DTC B1838: Short In Curtain Shield Airbag LH Squib Circuit (To +B)

Diagnosis start condition:

When the ignition voltage is 10 - 16 V.

DTC detecting condition:

Curtain airbag harness LH is shorted to power supply.
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.

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 curtain airbag module LH.

Is there poor contact?

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

No : Go to 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 GROUND TERMINAL REMOVAL OR INSTALLATION .
2. Disconnect the connector (AB31) from curtain airbag module LH.
3. Connect the connector (1N) in the test harness N to the connector (AB31).
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 GROUND TERMINAL REMOVAL OR INSTALLATION .
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 .
CHECK AIRBAG REAR HARNESS (CURTAIN AIRBAG MODULE 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 GROUND TERMINAL REMOVAL OR INSTALLATION .
2. Disconnect the connector (AB21) from seat belt pretensioner LH.
3. Disconnect the connector (AB81) from the adaptive force limiter LH.
4. Disconnect the connector (AB29) from lap seat belt pretensioner LH.
5. Disconnect the connector (AB67) from rear seat belt pretensioner LH.
6. Disconnect the connector (AB19) from side airbag module LH.
7. Disconnect the airbag resistor from test harness N.
8. Disconnect the connectors (AB6, AB17, AB18) from airbag control module.
9. Connect the connector (1BD) in the test harness BD to the connectors (AB6, AB17, AB18).
10. Install the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to GROUND TERMINAL REMOVAL OR INSTALLATION .
11. Measure the voltage between connector (7BD) in the test harness BD and chassis ground.
  Connector and terminal
  
  (7BD) No. 1 (+) - Chassis ground (-):
  
  (7BD) No. 5 (+) - Chassis ground (-):
Is the voltage less than 1 V?

Yes : Go to 4 .

No : Replace the airbag rear harness along with body harness.
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 GROUND TERMINAL REMOVAL OR INSTALLATION .
2. Disconnect the test harness BD from the connectors (AB6, AB17, AB18).
3. Connect all connectors.
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 B1838 displayed? (Current malfunction)

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

No : Go to 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.