Seat Belt Warning System: Inspection

CAUTION:

Before handling the airbag system components, refer to AIRBAG SYSTEM>GENERAL DESCRIPTION>CAUTION .
When inspecting the airbag main harness, disconnect the connectors of the driver's airbag module, passenger's airbag module and knee airbag module for safety reasons.
When inspecting the airbag rear harness, disconnect the side airbag module connector, curtain airbag module connector and seat belt pretensioner connector for safety reasons.

Trouble symptom:

Driver's and passenger's seat belt warning lights do not illuminate (blink) or they remain illuminating.
Warning buzzer does not beep.

CHECK FUNCTION.
1. Sit on the driver's seat and passenger's seat and disconnect the seat belts of the both.
2. Turn the ignition switch to ON (engine OFF).
3. Check the illumination of the driver's seat belt warning light in the combination meter, and the passenger's seat belt warning light in the warning box, and the sounding of the buzzer.
Do the driver's warning light and passenger's warning light blink and the buzzer sound while blinking?

Yes: Go to 2.

No: Go to 8.
CHECK FUNCTION.
1. Wait until the buzzer sound stops in step 1. (For approximately six seconds after starting sounding)
2. Connect and disconnect the seat belts of the driver's and passenger's.
3. Check the illumination of the driver's seat belt warning light in the combination meter and the passenger's seat belt warning light in the warning box.
Do the seat belt warning light blink ←→ go off according to the operation?

Yes: Go to 3.

No: Go to 4.
CHECK FUNCTION.
1. Wait until the buzzer sound stops in step 1. (For approximately six seconds after starting sounding)
2. Start the engine, and set the vehicle speed at 20 km/h (12 MPH) or more.
3. Check the seat belt warning lights of the driver's and the passenger's, and if the warning buzzer sounds.
Do the driver's warning light and passenger's warning light blink and the buzzer sound while blinking?

Yes: Go to 4.

No: Go to 9.
CHECK HARNESS.
1. Disconnect the ground terminal from battery sensor and wait for 60 seconds or more. Refer to REPAIR CONTENTS>NOTE>BATTERY .
2. Disconnect the connectors of the combination meter and the driver's seat belt buckle switch.
3. Check for short circuit to battery, open circuit and short circuit to ground between the combination meter and the driver's seat belt buckle switch.
  Connector & terminal
  
  (i10) No. 4 - (R108) No. 1:
Is the harness OK?

Yes: Go to 5.

No: Repair or replace the harness.
CHECK HARNESS.
Measure the resistance between the driver's seat belt buckle switch and chassis ground.

Connector & terminal

(R108) No. 2 - Chassis ground:

Is the resistance less than 10 Ω?

Yes: Go to 6.

No: Repair or replace the harness.
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

(R108) No. 1 - (R108) No. 2:

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

Yes: Go to 7.

No: Replace the belt assembly front INN LH. Refer to SEAT BELT SYSTEM>FRONT SEAT BELT>REMOVAL>BELT ASSEMBLY FRONT INN .
CHECK DATA MONITOR.
1. Sit in the passenger's seat.
2. Using Subaru Select Monitor, select [Data monitor] and display the data of [Front Passenger Seatbelt Status]. Refer to OCCUPANT DETECTION (DIAGNOSTICS)>DATA MONITOR .
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 [Belted] ←→ [Unbelted] according to the operation of the seat belt buckle?

Yes: Go to 9.

No: Go to 8.
CHECK AIRBAG SYSTEM AND OCCUPANT DETECTION SYSTEM.
Perform the check in accordance with the diagnostic procedure DTC B1650 of the airbag system. Refer to OCCUPANT DETECTION (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC B1650 OCCUPANT DETECTION SYSTEM MALFUNCTION .

Is the inspection result OK?

Yes: Go to 9.

No: Repair or replace with new parts according to DTC B1650.
CHECK PASSENGER'S SEAT BUCKLE SWITCH.
Perform the check in accordance with the diagnostic procedure DTC B1655 of the airbag system. Refer to AIRBAG (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC B1655 FRONT BUCKLE SWITCH RH FAILURE .

Is the inspection result OK?

Yes: Go to 10.

No: Repair or replace with new parts according to DTC B1655.
CHECK AIRBAG CONTROL MODULE AND COMBINATION METER.
Perform the inspection according to the basic diagnostic procedure for LAN system. Refer to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

Is the inspection result OK?

Yes: Go to 11.

No: Repair or replace with new parts according to the diagnostic procedure.
CHECK WARNING BOX POWER SUPPLY VOLTAGE.
1. Disconnect the warning box connector.
2. Turn the ignition switch to ON.
3. Measure the voltage between the ignition power supply and the warning box.
  Connector & terminal
  
  (R161) No. 4 (+) - Chassis ground (-):
Is the voltage 10 V or more?

Yes: Go to 12.

No: Check the harness for open or short between the fuse and the warning box.
CHECK WARNING BOX GROUND CIRCUIT.
1. Turn the ignition switch to OFF.
2. Measure the resistance between the warning box and chassis ground.
  Connector & terminal
  
  (R161) No. 1 - Chassis ground:
Is the resistance less than 10 Ω?

Yes: Go to 13.

No: Repair or replace the harness.
CHECK HARNESS BETWEEN WARNING BOX AND COMBINATION METER.
1. Disconnect the harness of the warning box and the combination meter.
2. Measure the resistance between warning box and combination meter.
  Connector & terminal
  
  (R161) No. 2 - (i10) No. 12:
Is the resistance less than 10 Ω?

Yes: Go to 14.

No: Repair or replace the harness.
CHECK COMMUNICATION STATUS BETWEEN WARNING BOX AND COMBINATION METER.
1. Remove the warning box, and install a properly operating warning box (new warning box).
2. Connect the connector and then turn the ignition switch to ON.
Is the warning box properly displayed?

Yes: Replace the warning box.

No: Replace the combination meter.