DTC B1837: Short In Curtain Airbag LH Squib Circuit (To Ground)

Diagnosis start condition: 

When the ignition voltage is 10 - 16 V.

DTC detecting condition: 

• Curtain airbag harness LH circuit is shorted to ground.
• Curtain airbag module 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 the curtain airbag module LH.

   Is there poor contact?

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

   No:  Go to  2.

2. CHECK CURTAIN 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 (AB31), and connect the connector (1N) in test harness N to connector (AB31).
   3. Connect the airbag resistor to the connector (2N) of test harness N.
   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 curtain airbag module LH. Ref. to AIRBAG SYSTEM>CURTAIN AIRBAG MODULE .

   No:  Go to  3.

3. CHECK AIRBAG REAR HARNESS (CURTAIN AIRBAG MODULE 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 (AB21) from Seatbelt pretensioner and adaptive force limiter LH.
   3. Disconnect the connector (AB29) from lap seat belt pretensioner LH.
   4. Disconnect the connector (AB67) from Second-row seatbelt pretensioner LH.
   5. Disconnect the connector (AB19) from side airbag module LH.
   6. Disconnect the airbag resistor from test harness N.
   7. Disconnect the connectors (AB6, AB17, AB18) from airbag control module.
   8. Connect the connector (1BD) in the test harness BD to the connectors (AB6, AB17, AB18).
   9. Measure the resistance between connector (7BD) in the test harness BD and chassis ground.

      Connector & terminal 

      (7BD) No. 1 - Chassis ground:

      (7BD) No. 5 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes:  Go to  4.

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

4. CHECK AIRBAG CONTROL MODULE  .
   1. Connect all connectors.
   2. Using the Subaru Select Monitor, perform the clear memory of [Airbag]. Ref. to COMMON (diag)>CLEAR MEMORY .
   3. Execute the inspection mode. Ref. to AIRBAG (DIAGNOSTICS)>INSPECTION MODE .
   4. Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>Diagnostic Trouble Code (DTC) .

   Is DTC B1837 displayed? (Current malfunction)

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

   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.