DTC B1655: Front Buckle Switch RH Failure

Diagnosis start condition:

When the ignition voltage is 10 - 16 V.

DTC detecting condition:

Buckle switch RH is faulty.
Seat harness is faulty.
Airbag rear harness is faulty.

CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to AIRBAG (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .

Wiring diagram:

Occupant detection system Ref. to WIRING SYSTEM>OCCUPANT DETECTION SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CHECK DTC .
Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

Is DTC for [Airbag ECU Malfunction] displayed? (Current code)

Yes: Perform the diagnosis for [Airbag ECU Malfunction]. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC B1000 AIRBAG ECU MALFUNCTION .

No: Go to 2.
CHECK AIRBAG REAR HARNESS AND SEAT HARNESS (BETWEEN AIRBAG CONTROL MODULE AND BUCKLE SWITCH) (OPEN CIRCUIT) .
1. Turn the ignition switch to OFF, and wait for 60 seconds or more after disconnecting the ground terminal from the battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
2. Disconnect the connector (AB93) from seat belt pretensioner RH.
3. Disconnect the connector (AB97) from the adaptive force limiter RH.
4. Disconnect the connector (AB91) from curtain airbag module RH.
5. Disconnect the connector (AB87) from side airbag module RH.
6. Disconnect the connectors (AB41, AB42, AB43) from airbag control module.
7. Connect the connector (1BF) in the test harness BF to the connectors (AB41, AB42, AB43).
8. Disconnect the connector (AB65) from the passenger's buckle switch.
9. Connect the connector (1D) in the test harness D to the connector (AB65).
10. Using a tester, measure the resistance in between connector (4BF) in the test harness BF and connector (3D) in the test harness D.
  Connector & terminal
  
  (4BF) No. 17 - (3D) No. 3:
  
  (4BF) No. 12 - (3D) No. 4:
Is the resistance less than 10 Ω?

Yes: Go to 3.

No: Check the seat harness, and if any fault is found, replace the seat harness. If there is no fault, replace the airbag rear harness together with body harness.
CHECK AIRBAG REAR HARNESS AND SEAT HARNESS (BETWEEN AIRBAG CONTROL MODULE AND BUCKLE SWITCH) (SHORTED BETWEEN LINES AND SHORTED TO GROUND) .
Using a tester, measure the resistance between connector (3D) in the test harness D and chassis ground, and between connector (3D) terminals.

Connector & terminal

(3D) No. 3 - (3D) No. 4:

(3D) No. 3 - Chassis ground:

(3D) No. 4 - Chassis ground:

Is the resistance 1 MΩ or more?

Yes: Go to 4.

No: Check the seat harness, and if any fault is found, replace the seat harness. If there is no fault, replace the airbag rear harness together with body harness.
CHECK AIRBAG REAR HARNESS AND SEAT HARNESS (BETWEEN AIRBAG CONTROL MODULE AND BUCKLE SWITCH) (BATTERY SHORT) .
1. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
2. Using a tester, measure the voltage between connector (3D) in test harness D and chassis ground.
  Connector & terminal
  
  (3D) No. 3 (+) - Chassis ground (-):
  
  (3D) No. 4 (+) - Chassis ground (-):
Is the voltage less than 1 V?

Yes: Go to 5.

No: Check the seat harness, and if any fault is found, replace the seat harness. If there is no fault, replace the airbag rear harness together with body harness.
CHECK CONNECTOR .
1. Turn the ignition switch to OFF, and wait for 60 seconds or more after disconnecting the ground terminal from the battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
2. Check for poor contact in airbag control module connector and passenger's buckle switch connector.
Is the check result OK?

Yes: Go to 6.

No: Repair or replace the poor contact part.
CHECK PASSENGER'S SEAT BUCKLE SWITCH .
1. Disconnect the test harness D and test harness BF.
2. Connect the airbag control module connector.
3. Connect the test harness Y to the buckle switch connector (AB65).
4. Install the ground terminal to the battery sensor and turn the ignition switch to ON.
5. Execute the inspection mode. Ref. to AIRBAG (DIAGNOSTICS)>INSPECTION MODE .
6. Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1655 displayed? (Current code)

Yes: Replace the airbag control module. Ref. to AIRBAG SYSTEM>AIRBAG CONTROL MODULE>REMOVAL .

No: Replace the buckle switch. Ref. to SEAT BELT SYSTEM>FRONT SEAT BELT>REMOVAL .