DTC B1927: Short In Rear P/T LH (To Ground)

Diagnosis start condition: 

When the ignition voltage is 10 - 16 V.

DTC detecting condition: 

• Rear pretensioner harness LH circuit is shorted to ground.
• Rear seatbelt pretensioner LH is faulty.
• Airbag control module is faulty.

Wiring diagram: 

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

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK POOR CONTACT OF CONNECTORS  .

   Check for poor contact of the connectors between the airbag control module and Rear seatbelt pretensioner LH.

   Is there poor contact?

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

   No  : Go to  2 .

2. CHECK AIRBAG REAR HARNESS (REAR PRETENSIONER HARNESS LH) (SHORTED TO GROUND)  .
   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 (AB94) from seat belt pretensioner LH.
   3. Disconnect the connector (AB98) from the adaptive force limiter LH.
   4. Disconnect the connector (AB96) from lap seat belt pretensioner LH.
   5. Disconnect the connector (AB100) from rear seat belt pretensioner LH.
   6. Disconnect the connector (AB92) from curtain airbag module LH.
   7. Disconnect the connector (AB88) from side airbag module LH.
   8. Disconnect the connectors (AB41, AB42, AB43) from airbag control module.
   9. Using a probe, measure the resistance between the connector (AB100) and chassis ground. Ref. to AIRBAG (DIAGNOSTICS)>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE PROBE .
      CAUTION:

      When measuring the resistance, make sure that the probe is inserted from the back side (harness side) of the connector. Also, do not insert the probe forcibly. 

      Connector and terminal 

      (AB100) No. 2 - Chassis ground:

      (AB100) No. 3 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes  : Go to  3 .

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

3. CHECK AIRBAG CONTROL MODULE 
   1. Connect all the connectors other than (AB100) of Rear seatbelt pretensioner LH.
   2. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
   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 B1927 displayed? (Current malfunction)

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

   No  : Go to  4 .

4. CHECK Rear seatbelt pretensioner LH  .
   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. Connect the connector (AB100) of Rear seatbelt pretensioner LH.
   3. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
   4. Using the Subaru Select Monitor, perform the clear memory of [Airbag]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
   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 B1927 displayed? (Current malfunction)

   Yes  : Replace Rear seatbelt pretensioner LH. Ref. to SEAT BELT SYSTEM>REAR SEAT BELT .

   No  : Go to  5 .

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.