DTC B1908: Short In Front P/T LH (To +B)

Diagnosis start condition:

When the ignition voltage is 10 - 16 V.

DTC detecting condition:

Seat belt pretensioner harness LH circuit is shorted to power supply.
Seat belt pretensioner LH is faulty.
Airbag control module is faulty.

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

Wiring diagram:

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

Courtesy of SUBARU OF AMERICA, INC.

CHECK POOR CONTACT OF CONNECTORS .
Check for poor contact of the connectors between the airbag control module and the seat belt pretensioner LH.

Is there poor contact?

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

No: Go to 2.
CHECK SEAT BELT PRETENSIONER .
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. Connect the connector (1N) in the test harness N to the connector (AB94).
4. Connect the airbag resistor to the connector (2N) of test harness N.
5. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
6. Execute the inspection mode. Ref. to AIRBAG (DIAGNOSTICS)>INSPECTION MODE .
7. Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1908 displayed? (Current code)

Yes: Go to 3.

No: Replace the seat belt pretensioner LH. Ref. to SEAT BELT SYSTEM>FRONT SEAT BELT .
CHECK AIRBAG REAR HARNESS (SEAT BELT PRETENSIONER HARNESS LH) (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 airbag resistor from the connector (2N) of test harness N.
3. Disconnect the connector (AB92) from curtain airbag module LH.
4. Disconnect the connector (AB88) from side airbag module LH.
5. Disconnect the connectors (AB41, AB42, AB43) from airbag control module.
6. Connect the connector (1BF) in the test harness BF to the connectors (AB41, AB42, AB43).
7. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
8. Measure the voltage between connector (7BF) in the test harness BF and chassis ground.
  Connector & terminal
  
  (7BF) No. 3 (+) - Chassis ground (-):
  
  (7BF) No. 8 (+) - Chassis ground (-):
Is the voltage less than 1 V?

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

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