Seat Belt Warning System: Inspection

CAUTION:

Before handling the airbag system components, refer to "CAUTION" of "General Description" in "AIRBAG SYSTEM". 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 if the driver's seat belt warning light in the combination meter and the passenger's seat belt warning light in the center information display illuminate, and if the buzzer sounds.
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 4.
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 if the driver's seat belt warning light in the combination meter and the passenger's seat belt warning light in the center information display illuminate.
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 : It may be a temporary poor contact. Check the contacting condition of harness and connector.

No : Go to 4.
CHECK DTC OF AIRBAG SYSTEM .
Read the DTC of the airbag system using the SUBARU Select Monitor. Refer to AIRBAG (DIAGNOSTICS)>Diagnostic Trouble Code (DTC) .

Is DTC detected?

Yes : Perform a check according to the DTC.

No : Go to 5.
CHECK DTC OF COMBINATION SYSTEM .
Read the DTC of combination system using the SUBARU Select Monitor. Refer to DIAGNOSTIC TROUBLE CODE (DTC) .

Is DTC detected?

Yes : Perform a check according to the DTC.

No : Go to 6.
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 check result OK?

Yes : Go to 7.

No : Repair or replace with new parts according to the diagnostic procedure.
CHECK DATA MONITOR .
1. Using SUBARU Select Monitor, select [Data monitor] and display the data of [Driver side seat belt state] and [Passenger seat seat-belt wearing state]. Refer to DATA MONITOR .
2. Fasten and detach the seat belt buckle, and read the data of the seat belt switch.
Does the seat belt switch display vary according to the operation of the seat belt buckle?

Yes : It may be a temporary poor contact. Check the contacting condition of harness and connector.

No : Go to 8.
CHECK HARNESS .
1. Disconnect the ground terminal from battery sensor and wait for 60 seconds or more.
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
  
  (i97) No. 4 - (St54) No. 1:
Is harness normal?

Yes : Go to 9.

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

Connector & terminal

(St54) No. 2 - Chassis ground:

Is the resistance less than 10 Ω?

Yes : Go to 10.

No : Repair or replace the harness.
CHECK SEAT BELT BUCKLE SWITCH .
Measure the resistance between the connector terminals of the seat belt switch when the seat belt is fastened and detached. Refer to SEAT BELT SYSTEM>Front Seat Belt>INSPECTION>SEAT BELT SWITCH>INSPECTION .

Is the check result OK?

Yes : System is normal. It may be a temporary poor contact. Check the contacting condition of harness and connector.

No : Replace the belt assembly front INN. Refer to SEAT BELT SYSTEM>Front Seat Belt>REMOVAL>BELT ASSEMBLY FRONT INN .