the data of the “Front Wheel Speed”.

Does the data display the wheel speed data correctly?

Check the following items.

• LAN system

• ABS

• VDC