DTC B1873: Short In Front Seat Cushion Airbag RH (To +B)

Diagnosis start condition:

When the ignition voltage is 10 - 16 V.

DTC detecting condition:

Short circuit failure in power supply (shorted in main harness power supply, shorted in front seat side airbag RH power supply, shorted in airbag control module internal circuit power supply)

Failure detection pattern:

"Primary" (high-priority diagnosis)

Warning light/indicator light:

Airbag warning light◦

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 .
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 B1873 displayed? (Current code)

Yes: GO TO 3.

No: Replace the seat cushion airbag module RH. Ref. to AIRBAG SYSTEM>SEAT CUSHION AIRBAG MODULE .
CHECK AIRBAG REAR HARNESS (SEAT CUSHION AIRBAG MODULE HARNESS RH) (SHORTED TO POWER SUPPLY) .
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 (AB99) from Rear seatbelt pretensioner RH.
4. Disconnect the connector (AB87) from side airbag module RH.
5. Disconnect the connector (AB91) from curtain airbag module RH.
6. Disconnect the airbag resistor from test harness D.
7. Disconnect the connectors (AB41, AB42, AB43) from airbag control module.
8. Connect the connector (1BF) in the test harness BF to the connectors (AB41, AB42, AB43).
9. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
10. Measure the voltage between connector (3D) in the test harness D and chassis ground.
  Connector & terminal
  
  (3D) No. 4 (+) - Chassis ground (-):
  
  (3D) No. 3 (+) - Chassis ground (-):
Is the voltage less than 1 V?

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

No: Replace the airbag rear harness along with body harness.