DTC B1903: Short In Front P/T RH (To +B)

Diagnosis start condition: 

When the ignition voltage is 10 - 16 V.

DTC detecting condition: 

• Seat belt pretensioner harness RH circuit is shorted to power supply.
• Seat belt pretensioner RH 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 seat belt pretensioner RH.

   Is there poor contact?

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

   No:  Go to  2.

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 (AB93) from seat belt pretensioner RH.
   3. Connect the connector (1N) in the test harness N to the connector (AB93).
   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 .

   Does the airbag warning light illuminate for six seconds and go off?

   Yes:  Replace the seat belt pretensioner RH. Ref. to SEAT BELT SYSTEM>FRONT SEAT BELT .

   No:  Go to  3.

3. CHECK AIRBAG REAR HARNESS (SEAT BELT PRETENSIONER 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 airbag resistor from the connector (2N) of test harness N.
   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 (AB89) from seat cushion airbag module RH.
   6. Disconnect the connector (AB91) from curtain airbag module RH.
   7. Disconnect the connector (AB87) from side airbag module RH.
   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. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
   11. Measure the voltage between connector (5BF) in the test harness BF and chassis ground.

       Connector & terminal 

       (5BF) No. 3 (+) - Chassis ground (-):

       (5BF) No. 7 (+) - Chassis ground (-):

   Is the voltage less than 1 V?

   Yes:  Go to  4.

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

4. CHECK AIRBAG CONTROL 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 all test harnesses.
   3. Connect all connectors.
   4. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
   5. Using the Subaru Select Monitor, perform the clear memory of [Airbag]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
   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 B1903 displayed? (Current code)

   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?

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

   No:  Finish the diagnosis.