Subaru Crosstrek Service Manual: Dtc b1818 short in passenger s airbag dual stage - 2nd step circuit (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.

• Airbag module harness (passenger’s side) circuit is shorted to power supply.

• Passenger’s 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 passenger’s airbag module.

Is there poor contact?

Replace the airbag harness.

Diagnostic Chart with Trouble Code > DTC B1818 SHORT IN PASSENGER’S AIRBAG DUAL STAGE - 2ND STEP CIRCUIT (TO +B)">Go to Step 2.

2.CHECK AIRBAG MAIN HARNESS (PASSENGER’S AIRBAG HARNESS).

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

2) Disconnect the connectors (AB7) and (AB2).

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 connector (AB9).

6) Using a probe, measure the voltage between the connector (AB9) and chassis ground. General Description > PREPARATION TOOL">

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. 3 (+) — Chassis ground (−):

(AB9) No. 4 (+) — Chassis ground (−):

Is the voltage less than 1 V?

Diagnostic Chart with Trouble Code > DTC B1818 SHORT IN PASSENGER’S AIRBAG DUAL STAGE - 2ND STEP CIRCUIT (TO +B)">Go to Step 3.

Replace the airbag main harness along with body harness.

3.CHECK AIRBAG CONTROL MODULE.

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

2) Connect the connectors (AB6, AB17, AB18) and the airbag control module.

3) Using a probe, short the terminals No. 3 and No. 4 of connector (AB9). General Description > PREPARATION TOOL">

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. 3 — (AB9) No. 4:

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

5) Perform the Inspection Mode. Inspection Mode">

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

Is DTC B1818 displayed?

Replace the airbag control module. Airbag Control Module > REMOVAL">

Diagnostic Chart with Trouble Code > DTC B1818 SHORT IN PASSENGER’S AIRBAG DUAL STAGE - 2ND STEP CIRCUIT (TO +B)">Go to Step 4.

4.CHECK PASSENGER’S AIRBAG MODULE.

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

2) Release the short circuit of connector (AB9).

3) Connect the passenger’s airbag module connector (AB9).

4) Connect the connectors (AB7) and (AB2).

5) Connect the connector (AB66) to the driver’s knee airbag module.

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

7) Perform the Inspection Mode. Inspection Mode">

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

Is DTC B1818 displayed?

Replace the passenger’s airbag module. Passenger’s Airbag Module > REMOVAL">

Diagnostic Chart with Trouble Code > DTC B1818 SHORT IN PASSENGER’S AIRBAG DUAL STAGE - 2ND STEP CIRCUIT (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.

Dtc b1817 short in passenger s airbag dual stage - 2nd step (to ground)

Dtc b1820 short in side airbag rh

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