DTC B1871: Open In Front Seat Cushion Airbag RH

Diagnosis start condition:

When the ignition voltage is 10 - 16 V.

DTC detecting condition:

Open circuit failure (open circuit in rear harness, open circuit in front seat cushion airbag RH, open circuit in airbag control module internal circuit, connector connection failure)

Wiring diagram:

Airbag system Ref. to WIRING SYSTEM>AIRBAG SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

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

CHECK POOR CONTACT OF CONNECTORS .
Check for poor contact of the connectors between the airbag control module and the seat cushion airbag module RH.

Is there poor contact?

Yes : Replace the airbag rear harness along with body harness.

No : Go to 2 .
CHECK SEAT CUSHION AIRBAG MODULE .
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 (AB89) from the seat cushion airbag module RH, and connect the connector (1D) in the test harness D to connector (AB89).
3. Connect the airbag resistor to connector (3D) in the test harness D.
4. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
Does the airbag warning light illuminate for six seconds and go off?

Yes : Replace the seat cushion airbag module RH. Ref. to AIRBAG SYSTEM>SEAT CUSHION AIRBAG MODULE .

No : Go to 3 .
CHECK AIRBAG REAR HARNESS (SEAT CUSHION AIRBAG MODULE HARNESS RH) (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 (AB99) from Rear seatbelt pretensioner RH.
5. Disconnect the connector (AB87) from side airbag module RH.
6. Disconnect the connector (AB91) from curtain airbag module RH.
7. Disconnect the airbag resistor from test harness D.
8. Disconnect the connectors (AB41, AB42, AB43) from airbag control module.
9. Connect the connector (1BF) in the test harness BF to the connectors (AB41, AB42, AB43).
10. Measure the resistance between connector (5BF) in the test harness BF and connector (3D) in the test harness D.
  Connector and terminal
  
  (5BF) No. 9 - (3D) No. 3:
  
  (5BF) No. 14 - (3D) No. 4:
Is the resistance less than 10 Ω?

Yes : Go to 4 .

No : Replace the airbag rear harness along with body harness.
CHECK AIRBAG CONTROL MODULE .
1. Disconnect the test harness BF from the connectors (AB41, AB42, AB43).
2. Connect all connectors.
3. Using the Subaru Select Monitor, perform the clear memory of [Airbag]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
4. Execute the inspection mode. Ref. to AIRBAG (DIAGNOSTICS)>INSPECTION MODE .
5. Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1871 displayed?

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

No : Go to 5 .
CHECK FOR ANY OTHER DTC ON DISPLAY .
Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

Is any other DTC displayed? (Current malfunction)

Yes : Perform the diagnosis for other displayed DTCs. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

No : Finish the diagnosis.