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Home >> Subaru >> 2021 >> Ascent Base >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System (Diagnostics) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC B1808: Short In Passenger's Airbag (To +B)

DTC B1808: Short In Passenger's Airbag (To +B)

Diagnosis start condition: 

When the ignition voltage is 10 - 16 V.

DTC detecting condition: 

Wiring diagram: 

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

G13867132Courtesy of SUBARU OF AMERICA, INC.
CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to AIRBAG (DIAGNOSTICS)>General Description>CAUTION .
  1. CHECK POOR CONTACT OF CONNECTORS  .

    Check for poor contact of the connectors between the airbag control module and the passenger's airbag module.

    Is there poor contact?

    Yes:  Replace the airbag harness.

    No:  Go to  2.

  2. CHECK AIRBAG MAIN HARNESS (PASSENGER'S AIRBAG HARNESS) (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 connector (AB2) from the roll connector.
    3. Disconnect the connector (AB66) from the driver's knee airbag module.
    4. Disconnect the connectors (AB6, AB17, AB18) from airbag control module.
    5. Disconnect the passenger's airbag module connectors (AB9) and (AB27).
    6. Connect the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
    7. Using a probe, measure the voltage between the connector (AB9) and chassis ground. Ref. to AIRBAG (DIAGNOSTICS)>General Description>PREPARATION TOOL>HOW TO USE PROBE .
      CAUTION: When measuring the voltage, make sure that the probe is inserted from the back side (harness side) of the connector. Also, do not insert the probe forcibly.

      Connector & terminal 

      (AB9) No. 1 (+) - Chassis ground (-):

      (AB9) No. 2 (+) - Chassis ground (-):

    Is the voltage less than 1 V?

    Yes:  Go to  3.

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

  3. 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. Connect the connectors (AB6, AB17, AB18) and the airbag control module.
    3. Connect the connector (AB2) to the roll connector.
    4. Connect the passenger's airbag module connector (AB27).
    5. Connect the connector (AB66) to the driver's knee airbag module.
    6. Using a probe, short the terminals No. 1 and No. 2 of connector (AB9). Ref. to AIRBAG (DIAGNOSTICS)>General Description>PREPARATION TOOL>HOW TO USE PROBE .
      CAUTION: When shorting the terminals, make sure that the probe is inserted from the back side (harness side) of the connector. Also, do not insert the probe forcibly.

      Connector & terminal 

      (AB9) No. 1 - (AB9) No. 2:

    7. Connect the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
    8. Execute the inspection mode. Ref. to AIRBAG (DIAGNOSTICS)>INSPECTION MODE .
    9. Read the DTC of [Airbag] using the Subaru Select Monitor. Ref. to AIRBAG (DIAGNOSTICS)>Diagnostic Trouble Code (DTC) .

    Is DTC B1805 displayed? (Current malfunction)

    Yes:  Go to  4.

    No:  Replace the airbag control module. Ref. to AIRBAG SYSTEM>Airbag Control Module>REMOVAL .

  4. CHECK PASSENGER'S 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. Connect the passenger's airbag module connector (AB9).
    3. Connect the ground terminal to the battery sensor and turn the ignition switch to ON. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
    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 B1808 displayed? (Current malfunction)

    Yes:  Replace the passenger's airbag module. Ref. to AIRBAG SYSTEM>Passenger's Airbag Module>REMOVAL .

    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.

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