Subaru Crosstrek Service Manual: Dtc b1863 short in driver s knee airbag (to +b)

Diagnosis start condition:

Ignition voltage is 10 V to 16 V.

DTC detecting condition:

• Airbag main harness circuit is shorted to power supply.

• Knee airbag module harness circuit is shorted to power supply.

• Knee airbag module is faulty.

• Airbag control module is faulty.

Before performing diagnosis, refer to “CAUTION” in “General Description”. General Description > CAUTION">

1.CHECK POOR CONTACT OF CONNECTORS.

Check for poor contact of the connectors between the airbag control module and the knee airbag module.

Is there poor contact?

Replace the airbag harness.

Diagnostic Chart with Trouble Code > DTC B1863 SHORT IN DRIVER’S KNEE AIRBAG (TO +B)">Go to Step 2.

2.CHECK KNEE AIRBAG MODULE.

1) Turn the ignition switch to OFF, disconnect the battery ground cable, and wait for 60 seconds or more.

2) Disconnect the connector (AB66) from knee airbag module.

3) Connect the connector (1N) in the test harness N to the connector (AB66).

4) Connect the airbag resistor to the connector (2N) of test harness N.

5) Connect the battery ground terminal and turn the ignition switch to ON.

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

Replace the knee airbag module. Knee Airbag Module > REMOVAL">

Diagnostic Chart with Trouble Code > DTC B1863 SHORT IN DRIVER’S KNEE AIRBAG (TO +B)">Go to Step 3.

3.CHECK AIRBAG MAIN HARNESS (KNEE AIRBAG HARNESS).

1) Turn the ignition switch to OFF, disconnect the battery ground cable, and wait for 60 seconds or more.

2) Disconnect the airbag resistor from test harness N.

3) Remove the instrument panel lower cover and column cover, and disconnect the connector (AB7) from (AB2).

4) Remove the console front panel and disconnect the connector (AB9).

5) Disconnect the connectors (AB6, AB17, AB18) from the airbag control module, and connect the connector (1AG) in the test harness AG.

6) Connect the battery ground terminal and turn the ignition switch to ON.

7) Measure the voltage between connector (3AG) in the test harness AG and chassis ground.

Connector & terminal

(3AG) No. 14 (+) — Chassis ground (–):

(3AG) No. 16 (+) — Chassis ground (–):

Is the voltage less than 1 V?

Diagnostic Chart with Trouble Code > DTC B1863 SHORT IN DRIVER’S KNEE AIRBAG (TO +B)">Go to Step 4.

Replace the airbag main harness along with body harness.

4.CHECK AIRBAG CONTROL MODULE.

1) Connect all connectors.

2) Clear the memory. Clear Memory Mode">

3) Perform the Inspection Mode. Inspection Mode">

4) Read the DTC. (Current malfunction) Read Diagnostic Trouble Code (DTC)">

Is DTC B1863 displayed?

Replace the airbag control module. Airbag Control Module">

Diagnostic Chart with Trouble Code > DTC B1863 SHORT IN DRIVER’S KNEE AIRBAG (TO +B)">Go to Step 5.

5.CHECK FOR ANY OTHER DTC ON DISPLAY.

Is any other DTC displayed?

Check DTC using “List of Diagnostic Trouble Code (DTC)”. List of Diagnostic Trouble Code (DTC)">

Finish the diagnosis.

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